Document byzJKK89vxex1Eok9owap8yKy

Reproduced By GLOBAL ENGINEERING DOCUMENTS With The Permission Of ANSI Under Royalty Agreement / ASA /' . f " .N. I'nt * Z2.1-1959 ' P.'.-.MtsC i of ZM939 UL'C 6l<i.851/.s9e WITHDRAWN American Standard Safety Code for ,,/ Head, Eye, and Respiratory Protection Sponsors Department of the Navy National Bureau of Standards U.S. Bureau of Mines Approved November 27, 19S9 AMERICAN STANDARDS ASSOCIATION American Standard Registered United Slates Patent Office An American Standard implies a consensus of those substantially concerned with its scope and provisions. The consensus principle extends to the initiation of work under the procedure of the Association, to the method of work to be followed, and to the final approval of the standard. An Ameiican Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The existence of an American Standard docs not in any respect pre clude any party who lias approved of the standard from manufacturing, selling, or using products, processes, or procedures not conforming to the standard. An American Standard defines a product, process, or procedure with reference to one or more of the following: nomenclature, composition, construction, dimensions, tolerances, safety, operating characteristics, performance, quality, rating, certification, testing, and the service for which designed. American Standards arc subject to periodic review. They arc reaffirmed or revised to meet changing economic conditions and technological progress. Users of American Standards are cautioned to secure the latest editions. Producers of goods made in conformity with uu American Standard arc encouraged to slate on their own responsibility in advertising, promotion material, or on tags or labels, that the goods are produeed in conformity with particular American Standards. The inclusion in sueli advertising and promotion medio, or on tags or labels, of information concerning tiic characteristics covered by tiic standard to define its scope is also encouraged. Published by AMERICAN STANDARDS ASSOCIATION IXCORPORATCn TO East Forty-fifth Street New York 17, N. Y. Copyrielit 1900 by American Standards Association. Incorporated Universal Decimal Classification 614.891/.894 Printed i-i U.I.A. m\1w.<r:to;i Foreword 'This Foreword is not a part of American Standard Safety Code for Head, Eye, and Respiratory Protection, Z2.1-1959.) Tlie first edition of this code yvas completed in the fall of 1920 and issued early in 1921. It was prepared with the cooperation of an advisory committee of 19 men who had been selected :(cause of their interest in and knowledge of the subject and ns being typical representatives of the interests most closely concerned. The code was developed from a set of safety standards originally prepared in cooperation between the War and Navy Departments and the National Bureau of Standards. The second edition was issued in 1922, after revision by a sectional committee organized under the procedures of the American Standards Association, and was published as National Bureau of Standards Handbook 112. 'flu; scope of the Z2 project was enlarged to include respiratory protection because of the many processes where simultaneous protection of lungs and eyes was needed, and a revision was pub lished in 1938 ns National Bureau of Standards Handbook 1124. In 1946 the sectional committee was reconvened and started work on a revision. A subcom mittee on eye protection was organized under the direct supervision of the National Bureau of Stand ards: a subcommittee on respiratory protection was organized under the supervision of the U.S. Bureau of Mines; and a sulicoiuittcc on head protection was organized under supervision of the Department of l lie Xavv. All parts of the standard had to be reviewed and brought up to dale in order to include new materials and devices which had been developed since 1938, particularly the use of plastics for eye protection. Suggestions for improvement gained in the use of this standard will be welcomed. They should he sent to the American Standards Association, Incorporated, 70 East Forty-fifth Street, New York 17. N. Y. The committee that developed this standard is as follows: I)n Leonakd Gkeemiuiic, Chairman R. L. Lloyd, Secretary Orpamiation Represented Name and Business Affiliation American Ceramic Society.............................................................John Past, Hay-O-Vae Company J. Earl Duncan, Pittsburgh Plate Gins. Company (Alt) American Contcrcncc of Governmental Industrial Hygienists. ..HonrrtT M. Brown, St. Louis Health Division American Foumlrymen's Society................................................... J. W. Younc. International Harvester Company American Gas Association............................................................. Edward C. Baumans, Public Service Electric ami Gas Company American Industrial Hygiene Association.................................... H. II. Sciirenk, Industrial Hygiene Foundation of America W. E. McCormick.The B. F. Goodrich Company (Alt) American Society of Mechanical Engineers................................ Theodore F. Hatch, University of Pittsburgh Thomas A. Walsh, Jr, American Optical Company American Society of Safety Engineers..........................................Charles W. Wyman, Western Electric Company, Inr W. F. Sciioltz, Allis-Chalmcrt Manufacturing Company (Ait) American Welding Society.............................................................Frederick C. Saacke, Air Reduction Company, Inc Associated Ccnernl Contractors of America................................ Annum L. ScitMUHL Association of American Railroads................................................M. B. Clayton, Southern Railway System Association of Casualty and Surety Companies..........................William M. Pierce, Employers Liability Assurance -Corporation, Ltd V. O. IJohn, Tim Employers Group (Alt) Hnusrli and Lnntb Optical Company..............................................Gordon Taylor . J. 1J. Lueck (Alt) General Services Administration........ .......................................... JoiinF. Kmnr Granite Cutter;.' International Association nf Amcri. u............... Edward Meade Industrial Medical Association....................................................... Carl Derneiil, Union Carbide Corporation L. Holland Whitney. American Telephone and Telegraph Company (Alt) 1 Organinition Jicpu'saueil Xante anti llusincsx Afliliaiion Industrial Safety Ec, jipment Associal' n...................................... Dahkci.l K. Auimit, Mine Safety Appliances Company F. If. Davis, Jh, Davis Emergency Equipment Company, Inc. C. II. Callaway, American Optical Company S. C. Hkkiunk, ltny-O-Vac Company A. F. Parmelee, United Stales Safety Service Company V. 1*. CorcKVtc, Industrial Safety Equipment Association (Ah) International Association of Governmental Labor Officials........Mourns Keeinit.i.u. New York State Department of Libor Craig II, ILark.n, New Jersey Department of Labor and Industry (Alt) International Association of Machinists........................................ W. G. Fl.lN'N William Damekon (Alt) International ISruthcrhood of Doitcrinakcrs, Iron Ship builders, mid Helpers ol America.......................................... John V. Keaiikky Metropolitan Life Insurance Gunpany........ ......... ....................... J- William Ieiinei. National Association of .Mutual Casualty Companies................. L. G. Mciti.k, Employers Mutuals of Wausau J. G Stknsett (Alt) Nntiunal Dureau of Standards........................................................IIalpii Staik K. L Ij.oyi> (Alt) K. K. I'LYi.En (Alt) National Electrical Manufacturers Association........ ..................If. W. Speiciikr, Wcstingliousc Electric Corpn'raitoii National Foundry Association............ ....................................... .C. T. Siikeiian National Safely Council.................................................................Kaiil L. Dunn, Corning Glass Works L. W. Hagerlt, Lumbermen's Mutual Casualty Company (Alt) National Society for the Prevention of Blindness........ ...............Leonako Cnr.ENntmc, Commissioner of Air Pollution <-f tlic City of New York James K. O'Neil (Alt) Pennsylvania Department of labor nnd Industry..................... Thomas A. Oiiavecz Telephone (.roup...............................................................................Eiu.e S. Minkii, American Telephone and Telegraph Company Cliaiii.m W. Wyman, Wc-tcrn Elenric Compauv. Inc (Alt) I'.S. Iturcau of Mines, Department of the Interior................. ..S. J. Peauce I.a whence It. Beiieeii (Alt) I'.S. De|mrtmrnt of Laiior, Ihircau of Laimr Standards.;.......... Siieijio.v W. Homan William G. Giuefin (Alt) IJ.S. Department of the Navy..........................................................II. I* Matiiews it. \V. Webster (Alt) U.S. Post OfTire Department............... ...........................................Kiiwaiui It. LaniiiiY U.S. Public Health Sendee............................................................. Donaed J. Birmingham Memlicr-at-Lirgc .................... .......................... ....................... Samuel Kensiiaw, Ohio Slate University Contents 1. Purpose nnd Scope......................................................................................................... 1.1 Purpose .................................................................. ...;............................................................. 1.2 Scope ............................................................................................................................................ 7 7 7 2. Exceptions .................................................................................................................. ................. 7 3. Definitions............................................................................................................................. 3.1 General Information....................................................................... 3.2 Specific Definitions............ ......................................................................................................... 7 7 7 1. General Requirements.......................................................................................................................... 10 5. Head Protection .................................................................. ............. ................................................. 5.1 Hats .......................................... 5.1.1 Tvjics and Classes................................................................................................... 5.1.2 Materials ............................................................................... 5.1.3 General Requirements .......................................................................................................... 5.1.4- Detailed Requirements..................... .................................................................................... 5.1.5 Physical Requirements ami Method* of Test....................... 5.1.6 Selection of ilcnd.Protcctivr Device* .................................................................................. 5.1.7 Training Aids............................ 5.1.f# Marking .............................. 5.2 Helmets mid Hand Shields................................................................... 5.2.1 Function ................................................... 5.2.2 Types..................... 5.2..`? Styles .................................................................... 5.2.* Detailed Requirements........................................................................................................... 5.2.5 Marking ................................................................................................................................ 5.3 Fare Shields............................................................................................................... 5.3.1 Function .............................................. 5.3.2 Intended Use*.............................. 5.3.3 Styles nnd Types...................................... 5.3.1 .Materials ....................................................................................................................... 5.3.5 General Requirement*......................................................................................................... 5.3.6 Detailed Requirements............................................................... 5.3.7 Marking ................. 5.3.3 Plnsical Requirement* nnd Method* of Test.......................................... 10 10 10 10 10 11 12 13 13 15 15 15 15 15 15 17 17 17 17 17 17 lit lit 10 6. F.ye Protection .................................................................................................................................. 6.1 Styles nnd Functions of Protectors................................. 6.1.1 floppies. Evecup................................................ 6.1.2 Spectacles. Metal or Plastic Frame............... 6.1.3 Gopplos, Flexible Fitting...................................................................................................... 6.1.4 Gopples, Plastic Eyeshicld............................................................... 6.1.5 Spectacle*. Plastic Eyeshicld.................................. 6.1.6 Gopgle*, Foundrymcn'*........................ 6.2 Materials nnd Methods of Testof Protectors.................................................................. (i.2.1 Materials................................................................................................................................. 6.2.2 Disinfection .......................................................................................................................... 6.2.3 Corrosion Resistance ...................................... 6.2.1 Water Absorption ................................................................................................................ (.2.5 Flammability ...................... 6.3 Lenses................................................................................................ 6.3.1 Types of lenses..................... 6.3.2 General Requirements ...................... 6.3.3 Dctnilcd Requirement*.......................................................................................................... 1 Methods of Test and F.xaminatinn of Ileuses..................................................................... 19 10 19 20 22 22 22 22 23 23 23 23 23 23 23 24 24 21 17 7. Respiratory Protection ....................................................................................................................... 7.1 Classification of Hazards.................. .......................................................................................... 7.1.1 Oxygen Deficiency................................................................................................................. 7.1.2 Gaseous Contaminants................ .......................................................................................... 7.1.3 Particulate Contaminants (Dusts, Fumes, Smokes, Mists, Fogs)...................................... 7.1.4 Combination of Gaseous and Particulate Contaminants................................................... 7.2 Classification of Respiratory Protective Devices.................................................................. .... 7.2.1 AtmosphcrC'Supplying Respirators .................................................................................... 7.2.2 Ail-Purifying Respirators.................................................................................................... 7.3 Requirements for Respirators.................... ................................................................................ 7.4 Selection of Respirators .............................. ................................................................................ 7.4.1 General Considerations.................. ...................................................................................... 7.5 Use and Maintenance of Respirators.......... ................................................................................ 7.5.1 General Considerations........................................................................................................ 7.5.2 Precautions To Be Taken in the Use of Respirators '......................................................... 7.5.3 Instruction in Use of Respirators....................................................................................... 7.5.4 Maintaining, Cleaning, Disinfecting, and Storing Respirators........................................ 27 27 27 27 23 28 23 28 30 33 31 34 36 30 30 39 10 Tables Tabic 1 Table 2 Table 3 Table 4 Table 5 Comparative Hat and Cap Sizes.................................................................... ..................... Transmittnnecs and Tolerances in Transmittance of Various Shades of Filler Dense*.. Selection of Eye- and Face-Protective Devices .............. ............................................... Color Code, for Gas-Mask Canisters................................................................ .................. Selection of Respiratory Protective Device...................... ................................................ 15 20 27 31 Figures Fig. 1 Fig. 2 Fig. 3 Brincll Hardness Penclrator Assembly................................................................................ Dimensions To Be Measured in Heat Deformation Test ................................................... Apparatus for Heat Deformation Test.................................................................................. 14 21 21 Appendix for Section 6 Al. Visible-Light Transmission and Haze Test................................................................................ A2. Water Absorption Test (For Weight and Dimensional Charges) .................. ....................... A3. Selection of Shade Numbers of Welding Filters .................. .................................................... A4. Maintenance and Disinfection of Eye Protectors ..................................................................... A5. Fitting of Goggles and Spectacles .............................................................................. ............... -13 -14 45 45 45 American Standard Safely Code for Head, Eye, and Respiratory Protection 1. Purpose ami Scope 1.1 Purpose. The purpose of this standard is to provide reasonable and adequate means, wr.ys, and methods for the proper selection and safe use of - head, face,, neck, eye, and respiratory protective equipment. 1.2 Scope. This standard shall apply to all oper ations or processes, excluding those relating to (I t communicable air-borne. diseases, or (2) x-rays, gamma rays, and high-energy particulate radiations such as alpha, beta, or neutron rays. 2. Exceptions Variations from the requirements of this standard may lie granted hy the administrative agency only when it is demonstrated to the satisfaction of the administrative agency that equivalent protection is afforded. 3. Definitions 3. I General Information 3.1.1 Where the word "approved" is used with qualification, it refers to approval by the adminis trative agency having jurisdiction over the specific requirement. 3.1.2 In this standard, the use of the word "shall" indicates a mandatory requirement. The word "should" indicates a recommendation. 3.2 Specific Definitions. As used in this standard, the following words shall have the indicated defini tions, and all other words shall have meaning according to their common usage. Abrasive-Blasting Respirator; Sec Respirator. Aerosol: A suspension of fine, solid, or liipiiil particles in air ns dust, fume, mist, smoke, or fog. Air-Line Respirator: Sec Respirator. Air-Regulating Valve: An adjustable vnlve be tween the air-supply line and the breathing tube of an air-line respirator or an nbrasivc-blnstimr respi rator whereby the flow of air to the facepiece, helmet, or hood may be regulated. Air-Supply Device: A band- or molor-operntcd blower for the hose mask or a source of respirable compressed air for the air-line respirator ami for tbc abrasive-blasting respirator. Air-Supply Line: A hose to conduct respirable air from the air-supply device to that portion of a supplied-air respirator carried on the wearer's person. Auxiliary Magnifier or Enlarger: A single lens or a pair of lenses joined together in a suitable manner to be inserted into the window in a welding helmet or hand shield to magnify or enlarge tin* area of the point of ojierution. Breathing Tube: A flexible tube through which air or oxygen flows to the facepiece of a respirator. Itriilge She: The distance between lenses on the nose side of each eye, expressed in millimeters. Canister: A detachable container filled with granular materials that remove gases or vapors from the air that is drawn through the unit; it may also contain mechanical filters to remove dust, mist, and smoke particles. Cartridge: A small canister. Cartridge-Type Respirator: See Respirator. Contaminant: A harmful material that is foreign to the normal atmosphere. Cover Plate: A removable, pane of colorless glass, plastic-coated glass, or plastic that covers the filler plate and protects it from damage. Croton Strap(s): As applied to protective hats and caps, it is that part of the suspension that supports the shell in proper position on the wearer's head and nets as a shock absorber when the shell is subjected to impnet; ns applied to helmets and face shields, it is that part of the suspension that supports the device in proper position in front of the wearer's face. Demand Respirator: See Respirator. Detachable Coupling: A device hy means of which the wearer of an air-line respirator mnv quickly detach the air-supply line from that part of the respirator worn on the person. Disinfection: Hie net or process of destroying organisms that cause disease. Dispcrsoid: A colloidal or finely divided substance. Dust: Finely divided solid particles generated hy processing (including handling, crushing, grinding, or pulverizing) materials such ns rock, ore, metal, coal, wood, and grain. 7 ,\ g.i-ligt ` liml ii..|nw in ji gas-mask facepiece through wdiich the wearer mav sec. /.'vc Size: A measurement expressed in millime ters mid denoting; the size of the Iens*holding section of an eye frame. Fxhalntiim J'ulrc: A device that allows exhaled air to leave a respirator and prevents outside air from entering it. Flint Mask: A device worn in front of the eves and a portion of or atl of the face, whose predominant function is protection of the eves and face. Facepiece: That portion of n respirator that covers the wearer's nose and mouth and makes a gaslight or dust-tight fit with Ids face; the head harness or lieadhauds and the breathing luhe are usually included in the facepiece assembly. Fitter: A device that removes contaminants from air drawn through it or that converts those con taminants into less harmful compounds. Filler Plate: A removable pane in the window that absorbs varying proportions of the ultraviolet, visible, and infrared rays according to the com position and density of the plate. Filler Respirator: See Respirator. Fop: Small liquid particles, condensed from the vapor phase, suspended in a gas such ns air. Full Facepiece: A facepiece that covers the wearer's nose, mouth, ryes, and face and makes n gaslight or dust-tight fit with his face. It includes evepiiTcs, the head hnrness. mid breathing tule. Funic: Solid dispersoids formed lv condensation of vapors, such as those from heated metals. (las Mash: See Respirator. (lagglcs: A device, with contour-shaped cyccups or facial contact with glass or plastic lenses, worn over the eyes and held in place by a headband for the protection of the eyes and eve sockets. Half'Mask Facepiece: A facepiece that rovers the wearer's nose and mouth but not ldtf)r.<yc*, and makes a gaslight or dust-tight fit with his face: the headbands are included in the half-mask assembly. Hand Shield: A device, usually held in the hand or supported on the wearer's ciicst, designed to protect the eyes and face during welding operations. Hat: A rigid device that is worn by the operator to provide protection to the head or portions thereof against impact, (lying particles, or electric shock, or any combination thereof, and which is held in place hv suitable means; brimlcss caps with jx.