Document Z4jR69Vqga3r1GwrKoaLRQ77p

RSV 0005275 respiratory protection table of contents t Preface ..................... .............................. .................................................................... ................................................ 2 Introduction ...................................................................................... ..................................................................... .. 2 Administration ................................................................................ ............................ .......................... ........................ 2 Respiratory Hazards.............................................. .................................. .................. ............................ . 2 Oxygen Deficiency......................................................................................................................................................... 2 Air Contaminants.............................................................................................................. ...................... ................... .. 2 Particulate Hazards........................................ ......................................................... ............................ ....................... 2 Gaseous Contaminants......................... *.................................................................................................................. .... 3 Threshold Limit Values....................................... .............................. ......................................................................... 3 Hazard Assessment..................................................................................................... ...................... ......................... 3 Hazard Control .................................................................................................................................. ...................... 3 Selection............................................................. ...................................................-......................................................... 3 Mechanical Filter Respirators........................................................................ ............................................................. 5 Chemical Cartridge Respirators....................................... .................... *....................................................................... 6 Gas Masks............................................. ................................ ...................... ................................................................... S Air-Line Respirators...................................................... .............................................. ................................................. 10 Hose Masks.......................... 12 Self-Contained Apparatus *.............................. 12 Oxygen Cylinder Reoreathing Type...................................................................... ......................................................13 Oemand-Type Apparatus................................................................................................................................................ 14 Warning Device................................ 14 Recharging Cylinders.......................................................................................... 16 Self-Generating Type Apparatus...............................*....................................................................... ........................ 16 Use of Prescription Spectacles and Audible Communication with Respiratory Protective Equipment.................. 16 Voice Amplification Unit........................................................................... 17 Outline for Selecting Respiratory Protective Devices......................................... .............................. ...................... 18 Training............................................ 19 Inspection. Maintenance, and Repair of Respiratory Protective Equipment ........................................................ 19 Medical Surveillance ..................................... 19 Approval Schedules................................... RSV q005276 ........ . 20 ho W i basic elements of respiratory protection Preface This booklet b intended for anyone concerned with establishing and maintaining a respiratory protection program, it presents certain basic information lor guidance purposes. However, it docs not purport to be all inclusive in content or scope. For more complete Information on spe cific problems (ho reader is referred to the following documents: 1. American National Standard Practicas lor Respiratory Protection, ANSI 768.2-Available from the American Naiional Standards Insti tute, Inc., 1430 Broadway. New York, New York 10016. 2. Respiratory Protective Devices Manual -- Available fram Committee on Respirators. P.O. Bpx 435, Lansing, Michigan 46902. 3. Breathing Apparatus lor tha Fira Service--Available from National Fire Protection Association, 470 Atlantic Avenue. Boston, Massachusetts 02110. 4. Threshold Limit Values -- Avail able from Secretary-Treasurer, The American Conference ol Governmen tal industrial Hygienists. 1014 Broad way. Cincinnati. Ohio 45202. For more complete information on the respiratory protective equipment described in this booklet, contact Mine Safety Appliances Company, 400 Penn Center Blvd.. Pittsburgh, Pa. 15235. Only qualified, trained personnel should use any respiratory protective device. introduction A successful respiratory protection program must contain eight basic ele ments. These are listed below not nec essarily in order of importance: 1. Administration. 