-nks are included as huts. Hcadhcnd: That part of the suspension consisting of u supporting hand that encircles the head. Head Harness (of (las Mask): A device fur holding the facepiece securely in place on the wearer's face. Helmet: A device that is. worn lv : person to shield the eyes, face, neck, and other parts of the head. Hand: A device that completely covers the bend, neck, and portions of the shoulders. Hone Mask IFitli Illower: Sec Respirutnr. Hose Mask IT'illtout Illower: See Respirator. Infrared Radiation: Electromagnetic energy with wavelengths from 770 to 107'millimicrons. Inhalation Valrc: A device tlint allows respirable air to enter the facepiece and prevents exhaled air from leaving the faeepiccc through the intake o|H'idng. Interpupillary Distance: The distance in milli meters between the centers of the pupils nl the eyes. Irrespirahle: Unfit for breathing. Iwus: The transparent glass or plastic device through which the wearer of (he protective goggics or sjHTliiclr* sees, and which provides prnti-ctum to the eyes against (lying objects, glare, or injurious ruiliutiofi. or a combination of these hazards. Lens, (larreetire: A lens ground to the wearer's individual eorreetive preseription. Lift Front: A type of mounting frame for weld ing helmets whieh is made id two comiceleil parts: the front part, which can he removed from the line of vision, eoutnins the high-density filler plate with its rover plate; and the buck part, which is fixed to the helmet, contains a low-density impact-resistant plate. Mist: Siis|H'iidcd liquid droplets generated by hrenking up a liquid into a disjicrscd slate. Mounting Plate ar Mounting Frame: Tindevice (bat bolds the filter and cover plate in their proper place on the helmet. Pnrtirulate Muttert Matter occurring in the form of mitiote separate particles, such ns dust. fume, mist, utid fog; a dis|iersoid. Vrefittert A low-resistnnee filter pad. placed in front of and in series with n regular dispersoid filter to lessen the dust load on (he Intler by removing the larger disjiersiiids from the air drawn through it. Praterlur: A devirc that provides head. faee. eve. or respiratory protection against the hazard* of processes encountered in employment or in the natural environment. Radiant Hnergy or Rndiatiam The energy of oliTtrnimigiii-tlc waves produced by the movement of nioiin-ules cxeitiil by the bent of nn electric are. or gas flame, or the passage of on electric current. Three kind- of radiant -n-rgy are jH-rlim-nt to this i^liin*liiri: t 11 ultraviolet radiation. (2l visi.-its *i"lit. and (.') infrared radiation. Resistance: Opposition to the passage of air, as through a filter or orifice. licitpirattic: Fit to he breathed. licit,:!ralor: A device to protect the wearer from the inhalation of irrcspirablc atmospheres. Abrasive-Wasting Respirator: A supplied-air respirator, similar in principle to the air-line respi rator, providing respiratory protection against dust and protection for the head and neck of the wearer against impact and abrasion by rebounding material during ubrnsive blasting operations. Air-Mne Respirator: A supplied-air respirator designed to be connected by a small-diameter hose to a supply of respirable air under positive pressure sufficient to deliver an adequate flow of air to n half-mask facepiece, full facepiece, helmet, or hood. Chemical-Cartridge Respirator: A nonemergency chemical-filter respirator usually having a half-mask facepiece and one or more cartridges to remove contaminants from the air drawn through them; it is designed for rcspirulory protection against low concentrations of gases and vapors or a combina tion of dispersoids, gases, and vapors. Demand Respirator: An atmosphere-supplying respirator in which air or oxygen is admitted to the facepiece only when the wearer inhales, and in quantities governed automatically by his hrealhing. Filler Respirator: A device designed for the wearer to inhale the surrounding atmosphere after it has passed through a filtering medium to remove contaminants. The filtering medium may chemically absorb or mechanically retain or obstruct the im purities. Gas Mask: A filter respirator having a full facepiece, a canister containing the suitable granular material with or without dispersoid filter, and a canister-carrying harness; it is designed for respira tory protection against gases or vapors or a com bination of dispersoids and gases and vapors. Helmet, Respirator: A rigid device that com pletely covers the head, neck, and portions of the shoulders of the wearer, and is provided with an air inlet and eyepiece. Hood, Respirator: A loose-fitting device that covers the head and neck of the wearer. It may be a nonrigid or a combination of a rigid head covering and a nonrigid skirt for the head covering. Hose Mask With lllotcer: A supplied-air res pirator having a full facepiece to which respirable air is forced through a large diameter hose by a hand- or motor-operated blower, and through which Respirators (Continued): the wearer can inhale whether or not the blower is operated. Hose Mask Without lllotcer: A supplied-air respirator having a full facepiece to which the supply of air is drawn from an inlet in respirable air through a large diameter hose by the wearer's breathing effort. Self-Contained llrcathing Apparatus: A res pirator in which the supply of air, oxygen, or oxygengenerating material is carried by the wearer. Supplied-Air Respirator: A respirntor that makes respirable air available to the wearer through a hose connected to a source of respirable air. Self-Contained llrcathing Apparatus: See Res pirator. Shield: A device to be held in the hand, or supported without the aid of the operator, whose predominant function is protection of the eyes ond face. Side Shield: A device of metal, plastic, or other material hinged or fixed firmly to the spectacle lens frame to protect the eye from side exposure. Snood: A flexible attachment to the back of a hood for protection agninst injury to the back of the head and neck. Spectacle: A device patterned after conventionaltype spectacle eyewear but of more substantial con struction, either with or without side shields, and with clear, impact-resistant filter or corrective lenses of glass or plastic. Supplied-Air Respirator: Sec Respirator. Suspension: That part of a protective hat, cap, helmet, or face shield that supports the device on the wearer's head; it usually consists of headband and crown strop. Temple: That part of <i spectacle or other protector extending to the car of the wearer and intended to position the device before the eyes. Temple Length: The measured length of a temple designated in inches. Timer: A device, ojreralcd by the wearer's respi rations, that indicates the approximate length of time that n universal gas mask has been worn. Toxic Dust: Dust that may be harmful to the respiratory tract or to other parts of the body through passing from the respiratory tract into the blood stream. Ultraviolet Radiation: Electromagnetic energy with wavelengths from 50 to 390 millimicrons. Valve: A device that permits the passage of air through it in one dirccti; > only. Vapor: Tin; gase./iis Malt: ttl a ibtancc that is a solid or liquid at ordinary temperature and pressures. Visible Light: Electromagnetic energy haring wavelengths within a range of 390 to 770 milli microns. <1. General Requirements 4.1 Head, eye, and respiratory protection in a manner provided by this standard shall he required where there is a reasonable probability of injury, illness, or disease of the body that can be prevented by such protection. 1.2 In such eases, employers shall furnish protectors of a type suitable for the work to he performed, and employees shall use such protectors. 4.3 No person shall be subjected, without protection, to a hazardous environmental condition. 4.4 Hygienic standards for industrial atmospheric contaminants arc published by tho American Stand ards Association, the American Industrial Hygiene Association, and the American Conference of Governincutal Industrial Hygienists. All of tb-se values should he used as guides in the control oi health hazards and should not be regarded ns fine lines between safe and dangerous concentrations. They only represent conditions within which it is felt that workers may he exposed continually for <Miour periods, day after day, without adverse elTeels on health. 4.3 Protectors shall meet the following minimum requirements: (1) They shall provide adequate protection against the particular hazards for which they arc designed. (2) They shall be reasonably comfortable when worn under the designated conditions. (3) They shall fit snugly and shall not unduly interfere with the movements of tho wearer. (4) They shall be durable. (5) They shall be capable of being disinfected. (6) They shall be easily clcanablc. 4.6 Protectors should be kept clean and in good repair. 4.7 Eye protectors shall be provided where machines or operations present the hnzurd of flying particles, pieces, or substances. 4.11 Respirators shall be provided where a process presents i!:o hazard of exposure to harmful vapors, gases, dusts, mists, or fumes. Where the process is enclosed or \riitikilcd. a supply of appropriate pro tectors shall be readily available for use in un emergency. 4.9 Workers whose vision requires the use of cor rective lenses in spectacles and who arc required bv this standard to wear protective goggles shall l provided with goggles of one of the following types: (1) Goggles whose protective lenses provide optical correction, or (2) Goggles that can he worn over corrective spectacles w! nout disturbing the adjustment of the spectacles, or (3) Goggles that incorporate corrective lenses mounted behind the protective lenses 4.10 Every protector shall le distinctly marked to facilitate identification of the manufacturer. 4.11 Only approved protectors shall he used. In such eases where the U.S. bureau of Miuv has issued an approval for a protector, the administrative agency may accept Midi approval as prima-facie evidence of compliance with this section, provided that the limits within which the bureau of Mines approval has been granted are not exceeded. 5. ITcxttl Protection 3.1 Hals 5.1.1 Types and Classes. Protective hats shall he oi two types and of the following classes: Type 1--Hat, full brim Type 2--Cup, hrimless with peak Class A--General Service. Protection against impact and flying particles; limited dielectric strength Class II--Utility Service. Protection against im pact and flying particles; high dielectric strength Class C--Special Service. Limited protection against impact; no dielectric strength (particular reference is made tc metallic protective luits and caps) Class I)--Firemen Service. Protection against impact and flying particles; limited dielectric strength; Type 1 only 5.1.2 Materials. Materials used in the construetion of protective hat and cap shells shall he water resistant, acid resistant, and fire resistant, and non conductors of electricity (except for CInss C which possesses no dielectric, strength). All materials emning in contact with the wearer's bend shall he mmirritating. Class b huts shnll contain no metai parts, either in the shell, sus|icttsion, or accessories. 5.1.3 General Requirement*. Each hat nr enp shall consist essentia :/ of a shell, a hcndhnnd, and :mua Mi.ips for support on die wearer's It- d. Provi sion shall ho made for adequate ventilation. 5.1.3.1 Shell. The shell shall he dome-shaped of one-piece seamless construction, with smooth, hard surfaces. Where reinforcing ribs arc used, they shall be sr design<;d as to deflect a falling object. For Class B hats, there shall be no holes in any part of the shell. 5.1.3.2 Headband. Unless otherwise specified, the headband shall be genuine vegetable-tanned leather, full grain and soft, or artificial leather conforming to Type II, Cjass 3 of Federal Specifica tions CCC-C-418. The headband should be smoothly finished on the surface that will contact the head. 5.1.3.3 Crown Straps. Crown straps shall be of closely woven webbing or suitable material with high tensile strength and a low total elongation. 5.1.3.4 Accessories. Accessories shall be suit able for the intended purpose. All accessories shall be made of suitable materials and shall show good workmanship. 5.1.3.4.1 Chin Strap. Unless otherwise specified, the chin strap shall be closely woven webbing, genuine leather, or clastic cotton webbing combination. 5.1.3.4.2 Winter Liner. The winter liner, unless otherwise specified, shall consist of two layers of closely woven fabric; if colored, the fabric shall bn fast dyed. The outer layer shall be water repellent and the inside layer a non-watcr-repcllnnt plain woven flannel with nap on the inside surface. 5.1.3.4.3 Lamp Bracket. The lamp bracket shall be plastic or metal; if metal, it shall be insulated from the inside of the shell. The bracket shall be designed for proper beam angle when the lint is worn in the normal position. 5.1.3.4.4 Welding Helmet Combination. When used in conjunction with a cap, the welding helmet shall meet the requirements o( 5.2. 5.1.3.4.5 Face Shield. When worn in con junction with a hat or cap, the face shield or eye shield shall meet the requirements of 5.3. 5.1.3.4.6 Hoods. These arc generally class ified as acid resistant, heat resistant, and abrasion resistant. They are frequently used in conjunction with protective caps. Hoods used in combination with caps shall be manufactured from an acceptable material suitable for the particular application, mid shall be so attached to the cap as to periu't good visibility. The hood shall be designed for com{art and safely. 5.1.4 Deitdled Requirement* 5.1.4.1 Shell. The Typo 1 hat shell shall have a continuous brim as an integral extension of the dome; with the hat held in a horizontal position,, the brim shall slope downward; the width of the brim shall be not less than 1V& inches and not more than 3 inches measured from the inside edge of the shell, except for Class D shells. The Type 2 cap shell shall include a peak or brim extending forward from the crown not less than 1% inches and shall be not less than 5% inches in width. The Class B hat or cap shell shall contain no holes, either through the crown portion or the brim portion, for the support of the headgear or for any other purpose; no metal or electrical conducting material shall he permitted either inside or outside the shell for any purpose. 5.1.4.2 Ilcadband. The headband may be ad justable or nonadjustablc. If adjustable, it shall cover the size range of commercial hat sizes 6% through 7%. If nonadjustablc, it shall be furnished in the specified head size. The surface of the headband in contact with the wearer's head shall lie not less than V/l Inches in width. Any padding or stiffener strips used shall be secured to the leather or artificial leather of the headband. Headband assemblies in tended for use in Class B hats or caps shall contain no metal or electrical conducting material. 5.1.4.3 Crown Straps. Crown straps may be adjustable or nonadjustablc. These straps when pro perly laced or assembled shall form a cradle for supporting the hat or rap on the wearer's head. The crown straps shall be designed to permit n clearance between the top of the wearer's head and the shell of not less than lVt inches. Crown-strap assemblies intended for use in Class B hats or caps shall contain no metal or electrical conducting material. 5.1.4.4 A cccssorics 5.1.4.4.1 Chin Strap. The adjustable chin strap shall l>c made of not more than two pieces of webbing, leather, or clastic cotton webbing com bination not less than inch in width and not less than 1C inches in length, excluding the attach ments to the bat or cap. The means for adjusting the chin strap shall assure a secure hold of the hat or cap on the wearer's head and quick removal of the hat or cap by releasing the strap. The chin strap shall also be adjustable for wearing at the back ol the bond. The webbing shall have no frayed or loose edges that may unravel. Leather, if used in the chin strap, shall be of suitable thickness, full grained, and smoothly finished on the surface that will he in contact with the chin. All metal parts shall be free from sharp or rough edges or projections, llivet heads shall be smooth. C in-*lrnp assemblies intended 12 fur use in Class B hats or caps shall contain no metal or electrical conducting material. 5.1.4.4.2 Winter Liner. The winter liner shall he designed to cover the skull, neck, and cars, or the skull and cars only, as specified. The carlug and neck part may he made either in one piece with the skull cap or may he attachable to it. The neck and caring parts shall he made to fit snugly hy means of a lace or chin strap. Winter liners intended for use with Class II hats or caps shall contain no metal or electrical conducting material. 5.1.4.4.3 Lamp Bracket. The lamp bracket shall he so designed as to permit adequate illumination directly in front of the wearer when the hat is positioned properly on the head. Caps for specific use in the mining industry may have metal brackets in place of plastic ones, provided insulating rivets are used to assemble the bracket to the shell. 5.1.4.4.4 Face Shield. Material for face shields or eye shields shall he in accordance with 5.3. The method of attachment to the hat or cap shall he such ns to permit easy replacement. A firm, sure fit shall he assured to provide adequate protection. Metal or plastic frames shall he provided to hold the shield firmly to the hat or cap shell. Snap-on or riveted attachments arc permitted, provided the shield is lurid securely. Attachments may he rigid or swiveled; see 5.3.C).fi. 5.1.4.4.5 Welding Helmet Combination. The welding helmet shall he attached to the protective cap in such n manner ns to permit easy removal, yet oiler a firm, positive method of attachment. The attachment shall lie such ns to permit ready lifting and lowering of the helmet as described in 5.24.1.3. 5.1.4.4.6 Hoods 5.1.4.4.6.1 Acid Type. Materials used in this application shall lie rubber, synthetic rubber, or plastic. When worn in conjunction with a protective hat or cap, the method of attachment and the design shall he such as to permit ease in movement, adequate visibility, proper ventilation, comfort, and safely. The window shall lie attached so as to provide adequate vision with the hat or cap at any angle. 5.1.4.4.6.2 Heat Type. Hoods nud masks arc available for protection against various degrees of heat. The mask tyjws consists of a plastic* or wire-screen face shield which can he attached hy means of a bracket to the brim of a hat or cap. This combination is used where the wearer tray come in contact with infrequent splashes of hot materials. Spectacles arc frequently worn under the wirc*scrccn mask. Th hood shall he made from material such as chrome leather, asbestos, or flameproof duck. The AMKHICAN STAM)AI(I) SAKKTY COOK KOIt design shall he similar to that of the acid-type hood and shall incorporate the same details as noted therein. 5.1.4.4.6.3 Abrasion Type. Material used for this type of hood shall he heavy rubberized fabric, chrome leather, or similar abrasive-resistant material. The design shall he similar to the acid-type hood and shall incorporate the same details of construction. 5.1.5 Physical Requirements anti Methods of Test 5.1.5.1 Preparation of Samples. All lints or caps shall lie prepared in the following manner for the tests described in this section. Using No. GO grit garnet pajicr, the entire exterior surface of the shell shall lie abraded until the basic material is exposed. All samples shall then lie conditioned in an oven for 96 hours at 50 2 C, then cooled in a desiccator and exposed for 96 hours in an atmosphere having 50 percent : 2 jierccnt rclntivc humidity and a leinjierature of 25 rt 2 C. 5.1.5.2 Insulation Resistance (Class A and Class I) Hats and Caps). When tested in accordance with the method sjiecifird in 5.1.5.4, Class A and Class D hats and caps shall withstand 2.200 volts, alternating current, 60 cycles per second (root-meansquare value) for 1 minute with leakage current not In excess of 3 milliampcrcs. 5.1.5.3 Insulation Resistance (Class fi Hats or Caps). When tested in nccordanec with the method specified in 5.1.54, Class B hats or caps shall with stand 15,000 volts, alternating current, 60 cycles per second (rool-mean-squarc value) for 1 minute with leakage current not in excess of ft milliampcrcs. Class II hats and caps when tested to breakdown shall not fail lielow 20,000 volts. Tests shall lie made after first subjecting the lints or caps to the impact resistance test described in 5.1.5.5. 5.1.5.4 Electrical Proof Test. The inside of the hat or cap shell (without suspension or accessories) shall he-filled with fresh tap water to within Vj inch of the junction of the brim with the crown. If the shell contains holes in the crown near the brim, it shall he filled to within H inch of the holes. The hat or cap shall then he submerged in the same type of water to the same level as that of the water inside. One terminal from the current source shall lie in contact with the water inside the shell, and the other terminal in contort with the water outside tiic shell. The circuit shall he provided with a voltmeter of sufficient capacity, and a miliinmcter of sufficient capacity and accuracy, to measure the specified current. For Class A and Class D hats and caps, 2,200 volts shall lie applied for l minute and current leakage, if w, noted. For Class B hats or 1IKAD, KYK, AM) IIKSl'IKATOKY IMtOTKCTION caps, 15,000 volts shall he applied contincoudy for 1 minute and current leakage, if any, noted; voltage shall then lie increased momentarily to 20,000 volts to delermine whether breakdown of the shell occurs. Care should he taken to keep the unsiihmcrgcd portion of tli shell dry so that flashover on application of voltage does not occur. Suitable precaution should he taken to prevent aecid -ntnl contact by persons with any part of the high-voltage circuit. 5.1.5.5 Impact Resistance 5.1.5.5.1 Classes A, B, and D Hats and Caps. When mounted on a standard head form, as described in Federal Specification GGG-H-142, with a crown clearance of V/< inches, the hat or cop shall not transmit an average force of more than (150 pounds from the impact of an ('-pound spherical steel hall approximately 5.(5 inches in diameter dropped onto the center of the crown from a height of 5 feet. The force transmitted shall he determined by mount* in" the standard head form on a Brincll hardness penctrator apparatus ns described in Federal Specifi cation C.GG-11-142. See Fig. 1. The impression bar shall he of a metal having a predetermined Rrincll hardness of 1(5-30 ns measured with a 500-kilogram load and a 10-inillimeter hall, in accordance with the procedures of American Society for Testing Materials Specification F.10-54T. 5.1.5.5.2 Gtass C Hals and Caps. Requireincut and test shall he the same ns specified in 5.1.5.5.1 except that the height of drop shall lie 3 feet. 5.1.5.6 Penetration Resistance. lints and caps of all classes shall he neither dented nor pierced for more than % inch, nor shall the shell he pushed down so ns to touch the standard head form, nor shall the crown straps pull out or break, when mounted ns specified in 5.1.5.5.1 and subjected to a l-pnund hardened steel plumb hoh with a point having an included angle of 36 degrees dropped stjuarely onto the center of the crown from a height of 1(1 feet. 5.1.5.7 Weight. Kxccpl for Class D, the weight of each hat or cap shall not exceed 15 ounces com plete with suspension, hut exclusive of winter liner or chin strap. 5.1.5.(1 Flammability, The thinnest section of the. shell shnti not burn at a rote greater than 3 inches per minute when tested by inserting one end of a 5-inch x V-inch strip of the shell .nnlorial in a lduc-fininn Ilunscn burner. The strip of the shell material shall be inclined at 45 degrees with the 5-inch longitudinal axis horizontal. The burner flame shall he :J.j inch high. After 30 seconds, the burner 13 shall be removed and the strip allowed to burn. Measurement of the rate of burning shall then he recorded. 5.1.5.9 Water Absorption. The shell material shall absorb not more than 5 percent hy weight of water when subjected to the test specified in 6.2.4. 5.1.5.10 Etlge Strength. Hats and caps in Classes A, C, and D shall show a deflection under a 40-pound load of not more than % inch and an ultimate strength of not less than 50 pounds when the jieak or front brim is chun|>cd in the supported edge position to a T-jig. in accordance with Federal Specification GGG-1I-142. 5.1.6 Selection of HeatUVrotccthe. Devices 5.1.6.1 Class A. Hats and caps under (Ids classification arc intended for protection against impact hazards encountered, for example, in mining, building construction, tunneling, timber work, nud manufacturing. Dielectric strength is incorporated as an extra safeguard for protection against voltagenot exceeding 600 volts. 5.1.6.2 Class If, This class covers safely lints and caps for protection of the wearer's head against electrical contact with exposed conductors of high voltage and against impact hazards. 5.1.6.3 Class C. The safely lint or enp in '.Ms class is designed sjiecificnlly for lightweight comfort with some impact protection. This class is usually manufactured from aluminum and offers no dielectric protection. 5.1.6.4 Class I). Tlic firemen's helmet covered under this classification is designed for a spedfie use where additional requirements arc; (1) wide brim--to give protection to ears and nrck; (2) heavy construction--to provide high-impact resistance and hump protection, with good abrasion qualities; (3) dielectric strength--for protection against voltages not cxreeding 600 volts. 5.1.7 Training Aids 5.1.7.1 Crotni Iaicc. The crown lace, if any. should always be tied with a square knot. This knot should lie secure in - order for the suspension to provide the required protection when the hat or cap is subjected to impact. If the entire susjiension is held in the shell hy a lace, this lncc shall also he tied in a square knot. 5.1.7.2 Clearance. To assure the proper protec tion when the hat or cap is being worn, the crown straps shall he so designed as to provide a minimum clearance of \\\ inches between the top of the wear er's head and the crown of the shell. In testing, this distance is measured hy placing a shell on a brail form in a position sii: 'ar to that when worn on u AMEKICAN STANIIAUI) SAKKTY COOK H)ll H rinell Hardness lY netrator Assembly lIl'.Ui. KYi:. AMI Ki:.<riHATOHY IMIOTKCTION a man's head. <V 23-pound weight is then placed on the shell and (lie distance between the crown of the test Mock and the underside of the top of the hat ior cap shell may he measured hy means of n rod inserted in a hole drilled through the center of the head form. 5.1.7.3 Painting. Caution should he exercised in painting any hat or cap shell as some paints reduce dielectric protection, attack and soften the shell material, and thus reduce impart protection. Tiie manufacturer shall he consulted with regard to tiie choice of paints for n particular hat or cap. n. 1.7.4 Insulating Safety Hats. Unlike rubber gloves, insulating safety hats or caps (Class 11) are not normally intended to come into contact with energized conductors or equipment. Nevertheless, periodic visual inspection and occasional electrical tests arc considered m.-ccssary and arc recommended. This is especially desirable in that this equipment is also used ns protection against impact hazards, and dielectric strength may he impaired hv impact. Insulating safety hats and caps shall lie inspected before each usage for cracks, signs of impact, and rough treatment. Shells mid suspensions shall he maintained in excellent condition at all limes, ai.d defective parts replaced. 3.1.7.5Cumparative Hat and Cap Sizes. Compa rati vc hat and cap sizes are shown in Table 1. 5.I.J Marking. ICaeh hat or cap shall he iden tified on tin: inside of tiie shell villi tiie name of the manufacturer and class of protection. For Class B, the hats and caps shall also he marked to indicate that cadi lias hern tested to meet the voltage test and breakdown requirements. Kadi hat or cap shall he accompanied hy instructions explaining the proper method of adjusting the suspension. i in 5.2 Helmets and Hand Shields 5.2.1 Function. The devices described in this section are designed to provide protection for the eyes, face, cars, and neck against intense radiant energy. Typical operations which require, helmets or hand shields include various kinds of arc welding and heavy gas cutting. 5.2.2 Types. The helmet and the hand shield arc the only permissible types for hand welding. 5.2.3 Styles. The helmet and the hand shield are made to the same basic design and of the same basic materials--a howl-shaped or modified bowl-shaped device containing a window witli filter plate which allows the wearer to see -the radiant object, vet prevents harmful intensities of radiation from reach ing his eyes. Thu helmet headgear has an adjustable frame hy which it is supported on the head, while the hand shield has a handle attached to tiie bottom hy which it is held in the hand. The basic designs may he modified to provide protection against special hazards, hut modified equipment shall meet (lie same requirements ns the basic design. 5.2.4 Detailed Hetjuircmcnts 5.2.4.1 Rigid Helmet 5.2.4.1.1 lichuct Body. The helmet body shall lie of such size and shape as to protect tiie face, top of the head, and the neck to a vertical line hack or tiie ears. It shall have an opening or openings in the front for a filter plate. Tiie helmet body shall he attached to the headgear in such n way that it will not come in contact with any part of the bond and that it can he lifted up fiom in front of the face and hold its position in front of tiie head. The helmet body shall he made of vulcanized fiber, reinforced plastic, or other suitable material which shall he heat and flame resistant, opaque to visible, ultraviolet, Table 1 Contjmrnlivc Hot nnd Cup Sizes American English Mcasuri-meni, inches Women** Sizing American English Measurement, inches Women'* Sizing ft filrl r.% f. 19 199s Small 7 7 Ik 6% 7 22 22-9k latrgc fitt 6Vk 1991 20 7Vi 7Vk 22!!i 0-9k 6% 20',k 7-9k 7 Vi 23 Vk 6Vi 6% 6-9k 6Vi 20Vi 20% Medium 7 Vs 7% 7% 7 Vi 23hi 23% Extra Large r.91 r.% 21 % 21 7-9i 7Vh 2VVi 24 6% r.9i 219.; 7% 7i 24% II 7T& 23% Non:: Thi: above measurement* nr to he made with material* dial wilt nt stretch. preferably -.villi a tape measure. In w-lcrtinc size*, measure cimimfercnre of head where dm hat U normally wiirn. Note nearest corresponding figure on chart for *iwi. Tlio-o sire* arc approximate and vary slightly among different manufacturers. Women** izcs am norma.iy < la--ilied a# im.,: -aU-d. although llio dimensional met hod could la: used. i6 ami infrared radiations, and capable < f disinfection. The inside of the helmet body shall have a low light-reflecting finish. Rivets or other metal parts, if terminating on the inside surface, shall be adequately insulated. 5.2.4.1.2 Weight. The helmet or hand shield, exclusive of filter or cover glasses, shall weigh not more than 24 ounces (o30 grams). 5.2.4.1.3 Headgear. The helmet shall have a headgear or cradle that shall hold the helmet body comfortably and firmly on the wearer's head, hut shall permit the helmet body to be tilted back over the head. The hcadgcai shall be readily adjustable, without the use of tools, for all sizes between com* mercial hat sizes 0% and 7%. The headgear shall liu made of materials which are noncombuslihlc or slow burning, resistant to heat, and capable of disinfection. Where required, the hendgear shall be fitted with a removable and replaceable sweatband covering at least the forehead portion of the head* hand. The sweathand shall be made of leather or other suitable material which is slow burning, heat resisting, and nonirritating. 5.2.4.1.4 Headgear Substitutes. The headgear may be replaced by an impact-resistant hnt or cap, or other suitable device to which the helmet body is connected, provided that the helmet body can be lifted and adjusted to permit unobstructed vision or lowered to furnish complete protection, as required. The alternative device shall meet the requirements for disinfection and resistance to heat, and, in addition, shall meet the applicable requirements of any additional functions such ns protection against falling objects ns detailed under 5.1. 5.2.4.1.5 Filler* and Cover-Plate Mounting. The front of the helmet body shall he provided with a light-tight plate-mounting frame or frames made of metal, plastic, or otiicr suitable material, which shall he attached securely to the body of the helmet or shall he an integral part of the helmet. The frame shall provide a window through which the welding or cutting operation may he seen by the wearer; the window shall lie not less than 3% inches wide and 1% inches high, or equivalent in area and visual field. The frame shall permit the removal and re placement of filter and cover plates without the use of tools and without damage to the plates or frame. The mounting shall he so designed tlini the filter plate will he not less than 2 inches (50.Q mm) from the eyes of the wearer. 5.2.4.1.6 Filter Plate. For helmets having only one working window, the filler plate shall he A.MKIIICAN STANIIAIII) SAKK'I'Y UlliK Kilt of such dimensions as to fit suitably into the frame and to cover the window; the filter plate shall he not less than 0.03 inch (2 mint nor more than 0.15 inch (3.8 mm) thick. If auxiliary windows ar$ provided, the dimensions of the innin window used for watching (lie arc shall he as specified in b.2.4.1.5. If two windows arc provided in place of the main window, their equivalent dimensions shall lie as specified in 5.2.4.I.5. Filter plates shall he free from striae, waves, or other defects which impair their optical quality. Filler plates shall conform with the radinnt-cncrgy transmission requirements shown in Tabic 2, page 26, and shall he uniform in luminous (visible) transmittance within 20 percent. Tiie dominant Hnc shall he between 490 and COO milli microns. Filter-plate surfnccs shall he flat ami sub stantially parallel; prismatic effect shall not exceed Vti prism diopter (8 minutes of arc). 5.2.4.1.7 Cover Plate. Cover plates, made of plain glass, of glass coated on one or on both sides with plastic, or of a simv-b'irning solid plastic sheet shall he used to protect the filter plates from damage. The cover plates shall he the same size and shape as the filter plates. They shall transmit not less than 75 percent of the luminous radiation and shall lie substantially free from optical imperfections. 5.2.4.2 Hand Shield. Hand shields shall lie constructed of materials similar to those used fotj the helmet and in like manner. The materials, lens mounting arrangement, and filter and cover plates shall conform In the requirements for the correspond ing parts of the helmet body with headgear. The handle shall lie made of n material that is a non conductor of electricity and is noneomhustihin or slow burning. It shall he of such size and shape as to he held easily hy one hand and shall lie firmly attached to the bottom of the shield. Hand shields intended for use by others than welding operators shall have filler and cover plates suitable for the intended use. 5.2.4.3 A'anripid Helmet. Helmets may he made of nonrigid materials where they arc to lie used in confined spaces or may he collapsible for convenience in enrrying or in storage. The helmets may lie of the same general shape as the rigid helmet except that a more complete covering of the top of the head is necessary in order to maintain the face, side, and windows in proper position. The requirements for the filter plates, cover plates, anil lens-mounting frame are the same ns for the rigid helmet. A head, gear may he used. The material shall lie tioncondueling and opaque to ultraviolet, visible, and in< frnred radiations. It mil withstand the test for him*. m:. am* hksi'IHatouy numxTioN resistance lo flame described in Federal Specifications for Plastics, Organic; General Specifications Test Methods L-P-406. Stitched scams shall lie welted and no stitching shall he exposed, 5.2.1.4 Attachments and Auxiliary Equipment 5.2.1.4.1 Lift Front, The lift front shall he fabricated from suitable material, such ns thermo* setting resin, die-curt aluminum or magnesium alloy, or stamped or drawn metal. A snap hinge shall be provided so that the front part will stay up or down hut will not remain in a partially opened position. The lift-front seal against the helmet shall he light tight. The lift front shall he designed to accommodate threw plates: an impact-resisting plate in the hack or fixed part, and a filter.plate and cover plate in the front part. 5.2.4.4.2 Chin Rest. To avoid contact of the helmet with the face of the wearer, a chin rest should he provided. The chin rest shall he constructed of suitable, rigid material and shall he detachable from the body of the helmet or hand shield. 5.2.4.4.3 Snood. Snoods or hack-of-headnnd-neek protectors shall he of material that is (lame resistant, that is a good insulator of heat and electricity, and that is capable of being disinfected. Such devices shall he designed for casj- attachment to the helmet or helmet headgear or cradle. 5.2.4.4.4 Apron. Aprons or bibs for helmets shall bo of nonflammable, nonconducting material that is flexible and capable of being disinfected. AH joints between the helmet and the bib or apron shall be light-tight. 5.2.4.4.?) Auxiliary Magnifier or Enlarger. This may be made of glass or transparent plastic material of optical quality. If used, it shall be the same size ns the filler plate. 5.2.4.5 Special Protective Devices. When re spiratory protection is needed against airborne con taminants encountered during welding operations, the appropriate respiratory protective device shall be worn in conjunction with n helmet or hand shield. 5.2.4.6 Flammability. The thinnest section of the rigid helmet or hand shield shall not burn at a rale grenter than 3 inches per minute when tested by inserting one end of n 5-inch x VSr'uch strip of the helmet material in a blue-flame Bunsen burner. The strip shall be inclined at 45 degrees with the 5* inch longitudinal axis horizontal. The burner flnrno shall he :Jj inch high. After 30 seconds, 'he burner shall he removed and the strip allowed to burn. Measurement of the rate of burning shall then bo recorded. 5.2.5 Harking. Helmets, shields, and filler plates 17 shall bear a permanent and distinctive marking by which the manufacturer may be readily identified. In addition, all filter plates shall be marked with the shade number; if made of heat-treated glass, they shall be marked with the letter "II." 5.3 Face Shields 5.3.1 Function. The devices described in this section arc designed to provide protection to the face (i.c., the front part of the head including fore head, eyes, checks, nose, mouth, chin) and neck, where required, from flying particles and sprays of hazardous tiquids and, in avldition, lo provide anti glare protection where required. 5.3.2 Intended Uses. Some typical uses for face shields include the following: (1) woodworking operations where chips and particles fly; (2) metal machining causing flying particles; (3) bulling, polishing, wire brushing, and grinding operations where flying particles or objects may strike the face; (4) spot welding; (5) handling hot or corrosne materials. 5.3.3 Styles and Types. Face shields shall com prise three basic styles: headgear without crown protector; headgear with crown protector; headgear with crown protector and chin protector. 5.3.3.1 Window. Each of these styles shall accommodate any of three styles of windows: (1) clear transparent; (2) colored transparent; (3) wire screen. 5.3.4 Materials. Materials used in the manu facture of face shields shnll combine mechanical strength and lightness of weight to a high degree, shall be nonirritaling to the skin when subjected to perspiration, .md shall bo capable of withstanding frequent disinfection. Where metals are used, they shnll be resistant to corrosion. Plastic materials shall be slow burning. Clear or colored plastic materials used in windows shall he of an optical grade and shnll provide equivalent performance with the applic able optical, physical, and radiant-energy require ments specified in 6.3.2 and 6,3.3. 5.3.5 General Requirement* 5.3.5.1 Assembly. Face shields shall consist essentially of a detachable transparent plastic window, wire-screen window, or opnquc frame with window; a tilting support, an adjustable headgear, and, as required, a crown protector and chin protector. 5.3.5.2 Window Shape, The plastic or wirescreen window shall be designed to fit the contour of the window support and to maintain that contour. 5.3.5.3 Window Support. There shall be attached to the her''gear a window-supporting or Ull.lill.i.v >| * \li Will s\l I. II .1 <1*1. I`l w window-holding mtiiilicr which shall consist of a suitable material. It shall he frielionally attached band with or without crown protector. The window to the sides of the headgear to permit easy tilting, support shall position the window in front of the either upward or downward, of the supporting tv face in such n manner as to provide clearance for member and of the window attached thereto. Th'* the nose ami eyeglasses of the wearer. window shall he capable of being tilled suflicicri 5.3.5.1 W'indow Attachment. The attachment upward so that the center of its bottom edge shall of the window to the window support shall he such be out of the line of horizontal vision. The tension as to permit easy removal and replacement. The of the tilting mechanism shall he sufliciciit to hold several sizes and l\ jh:s of windows shall he inter* the window without slippage in cither the up or the changeable for attachment to the window support. down position. 5.3.5.5 Headgear. The headgear shall consist 5.3.6.1 Headgear. The headgear shall he ad of at least a headhand and a crown strap. The head* justable, without the use of tools, for all commercial gear shall be made from materials having low heal conductivity. The design shall he such as to liobl the window and window support comfortably and hat sizes 6% and 7%. Adjusting devices shall he positive and shall hold firmly in place after being so adjusted, 'fhe crown strap or band shall be firmly in place on the wearer's head, and shall attached to, and extend between, the front and rear provide for tilting the window away from the face. centers or from the middle sides of the headband. 5.3.5.6 Crown Protector. The crown protector It shall form an arc over the head to assist in shall he shaped to cover at least the frontal portion positioning and holding the headgear in place. of the head and shall extend around each side at Adjusting devices, if used, shall he positive and least to the edges of the window. It may lie designed shall ho." I firmly in place after being so adjusted. to he an integral part of the window support, or it All mechanisms and movements shall lie protected may he a separate assembly. The design shall he so that the wearer's hair cannot catch in the adjust such as to provide a comfortable clearance over the ing devices. Not less than the forehead portion of the forehead and head of the wearer. headband shall he provided with a removable and 5.3.5.7 Chin Protector. The chin protector shall replaceable cushioned swc-alband tiiat shall he non- he shaped to cover at least the chin and upper irritating and liontoxic. part of the neck and shall extend at least to the 5.3.6.5 Crown Protector and Chin Protector edges of the window. The design shall he such The crown protector and chin protector shall . as to provide a comfortable clearance under the chin made of vulcanized fiber, plastic, or other suitable of the wearer. material Jmving nn impact resistance not less than 5.3.6 Detailed Requirements that of the plastic window. When the crown protector 5.3.6.1 Window Dimensions. Plastic or wire.* is used in conjunction with the chin protector for screen windows without frames shall he not less than protection against sprays of hazardous liquids, the V\-> inches wide at the top and 8% inches wide at assembly of the crown protector and window support the bottom, measured over their curved surfaces and the assembly of the chin protector and window when-attached and in position on the window support, shall he splash-proof, i.c., shall not allow liquids and not less than 6 inches high. Windows, when to pass through any openings in the assembly and used in frames, shall he not less than 4 inches wide reach the face, forehead, or chin of the wearer. mid 2 inches high, und the frames shall conform to 5.3.6.6 Headgear Substitutes. For additional the dimensions specified for windows without frames. protection, the headgear may he replaced by an Plastic windows shall he not less than 0.010 inch impact-resistant lint or cap or other suitable device nominal thickness. to which the window support is connected. The 5.3.6.2 Wire-Screen Window. The exposed allnchmcnt may he either rigid or swiveled. If borders of wire-screen windows shall he suitably swiveled, the design shall he such os to permit lifting bound or otherwise covered in such a manner us to and adjusting of the window to permit unobstructed eliminate nnv sharp, rough, or unfinished edges. vision or lowering to furnish protection, us required. Openings in the wire screen shall not exceed 0.0293 The substitute device shall meet the requirements inch (0.73 nun) in the maximum dimension. Ilrighl* for low-heat conductivity and disinfection, and, in finished metul should he used in the window to aid addition, shall meet the applicable requirements of in reflection of radiant energy. any additional functions such as protection against 5.3.6.H Window Support. The window support fulling objects, ns detailed under 5.1. shall be made of vulcanized fiber, plastic, or other 5.3.7 Mar!;ing Fach headgear and carh plasi HEAD, eye, and respiratory protection* window shall bear a permanent and legible marking by which the manufacturer may be readily identified. In addition, each window offered for protection ngninst glare shall bear its shade designation. 5.3.7.1 Marking for Special Operating Condi tion, When face shields arc to be used in atmospheres or working areas requiring special conditions of noneonduclivity or non; arking, then all. materials used shall meet these requirements. Face shields shall be plainly and permanently labeled, identifying them as "nonconduetive face shield" or "nonsparkiug face shield." 5.3.11 Physical llcouircrncnls and Methods of Test 5.3.21.1 Impact Resistance, Plastic-Window Face Shield. The face shield shall be mounted on a holder consisting of a standard wooden hat block, size 7, mounted vertically on a wooden support fastened securely to a base. The fata; shield shall he so mounlcd that the headband fils snugly around the periphery of the base of the block and the crown strap is in contact with the crown portion of the block. An additional supporting block, approximately 1 inch wide and curved to conform to the shape of the plastic window, shall bn provided as a support for the window* at its lower end or, if the face shield is provided with a chin rest, as a support under the chin rest. The face shield u'ill then rest in a position such that the axis of the cylindrical window is horizontal and the outer surfacr of the window is uppermost. The impact test shall be made at room temperature (G5 F to 05 F) under normal humidity conditions. A %-inch-diamctcr steel hall, weighing approximately 1.56 ounces, shall be freely dropped from a height of 50 inches onto the apex of the window at a point approximately 3 inches below the top edge of the window. The window shall not he fractured nor separated nor removed from any of its points of fastening to the headgear by the impact of the steel ball. 5.3.21.2 Penetration Resistance, Plastic-Window Face Shield. The face shield shall be mounted in the manner described in 5.3.21.1 and shall- he tested under similar conditions. A pointed projectile of suitable size, consisting of a new Singer number 135 x 17 size 25 needle fastened into a holder, weighing approximately 1.56 ounces, shall he freely dropped, needle! point downward, from a height of 50 inches onto thi! apex of the window at a point apr-oximatcly 3 inches below the top edge of the window. The projectile, may he guided, hut not restricted, in its fall by d...pping it through a lube extending to within approximately 4 inches of the face-shield 19 window. The window shall not be fractured nor pierced through by the impact of the projectile. 