2. Knowledge of respiratory hazards. 3. Assessment of respiratory hazards. 4. Control respiratory hazards. 5. Selection ot proper respiratory protective equipment. 6. Training. 7. Inspection, maintenance and re pair of equipment. 8. Medical surveillance. Administration Responsibility and authority for ad ministration of a rcspiratn'Y protec:.on program must bo assigned to one individual who may and probably will have assistance. The necessity tor central authority and responsibility is to insure that there is coordination and direction. The respiratory protec tion program will vary widely depend ent upon many factors and may in volve specialists such as safety per sonnel. industrial hygienists, health physicists, and physicians or a single individual with no special training, tn any case, overall responsibility must reside in a single individual if ihc pro gram is to achieve optimum results. Respiratory Hazards Toxic materials can enter the body tn three ways: (1) through the gastro intestinal tract. (2) through the skin, and (3) through the lungs. Of these three modes of entry, the human res piratory system presents the quickest end most direct avenue of entry be cause of its intimate association with the Circulatory system and the con stant need to oxygenate our tissue cells to sustain life processes. Hence, there are two basic respiratory hazards: 1. Oxygen deficient air. 2. Air laden with contaminants. Oxygen Deficiency The normal content of oxygen in the air is 20.9 per cent by volume. Oxygen concentrations below 16 per cent will not support combustion and are considered unsafe for human exposure because of harmful effects on bodily functions, mental processes, and coordination. At low oxygen concentrations, collapse can be im mediate. without warning and death can ensue within minutes. While 16 per eent oxygen (at sea level) is gen erally considered the lower limit for safe human exposure, the partial pres sure of oxygen within ihc lung Is the Important factor.Therefore, under con ditions of significantly reduced atmos pheric pressure, which occur at high altitudes, the low sale limit is higher than 1$ per cent by volume. Current legislation requires that the oxygen percentage in a working place be not less than 19 5 tn assessing exposure conditions, it is important to remember that oxy gen deficiency can occur in confined spaces by displacement ol air by other gases and vapors; or by means ot oxidation proersres such as lire, rust ing. aerobic bactcna, etc., where oxy gen is consumed Air Contaminants Air contartvn.mis include porliculate matter n the tonn ot Ciscte'.e particles ol solids or liquids, gaseous material in the foini of a true gas or vapor, or a combination of both gas eous and particulate matter. Particulate Haxards Particulate contaminants may be classified according to their physical and chemical characteristics and their biological effect on the body. The particle diameter in microns (1 microns 1/25.400 inch) is of utmest importance. Particles below 10 microns in diameter have e greater opportunity to enter the respiratory eysicm end particles below 5 microns tn diameter are more apt to reach the deep lung or alveolar spaces. In the healthy lung, particles from 5 to 10 microns in diameter are generally re moved from the respiratory system by the constant cleansing action of the ciliated epithelium In the upper res piratory tract. However, with exces sive "dust" exposures or diseased systems the efficiency of the cleans ing action can be markedly reduced. Types of Particulate Matter The various types of airborne par ticulate contaminants (sometimes called "aerosols'* or "dispersoids ) may be classified as follows: Oust--Mechanically generated solid paniculate matter (usually found in the harmful size range of from 0.5 to 10 microns). Mist end Fog --Liquid particulate matter (usually found in the size range from 5 to 100 microns). Fumes--Solid condensation parti cles of fine diameter, commonly gener ated from molten metal as metai fumes (size range from 0.1 to 1J) micron). Smoke--Chemically generated par ticulate matter of organic origin. (Usu ally found in the size range from 0 01 to 0J micron}. Living Organisms -- Airborne bac teria and virus (usually found in the size range from 0.001 to 15 microns). Classification of Particulate Mailer According to Biological Cltects The fate of particles which reach the deep lung or alveolar spaces de pends to a laige degree on their solu bility. particle size, chemical charac teristics. and metabolism in the body. Hence, paniculate contaminants can be ctassitred according to their bio logical effects as fellows: Inert Aerosols --Which produce minor irritation or discomfort, but in sufficient quantity can overwhelm Iho protective mechanism of tho upper respiratory tract Allergy Producers --Which can cause severe reactions with seme sen sitized individuals. "zmzwwT-iw !W RSV 0005277 w Chemical Irritant* --Which can dam* age the sensitive mucous membranes pr lung (issue by chemical reaction. Fibrosis Producers -- Wmcn can cause the development ol scar tissue In the lung such as silicosis from quartz (silicon dioxide} exposures and Mbcstosis from asbestos exposures. Cancer Producers--Such as asbes tos. chromates and radioactive pani culate matter. Systemic Poisons --Such as lead, cadmium, arsenic which can damage Certain critical organs and systems. Fever Producers --Such as the fumes of zinc and copper. Gaseous Contaminants Gaseous contaminants occurring as true gases such as sullur dioxide, carbon monoxide, etc., or vapors from organic liquids can likewise be classi fied according to their chemical charscterisics and biological effect on the body. Types of Gaseous Contaminants 'Chemically, gaseous contaminants may be classified as follows: Inert Gases--Such as helium, argon, neon, etc. which do not metabolize in the body but produce an oxygen defi ciency by displacement ol air. Addle Gases--Such as sulfur diox ide, hydrogen sulfide, hydrogen chlor ide ete. which are acids or produce pclds by reaction with water. Alkaline Gases--Such as ammonia, phosphine etc., which are alkalis or produce alkalis by reaction with water. Organic Compounds --Which can exist as true gases or vapors from or ganic liquids. Organomelallie Compounds--Com prised of metals attached to organic groups such as tetraethyl lead and organic phosphates. Classification of Gaseous Contaminants According to Biological Effects Gaseous contaminants may be clas sified according to biological elfoets as follows: Asphyxiants--Which Interfere with tho uptake, transport or utilization of oxygen in Uic body. Simple asphyx iants such as nitrogen, methane, hy drogen. etc. can create an oxygon deficiency by air displacement. Chemical Asphyxiants -- Such as catbon monoxide interfere with the uptake and transport of oxygen by the hemoglobin of the red blood cells while hydrogen cyanide inter teres with "Internal respiration" or *<ddt<on of the tissue ceils. Chemical Irritants--Such as acid and alkaline gases which can iihtato tho respiraiory system and cause the equipment and procedures are avait- development of pulmonary edema cr abfo and thoroughly understood by fluid in the lung, affected personnel. Anesthetics--Such as chloroform, ether, carbon tetrachloride which can Hazard Control cause loss of feeling, unconscious ness. and death. Systemic Poisons--Such as metal lic mercury vapor, hydrogen solltde, arjinc etc. which can damage critical organs and systems of the body. Obviously, hazard control should start at the process, equipment, and plant design levels where effluents can be effectively controlled at the oulset With'operating processes, the problem becomes mere difficult. How Threshold Limit Values ever, in ell cases, consideration should The degree of effect of both gas eous and particulate contaminants depends largely upon the airborne concentration and the amount of exposure. Accordingly, a listing of Threshold Limit Values (T.L.V/s) aro published yearly by the American Conference of. Governmental Industrial Hygienists as guides for exposure concentration whieh a healthy individual normally- can tolerate for a hours a day. live days a week without harmful effects. Airborne parucuiate concentrations be given to the use ot effective engi neering controls to eliminate and/or reduce exposure to respiratory haz ards. This would Include considera tion of process encapsulation c iso lation, use of less toxic materials in the process and suitable exhaust ven tilation. filters and scrubbers to con trol the effluents. However, since It is not always practical to eflect and maintain engi neering controls, proper respiraiory protective devices should be made available and used for respiratory pro are generally listed as milligrams per tection when required. Since there eubic meter of air (rrg/m'} and gase are many types ol such devices, it is ous concentrations are listed as parts per million (ppm) by volume. Important that they be selected with utmost care to ensure that the proper The latest listing ol Threshold Limit protection is afforded and that per Values can be obtained at nominal coal sonnel be thoroughly trained in their Irom the America^ Conference of Gov use and limitations. Only equipment ernmental Indus rial Hygienists. 1014 approved by the National Institute for Broadway. Cincinnati, Ohio 4S2Q2. Occupational Gaiety and Health Hazard Assessment (NIOSH) / Mining Enforcement and Safety Administration (MESA) should Proper assessment of the hazard be selected where possible. la the first important step to protec tion. This will require thorough knowl . Selection edge of the process, related equip ment, raw materials, end-products, and by-products which can possibly create an exposure hazard. Air samples must be taken with proper sampling instruments during all con ditions of operation to assess the at mosphere for oxygen content and con centration levels of particulate and/or gaseous contaminants. The sampling device and the type nnd frequency of sampling (continuous or spot) will be dictated by the exposure and operat Respiratory protective devices vary in design, application, and protective capability. Tho user must, thcreforo, assess the inhalation hazard and un derstand the specific use and limita tions of available equipment to assure proper selection. Respiratory protective devices are tested and approved by NIOSH/MESA for protection against a wide range ol Inhalation hazards, from oxygen-de ficient and/or highly toxic atmos ing conditions. Breathing zono sam pheres to those containing "nuisance" ples are recommended and sampling dusts. While not all types of respira frequency should be sufficient to tory protective devices are covered assess the average exposure under under the current NIOSH approval