5.3.21.3 Visible Transmittance, Plastic Win dows. The total visible (luminous) transmittance of clear or colored windows shall he determined by auy standard method recognized as suitable by the National Bureau of Standards. A suggested method is described in 6.3.4.6.2. Clear windows shall transmit not less than 85 percent of the incident visible radia tion. Colored windows shall tra :smit as follows: Shade Percent Transmittance Light Medium Dark 50 7 23 dr 6 14 6 5.3.21.4 Flammability, Plastic Windows. The clear or colored plastic window shall burn at a rate not greater than 3 inches per minute when tested by inserting one end of a 5-inch x %-inch strip of the material in a blue-flame Bunsen burner, 'llic strip shall he inclined at 45 degrees with the 5-inch longitudinal axis horizontal. The burner flame shall be % inch high. After 30 seconds, the burner shall he removed from the strip and the strip allowed to burn. Measurement of the rale of burning shall then lie recorded. 5.3.8.5 Disinfection. AH face-shield materials shall be such as to withstand, without visible deterior ation, washing in detergents and warm water, rinsing to remove all traces of detergent, and disinfection by one of the following methods: (1) Immersion for 10 minutes in a solution of formalin made by placing one part of 40 percent formaldehyde solution in 9 parts of water at a room temperature of 68 F. (2) Subjection to a moist atmosphere of formaldehyde for a period of 10 minutes at room temperature of 68 F. (3) Immersion for 10 minutes in a solution of modified phcnolics, hypochlorite, or quaternary ammonium compounds in strength specified by the manufacturer at a room temperature of 68 F. 6. Eye Protection 6.1 Styles and Functions of Protectors 6.1.1 Gaggles, Eyecup 6.1.1.1 Ilasic Types. Eyecup goggles shall com prise two basic types as follows: Cup-Type Gaggles designed to be worn by individuals who do not wear corrective spectacles. Cavcr-Cnp-Type Goggles designed to fit over corrective spectacles 20 (>.1.1.2 Models. The two basic types of eyccup goggles shall he subdivided into the following classes: Chipper's Models providing protection ngainst flying objects. Dust and Sptash Models providing protection against relatively fine dust particles or liquid splashes. Welder's and Cutter's Models providing pro tection against glare and injurious radiations. The basic designs may be modified to provide more protection against special hazards, but the modified equipment shall meet the same requirements as the basic design. , 6.1.1.3 General Requirements. Evecup goggles shall consist of two ../coups, with lenses and lens, retainers, connected bv an adjustable bridge, and a replaceable and adjustable headband or other means for retaining the cyecups comfortably in front of the eyes. Specific applications for the use of eyccup goggles will be found in Table 3. (See page 27.) 6.1.1.4 Detailed Requirements 6.1.1.4.1 Eyccup Material. Evccups shall be made from a plastic or other material of such com position as to withstand the heat deformation test outlined in 6.1.1.5 and the disinfection, water ab sorption, and flammability tests outlined in 6.2. 6.1.1.4.2 Vision and Fit. Eyccups shall be right and left in pairs and shall permit an effective angle of vision not less than 105 degrees, assuming that the pupil of the eye is located 17 millimeters behind the inner surface of the lens. The edge of the cyecup which bears against the face shall have a smooth surface free from roughness or irregularities which might exert undue pressure or cause discomfort to the wearer. The cyecups shall be of such shape ami size as to cover completely the entire eye sockets, and the depth of the eyccup shall be such that the lenses will not interfere with the eyelashes of the wearer. The cyecups of covcr-cup-typc goggles shall be designed so that they provide ample clearance and will not interfere with the spectacles of the wearer. 6.1.1.4.3 Ventilation Chipper's Models. Eyccups shall be ven tilated in a manner to permit circulation of air. Ventilation openings shall be such as to exclude a spherical particle 0.04 inch in diameter. Dust and Splash Models. Eyccups shall be ventilated in a manner to permit circulation of air. The ventilation openings shall be baffled or screened to prevent the direct passage of dust or liquids into the interior of the cyecups. Welder's and Cutter's Models. Eyecups shall he ventilated in a manner to permit circulation of air. The ventilation openings shall be baffled to AMKIUCAN 5TVM)Ai;lt SAKKTY OlIlK 1Oil prevent the passage of light rays into the interior of the cyecups. 6.1.1.4.4 Lens Retainers. Each cyecup shall be provided with a lens retainer bearing evenly on the lens with sufficient pressure effectively to retain fragments in the event of lens breakage. The design shall be such as to permit the ready removal or replacement of lenses. Lens retainers for welder's and cutler's models shall be such ns to accommodate a filler lens, fiber gasket, and cover Jens. 6.1.1.5 Heat Deformation Test. Goggles shall be tested for heat deformation by mounting the cyecup on a wooden block with a weight ns shown in Fig. 3, and by placing the whole assembly in an oven at 150 F for one hour. After one hour the assembly shall be removed from the oven and allowed to cool, after which the dimensions (At, (B), and (D) shown in Fig. 2 shall be measured. The maximum deviation from the original dimensions shall not exceed the following: For dimensions (A) and (B), percent, and for dimension (D). 5 percent. After testing, the retaining ring and the cup of the eyccup shall fit in a snug hut not tight manner, 'flic cyccup shall be mounted on the wooden block ns follows: With the facial edge of the cup down and the lens horizontal, the bridge side fastened to the block by means of a piece of wire, with the cyecup resting on the edge of the block, which has a % fi-incli radius, and the 680-gram weight suspended from the cyccup by means of a piece of wire, one end of which is -ttlachcd to the weight and the other end fastened in the temple-side hcadstrap hole. 6.1.2 Spectacles, Metal or I'iistic Frame 6.1.2.1 Description. Spectacles shall consist of two lenses and two lens frames, of suitable size and shape for the purpose intended, connected by a nose bridge and supported on the face by temples or other suitable means. Where required, cable-type temples shall be adequately insulated over that portion in contact with the cars or head of the wearer. The spectacles shall be furnished with or without side shields, depending upon their intended use. The frames and side shields when provided shall be made of metal or slow-burning plastic material. 6.1.2.2 Protection. Spectacles shall provide protection to the eye from flying objects and, where required, from glare and injurious radiations. Spectacles without side shields arc intended to provide frontal eye protection only. Where side as well as frontal eye protection is required, the spec tacles shall be provided with side shields. The edge IlKAIt, KYK. AM) HKSt'lUATOItY IMUITKCTION Fig. 2 Dimensions To He Measured in Ilrat Deformation Test BRIDGE SIDE TEMPLE SIDE Fig. 3 Apparatus for Ileal Deformation Test 21 of the side shield shall have a smooth finish or shall he padded. 6.1.2.3 Marking. These frames shall he designed for industrial exposure and shall bear a trade-mark identifying the manufacturer. Specific application for use will he found in Table 3. (Sec page 27.) 6.1.2.4 Materials and Methods of Test 6.1.2.4.1 General. In addition to the specific requirements outlined hereafter, materials used shall be capable of withstanding the disinfection, corrosion resistance, water absorption, and flammability tests outlined in 6.2. 6.1.2.4.2 Strength of Lens Containers. That portion of the frame which supports the lenses shall be of sufficient strength to withstand, without break age and without dislodging the lens, the fractureresistance test for lenses specified in 6.3.4.2. 6.1.2.4.3 Strength of Soldered Joints (MetalFrame Spectacles). The soldered or brazed joints shall be given the following tests to demonstrate their strength and durability. The lens containers with lenses in place shall be gripped one in each hand, with the thumbs hearing on the outer surface near the bridge and the fingers on the inner surface of the lenses near the junction of the bridge and the lens container. The frames shall then be bent, the direc tion of motion being in a plane perpendicular to surface of the lenses, until the outer surfaces of the lenses face each other, the outer ends of the frames touching. The frames shall then be bent back to their original shape and a careful inspection made for failure in the joints. All frames tested shall pass this test without developing visible joint fracture. 6.1.2.4.4 Mat Transverse Test (Metal-Frame Spectacles). The right-lens container of each frame tested shall be laid flat, with the outer surface of the lens downward, on a firm, level support so that the left lens and one half of the bridge project beyond the edge of the support, and it shall be held in this position. A spring balance shall be attached to the outermost portion of the frame of the left lens, and a downward force of 11 ounces shall be applied while the right-lens frame is rigidly held. After removal of the load no permanent deformation shall be apparent in the frame. 6.1.2.4.5 Edge Transverse Test (MetalFrame Spectacles). The right-lens container of each frame tested shall be held vertically in one hand and the lower edge of the left-lens container, as worn, shall be pressed against one of the platforms of an equal-arm balance having a weight of 3 pounds on the other platform. The pressure shall be increased until the weight is balanced, whereupon the frame shall he removed and examined. No permanent deformation shall be apparent in the bame. 6.1.3 Goggles, Flexible Filling 6.1.3.1 Description. Goggles shall consist of a frame (composed of a flexible, chemical-resistant, nontoxic, nonirritating, and slow-burning material, fo;*ning a lens holder), lenses, and a positive means of support on the face such as an adjustable head band of suitable matcriui to retain the frame comfort ably and snugly in place in front of the eyes. The lens holder shall lie such that the lenses arc held firmly and tightly and may be removed or replaced without the use of tools. The goggles may be ventilated or not, as required by their intended use. Where chemical goggles arc ventilated, the ojicnings shall be such as to render the goggles splashproof. 6.1.3.2 Protection. Goggles shall provide eye protection from fine dusts, fumes, liquids, splashes, mists, and spray. 6.1.3.3 Application. Specific application for use of flexible fitting goggles will be found in Table 3. 6.1.3.4 Materials and Methods o] Test. Plastic lenses used in flexible fitting goggles shall be not less than 0.050 inch in thickness. Materials used shall be capable of withstanding the disinfection, corrosion resistance, water absorption, and flam mability tests outlined in 6.2. -6.1.4 Goggles, Plastic Eycshield 6.1.4.1 Description. The goggles shall consist of a frame of plastic material, lens or lenses, and a means of support such ns an adjustable headband to retain the goggles in front of the eyes. The frame and Jens need not be of the same material. The lens need not he an integral part of the goggles. The frame may he translucent, clear, or opaque, and may he ventilated or not, ns required by its intended use. The edge of the frame which bears against the face shall have a smooth surface free from roughness or irregularities which might cause discomfort to the wenrer. 6.1.4.2 Protection. The goggles shall provide protection against flying objects nnd, where required, against glare and injurious radiations. Where the goggles arc used for protection against injurious light radiation, the lenses nnd frames shall meet the requirements of Table 2 (see page 20) and the frames shall prevent the passage of injurious light rays. 6.1.4.3 Application. Specific application for use of plastic eycshield goggles will ho found in Table3. (Sec page 27.) 6.1.4.4 Design. Goggles shall he so designed as to cover completely the eye sockets nnd the facial AMKIUCAN STANIlAIUI .SAKKTY COOK I'OK area immediately adjacent to and surrounding the eyes of the wearer to protect the eye from side exposure. Where required, the design shall be such that the goggles will fit over ordinal y spectacles worn by the wearer. Goggles shall be so designed ns to alTord an effective angle of vision of not less than 105 degrees, assuming that the pupil of the eye is located 17 millimeters behind the inner surface of the lens. When lenses arc not an integral part of the frame, the method of attachment of lens to frame shall he such that the lens will not be inwardly dislodged from its scat when it is subjected to the fracture-resistance tests specified in 6.3.4.2. 6.1.1.5 Materials and Methods of Test. Where plastic lenses arc used in plastic eycshield goggles, they shall he not less than 0.050 inch in thickness. If glass lenses are used, they shall be not less than 3.0 millimeters nor more'than 3.fl millimeters in thickness. Materials used shall be cupahlc of with standing the disinfection, corrosion resistance, water absorption, and flammability tests outlined in 6.2. 6.1.5 Spectacles, Plastic Eycshield 6.1.5.1 Description. Spectacles shall consist of a frame of metal, fiber, or plastic material, plastic lens or lenses, and temples or other suitable means of support to retain the frame before the eyes. The lens or lenses need not be an integral part of the frame. The spectacles shall have side shields, if required by their intended use. 6.1.5.2 Protcct'on. Spectacles shall provide protection to the eye from flying objects and, where required, from glare nnd injurious radiation. Spec tacles without side shields provide frontal eye pro tection only. Where side as well ns frontal eye protec tion is required, the spectacles shall lie provided with side shields. 6.1.5.3 Application. Specific application for use of plastic eycshield spectacles will be found in Table 3. (See page 27.) 6.1.5.4 Materials and Methods of Test. Plastic lenses used in plastic eycshield spectacles shall be not less than 0.050 inch in thickness. Materials used shall be capable of meeting the applicable require ments und withstanding the tests outlined in 6.2 and 6.3. 6.1.6 Goggles, Foundrymen's 6.1.6.1Description. Goggles shall consist of a mak made of n flexible, nonirritnling, and noncombustible or slow-burning material, such ns leather or flexible plastic, metal lens holders attached thereto, lenses, and a positive means of support on the face, such ns an adjustable headband, to retain the mask c'imf.irl..bly and snugly ' \ place in front of the eves. iii. ui. mi.. ami lii.'i-iiumiiv I'lanicirnoN Tltc clips of tin* mask in contact with the face shall he provided with n binding of cordur<; or other suitable material. The lens holders shall be so designed that the lenses ore held firmly and tightly and may he readily removed or replaced. The lens holders shall he ventilated to permit circulation of air. Veil:ilntion openings shall exclude a spherical particle 0.0-1. inch in diameter. For protection against heavy concentrations of dust, U use of a fine-mesh screen lining (o.g., 100-mesh screen) is recommended. Such lining shall he suitably and permanently fastened to the inside surface of each lens holder assembly. 6.1.6.2 Protection. The goggles shall provide protection against impact and hot-metal splash hazards encountered in foundry operations such ns melting, pouring, chipping, babbitting, grinding, and riveting. Where required, they shall also provide protection against dusts. 6.1.6.3 Application. Specific application for use of foundrvtncii's goggles will he found in Table 3. (Sec page 27.1 6.1.6.4 Materials and Methods of Test. Ma terials used shall he capable of withstanding the disinfection, corrosion-resistance, water-absorption, and flammability tests outlined in G.2. 6.2 Materials and Methods of Test of Pro tectors 6.2.1 Materials. Materials used in the manu facture of eye protectors shall combine mechanical strength and lightness of weight to a high degree, shall he nonirritating to the skin when subjected to perspiration, and shall withstand frequent disinfec tion by the methods hereinafter prescribed. Where metals arc used they shall he inherently corrosion resistant. 6.2.2 Disinfection. AH materials shall lie such ns to withstand, without visible deterioration or discoloration, -washing in detergents and warm water, rinsing to remove all traces of detergent, and disinfec tion by the following methods: (1) Immersion for 10 minutes in a solution of formalin made by placing one part of 40 percent formaldehyde solution in 9 parts of water at a room temperature of 60 F. (2! Subjection to a moist atmosphere of formal dehyde for n period of 10 minutes at a room tem perature of 68 F. (3) Immersion for 10 minutes in a .dulion of modified phcnolics, hypochlorite, or quaternary am monium compounds in strength specified by the manufacturer at a room temperature of 60 F. 23 6.2.3 Corrosion Resistance. Metal parts shall he tested for corrosion resistance by placing them in a boiling aqueous 10-perccnt (by weight) solution of sodium chloride for a period of 15 minutes. The parts upon being removed from this solution shall be immediately immersed in a 10-pcrccnt (by weight) aqueous solution of sodium chloride at a room tem perature of 68 F. They shall then he removed from this solution and, without wiping off the adhering liquid, allowed to dry for 24 hours at room tem perature. The metal parts shall then be rinsed in lukewarm water and allowed to dry. On visual in spection, the metal parts shall show no signs of roughening of the surface resulting from corrosion. 6.2.4 Water Absorption. Plastic parts shall he tested for water absorption and the results calculated in accordance with Test Method No, 7031 of Federal Specification L-1M06 (see Appendix). The amount of the water absorbed shall not exceed 5 percent. 6.2.5 Flammability 6.2.5.1 Eyecup Goggles. Eyccup goggles shall he tested for flammability by use of a %-inch-diamclcr Bunsen burner, adjusted for a % -inch-high nonluminous flame of commercial natural gas (1,0001,200 British thermal units). The temple side of the specimen shall he held at the tip of this flame in a draft-free room and the time (in seconds) required to ignite the material so that it will remain burning after the flame is removed shall be determined. The time required to ignite the specimen in the manner described shall be not less than 4 seconds. 6.2.5.2 All Other Types. Where plastic ma terials arc used, such materials shall he slow burning. Cellulose nitrate, or materials having flammability characteristics approximating those of cellulose nitrate, shall not he used. Flammability of the ma terials shall he no greater than that exhibited by cellulose acetate or acetate butyrate. 6,3 Lenses 6.3.1 Types of Lenses. Lenses intended for use in protectors covered by this code shall comprise three basic types as follows: (1) Clear Lenses. Impact resisting, providing protection against flying objects (2) Filter Lenses, Impact resisting, providing protection against (a) Hying objects, glare, and injurious ra diation (b) Flying objects and glare (3) Prolccfn c-Corrcc/ii c Lenses, either clear or filler, ns specified, for persons having defective vision. 6.3.2 General Requirements 6.3.2.1 Optical Quality. All lenses shall be made of material suitable for ophthalmic use and both surfaces of the lenses shell be well polished and free from visible surface defects. The lenses shall be free from striae, bubbles, waves, and other visible defects and flaws which would impair their optical quality. 6.5.2.2 Primin';c and Refractive Power. The prismatic effect of a noncorreetive lens shall not exceed 3/i c. prism diopter (2 minutes angular devi ation). The refractive power, in any meridian, of any noncorreetive lens shall not exceed plus or minus \\diopter. The difference in refractive power of any two meridians shall not exceed \\ diopter. 6.3.2.3 Size Tolerances. Circumferential toler ances of lenses shall he held sufficiently close to permit interchangeability or replacement in their respective frames. 6.3.2.4 Edpcs. The edges of the lenses shall lie smooth and, where required, lenses shall be bevelled ami such bevelled edges shall be dull finished. 6.3.2.5 Haze. Lenses of all types shall exhibit not more than 6 percent haze when tested in accord ance with the requirements of Federal Specification L-P-406 (see Appendix). 6.3.2.6 Lenses for Persons Having Defective Vision. Employees whose vision requires the use of corrective lenses in spectacles and who arc required by these rules to wear protective goggles shall be provided with goggles of one of the following types: (1) Goggles whose protective lenses provide the proper optical correction nnd withstand the drop test specified in 6.3.4. (Such lenses are exempted from the requirements for parallelism of surfaces. Minimum thickness of prescription lenses shall be 3.0 millimeters, except in the ease of lenses of strong plus power, when the edge thickness may be reduced to 2.5 millimeters, provided they meet the impact test specified in 6.3.4.) (2) Goggles which can be worn over correc tive spectacles without disturbing the adjustment of the spectacles. (3) Goggles which incorporate corrective lenses mounted inside the protective lenses. 6.3.3 Detailed Requirements 6.3.3.1 Lens Thiclcncss. Glass or plastic lenses for use in cyccup goggles, metal- or plastic-frame spectacles, or foundrymen's goggles shall :.e not less than 3.0 millimeters, nor more than 3.8 millimeters in thickness. Plastic 'eoscs for use in flexible-fitting goggles, AMI.KH.A.N MA.MHItll .n.UKH i.wlll. f-(( plaslic-cycshield goggles, or plastic-eycshicld spec tacles shall be not less than 0.050 inches in thickness. 6.3.3.2 Marking. Each lens shall be distinctively marked in a manner by which the manufnetur may be identified. Such marking shall be clear ' and permanent and so placed as not to interfere with the vision of the wearer. In addition, each filter lens shall be marked with the shade number. G.3.3.3 Transmittance 6.3.3.3.1 Filter Lenses. Filler lenses shall meet the radiant-cncrgy-transmission requirements hereinafter specified (see Table 2, page 26), nnd shall be uniform in luminous (visible) transmittance within 20 percent. The dominant line shall be between 490 nnd 600 mu (millimicrons). Filter lenses shall be supplied in pairs. For shades 1.5 to 2, inclusive, both lenses of a pair shall have the same visible transmittance within 10 percent; for shades 2.5 nnd darker, both lenses of a pair shall have the same luminous transmittance within 20 percent. 6.3.3.3.2 Clear Lenses. Clear lenses shall transmit not less than 89 jierccnt of the incident luminous radiation. 6.S.3.4 Lens Strength. All lenses shall be cap able of withstanding the fracture resistance tests specified in 6.3.4.2. 6.3.4 Methods of Test and Examination of lenses 6.3.4.1 Tests for Prismatic and Refractive Power and for Definition. Lenses of all types shall be tested for prismatic nnd refractive power and for definition by any standard methods which are of sufficient accuracy for the purpose and are equiva lent to the following National Bureau of Standards' methods: (See note below.) 6.3.4.1.1 Prismatic Power. The lenses may be tested for prismatic power with an 8-power telescope which has an effective aperture of 0.75 inch and is equipped with cross hairs in the focal plane of the ocular. The telescope is to be focused on an illuminated target at a distance of 35 feet from the telescope objective, comprising a central dot and a concentric circle 1* inch in diameter. TSic telescope is to be so aligned that the image of the central dot falls on the intersection of the cross hairs in the focal plane of the ocular. The lens is to lie held in front of the objective lens of the telescope and, if the intersection point of the cross hairs falls without the image of the. circle, the prismatic power of the goggle lens exceeds prism diopter. No-.*,; I.ctisr* may lie checked fur heat strenylhenin- f, n'"an. of a polariscopc. l.EAl), EYE, AND UESriUATOUY rUOTKCTION 6.3.4.1.2 Refractive Power. The lenses may he tested for refractive power hy any suitable instru ment such os a vertometer, lensometer, or telescope. The lenses may he tested for refractive power with an I'-jmwur telescope which has an effective aperture of 0.73 inch and is focused at a distnnee of 33 feet on an illuminated test chart. As a test chart, the resolving power chart pattern 20 of National Bureau of Standards Miscellaneous Publication Ml66 and National Bureau of Standards Circular C333 may he used. An advantage in adopting this chart is that hy its use it becomes possible to provide all inspect ors wilii identical charts, whereas if charts arc improvised at different places they arc likely to he different. The lens to he tested shall he placed in front of the. IciescojK! objective which is then brought to the sharpest possible focus. The pattern marked 20 should he. clearly resolved with the tnrget placed at a distance of 35 feet from the tc:lesco|ie objective used for-testing lenses. The telescope is calibrated hy successively locating the position of best focus with first a standard lens of plus \\f! diopter in front of (lie objective and then with a standard lens of minus j-j R diopter in front of the objective. These positions are marked hy scratches on the draw lube or hy other suitable index marks. Hie lens is to be held in front of the calibrated telescope and if the position of tin: best focus falls outside the index marks, the refractive power is in excess of Vi n diopter. 6.3.4.1.3 Definition. The lenses may he tested for definition with an 3-power telescope which has an effective aperture of 0.75 inch and is focused at n distance of 35 feet on an illuminated test chart. As a test chart the resolving power chart pattern 20 of National Bureau of Standards Miscellaneous Publication Ml66 and National Bureau of Standards Circular C533 may he used. An advantage in adopting tins chart is that hy its use it becomes possible to provide all inspectors with identical charts, whereas if churls are improvised at different places they arc likely to he different. The lens to he tested shall he placed in front of the telescope objective, which in turn is then brought to the sharpest possible focus. 'Hie pattern marked 20 should he dearly resolved with the target placed at n distance of 35 feet from the telescope objective used for testing lenses, 6.3.4.2Fracture Resistance--Lenses o) All Types 6.3.4.2.1 Lens in Frame. The frame with lens shall he supported on a wooden block of such size and shape ns to fit the frame securely hut not :p> touch tiie lens. A neb-diameter steel hall, '''weighing approximately 1.56 ounces, shall ho. freely 25 dropped from a height of 50 inches onto the horizontal upper surface of the lens. The edge of the lens shall not chip from the shock nor' shall the lens be displaced from the frame. 6.3.4.2.2 Lens on Block. The lens shall he removed from the frame and placed horizontally on the end of a hardwood tube having an upper periphery conforming in shape and size to the lens to he tested and n wall thickness not greater than *}j(i inch. A washer of rubber packing not more than % inch thick and of the same sha|ic and size as the end of the tube shall 1m: placed between the lens and the tube. Tlie rubber washer shall he of the quality required for a grade A gasket in Federal Specification Hlf-G-156. The %-inch steel hall shall Ire freely dropped from n height of 50 inches onto the horizontal outer surface of the lens, 'lire lens shall not fracture from tire impact of the steel hall. 6..1.4.2.3 Breakage Pattern. As a test to determine the type of breakage pattern exhibited hy a lens when subjected to a force sufficient to break it, a lens may he broken hy increasing the height of drop of the %*inch steel hall or hy employing n heavier hall. If made of glass, tire lens shall break predominately with radial cracks with a minor tendency toward concentric cracks. Any tendency to break with lines of cleavage parallel to the surface indicates an unsatisfactory heat treatment; and the lenses represented hy that sample shall he considered ns not conforming to these requirements. 6.3.4.3 Penetration Resistance for Plastic Lenses. The frame and lens shall he supported on a wooden block- of such size' and shape ns to fit the frame securely. A pointed projectile of suitable size, consisting of n new Singer number 135 x 17 size 25 needle, fastened into a holder weighing approximately ] .56 ounces, shall lie freely dropped, point down ward, from a height of 50 inches onto the horizontal outer surface of the lens. The projectile may he guided, hut not restricted, in its fall hy being dropped through n tube extending to within approximately 4 inches of the lens. The lens shall not Ire pierced through from the impact. 6.3.-1.4 //are. Haze of till types of lenses shall ho determined hy test method No. 3021 of Federal Specification L-IM06, Plastics, Organic, General Specifications, Test Methods. B.3.4.5 Flammability. Where plastic materials arc used in lenses, such material shall Ire slow burn ing. Cellulose nitrate, or materials having flam mability characteristics approximating those of cel lulose ni'vatc. shall not h- used. 2(< AMERICAN STANDAltl) SAFETY CODE FOH 6.3.4.6 Ultra violet. Luminous, and Infrared Transmittance, The uliraviole*, luminous (total vis* ihlc), and'infrared transmittance of lenses of all types shall he determined by any standard method recognized ns suitable by tire National Bureau of Standards. The following methods arc suggested: 6.3.4.6.1 Ultraviolet Transmittance. The source of radiant energy for determining the ultra violet spectral transmittance shall be a quartz mercury are or other source emitting an intense and prefer ably discontinuous spectrum. The intense emission lines of the quartz mercury arc at 313 mu, 331 mu, 303 mu, and 405 mu arc conveniently distributed and well adapted foi making these measurements. If other sources arc used, the wavelengths closest to the above values of the mercury arc may be used. 6.3.<L6.2 Luminous Transmittance. The standard source of radiant energy used in the meas urement of the luminous transmittance of filter lenses shall be n Projection Type Lamp No. T-8 (or other high-powered gas-filled tungsten filament incandescent lamp) operated at the color temperature (2854 K) corresponding to CIE1 Source A. The luminous transmittance shall be determined by one of the following means: (1) Photometrically by an observer having normal color vision, ns determined by recognized color vision chart `ests such ns those employing pscudn-isochromatic plates; (2) With a physical photometer consisting of a thermopile (or other radiometer) and a lumi 1 Inlrrn.ilional Commission on Illumination nosity solution having a spectral transmittance curve which coincides closely with the luminous-efficiency curve of the average eye; (3) By measuring the spectral transmit tance and calculating the luminous transmittance through the use of published data on the spectral radiant energy of CIE Soutcc A and the relative luminous efficiency, of the average eye. The standards of luminous transmittance main tained by the Nationn! Bureau of Standards are based on the latter method. 6.3.-L6.3 Infrared Transmittance. The same standard source of radiant energy used in determin ing the transmittance of luminous radiation shall be used also in the measurement of the transmittance of the total infrared radiation. One of the following methods shall be used for determining the total infrared transmittance: (1) lly observing the infrared spectralenergy distribution curves of a gas-filled lamp, with and without the lens placed before -the entrance slit of the spectrometer, and integrating the area under each of the two curves between the spectral limits of 700 mu and 4000 mu. (2) By observing the integrated transmit tance with a physical radiometer (c.g., a thermopile) covered with a deep red filter (e.g., Corning 2404) which has a high and uniform transmittance through the infrared spectrum and transmits less than 0.5 percent of the luminous radiation. The latter method is employed at the National Bureau of Standards in the test of welding glass for government purchase. Table 2 Transniittnnees and Tolerances in Transmittance of Various Shades of Filter Lenses Optical Density Luminous Transmittance Shade Transmil- Number Maximum Standard Minimum Maximum Standard Minimum lance . 313 mu Percent Percent Percent Percent Percent lJi 0.20 1.7 0.36 2.0 0.5 V 2.5 0.75 3.0 1.07 <1.0 1.50 5.0 1.93 6.(1 236 7.0 2.79 n.o 3.21 9.0 3.61 10.0 4.07 11.0 4.50 12.0 4.93 13.0 :-/ 14.0 5.79 0.214 0.300 0.129 0.613 0.057 1306 1.714 2.143 2.571 3.000 3.429 3.057 4.206 4.714 5.143 5.571 0.17 0.26 036 034 0.75 1.07 1.50 1.93 2.36 2.79 .3.21 3.64 4.07 4.50 4.93 536 67 55 43 29 10.0 0.50 3.16 1.10 0.44 0.164 C.061 0.023 0.0005 0.0032 0.0012 0.00044 613 50.1 373 22.8 13.9 5.10 1.93 0.72 0.27 0.100 0.037 0.0139 0.0052 0.0019 0.00072 0.00027 55 43 29 18.0 8.50 3.16 1.18 0.44 0.164 0.061 0.023 0.0005 0.0032 0.0012 0.0CU44 O.OCilfi 25 20 15 12 9.0 5.0 2.5 13 1.3 1.0 0.0 0.6 0.5 03 0.4 0.3 0.2 0.2 03 0.2 03 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.05 0.05 0.05 ( V> Maximum Spectral Transmil lance in the Ultraviolet and Violet 334 mu 365 mu IVre.cnt Percent 0.8 0.7 03 03 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.05 0.05 0.05 0.05 25 20 14 5 03 03 0.2 0.1 0.1 0.1 0.1 0.1 0.05 0.05 0.05 0.05 405 nut Prrrrnt 65 50 33 15 6 1.0 0.5 03 03 03 03 03 0.1 0.1 0.1 0.1 HEAD, EVE, AND UESl'lUATOUY PHOTKCTJON Table 3 Selection of Eye- ami Face-Protective Devices Hazard Involved Relatively large Hying objects Dust and small flying particles Dust and wind Molten luclal Cases, (times, and smoke Liquids Reflected light or glare Injurious radiant energy (moderate * Injurious radiant energy (intense) Part To lie Protected Eyes, Face Eyc.i, Face Eyes Eyes, Face Eves Face Eyes, Face Eyes Eyes Eyes, Face Permissible Protective Devices Type Reference Goggles Spectacles Face shields 6.1.1, 6.1.4, and 6.1.6 6.1.2, 6.1.5 5.3.3 Goggles Spectacles Face shields 6.1.1, 6.1.4, and 6.1.6 6.1.2, 6.1.5 5.3.3 Coggle* Spectacles 6.1.1, 6.1.4 6.1.2, 6.1.5 Goggles Spectacles Face shields 6.1.1, 6.1.4, and 6.1.6 .<.1.2, 6.1.5 5.3.3 Goggles 6.1.3, 6.1.4 Goggles Face shields Goggles Spectacles Goggles Helmets Hand shields Face shields Helmets Hand shields 6.1.3, 6.1.4 5.3.3 6.1.4 6.1.2. 6.1.5 6.1.1 All described in 5.2 Ail described in 5.2.4.2 5.3.3 (must include crown protector and chin protector) Ail with spectacles described in 6.1.2 AH with spectacles described in 6.1.2. Z.U 27 7. Respiratory Protection 7.1 Classification of Hazards. Hazardous at mospheres fall into the following broad groupings: Oxygen deficiency Gaseous contaminants: Immediately dangerous to life Not immediately dangerous to life Particulate contaminants (dusts, fumes, mists, fogs) Combination of gaseous and particulate contam inants Immediately dangerous to life Not immediately dangerous to life 7.1.1 Oxygen Deficiency. The oxygen content of normal air is about 20.9 percent by volume. Atmospheres in confined spaces such ns wells, mines, holds of ships, tanks, n:ul burning buildings may contain a lower percentage of oxygen cause of dilution or displacement of the nir by other gases or vapors, or because of the loss of oxygen by its reaction wor absorption by, other substances. Wlieu tlie oxygen content of the air is about Ifi percent, the flame of a safely lamp will he extin guished. Below this concentration, a person breath ing the air exhibits symptoms ranging from increased volume of breathing and acceleration of pulse rate to unconsciousness and death, depending on the oxygen content of the air and the degree of his physical activity. 7.1,2 Caseous Contaminants. Gaseous con taminants may be classified into two broad groups as follows: toxic and inert. Hie toxic or poisonous gases may produce harmful or objectionable response in man in relatively low concentrations, whereas the inert gases produce undesirable effects primarily by displacement of oxygen. The term "gases" as used here applies equally to gaseous substances (sucli as nitrogen, enrbon monoxide, and carbon dioxide) and tlie vapors of volatile substances (such ns benzene nnd carbon tetrachloride). The toxicity of gases nnd vapors for man varies over a wide range. For instance, a 10-minute exposure to a concentration of 120 parts per million (ppm l of phosgene may be * Oaf. whereas one may safely breathe 1,000 ppm of dichlorodifitioro-melhane (freon) throughout a working day. 7.1.2.1 Gaseous Contaminants Immediately Dangerous to Ufe. Gaseous contaminants immediately dangerous to life arc gases present in concentrations that would endanger the life of a person breathing tliei.i for even a short period of time. For example, 400 to 500 parts of sulfur dioxide per million parts of air (0.0-l to 0.05 percent) by volume is considered to he dangerous for a short exposure. 7.1.2.2 Gaseous Contaminants Not Immediately Dangerous to Life. Gaseous contaminants not immediately dangerous to life are gases present in concentrations that could he breathed for a short period without endangering the life of a person breathing them, but which might produce discomfort and possible injury after a prolonged single exposure or repeated short exposures. For instance, the thresh old limit value for sulfur dioxide has been set at 5 ppm, based primarily on the irritating effect of this gas on the nose, eyes, and throat. 7.1.3 Particulate Contaminants (Dusts, Fumes, Smokes, illists. Fogs). Particulate con taminants may be classified, according to their mode of action, into three broad groups as follows: (1) Toxic particulate contaminants that may pass from the lungs into the blood stream and arc carried to the various parts of the body to exert their injurious effects. These effects may he chemical irritation, systemic poisoning, neoplasms (tumors), or such effects as hay fever, asthma, or simple febrile reac tions. (21 Fibrosis-producing dust, such as asbestos and free silica, or other pneumoconiosis-producing dusts that arc not taken up by the blood stream but remain in the lungs and may cause significant pul monary impairment. (3) Nontoxic and nonfibrosisproducing particles (so-called nuisance dusts and mists) that may dissolve and pass directly into the blood stream or may remain in the lungs producing neither local nor systemic effects. Particulate contaminants may be classified accord ing to their physical properties into three broad groups as follows: (1) solid, such as dusts and fumes; (2) liquid, such as mists and fogs; arid (3) a combination of solid and liquid, such as silicawater sprays and paint sprays. The majority of particulate contaminants arc not immediately dangerous to life; that is, days, weeks, or even years of exposure may transpire before harmful effects arc noted. Notable exceptions arc dusts and mists containing the organic phosphorus insecticides which, if present in high concentrations, AMKISICAN STA.M1AKI) SAFKTV CODK FOIt may incapacitate or even kill a man in a very short time. Other exceptions to this generalization are certain radioactive particulates and the toxic war smokes such as diphcnylchloroarsinc (DA) and diphcnylamincchloroarsitic (DM). 7.1.4- Combination of Gaseous and Parti culate Contaminants. In addition to atmospheres containing gaseous nr particulate contaminants, there arc those in which both types occur simultaneously. The contaminants may be entirely different substances, such ns carbon monoxide and oxides of nitrogen produced by blasting and the dust from the blasted material, or they may be the same substance in the liquid and in the vapor form, such as s'Milly volatile liquids that arc atomized. The simultaneous occurence of both gaseous and particulate contaminants in an atmosphere complicates the procedure for providing adequate respiratory protection against them. 7.2 Classification of Respiratory Protective Devices. Respiratory protective devices fall into the following broad groupings on the basis of their mode of functioning: Atmosphere-supplying respirators Self-contained type Hose type Air-purifying respirators Gas masks or chemical cartridge respirators Sclf-rcscue-type respirators Dispersoid (dust, fume, mist) respirators Combination gas and dispersoid respirators A more detailed classification, brief description, and the limitations of the various types of respir ators follow: 7.2.1 Atmosphere-Supplying Respirators. Atmosphere-supplying respirators provide a respir able atmosphere to the wearer independent of his immediate atmospheric environment. They may be divided into two main subgroups: self-contained breathing apparatus and hose-type respirators. 7.2.1.1 Self-Contained Breathing Apparatus. A self-contained breathing apparatus is a respirator by means of which the user may obtain respirable air or oxygen from a supply of air, oxygen, or oxygengenerating material which is nn integral part of the respirator as worn. Self-contained breathing apparatus mov be divided into two main subgroups: rccireulating-type and demand-type. 7.2.1.1.1Recirculating-Type Self-Contained Breathing Apparatus. Rccirculating-typc self-con tained breathing apparatus may furnish respirable oxygen io the wearer fi m cither (1) a cylinder of iii- m*. iu:. \M> ir..'>i,ntATiiiiY riM)TK:Tiu\ compressed oxygen or (21 o canister containing an oxygen-generating material. (1) Compressed Oxygen Type. The mode of functioning of the compressed-oxygen type is ns follows: High-pressure oxygen from the cylinder passe; through a pressurc-rcducing-nnd-rcgulating valve and an admission valve into a breathing bag from which the wearer inhaW through a corrugated breathing tube connected to a mouthpiece or facepiece through a one-way check valve. The wearer's exhaled breath passes through another check valve and corrugated breathing tube to a container of chemical which removes the exhaled carbon dioxide. It then passes through a cooler and enters the breathing bag. In normal use, oxygen enters the breathing bag from the supply cylinder only when the volume of gas iu the bag has dccrc. sed sufficiently to allow a pressure plate to aet upon the admission valve which then admits oxygen until the wearer exhales. In the event that the prcssurc-rcducing-andregulating valve or the admission valve docs not function properly, oxygen may be admitted directly from the oxygen cylinder to the bag through a manually operated by-pass valve. Suitable pressurerelease ami saliva traps are provided. (2) Self-Generating Type. The mode of functioning of the self-generating type is as follows: ; Water vajwr in the wearer's exhaled breath reacts with the granular chemical fill of the canister to libernto oxygen which then enters the breathing bag from which the wearer inhales through a corrugated breathing tube connected to a facepiece. Check valves maintain a unidirectional flow of gases in the closed system. The rate of evolution of oxygen is governed by the volume rate of breathing of the Wearer. Exhaled carbon dioxide is removed by the canister. A suitable manually operated pressure-relief valve is provided. 7.2.1.1.2 Demand-Type Self-Contained breathing Apparatus. Demand-type self-contained apparatus is designed to supply air or oxygen to the wearer. These gases are not to lie used interchange ably; that is, oxygen should never be used in an apparatus designed for compressed air, and vice versa. The mode of functioning of the demand-type selfcontained breathing apparatus is as follows: Oxygen or air is admitted to the facepiece from a cylinder of the compressed gas through a two-stage pressurereducing mechanism only when the wearer inhales, and in quantities governed by his breathing. The fearer's exhaled breath escapes to the surrounding atmosphere. '!) 7.2.1.1.3 Limitations of Self-Contained Breathing Apparatus. The self-contained breathing apparatus has no limitation as to (lie concentration of gas or particulate matter or as to a deficiency of oxygen in the atmosphere in which it is worn. How ever, many gases arc very irritating to the skin and to mucous membranes when present in high concen trations; and hydrocyanic acid gas can be absorbed in dangerous amounts through the unbroken skin. The wearer has complete freedom of movement, and may leave the work area through any available exit. The length of time that he may remain in the irrespirable atmosphere is dependent upon the amount of oxygen or air made available to him by the apparatus and upon bis activity. Self-contained breathing ap paratuses are rated according to whether they will protect for two hours, one hour, three quarters of an hour, or one-half hour while doing heavy work. If this tyjie of respirator is to be used safely and with confidence, rather extensive training is required not only in its care and use but also in an understanding of its limitations. 7.2.1.2 llose-Typc Atmosphere-Supplying Res pirators. Hose-type atmosphere-supplying respirators make air available to the wearer through a hose connected to a supply of respirable air. They may be divided into four main subgroups: (1) hose mask with blower, (2) hose mask without blower, (3) air line respirator, and (4) abrasive-blasting respirator. 7.2.1.2.1 Hose Mask with Blower. The hose mask with blower (Type A supplied-air respirator) consists of a full facepiece to which respirable air is forced through a large-uiamctcr flexible hose by a band or motor-operated blower, and through which the wearer can inhale whether or not the blower is operated. Cheek valves allow air flow only toward the facepiece. The hose is attached to the wearer's body by means of a rugged safety harness which has provision for the attachment of a safety line; with this harness and line the wearer may be drawn to safety in an emergency. Usually, the hose mask with blower is designed so that two faccpiccc-harncss-and-hosc assemblies may be attached to a single, double-outlet blower. 7.2.1.2.2 Limitations of Hose Mask With Blower. The hose mask with blower (Type A suppliedair respirator) has no limitations as to concentration of gas or particulate matter or a deficiency of oxygen in the atmosphere in which it is worn. However, many gases arc very irritating to the skin and mucous membranes when present in high concentrations; and hydrocyanic acid gas can be absorbed in dangerous amounts through the unbroken skin. The wearer is ;o limited by the length of the nir-supply hose to travel within 150 feet o! the blower which must be in respirable air. He must return to fresh air by retrac ing his route in the contaminated atmosphere, other wise the air-supply hose would become entangled. It provides respiratory protection for an unlimited p. riod. 7.2.1.2.3 Hose Mask Without Blower. The hose mask without blower (Type B supplied-air res pirator) consists of a full facepiece to which a supply of respirable air may be drawn through a large-diameter flexible hose by the wearer's breath ing effort. Cheek valves allow air flow only toward the facepiece. The hose is. attached to the wearer's body by a suitable harness. The air-inlet end of the hose is provided with a fine-mesh screen to prevent entrance of coarse particulate matter and with a means of anchoring the inlet in respirable air. 7.2.1.2.4 Limitations of Hose Mask Without Blower. The hose mask without blower (Type B supplied-air respirator) is limited to use in any atmosphere from which the wearer can escape un harmed without the aid of the respirator. The wearer is limited by the length of the air-supply hose to travel within 75 feet of an assured source of respirable air in which the air-inlet end of the hose must be placed. It provides respiratory protection for an unlimited period. 7.2.1.2.5 Air-Line Respirator. Air-line res pirators (Type C supplied-air respirators) consist of a half-mask facepiece, full facepiece, or a loose-fitting helmet or hood to which respirable air is supplied through a small-diameter hose. They may be divided into two classes: (1) continuous-flow class and (2) demand class. 