re the variable operating and exposure quirements. it is desirable to select conditions. NlOSHA'ESA-approved equipment Should exposure concentrations whenever possible. exceed the recommenced lim.ls, haz Respiratory protective devices fa!l ard control procedures should be im Into three classes: air-purifying, sup- plemented promptly. plicd-air, and self-contained breath Also, in ossessmg the overall haz ing apparatus. ard potential, consideration should be given to possible emergency condi Air Purifying Devices tions which can arise in order to as Air-purilying devices remove con sure that proper emergency control taminants Irom tho atmosphero and RSV 0005278 on bo used only in atmospheres con taining sufficient oxygen lo sustain life (at least 19.S percent by volume at saa revel) nnd within specified concentra tion limitations of tha specific device. Various chemicals remove specific gases and vapors, and mechanical hlters remove particulate matter. The useful tile ol an air-punlying device is dependent upon the concentr; :;on of the contaminants, the breathing volume of the wearor, and the capac ity ol the eir purifying medium. The basic types of air-purifying devices are: Mechanical Finer Respirators pro* vide respiratory protection against particulate matter such as nonvolatile dusts, mists, or metal fumes. Selec tion ot the appropriate respirator is based on the typo, toxicity, and par ticle size of the participle matter. Specific types of mechanical filter respirators are approved under NIOSH/MESA 30 CFR Part 11, Subpart K. Chemical Cartridge Respirators provide respiratory protection against certain gases end vapors in concen trations not in oxcess of 0.1 percent by volume. Specific types ef chemical cartridge respirators are approved un der NIOSH/MESA 30 CFR Part 11. Subpart L. Combinations of Chemical Car tridge and Mechanical Filter Respira tors provide respiratory protection where exposure is both gaseous and particulate. Gas Masks provide respiratory pro tection against certain specific gases and vapors in concentrations up to 2 percent by volume or es specified on the canister label and against particu late metier. Specific gas masks are approved under NIOSH/MESA 30 CFR Part 11. Subpart I. NIOSH/MESA are accepting for lasting and approval vinyl chloride gas masks and certain Chin-style masks. The basic types of supplied-air de vices ere; Air-Line Respirators with constant flow, demand, or pressure-demand flow. Hose Masks with or without blower. Suppied-air devices are approved under NIOSH/MESA 30 CFR Part 11. Subpart J. Self-Contained Breathing Apparatus Seif-contamed breathing apparatus provide complete breathing protection for various periods ot time based on the amount ol breathing air or oxygen supplied and the breathing demand of the wearer. The basic types ol self-contained breathing apparatus are: Oxygen Cylinder RubreathfngTypa. Chemical Oxygen Rebreething (self-generating) Type. Demand and Pressure-demand Types. Self-contained breathing apparatus are approved under NIOSH/MESA 30 CFR Part 11, Subpart H. There is one limitation applicable to all respiratory protective equipment. Certain gases are capable of harming the body by means other than through the respiratory tract. For example, ammonia, in concentrations of ap proximately 3 percent or higher, can cause skin bums--particularly on moist skin. To avoid that possibility, protective clothing should be worn in addition to the proper respiratory pro tection. Similarly, protective clothing should be worn when appreciable amounts of gases such as hydrocyanic acid are present. Hydrocyanic acid, a gas at Nightly above room tempera ture, is capable ol penetrt?:ng the skin and causing systemic poisoning, al though to do so, concentrations con siderably higher than those required for poisoning through the respiratory tract must be present Supplfed-Air Devices Supplied-air devices deliver breath ing air through a supply hose con nected lo the wearer's facepiece. It is imperative that the air delivered be free of contaminants. The air source must bo locatod in clean air and moni tored frequently. With tho exception of Hose Masks with Blowers. these devices should bo used only In atmos pheres not immediaiely dangerous to Ida or health. Figure 1--Dwstfee^ 77 Respirator Is a stogfe-ftiter unit providing resptraiory pro tection against dusts end mists having Threshold Until Value net less than 0.0$ milligram per cubic meter or LO mttlion particles per cubic tool. 0005*79 Figure 2---Comfo- it Rwpirxtof with Type * H Ultra Filter- Cartridges la a twin-filler unit providing respiratory protection again*! radionuclides end dusts, fumes, and mills having a Threshold Limit Value . less than 0.05 milligram per cubie meter, where ihe contaminant concentration doee not exceed 10 times the concentration limit for the radionuclide btvetved or 10 times the TLV, Figure J--Ultra-Twin'" Respirator is a lull taecpiece unit with receptacles for two Type H Uflra FHter Cartridges providing prelection ogainst inhalation of dusts, fumes, and misia having a Threshold Limit Value test than 0.05 milligram per cubie meter, and against radionuclides. Figure 4--Ultra Filter* Respirator la a full facepiece unit with a tingle oval cartridge providing respiratory prelection against radionuclides and duels, fumes, and mists having a Threshold Limit Value lest then 0.0S milligram per cubic meier. Mechanical Filter Respirators Mechanical filler respirators offer respiratory protection against air borne