7.2.1.2.5.1 Continuous-Flow Class AirLine Respirator. Contimm-is-flow class air-line res pirators (Type C and CE supplied-air respirators) supply a continuous flow of respirable air to the facepiece, helmet, or hood through a small-diameter hose. The wearer's exhaled air and the excess air entering the facepiece, helmet, or hood covering escapes to the surrounding atmosphere. Provision is made for attaching the air-supply hose to the wearer and for detaching the air-supply'hose rapidly in an emergency. The respirator is designed to allow at least 4 cubic feet of air per minute to enter the facepiece nnd at least 6 cubic feet of air per minute to enter the helmet or hood. 7.2.1.2.5.2 Abrasive-Blasting Respirator. The principle of operation of the abrasive-blasting respirator (Type CE supplied-air respirator) is the AMKUICAN STANDM(l> SAFETY CODE FOK same as that of the continuous-flow class air-line respirator. However, it is constructed so that it will protect the head and the neck of the wearer and the eyepiece of the respirator from the rebounding abrasive. The respirator is designed to allow at least 4 cubic feet of air per minute to enter the facepiece nnd at least 6 cubic feet of air per minute to enter the helmet or hood. Only a full facepiece or hood nnd helmet is used with this respirator. 7.2.1.2.5.3 Demand-Class Air-Line Res pirator. Demand-class air-line respirators (Type C supplied-air respirators) supply respirable air to the facepiece only when the wearer inhales, and at a rate governed by his volume rate of breathing. A source of respirable air, either an air compressor or a container of compressed air, is attached by a smalldiameter hose to a demand valve which is actuated by a slight negative pressure created when the wearer inhales. Upon actuation, it allows air to flow to the facepiece through a flexible corrugated breathing tube. Upon exhalation, the demand valve closes and permits no air to flow to the respirator. The exhaled breath escapes to the surrounding atmosphere through an exhalation valve or valves. The demand valve is attached to the wearer so as to allow the air-supply line to be dragged behind the wearer without exerting a pul! on the facepiece. Provision is made for detach ing the air-supply hose rapidly in an emergency. Helmets or hoods arc not used with this respirator. 7.2.1.2.6 Limitations of Air-Line Respira tors. The air-line respirator (Type C supplied-air respirator) and the abrasive-blasting respirator (Type CE supplied-air respirator) are limited to use in concentrations of gases or vapors that are not im mediately harmful or from which the wearer can escape unharmed without the aid of the respirator. They arc not to be worn in an oxygen-deficient atmosphere. The wearer's travel is limited by the length of the air-supply hose, and he must retrace his route in the contaminated atmosphere to return to fresh air while wearing the respirator. These respirators shall be used within the limits set by the manufacturer for nir-supply hose length nnd range of air pressure applied to the inlet of the air-supply hose. They provide respiratory protection for an unlimited period. 7.2.2 Air-Purifying Respirator*. Air-purifying respirators remove gaseous or particulate contamin ants, or both, from otherwise respirable air that is inhaled by the wearer. They may be divided into three classes: (1) chemical-filter type, (2) mccnan-, leal-filler type, and (3) combination chemical- nnd \v mechanical-filler type. iik.mi. i:vk, ami iu;si*m.mntY I'itommoN 7.2.2.1 Chcmical'Fil/nr Respirators. Chemicalfiller respirators such as gas masks, chemical-cartridge respirators (non-cnicrgency gas respirators), and selfrescue-type respirators remove toxic gases and vapors from inspired air by sorption, chemical reaction, or oxi lation by the granular fill ol the canister or cartridge. The exhaled breath escapes to the surround ing atmosphere. 7.2.2.1.1 Cas Masks. Gas masks consist of a canister, containing the appropriate grnnular fill, a full facepiece, and a body harness to hold the canister securely in place on the body of the wearer. The inspired air is drawn through the canister and enters the facepiece in such a manner as to inhibit the accumulation of moisture on the eyepieces. A check valve prevents exhaled breath from entering the canister and allows it to be forced out through nn exhalation valve in the facepiece to the surround ing atmosphere. The facepiece is held securely to the wearer's face by an clastic head harness. Universal gas masks have an indicator or timer which shows when the canister should be changed for protection ngainst carbon monoxide. Gas masks arc designed to provide respiratory protection against a single specific gas such as chlorine, a single class of gases or vapors such as /.j.i 3L organic vapors, or a combination of two or more classes of gases or vapors such as acid gases and organic vapors or all gases and vapors. The canisters of many types of gas masks arc manufactured in two sizes, namely, regular or "industrial size," and the large or "supersize" canisters. Everlhing else being equal, the large canister provides a longer service time than the regular size between changes of canisters, but the limitations of both in regard to maximum concentration of gas against which they will protect arc the same. In most eases, a ennister designed for a single gas or a single class of gases and vapors will afTord respiratory protection for a considerably longer period than will a canister of the same size designed for protection against a multiplicity of gases and vapors. Gas-mask canisters manufactured in the United States of America are marked in bold letters with the name of the atmospheric contaminants for which the canister is intended or with the words "UNI VERSAL GAS-MASK CANISTER" in capitals, as well as being given a distinctive color in accordance with the American Standard Safety Code for Iden tification of Gas-Mask Canisters, K13.1-1950. These colors serve as an aid to rapid identification of canisters. The table from 6.1 of the above code is reproduced here for ready reference (see Table 4). Table 4 Color Code for Gas-Mask Canisters Canister, Type Letter Atmospheric Contaminants To lie Protected Against Color Assigned1 A A A 15 c: I) AK, etc AH AI5C N Acid gases 1 lydrocyanic acid gas Chlorine gas Organic, vapors Ammonia gas Carhon monoxide Dust, fumes, mists, fogs, and smokes in combination with any of the above gases or vapors Ariil gases mid organic vapors Acid gases, organic vapors, and ammonia gas AH of the above atmospheric C'v.iamin.ants White2 White with Vi-inch green stripe around the canister near the liotton White with Vi-inch yellow stripe around the'eanister near the bottom Ulack2 C.recn Riuc Vi-ineli contrasting black or white stripe around the canister near the lop Yellow Ilrown Ucd. Filters tire included in this canister, but stripes to indicate them arc unnecessary. Note 1: Cray Khali not lie assigned as the odor (or any gas-mask canister. Note 2: Canisters for n single pas nr vapor oilier than ommonin or rarl.m monoxide -hall have a Vi-inch colored stripe around the canister near I lie h"llo:u. ;i2 7.2.2.1.2 Limitations of Gas Masks. The gas mask is limited to use in atmospheres containing at least 16 percent of oxygen and not more than 2 percent of most toxic gases (3 percent of ammonia). Many gases arc very irritating to the skin and to the mucous membranes when present in these maximum concentrations; and hydrocyanic acid gas can he absorbed in dnngcous amounts through the unbroken skin, its effects depending mainly upon the concentration of the gas and the duration of the exposure. The wearer has complete freedom of movement. A gas mask provides respiratory protec tion for a period that depends on the type of canister, the concentration of the gas, and the activity of the wearer. A gas mask with canister for protection against carbon monoxide should have an indicator to show when the. canister is to be replaced. No practicable met bod is available to warn the wearer of leakage of relatively odorless gases through the canister. It is important that the proper gas-mask canister lie used for the intended purpose. For instance, an ammonia gas-mask canister will not afford respiratory protection against acid gases, organic vapors, or carbon monoxide. 7.2.2.1.3 Chemical-Cartridge Respirators. Clicmical-cartridgc respirators (non-cmcrgcncy gas respirators) consist of a lialf-niask facepiece to which is attached one or two cartridges. Like canisters, the cartridges arc filled with granular materials that remove gases or vapors from the air drawn through them. Clicck valves prevent exhaled breath from entering the cartridges and allow it to be forced out through on exhalation valve in the facepiece to the surrounding atmosphere. The facepiece is held secure ly to the wearer's face by clastic headbands. The cartridges arc usually designed to provide respiratory protection against, single gases or vapors or against single classes of gases and vapors. They are easily removed and replaced. 7.2.2.1.4 Limitations of Chemical-Cartridge Respirators. The chemical-cartridge respirator (nonemergency gas respirator) is limited to use in atmospheres that arc not immediately dangerous to life; hence, it shall not be worn in an atmosphere deficient in oxygen. The wearer has complete freedom of movement. A chemical-cartridge respirator provides respiratory protection for a period that depends on the type of cartridge used, the concentration -if the gas or vapor, and the wearer's activity. Its use is limited to low concentrations of certain gases and vapors such a' a maximum of 0.1 percent (1,000 ppm) of organic vapors. It should not be used for AMKIUCAN STANll.MUl SAFETY CODE FOU protection against (1) harmful gases or vapors that cannot be detected by the sense of smell; (2) gases or vapors that are highly toxic in low concentration, such as phosgene and arsine; or (3) concentrations of gases and vapors that are highly irritating to the eyes. It is important that the proper chemical cartridge lie used for the intended purpose; for instance, an organic vapor cartridge will not afford respiratory protection against ammonia. Knitted cotton covers for the face-contacting surface of the facepiece should not he used since they are not gaslight. 7.2.2.1.5 Sclf-Rcscuc-Typc Respirators. The sclf-rcscuc-type respirator is designed to provide the greatest possible respiratory protection consistent with flic practicability of carrying the device at all times so that it is always available for use durin'g escape in the event of a catastrophe. It consists essentially of a small filter element, a mouthpiece, a nose clip, and a means of carrying the device conveniently on the body or storing it near the work location. Most filter elements are similar to chemical cartridges made for protection against specific gases or vapors, but particulate filters arc also available. One sclf-rcscuc-type respirator offers protection against carbon monoxide present in the atmosphere following an explosion or fire in a mine. The filter cartridge for this type shall he protected from moisture to keep the chemical fill active. 7.2.2.1.6 Limitations of Self-Rescue-Type Respirators. Sclf-rescuc-typc respirators should never he used as a working tool, but only as a means dur ing escape from a contaminated area to enhance the possibility of reaching a safe atmosphere or a more positive type of respiratory protective equipment. The magnitude of protection afforded usually falls be tween that provided by gas masks and by chemicalcartridge respirators. For example, the sclf-rcscuctype respirator for protection against carbon monox ide will provide at least 30 minutes service in an atmosphere containing 1 percent by volume of carbon monoxide. 7.2.2.2 Mcchanical'FiUcr Respirators. Meehanicni-filtcr respirators such as dust, fume, or mist respirators remove particulate matter from the inspired air by capture on the filter, which is usually a fibrous pad. These respirators consist of a full or half-mask facepiece to which are attached one or two filters through which the inspired air is drawn. Cheek valves, present in most mechanicalfilter respirators, prevent exhaled breath from passing through die filters and allow it to be forced out through an exhalation vu in the facepiece to the II KAO. KVE, AXI) HKSP1KATOHY PKOTECTION surrounding ulmosphcrc. Tlie facepiece is held sc* curdy to the wearer's face by clastic headbands. Knitted cotton covers arc sometimes used to. cover the face-contacting surface of the facepiece to absorb perspiration and to prevent irritation of the sldn when the respirator is worn in hot places or in air containing certain irritating dusts such as lime. Mcclianical-fdtci respirators arc designed to provide respiratory protection against a single specific dust, fume, or mist, a single class such as toxic dusts, or a combination of several classes of particulate matter such as dusts, fumes, and mists. The filters may be of the single-use or re-usable type. Single-use filters cannot be cleaned and re-used, but should be discarded after they have served their purpose, lie-usable filters, cleaned mechanically ac cording to the manufacturer's instructions, may be re-used. They should never be washed or treated with solvents. 7.2.2.3 Limitations of Mechanical-Filter Res pirators. There is a practical limit for the concentra tions in which a tncchnnicnl-fiUcr respirator should be used. This is determined by the time required to plug the fdler. For example, if the concentration is so high that the filter must he changed several times an hour in order that the wearer can inhale without undue resistance, a more suitable type of respiratory protective device should he selected. Mechanical-filter respirators should not he used in sand- or shotblasting operations in which one might he exposed to heavy concentrations of particulate matter and to rapidly rebounding particles of the abrasive. For such conditions, the abrasive-blasting respirator shall he used. Mechanical-filter respirators do not protect against gases and vapors or against an atmosphere deficient in oxygen. The wearer lias complete freedom of movement. The useful life of the filters is limited by tlie build-up of resistance to inhalation as the con taminant is removed by the filter. Tlie higher the concentration of contaminant in the air drawn into the filter and the greater the wearer's activity, the more rapidly the resistance to inhalation increases. Tilts applies particularly to dusts and fumes. Hence, the use of dust and fume respirators in high con centrations of these contaminants requires frequent replacement of disposable filters or frequent cleaning of re-usable fillers. 7.2.2.4 Combination Chemical-and-MrtchanicalFillcr Respirators. Combination chcmicnl-nnd-inechanicnl-fiher respirators remove toxic gases and vapors and particulate matter from inspired air. Some gas-mask canisters contain special fillers which /.-*.! 33 provide respiratory protection against particulate matter, in addition to the respiratory protection against gases and vapors furnished by their granular fill. Some chemical-cartridge respirators contain filters for the same purpose. Others have filters attached so that the filters may he changed one or more times before the cartridges ore changed. The type of protection afforded by tlie filters in gas-mask canisters and clicmical-cartridgc-rcspirator cartridges is stated on their labels. 7.2.2.5 Limitations of Combination Chemicaland-Mcchanical-FUtcr Respirators. The limitations of combination chcmical-and-mcchanical-fillcr respira tors generally arc the same as for each type of respirator given in the preceding sections. However, tlie limitation of dust filters in regard to protection against gases and vapors given in 7.2.2.3 obviously is modified by the type of protection afforded by the chemical-filter respirator (gas-mask or chemicalcartridge respirator) against gases and vapors. 7.3 Requirements for Respirators. Respirators of all types should lie capable of providing an adequate degree of respiratory protection against given atmospheric contaminants when the proper type has been chosen and when it is maintained and used correctly. Specific requirements for most of the types of respirators used in industry in the United States of America have been set up by the Federal Durcau of Mines. These requirements arc published as Bureau of Mines Schedules, a list of which fol lows:2 Bureau of Mines, Procedure for Establishing a List of Permissible Self-Contained Mine Rescue Breathing Apparatus; Fees, Character of Tests, and Conditions Under Which Mine Rescue Breathing Apparatus Will Be Tested: Schedule 13, March 5, 1919, 13 pp; Schedule 13A (revision of Schedule 13), January 21, 1930, 12 pp; Schedule 13B (re vision of Schedule 13A), August 12, 1935, 12 pp; Schedule 13C (revision of Schedule 13B), July 9, 1946, 11 pp; Schedule 13D (revision of Schedule 13C), September 22, 1956, 12 pp. (Code of Federal Regulations reference: 30 CFR Part 11.) Bureau of Mines, Procedure for Establishing a List of Permissible Gas Masks; Fees, Character of Tests, and Conditions Under Which Gas Masks Will Be Tested: Schedule 14, May 22, 1919, 13 pp; Supplement to Schedule 14, January 6, 1920, 4 pp; 2 Copies of the most recent Bureau of Mines Schedules and List of Respiratory Protective Device* Approved by the Bureau of Mines may he obtained from tlie PitMiration* DistninitKin S-rtirn, Bureau ol Minr*. -tflOO Forties Street, l'itt*hurcli 1.1. Pennsylvania. .;i- AMKKICA.N STAMI.M1I) SAKKTY COIII- I'Olt Schedule 14A (revision of Schedule 14), August 25, 1923, 15 pp; Schedule 1413 (revision of Schedule 14A), August 7,1930,13 pp; Schedule 14C (revision of Schedule 1411), August 20,1934,17 pp; Schedule 141) (revision of Schedule 14C), May 9,1935,17 pp; Schedule 14E (revision of Schedule 14D), December 24,1941,19 pp; Schedule 14F (revision of Schedule 14E), April 23, 1955. (Code of Federal Regulations reference: 30 CFR Part lb.) llurcau of Mines, Procedure for Testing Hose Masks for Permissibility: Schedule 19, April 23, 1927, 8 pp; Supplement to Schedule 19, August 20, 1934, 3 pp. Procedure for Testing Supplicd-Air Respirators for Permissibility: Schedule 19A (re vision of Schedule 19 and supplement, enlarged to include special hose masks without blowers, nir*linc respirators, and abrasive-blasting helmets, hoods, or masks), August 9, 1937, 21 pp; Schedule 19A ns amended in the Federal Register on March 13, 1948. to include Type C, demand-class supplicd-air res pirators; Schedule 19B (revision of Schedule 19A), April 19, 1955. (Code of Federal Regulations refer ence: 30 CFR Part 12.' Bureau of Mines. Procedure for Testing Filter-Type Dust, Fume, mu! Mist Respirators for Permissibility: Schedule 21. August 20. 1934, 14 pp; Schedule 21A (revision of Schedule 211, April 19, 1955. (Code of Federal Regulations reference: 30 CFR Part 14.) Bureau of Mines, Procedure for Testing Nonemergency Gas Respirators (Chemical Cartridge Res pirators) for Permissibility: Schedule 23, November 13. 1944. 10 pp; Schedule 23A (revision of Schedule 23), April 23. 1955. (Code, of Federal Regulations reference: 30 CFR Part 14A.) Each respirator that lias been approved by the Bureau of Mines has met (lie requirements of the pertinent schedule that was in effect at the time of the approval. In general, each revision of n Bureau of Mines schedule makes these requirements more severe. A Bureau of Mines approval on a respirator remains in effect even though the schedule under which it was approved lias been revised one or more limes since then. Hence, if the user wishes to check on the minimum performance that he may expect from tiic respirator, lie should consult the schedule or revision thereof, which is shown in the list of schedules as being in effect when the approval was granted. The Bureau of Mines performance requirements for n respirator are based on its field of uso nnd upon three fundiimentnl requirements for n satisfac tory device: (11 It must provide adequate protection for a satisfactory period; (2) It must he reasonably comfortable and convenient to wear; and (3) It must be constructed of durable materials. If no Bureau of Mines schedule applies to a respirator being considered for use, it should lie examined to sec that it fulfills these three requirements. Further judgment might be based on its compliance with the performance requirements of the most closely related respirator approved by the Bureau of Mines. 7.4 Selection of Rcspirulors 7.4.1 General Considerations. In choosing a respirator to he used for respiratory protection in any given situation, the following factors should he considered: (1) the nature of the hazard; (2) the severity of the hazard; (3) the type of con taminant; (4) the concentration of the contaminant; (5) the period for which respiratory protection must be afTordcd; (G) the location of the contaminated area with respect to a source of respirable air; (7) the expected activity of the wearer; and (8) the operating characteristics and limitations of the avail able respirators. Table 5 lists the hazards and the respirators that arc designed specifically to nfTord respiratory protec tion against them. By reference to this table, nnd by considering the foregoing factors, the user r.-.n determine the type of respirator that should be used. Tlte self-contained breathing apparatus and the hose mask with blower would give respiratory protec tion against any of the hazards listed, but these devices arc not included in the list of respirators that could lie used in the less hazardous situations liccnuse their use would amount to "over-engineering_. Even though most of the factors in 7.4.1 arc interrelated, a brief discussion of each follows: 7.4.1.1 Nature of the Hazard. The user should determine whether or not the atmosphere is deficient in oxygen, and whether the contaminant is gaseous or particulate, or a combination of the two. 7.4.1.2 Severity of the Hazard. The user should determine whether or not tho atmosphere is im mediately dangerous to'life. This is discussed under Classification of Hazards in 7.1. 7.4.1.3 Type of Contaminant 7.4.1.3.1 Gaseous Contaminant. Where tho contaminant is gaseous, the user should determine whether it is an acid gas, an organic vapor, ammonia, carbon monoxide, or a mixturo of two or more of these gaseous contaminants. This information is essential to the choice of the proper gas mask or chcmical-curt! idge respira because the different JltAl', EYE, AND ItESPIKATOHY I'KOTECTiON Table 5 Selection of Kespirntory Protective Device Hazard Respirator Oxygen deficiency Self-contained '-reathing apparatus Hose mask with blower Caseous contaminant immediately da""* -otis to life Self-contained breathing apparatus Hose mask with blower Gas mask Not immediately dangerous to lifo Air-line respirator Hose mask without blower Chcmical-rnrtridge respirator Particulate contac.ir.ant Dust, mist, or fume respirator Air-line respirator "Abrasive-blasting respirator Comliin.ilinn gaseous and particulatcd contaminant' Self-contained breathing apparatus Immediately dangerous to life Hose mask wilh blower Gas mask with special filter Not immediately dangerous to life Air-line respirator Hose mask without blower Chcmical-rartridgc respirator with special filter Z.M o') types of gases require different absorbents or com binations of absorbents to remove them from the inspired air. 7.4.1.3.2 Particulate Contaminant. Where the contaminant is particulate, the user should know its physical form; that is, whether it is a dust, fume, or mist. Furthermore, he should know whether it is a toxic type (containing, for instance, arsenic, anti mony, cadmium, or lead), a pneumoconiosis-produc ing type (containing, for instance, asbestos or free silica), or a type having a low order of toxicity and being nonfibrosis producing (containing, for in stance, (lour or wood). This information is essential to the choice of the proper dispersoid respirator, as a respirator designed to protect against one type of particulate matter docs not necessarily afford adequate protection or service life against the other types. 7.1,1.4 Concentration of Contaminant 7.4.1.4.1 Gaseous Contaminant. Where the contaminant is gaseous, the maximum expected con centration of the gas should he known. Where this is above 3 percent by volume of ammonia gas, or 2 percent by volume of other gases, a gas mask is not adequate nrnl should not be used. If it is above 0.1 percent by volume (1,000 ppm) of organic: '.*apors, an organic-vapor chcmical-carlridgc respirator is not ndequale and should not be used. 7.4.1.1.2 Particulate Contaminant. Where ilic contaminant is particulate, the proper type of dispersoid respirator may give an adequate degree of protection, yet its service life may he too short to be practicable or economical. That is, the filter may plug too readily with a rapid increase in the inhalation resistance, thus necessitating frequent changing or cleaning of the filler material. Where practicable, an air-line respirator should be used in high concentrations of particulntc matter. 7.4.1.5 Period of Required Respiratory Protec lion. The period of respiratory protection required has considerable bearing on the decision about which type of respirator to use in any given situation. The self-contained breathing apparatus, the gas mask, and the chemical-cartridge respirator provide respira tory protection for a limited period, whereas the hose mark with blower, the air-line respirator, nnd the abrasive-blasting respirator do so for on unlimited period; thus, for protracted periods of use, the latter types olTcr some advantages. 7.4.1.6 Location of Contaminated Area with Respect to Source of Respirable Air. This is a factor that is frequently overlooked when choosing a respira tor. In using a hose mask, air-line respirator, or abrasive-blasting respirator, the distance that the wearer can go into a contaminated atmosphere is limited by the length of the hose connected to the source of respirable air. Furthermore, the presence of the hose requires that he enter and leave the area hy the same route. When wearing a self-contained breath ing apparatus or a gas nsk, a person may leave the :jo AMKIUCAN STA.M)Al(l) SAKIH V COOK KOIt contaminated area by another exit, hut he should make certain that the device will afford protection for a period adequate for him to reach fresh airf taking into account possible delays. For instance, in mine-rescue work, the maximum distance from fresh air that a crew wearing 2-hour self-contained In -milling apparatus should cover is 1,000 feet (2,000 feet round trip) under ideal conditions. This distance is decreased to not more than 50 feet frem fresh air if the crew has to crawl in a low passage. 7.4.1.7 Activity of the Wearer. In many in stances, the respirator that would be first choice from the standpoint of respiratory protection or period of protection cannot be used because it would limit the activity of the wearer. For instance, a hose mask would not be practicable for use where the wearer has to weave in and out of a scries of obstructions such as pipes because of the difficulty of pulling the heavy hose after him and his inability to escape quickly to fresh air in event of danger. An air-line respirator would likewise be rather impracticable for use where the wearer must be moving about constantly in the contaminated area, or going from one room to another, because of the inconvenience and tripping hazard of the air-supply hose. The activity of the wearer has a marked clTcct on the life to be expected from a self-contained breath ing apparatus, gas mask, chemical-cartridge respira tor, or dispersoid respirator. The volume of air breathed by a man walking at a rate of 4 miles per hour is more than three times that breathed when he is standing still, lienee, the supply of oxygen in a self-contained breathing apparatus is used up faster, the absorbent capacity of a gas-mask canister or a chemical cartridge is exhuusted faster, and the filter of a dispersoid respirator would be plugged faster while the wearer is exercising than when he is at rest. 7.4.1.0 Operating Characteristics and Limita tions of the Available Respirators. The operating characteristics and limitations of respirators have been discussed in 7.2. 7.5 Use ant! Maintenance of Respirators 7.5.1 General Considerations. Respirators arc used to supplement other methods of control of air borne contaminants rather than to substitute for them. Every effort should be made to prevent the dissemination of contaminants into the breathing zones of the workers. In some instances, it if r>eccssary to use respirators only until these control measures hnve been taken; in others, such measures are im practicable, and the continued use of respirators is necessary. 7.5.2 Precautions To lie Taken in the Use of Respirators 7.5.2.1 Precautions To Be Taken in the Use of a Self-Contained Breathing Apparatus (1) The wearer of a self-contained breathing apparatus should be physically sound and fit and should be thoroughly trained in the construction, testing, use, care, and limitations of the apparatus before he attempts to wear such apparatus in a hazardous situation. (2) Make certain that the self-contained breathing apparatus is in good operating condition. (3) Make certain that the apparatus is capable of supplying air or oxygen for the period that the wearer must remain in the contaminated area. (4) Adjust the apparatus to the wearer and test for tightness according to the manufacturer's instructions. (5) If the wearer is to enter a confined space containing an atmosphere that is extremely hazardous, connect a strong life line to his body. This will serve (a) as a means of guiding him to the exit; (h) as a means of transmitting prearranged signals between him and the men at the fresh-air base; and (c) as a means of aiding in rescue operations in ease of an accident or emergency. This life line should be held by two attendants, at least one of whom is wearing a similar apparatus. (6) Enter the contaminated area cautiously, and, if the contaminant is detected by odor, taste, or eye, nose, or throat irritation, return to fresh air immediately and ascertain the cause. (7) Bear in mind the time limitations of the apparatus and allow an adequate margin of time for the return to fresh air. (0) The mouthpiece and nose clip, or the facepiece, should not be removed until the wearer is certain that he is in respirable air. 7.5.2.2 Precautions To Be Taken in the Use of a Gas Mask (1) Make certain that the gas mask is in good operating condition. (2) Adjust the canister harness on the body so that, when the facepiece is put on, there is some slack in the breathing tul>c when the wearer's head is in the normal position. (3) Adjust the facepiece to make a gaslight fit on the wearer's face. There arc two means of testing a facepiece for a gaslight fit: (a) Close off the exhalation valve and exhale gently into the facepiece. If a slight positive pressure can be built up in the facepiece without any ind ition of outward leakage of JIHAD, KYK. AM) UKSI'IIIATOIIY I'HOTECTION nir between the facepiece and the face, it is adjusted properly, (b) Close of! the breathing tube, inhale so that the facepiece starts to collapse, and hold the breath for about ten seconds. If the facepiece stays in its partially collapsed condition and no inward lc.ikngc of nir is detected, it is adjusted properly. (4) Test the complete gas mask for .gaslightness by closing off the air-intake at the bottom of the canister, cither with the palm of the hand or with the bottom canister seal, and inhaling as in (3)(b) above. This test checks the gnstightness of the canister or timer gaskets and of the connection between the breathing tube and the canister or tinier. (5) Make certain that the contaminated at mosphere is not deficient in oxygen. (6) Enter the .contaminated area cautiously. If the odor of the contaminant is noted, return to fresh air immediately and ascertain the cause of the leakage. (7) Make certain that the canister has enough residual life to give respiratory protection for the period that the wearer expects to be in the con taminated area. It is good practice to attach a fresh canister to the mask before entering an extremely hazardous atmosphere, especially one containing a gas that has poor warning properties, such as methyl bromide. (8) The facepiece should not he removed or fresh canisters attached until the wearer is certain that he is in respirable air. (9) After leaving the contaminated area, re place the bottom seal on the canister to prevent deterioration of the canister contents. This is par ticularly important in the case of universal gas-mask canisters. (10) Where the contaminant is a single gas or vapor, or a mixture of two or more gases or vapors of the same type, longer service time will he obtained if a canister is used that is designed especially for protection against the contaminant than would be obtained if a universal gas-mask canister were used. Firemen generally use the universal gas mask canister because they arc never certain what gases they might encounter. 7.5.2.S Precautions To Be Taken in the Use of a Hose Mask With Blower (1) Make certain that the hose mask is in good operating condition. (2) Set the blower in an assured source of respirable air. /..i 37 (3) Connect the proper length of hose (not over 150 feet) to the blower and to the facepiece, making sure that all gaskets arc in place and that the connections are tight. Where more than one hose line is to be used, each should originate at the blower. (4) Before entering a confined space such as a tank or sewer containing an atmosphere that is extremely hazardous, connect a strong life line to the D-ring of the body harness. This life line should be held by two attendants so that the wearer can be removed from the contaminated atmosphere in case of accident or emergency. (5) Operate the blower for a minute or two at a rapid rate to blow any dust out of the hose and to make sure that air is l>eing delivered to the facepiece. (6) Adjust the body harness securely to the wearer. (7) Adjust the facepiece to the wearer so that it makes a gaslight fit with his face. There arc two means of testing for a satisfactory facepiece fit: (a) Close off the exhalation valve and exhale gently into the facepiece. If a slight positive pressure can be built up in the facepiece without any indication of outward leakage of air between the facepiece and the face, it is adjusted pro|ierly. (b) Close off the breathing tube or tubes, inhale so that the facepiece starts to collapse, and hold the breath for about 10 seconds. If the facepiece stays in its partially collapsed conditions and no inward leakage of air is detected, it is adjusted properly. (8) Operate the blower, and adjust the flow of air to the wearer's satisfaction. The blower should be operated continuously during the use of the mask. (9) Check on the prearranged signals be tween the wearer and the blower operator. (10) Enter the contaminated area cautiously. (11) Be careful that the hose is not en dangered by sharp edges or falling objects, and re member that the wearer must retrace his steps and leave by the same route that he entered. (12) If the continuous flow of air to the facepiece is interrupted, the wearer should return to fresh air and ascertain the cause. (13) The facepiece should not be removed until the wearer is certain that he is in respirable nir. 7.S.2.4 Precautions To Be Taken in the Use oj a Hose Mask Without Blower (1) Make certain that the hose mask is in goad ojtcrating condition. (2) Securely fasten the air-intake of the respirator in an assued source of respirable air.  to (3) Connect llic proper length of hose (not over 75 feet) to the air-intake and to the face piece, making sure that all gaskets arc in place and that the connections are tight. (4) Adjust the body harness to the wearer. (5) Adjust the facepiece to the wearer so that it makes a gastight fit with his face. There arc two means of testing for a satisfactory facepiece fit: (a) Close off the exhalation valve and exhale gently into the facepiece. If a slight positive pressure can he built up in the facepiece without any indication of outward leakage of air between the facepiece and the face, it is adjusted properly, (b) Close off the breathing tube, inhale so that the facepiece starts to collapse, and hold the breath for about 10 seconds.. If the facepiece stays in its partially collapsed condition and no inward leakage of air is detected, it is adjusted properly and is gastight. (6) Make certain that the atmosphere to be entered is not so hazardous that the wearer cannot escape unharmed without the aid of the respirator. (7) Enter the contaminated area cautiously and leave by the same route. 7.5.2.5 Precautions To lie Taken in the Use of an Air-Line Respirator (1) Make certain that the air supply is respir able. Close attention should be paid to the location of the intake to the air-supply device to make certain that the entering air is not contaminated. A suitable filter should be provided to remove objectionable odors, oil and water mist, and rust particles from the air delivered to the air-supply line. A suitable rcducing-typc or dcmnnd-ty]>c valve and an excesspressure relief valve should also he provided. For supplying respirable air, the use of low-pressure externally lubricated blowers is preferable to highpressure internally lubricated compressors, since the latter may add objectionable odors to the nir and may produce carbon monoxide upon overheating. Internally lubricated compressors should be equipped with an automatic shut-off which is actuated if they become overheated. (2) Make certain that the air-line respirator is in good operating condition. (3) Attach the proper length of air-supply hose to the source of compressed nir and to the breathing tube. (4) Adjust the pressure of the air at the inlet to the air-supply hose so that it is within the proper pressure range. (5) Adjust the facepiece, helmet, or hood to AMKHICAN STANDAUI) SAFKTY CUllK Fwit the wearer according to the manufacturer's instruc tions. A full facepiece or half-mask facepiece should be adjusted so that all the excess air leaves the facepiece through the exhalation valve and none is felt leaking out under the edge of the facepiece. (6) When the rate of flow of air into the facepiece, helmet, or hood seems to be excessive, the wearer may decrease the flow of air by means of the air-regulating valve with which most air-line respirators ore equipped. However, to prevent the contaminant in the surrounding air from reaching the wearer's breathing zone, the flow of air should not be decreased below 4 cubic feet per minute for facepieces, or below 0 cubic feet per minute for helmets or hoods. Hence, the air-regulating valve should be used judiciously on an air-line respirator. (7) Enter the contaminated area cautiously and leave by the same route. (8) Each air-line respirator is equipped with a quick-acting detachable coupling by means of which the wearer can quickly disconnect the respira tor from the air-supply line to facilitate escape in an emergency such as fire. The wearer should practice using this coupling before wearing the respirator in a contaminated atmosphere. 7.5.2.6 Precautions To Be Taken in tlir Use of an Abrasive-Blasting Respirator. The precautions to be taken in the use of an abrasive-blasting respirator arc the same: as those given for the air-line respirator, with the following additional precautions. (1) Make certain that the shatterproof eye piece and the protective cover glass (if furnished) arc in place. Under no circumstances should regular window glass be used in place of the shatterproof eyepiece. Clean the inner and outer surfaces of all eyepieces. (2) Make certain that the protective wire screen or perforated-metal eyepiece is clean and in place. 7.5.2.7 Precautions To Be Taken in the Use of a Chemical-Cartridge Respirator (1) Make certain that the atmosphere to be entered is not dangerous to life. (2) Make certain that the respirator is in. good operating condition, that the gaskets arc in place, and that the proper chemical cartridges arc securely mounted in the respirator. (3) Adjust the respirator to the wearer's face so that it makes a gaslight fit with his face. There arc two means of testing for a gastight fit: (a) Close off the exhalation valve and exhale gently into the facepiece. If a slight nsitivc pressure can be built iii;\n. i:vi:. am kksimkatiiky rmm:rn<i.\ ujt in the facepiece without any indication of outward leakage of air between the facepiece and the face, it is adjusted projwrly. (b) Close olT the inlets to the face piece by cardbonrd discs or stoppers usually furnished by the manufacturer, inhale so that the facepiece starts to c.Mlapse, and hold the breath for about 10 seconds. If the facepiece remains in its partially collapsed condition and no inward '^akage of air is detected, it is adjusted properly. If the second method is used, the cardboard discs or stoppers must be re moved and the cartridges assembled with the face piece without disturbing the fit of the facepiece on the wearer's face. (4) Enter the contaminated area cautiously. (5) When leakage of the contaminant is noted hy the wearer, lie should discard the used cartridges and replace them with fresh ones. (0) Knitted cotton cloth must never he used to cover the face-contacting edges of chemical-carI ridge respirators, since the cloth cover is not gastight. 7.5.2.JI Precautions To lie Taken in the Use oj a Dispersant (Dust, Mist, or Fume) Respirator (1) Make certain that the respirator is in good operating condition and that the proper fillers arc securely fastened in place. (2) Adjust the respirator to the wearer's face so that it makes a dust-tight fit with his face. There are two menus of testing for a satisfactory facepiece fit: (a) Close olT the exhalation valve and exhale gently into the facepiece. If a slight positive pressure can he built up in. the facepiece without any indication of outward leakage of air between the facepiece and the face, it is adjusted properly, (b) Close off the irdets to the facepiece hy cardboard discs or stoppers usually furnished by the manufacturer, inhale so that the facepiece starts to collapse, and hold the breath for about 10 seconds. If the facepiece remains in its partially collapsed condition, and no inward leakage of air is delected, it is adjusted properly. If the second method is used, the cardboard discs or stoppers must be removed and the filters assembled with the facepiece without disturbing the fit of the facepiece on the wearer's face. (3) As the total amount of solid particulate matter removed from the inspired air by the filler increases, the resistance to inhalation inci<-..scs and finally reaches a value such that the wearer is conscious ol increased dilliculty in breathing. At this time, disposable-type filters should he discarded and replaced, hy fresh filters, and reclcanahle-typo :>') filters should be cleaned in accordance with the manufacturer's instruction. Under no circumstances should respirator filters be washed or dry cleaned. (4) In atmospheres containing particulate matter that is irritating to the skin, or where excessive perspiration nmy occur, a knitted cotton cloth, furnished by the manufacturer, may he used over the edge of the facepiece to prevent contnct between the rubber portion of the facepiece and the wearer's face. This must not be used on fume respirators. (5) When the facepiece is removed, the wearer may obtain visual evidence of the dusttightness of the facepiece fit by looking at his re flection in a mirror and noting the presence or absence of dust streaks on that portion of ins face that was covered hy the facepiece. 7.5.3 Instruction in Use of Respirators 7.5.3.1 General Considerations. For the safe use of any device, it is essential that the user be properly instructed in its selection, use, and mainten ance. Tills is particularly important with respect to respirators. Competent persons should give such instruction to the. supervisors of all groups who may he required to wear respirators at their work. The supervisors, in turn, should instruct their men. No person should he allowed to wear a respirator of any type until he has received such instruction. Such instruction should cover: (1) An explanation of the n^d for using the respirator (2) Its operating principle (3) Steps to he taken to assure that it is in good operating condition (4) Proper adjustment of the respirator to the wearer (5) Proper use and maintenance of the res pirator The very presence of self-contained breathing apparatus, hose masks will: blowers, or gas masks on the property of any organization is an indication that they arc expected to he used in nn emergency situation or in one that is dangerous to life. All persons who may have occasion to use these respira tors, or cause them to he used, should he properly trained in their use before circumstances require that they use them to protect their lives and the properly of their employer. In addition to this, efforts should bo made to foresee possible emergencies and plans of action should he formulated so that when respir atory protection is needed, rescue or repair operations will proceed smoothly and safely. Merely talking nhou Mich respirators as the self- 10 AMEHICAN STANUAIU) SAFETY CODE FOIl contained breathing apparatus, the hose mask with blower, and the gas mask is not enough. The men should be given an opportunity to handle the respira tor, have it fitted to them properly, test the gastightness of the facepiece fit, wear it in normal air for a period long enough for them to become familiar with u, and, finally, they should actually wear it in an irrcspirablc atmosphere. Such an atmosphere may be created by burning a half-ounce formaldehyde candle in a room of about 4,000 cubic foot capacity. Not only would this atmosphere be irrcspirablc, but it would be irritating to the eyes. This atmosphere is similar to that used by the Bureau of Mines in the training of men in the use of the self-contained breathing apparatus. After a person has worn one of these devices for a prolonged. period in this formaldehyde-air mixture without any ill effect, he need only remove the facepiece or nose clip moment arily to be convinced of the efficacy of the respirator. Such training breeds confidence in the trainees that should stand them in good stead in an emergency situation. A less severe training atmosphere that can be built up in any room without damage to its contents, or to other people in the same building, may be prepared by vaporizing isoamyl acetate to the amount of 173 cubic centimeters per 1,000 cubic foot capacity of the room. The liquid isoamyl acetate is vaporized from a doth wick placed in front of a fan in the room. This produces a concentration of about 1,000 parts of isoamyl acetate per million parts of air (0.1 percent) by volume. If the odor of isoamyl acetate is detected by a person wearing an emergencytype respirator, he would be able to detect the odor of phosgene or chlorine if he entered a 2-pcrccnt concentration of either of these gases while wearing the device. Isoamyl acetate vapor in this concentra tion is used by the Bureau of Mines as a preliminary means of testing the gastightness of gas-mask face pieces before actually wearing them in highly toxic concentrations of gases. 7.5.4 Maintaining, Cleanings Disinfecting, and Storing Respirators 7.5.4.1 General Considerations. It is especially important that respirators be properly maintained and stored. The life of the wearer may be dependent on their proper functioning and ready availability. Adequate attention to cleaning and disinfcc!i>.g is also required because the respiratory inlet coverings arc worn on the face. Whenever possible, a centralized maintenance, cltruing, and storage station should be established to care for equipment of this type. It should be equipped adequately and manned by trained personnel. 7.5.4.2 Procedures Applicable to All Respira tors 7.5.4.2.1 Inspection. All respirators should be inspected at regular intervals to make sure that they are ready for use. For respirators that are used and maintained daily, Inspection becomes a rather automatic function; however, it is often neglected for respirators that are stored throughout a plant for use in emergency situations. These devices should be checked as regularly as fire extinguishers; as a matter of fact, it is good practice to integrate these inspection and maintenance programs. All rubber parts such as facepieces, mouthpieces, exhalation valves, breathing tubes, and headbands should be inspected carefully for signs of deterioration such as hardening, checking, or tackiness. During the inspection, time should be given to "working" the rubber between the fingers with a stretching and massaging action. This will reveal defects in rubber parts and prolong the life of non-defective parts. A check should be made to see that all gaskets are present and that they arc held in place tightly. Metal parts should be checked for signs of cor rosion, and plastic and glass parts for breakage. 7.5.4.2.2 Maintenance. When it is necessary to replace worn or deteriorated parts, only those made specifically for the device should be used and the repair work should be accomplished by experi enced personnel. Makeshift repairs for respiratory protective equipment cannot be tolerated. After equipment that is used frequently is cleaned and disinfected, it should be repaired routinely; emer gency equipment should be repaired immediately after inspection reveals the need for repairs. Repairs to intricate parts should not be attempted unless adequate facilities and trained personnel are available. For most users, it is preferable that parts of this type be replaced as a unit or returned to the manufacturer for repair. 7.5.4.2.3 Cleaning and Disinfecting. Respir atory protective equipment shoutd he cleaned and disinfected after each use. However, because of the wide variety of materials used in these devices, the manufacturer should be consulted for the cleaning and disinfecting method best suited to his products. In general, facepieces and mouthpieces for respir atory protective devices arc made from rubber or rubber-like compounds. Usually, these can be cleaned with detergent and lukewarm water by hand-brushing or agitation in a washing nachine. Formaldehyde, m: ui. i:vi:. \ni> iiksimuatohv wiotkction modified phenol ics, hypochlorite, or quaternary am monium compounds in the proper strength can be used to disinfect the parts. Normally all detergent is rinsed from the protective device before disinfecting; however, there arc several combination cleaning and disinfeetsrg materials available in both liquid and powder form which contain a detergent and quater nary ammonium salts and thi p-rmits combining the washing and disinfecting operations. After cleaning and disinfecting, the parts should be rinsed in clean water and dried quickly for most disinfectants. It may not lie desirable to rinse parts treated with quaternary ammonium compounds since their disinfectant prop erties will continue indefinitely and may not produce a skin irritation. After reassembly, the device should be placed in a clean and dust-tight container. Hot water, steam, solvents, and ultraviolet light diouM be avoided in the cleaning and disinfecting of rubber parts bemuse all have deteriorating effects. If paint or other diflicult-to-rcmovc substances arc en countered. it is preferable that they be removed by mild caustic cleaners rather than by solvents. 7.5.1.2.1 Storage. All types of respirators should be stored in clean ami dry compartments under conditions of moderate temperature. Most devices of this type are received in rc-usablc cartons or cases and should be kept in these containers during the period of storage. Exposure to heat, sunlight, extreme cold, and excessive moisture is harmful to respiratory pro tective devices if the exposure continues over ex tended periods. I n some cases, it is necessary to locale respiratory protective devices at convenient stations throughout the work area for ready availability in the event of an emergency. Special care must be taken to insure ade quate storage under these conditions. In some in stances. it is necessary to construct special compart ments to protect the equipment from the process mate rials as well as from the elements. Additional cmcrgcncy-type respiratory protective devices should be stored just outside the immediate danger area so that men can retreat to them and don them for judicious re-entry into the contaminated area to carry out rescue or repair operations. No respirator can he adequately stored outside its carrying case or carton in a tool box or clothing locker. 7.0.1,3 Special Procedures for Mainlainii:? ('.leaning. Disinfecting, and Storing Respirators 7.o. l.3.1 Self-Contained Breathing Appara tus. In compressed ":ygcn recirculating apparatus, make sure the carbon dioxide removing chemical is II replaced after use and that the oxygen cylinder is re filled to rated capacity in order to insure full service life. The cylinder pressure should be checked peri odically and brought to rated pressure if necessary. The tightness of the high pressure and low pressure sides of the apparatus should be checked periodically following the manufacturer's instructions. In selfgenerating apparatus, periodic tightness tests as out lined by the manufacturer should be followed. 7.S.4.3.2 Hose Masks. Check the blower pe riodically for proper operation. Check hose for wear and tear after each use and steam clean when neces sary. Keeping hose capped when not in use will pre vent entrance of dust or other contaminants. T.5.4.3.3 Air-Line Respirators. The facepiece should be serviced after cacli use just as for all other respiratory protective equipment. The flowcontrol valves should he inspected after each use and cleaned and repaired if necessary. Chemical car tridges in the continuous-flow c.ontrol-valvc assemblies should he changed when necessary. Air-linc hose should he checked for wear and tear after each use and he steam cleaned when necessary. The air-supply system should he inspected routinely to insure continued proper functioning. Air compres sors, air-cylinder manifold systems, pressure reducers, pressure-release valves, air-linc filters, air-line instru mentation, and permanent piping and outlet fittings must be kept in good repair to assure satisfactory condition of the air reaching the breathing zone of the wearer. 7.5.4.5.4 Gas masks. Check the facepiece to be sure that (1) the eyepieces are not broken and that they are held firmly in place; (2) the rubber portion of the faccpiccc is flexible and free from cracks; (3) the head harness is flexible and that the straps and buckles arc in good condition; (4) the exhalation valve is in place, works freely, and has no dirt on its contact surfaces; (5) the breathing tube is flexible and free from cuts and that it is securely fastened to the canister neck nr to the outlet of the timer: (0) the canister is of the proper type, is free from dents and rust spots, and is securely attached to the canister harness. If a timer is used, check to be sure that the gaskets arc in place and arc making proper contact, and that the tinier is reset when a new canister is attached. Universal gas-mask canisters should lie replaced after one year from date of break ing seal if not exhausted before this time. Canisters should he stored in a cool, clean, dry location and the stock rotated so lliut no canister remains in storage for more than four years before it is used. 7.5.4.3.5 Srlf-Rcsciicr? Frequent inspection 12 is the most important phase o the mruitonancc pro gram with this type of equipment because the equip ment is seldom used but must always be ready. The type which oiFcrs protection against carbon monoxide utilizes hopealite in the chemical fill and must be pro tected from moisture to remain cflfcctivc. Follow the manufacturer's recommendations for checking the moisture seal at reguiut and frequent intervals. 7.S.4.3.6 Dispcrsoid and Chemical-Cartridge Respirators. Mechanical filters of the "throw-away" type should be discarded when the breathing resist ance becomes bothersome to the wearer. In mpst plants with centralized maintenance stations, the fil ters arc destroyed and discarded at the time the respirator is serviced. Some respirators employ rc-clcnnable filters, in which case the filters are cleaned when the respirator is being serviced. Chemical cartridges should be changed when the wearer detects the odor or irritating effect of the con taminant. In plants with centralized maintenance sta tions, cartridges arc sometimes discarded after a given period of use (based on group experience), but in most cases the wearer is responsible for discarding and replacing cartridges in his respirator. Particular care should be exercised in the storage of chemical cartridges because they usually deteri orate if exposed to excess moisture and to gaseous air contaminants. Cartridges should not be stored in the area where it is necessary for the workmen to use chemical-cartridge respirators. Appendix for Section 6 (This Appendix i* not a port of American Standard Safety Code for Head, Eye, and Respiratory Protection, Z2.1-I959, but is included to facilitate its use.) Al. Visible-Light Transmission and Haze Test3 Al.l Specimen. The test specimens shall he 2 inches in diameter, minimum. They inay be cut front the plastic sheets or molded pieces or they may be prepared from a plastic material in the customary manner peculiar to the physical properties of the plastic to be tested (by compression molding, injec tion molding, laminating, casting, etc). The surfaces of the test specimens shall be substantially flat and parallel. The thickness of the test specimen shall be as furnished or, for comparative purposes, shall be 0.125 d= 0.005 inch. A 1.2 Apparatus. The apparatus shall consist of a haze meter, detailed drawings of which are obtain able from Organic Plastics Section, National Bureau of Standards, Washington 25, I).C. The light source shall consist of a concentrated filament lamp mounted in front of a reflector. It shall be placed within a cylindrical shield the inside of which is blackened. The base of the cylindrical shield opposite the re flector shall be closed and equipped with a l*inch cir cular aperture. A circular blackened disk containing a similar aperture shall be mounted directly in front of a photoelectric cell 18 inches from the first aper ture. The photoelectric cell shall be the Weston Photronic cell. Types I or 111, with Viscor filler. The cell shall be connected at an ammeter with a 100-microampere range and an internal resistance not exceed ing 50 ohms. If a dark room is not available, the light source unit and the photoelectric cell unit may be mounted in a suitable box finished on the inside in dull black to reduce reflection to a minimum. The box lid, also finished in dull black on tire inside, shall fit tightly to prevent any external light from reaching the photoelectric cell. The lid shall be closed when making measurements unless the measurements arc made in a dark room. A suitable storage battery or voltage stabilizer shall be used to operate the lamp. Hie intensity of the lamp shall be adjustable by means of a rheostat. * Tli'w lri j* icchnirnlly the same as Method No. 3021 of Federal Spccifieal5-* L-l'-tOO. A1.3 Procedure Al.3.1 Care shall be taken to remove dust and grease from the specimens prior to measurement. At least three measurements of the light transmission and haze shall be made and averaged for each test specimen. Al.3.2 Light Transmission Determination. The light is adjusted in intensity so that n current of 100 microamperes is obtained from the photoelectric cell. The specimen is then placed in front of the aper ture (A) at the photocell. Of the light incident on the sample, a fraction is transmitted undeviated, and a fraction is scattered by the surfaces and the interior of the sample. The photoelectric cell receives the un deviated fraction of the light and that part of the scattered light which is not deflected at angles greater than about 90 degrees. The total light transmission of the plastic as defined is the fraction of the original light received by the photoelectric cell which con tinues to reach the sensitive element when the plastic is placed over the aperture (A) at the photoelectric cell. When the initial reading is 100, a reading of the micronmmctcr taken with the specimen at position (A) gives the percentage total light transmission di rectly, and a reading obtained with the specimen at position (B) gives the percentage parallel light trans mission directly. Al.3.3 Iinse Determination. The specimen is then placed at the aperture (B) 18 inches distant from aperture (A) and just in front of the cylindrical shield covering the light source, and the microammeter is read again. The photoelectric cell still re ceives the undeviated fraction of the total light hut collects only that small portion of the scattered light which is confined to the small solid angles subtended by aperture (A) at points in opening (B). The differ ence between the photoelectric current with the sam ple at (A) and at (B) is a measure of the light scat tered, assuming that a linear relation exists between the photoelectric current and the total light incident upon the sensitive element of the cell. The current is practically proportional to the total incident light for no external resistance; the deviation is only slight for the 50-ohm resistance in the microammcter as specified. Percentage of haze is calculated by dividing 43 II .\m:.\uix r the difference between the readings of die microatn- A2.1.5 Finish. The test specimens for sheets, ntetcr in positions (A) and (B), respectively, by the rods, and tubes shall be machined, sawed, or sheared e reading in position (A) and multiplying by 100. from the sample so as to have smooth edges free from j A 1.4 Report. The report shall include the data cracks. The cut edges shall be made smooth by finish specified under Section I, paragraph 8 of Specifica ing with No. 000 or finer sandpaper or emery cloth. te n I.-P-406 and the following: Sawing, machining, nnd finishing operations shall be (T) Average percentage of total diffuse light trans slow enough so that the material is not heated ap mission preciably. (21 Average percentage of parallel light transmis sion (3) Average percentage of haze A2.2 Apparatus (1) Circulating air oven maintained at 122 4 F (50 2C) A1.3 Definition A 1.5.1 Ilase. Haze is defined as that fraction of the total transmitted light from a normally incident beam which is not transmitted in a straight line. If 7' (2) A desiccator (31 Analytical balance (41 Micrometer, gage, or caliper capable of meas uring accurately to 0.001 inch be the total light transmitted. Tr tlic parallel light transmission, i.c,,the amount transmitted in a straight line, and T.i the. diffuse light transmission, i.c., the amount transmitted in all directions but rectilinearly, then A2.3 Procedure A2.3.1 Three specimens of the sample to be tested shall be. conditioned in an oven at 122 -4. 4 F (50 2 C) for 24 hours. After conditioning, the speci mens shall be cooled in a desiccator and weighed. Dimensions of the specimens shall he measured with a micrometer gage to 0.001 inch. The specimens shall .Measurements of haze shall lie equivalent to those which would be obtained by the CIE4 Standard Ob server and CIE-1 Standard llluminant A. then lie completely immersed in distilled water main tained at a lemjicralurc of 77 rfc 4 F (25 dr 2 Cl. At least 50 milliliters of distilled water shall he em ployed for immersing each specimen. At the end of A2. Water Absorption Test5 (For Weight anti Dimensional Changes) 24 hours immersion, each specimen shall be removed, the surface moisture quickly absorbed by a dry cloth, and the sfiecinicn reweighed. If the specimen is `/ A2.1 Specimen* A2.1.1 Maiding Cowpounds. Test specimens for molding compounds shall he disks 2 inches in diameter by 0.125 d: 0.007 inch thick. A2.1.2 Sheets. Test specimens of laminated rumpountls and specimens cut from material shall he 1 by 3 inches by the thickness of the sheet. A2.1.3 Rods. The lest specimen for rods shall be 1 inch in length for rods 1 inch in diameter or under and V inch in length for larger diameter rods. The diameter of (he specimen shall be the diameter of the finished rod. A2.1.4 Tubes. The test specimen for tubes less than 3 inches in inside diameter shall he the full sec tion of the tube and 1 inch in length. For tubes 3 inches nr more in inside diameter, n rcctngui~. speci men shall lie cut 3 inches in length in the circumfer ential direction of the tube nnd 1 inch In width inch or less in thickness, it shall he pul in a weighing Iiollle immediately after removing the surface mois ture and shall he weighed in the bottle. The dimen sions shall then he remeasured. A2.3.2 When materials arc known or suspected to contain any appreciable amount of water-soluble ingredients, the specimens after immersion, weighing, and measuring shall he reconditioned for the same time and temperature ns used in the original drying period. They shall then he cooled in a desiccator and immediately reweighed. If the reconditioned dry weight is lower than the conditioned dry weight found after the original drying before immersion, the differ ence shall he considered ns water-soluble matter lost during the immersion test. For such materials, the water absorption value shall be taken ns the sum of the incrense in weight on immersion nnd of the weight of the water-soluble matter. lengthwise of the tube. A2.4 Report. The report shall include the data specified under Section 1, paragraph 8 of Spccifica* I Intermit ion..1 Commission on Illumination. :,Tiii- tr<! is technically the satnc as Method No. 7031 of FrITal JjjHMTlM'ation I.-P-IOft. tion I.-P-406 nnd the following: 'll The percentage terease in weight during ini- mersion calculated to nearest 0.01 percent ns follows: Increase in weight, percent = wet weight -- conditioned weight conditioned weight (2) The percentage of soluble matter lost during inline, don, if determined, calculated to nearest 0.01 percent as follows: Soluble matter lost, percent = conditioned weight -- reconditioned weight conditioned weight When the weight on reconditioning the sjiccimcn after immersion in water exceeds the conditioned weight prior to immersion, report "no loss of soluble matter.'' (ill The percentage of water absorbed in 24 hours, which is the sum of the values in items (1) and (2). (4) The percentage change in each dimension dur ing immersion. In) Observations regarding any change in physi cal condition of the specimen. A'5. Selection of Shade Numbers for Welding Fillers The following is a guide for the selection of the proper shade numbers of fdter lenses or windows used in welding. These recommendations may be var ied to suit the individual's needs. Suggested Welding Operation Shade Number Shielded metal-arc welding Vt,;-, (-, /a-j-inch electrodes 10 Inert-gas mctal-arc welding (nonferrous) Vie.-, Vaa*i Vkv %2-ch electrodes Inert-gas metal arc welding (ferrous) 11 Vi *, %*.** Vs'i %2-inch electrodes Shielded mctal-arc welding 12 %:> '4-inch electrodes 12 %-inch electrodes 14 Atomic hydrogen welding 10-14 Carbon-nrc welding 14 Soldering 2 Torch brazing 3 or 4 Light cutting, up to 1 inch 3 or 4 Medium cutting, 1 inch to 6 inches 4 or 5 Heavy cutting, over 6 inches 5 or 6 Gas welding (light), up to Vk inch 4 or 5 Gas welding (medium), Vk inch to l/j inch 5 nr Gas welding (heavy), over VV inch 6 or 0 Notk: In pas welding or oxygen cutting, where the torch . produces a high wllow light, it is desirable to use a fdter or lens that absorbs the yellow or sodium line in the visible ' light of tlic opcri.tion. I.i A4. Maintenance and Disinfection of Eye Protectors A4.1 Maintenance A4.1.1 It is essential that the lenses of eye pro tectors be kept clean. Continuous vision through dirty lenses can cause eye strain, which could possibly re sult in substandard production by the operator. Daily cleaning of the eye protector with soap and hot water is recommended. A4.1.2 Replace pitted lenses. Pilled louses, like dirty lenses, can he a source of reduced vision. They should he replaced periodically. Deep scratches or ex cessive pilling of lenses are apt to weaken the lenses and cause them to break more readily. Ai.1.3 Replace headbands. Slack, worn-out, sweat-soaked, or twisted headbands do not hold the eye protector in proper position. Visual inspection can determine when the elasticity is reduced to a point beyond projier function. At. 1.4 Keep goggles in case when not in use. Sjjectaclcs, in particular, should he given the same earc as one's own glasses, since the frame, nose pads, and temples can he damaged by rough usage. A t.2 Disinfection. Personal protective equipment which has been previously used shall he disinfected before being issued to another employee. Even when each employee is assigned protective equipment for extended periods, it is recommended that this equip ment lie cleaned and disinfected regularly. Several methods for disinfecting eyc-prolcclivc equipment arc acceptable. The most effective method is to disassem ble the goggles or spectacles and thoroughly clean all parts with soap and hot water. Carefully rinse all traces of soap and replace defective parts with new ones. Swab thoroughly or completely immerse all parts for 10 minutes in a solution of germicidal de odorant fungicide. Remove parts from solution and suspend in a clean place for air drying at room tem perature or with healed air. Do not rinse after re moving parts from solution because this will remove the germicidal residue which retains its effectiveness indefinitely. The dry parts or items should he placed in clean, dust-proof containers, such as a box, hag, or plastic envelope to protect them until re-issue. A5. Fitting of Goggles and Spectacles A5.1 Cup Goggles. The first step in fitting cup goggles is to adjust the nose bridge. Both the bull* and link-chain bridges r goggles arc adjustable to u< accommodate the individual wearer. Both types of bridges usually have some means lor shortening or lengthening. In either case, to shorten or lengthen the bridge, the instructions of the manufacturer should be followed. Chain not needed after adjustment should be cut off. The chain should be insulated to protect the nose of the wearer. The proper procedure for adjusting headbands is to keep the band loose enough to slip two fingers under it, palm side down, without stretching. Head bands should be worn low and flat and approximately at the base of the skull in order to hold goggles in a comfortable position. Most cup goggles arc thinner and slanted away at the lower nasal sides, which makes for comfort as well as easy identification in getting them right side up. A3.2 Spectacles. The first step in fitting spectacles is to determine the proper eye and bridge sizes. This is done best by using fitting samples and placing the sample spectacles on the nose to arrive at the proper size. The adjustable rocker pads should fit flush against the sides of the nose without allowing the metal bridge of the spectacle to rest on the nose bridge of (he wearer. The small metal arms, to which the pcarloid pads arc attached, can be readily adjusted by round nose pliers which are especially designed for this purpose. To fit the temples comfortably over the cars, hold (he spectacle firmly in one hand and shape the bow of the temple gradually by drawing it slowly between thumb and forefinger of other hand. Temples should be angled down from frame to ear so that lenses will be perpendicular to the line of vision. Prescription safely spectacles should be fitted only by qualified optical personnel. American Standards The standard In this booklet is one of over 1800 standards approved to date by the American Standards Association, Incorporated. The ASA provides the machinery for creating voluntary standards. It serves to eliminate duplication of standards activities and to weld conflicting standards into single, nationally accepted standards under the designation "American Standard." Each standard represents general agreement among maker, seller, and user, groups as to the best current practice with regard to some specific problem. Thus the completed standards cut across the whole fabric of production, distribution, and consumption of goods and services. Manufacturers, consumers, technical organizations, and governmental agencies --all substantially inlet ested and affected groups -- are represented on the committees which develop and regu larly revise American Standards. The completed standards are used widely by industry and commerce and often by municipal, state, and federal governments. The ASA, under whose auspices this work is being done, is the American clear inghouse for standards activity on the national level. Founded in 1918, it is a federation of more than 100 trade associations, technical societies, professional groups, and consumer organizations. Somo 2200 companies ore affiliated with the ASA as company members. ASA is the United States member of the International Organization for Stand ardization (ISO). Through this channel American industry makes its position felt on the international level. American Standards are on file in the libraries of the national standards bodies of 41 countries. For a free list of all American Standards or information about membership in the ASA write: AMERICAN STANDARDS ASSOCIATION INCORPORATED 70 EAST FORTY-FIFTH STREET NEW YORK 17, NEW YORK