particulate matter including dusts, mists, metal fumes, and smokes. They consist essentially of a soft resil ient facepiece of either half-mask or futMace design, to which is directly attached one of several types of me chanical filters made up of some fi brous material which removes the harmful particles by physical trapping cs air is inhaicd-through the material. Caseous matter such as air itself v/ilf pass through the fitter, but solid or liquid particles are trapped ih much the same manner as rocks and peb bles are separated from sand in a screening process. The filter must be highly efficient. however, to slop Ihe small haimful particles. Mechanical filler respirators do not provide pro tection 05.nir.st gases, vapors, or oxy gen deficiency. There aro many classes of mechan ical filler respirators consistent with the various classes of airborno particufato matter. Although one respirator can be made to provide effective pro tection against all true particulates, in most cases it will be loo expensive and perhaps too cumbersome for the great majority of exposures. Hence, many special-purpose respirators are offered to provide ihe most economi cal and efficient protection against specific particulate hazards. Note: Not all part'cufato matter is tlabta. Some will hydrol'te and re'ease acd g;*r.c* while others arc volatile, producing vapors. Mechanical filter as such wilt not otter protection against gases or vapors. NIOSH/MESA. the official approval agency for recpiraiory protective equipment, tests and certifies me chanical filler rcspir.TiorS under 30 CFH Part 11, Suhpart K. They wifi ap prove respirators for one or any com bination ol Iho following particulate hazards' nuisance. fifircsis-p'Oducing and/or toxic dusts, mists and fumes; radon daughters and radionuclides. Other then the difference between a hall-mask facepiece end a full facepiece, which is used when the particu late exposure is harmful or irritating to the eyes es well as the respiratory tract, the filter is the most essential distinction among classes with re spect to breathing area (size), resist ance to breathing, efficiency in filter ing particulates of specific size ranges, and time required to clog the filter. For example, in choosing a respira tor for protection against particulates more toxic than cadmium which will have to effectively filter particles as small as tobacco smoke, the user must accept an increase in bulk, weight, and cost of the product as compared to Iho need for a respirator to protect against so-called nuisance dusts. In selecting a mechanical filler res pirator, it is important that the right type be chosen: and it is equally im portant that tho respirator bo ap proved. The illustrations and captions wilt servo as a guide in thn selection of proper respirators (Figures 1 to 4). im un RSV 0005280 ui" S > -- iii - ^ ^ ~*x*x*^ -1 Figure S--Cemfe* II Chemical Cartridge Respirator with Hoatlng-jreke suspension. Figure b--MSA* bteuthpiece Respirator for escaping Item gaseous atmospheres. Chemical Cartridge Respirators Chemical cartridge respirators af ford protection against light concen trations (10 ppm to 1000 ppm by vol ume, depending upon the contami nant) of certain acid gases, alkaline gases, organic vapors, and mercury vapors by utilizing various chemical fillers to purify the inhaled air. They differ from mechanical filler respira tors only in that they use cartridges containing chemicals lo remove harm ful gases and vapors. Many gases and vapors are dan gerous or irritating to breathe. Some 4.ro hazardous or discomforting, or both, in extremely low concentrations. Although not usually Immediately narmful lo lile or health, light concen trations of these gaseous materials may cause nausea and headache that reduce worker output and sometimes produce chronic disorders which may eventually bo fatal. Worker health as well as efficiency is involved- Organic vapors, such as Ihe vapors or acetone, alcohol, benzene, carbon tetrachloride, and gasoline; acid gases, such as chlorine and sulfur dioiide: and other gaseous materials, such as gases of ammonia and mer cury vapor, are the contaminants with which we are concerned. The simplest and most convenient type of respiratory protective equip ment to use in these cases is the chemical respirator (Figure S) equipped with the proper chemical filtering elements. These filtering elements are usually called "cartridges," and. the most common types are listed below: GMA Cartridge, for protection against certain organic vapors: pro vides tor concentrations up to 1000 ppm (0,1 percent by volume). 6MB Cartridge, for 10 pom chlorine and 50 ppm sulfur dioxide and hy drogen chloride. CMC Cartridge, for protection against certain acid gases and/or or ganic vapors. GMD Cartridge, for protection against ammonia, in concentrations up to 300 ppm. The Mersorb Cartridge is satisfac tory for use against all exposures to metallic mercury vapor under condi tions of normal temperatures and pressures. Under these con Jiiions, tho air is saturated with mercury vapor at a concentration of about 4 ppm. This chemical cartridge respirator will Af ford a long service life at this concen tration, but the cartridges should bo changed after each 0 hours of uso to provide for an adequate safety factor. NIOSH/MESA Subpan L covers chemical cartridge respirators. NIOSH/MESA will issue certificates of approval to manufacturers whose products meet their performance re quirements, and the approval number will be shown on the respirator and/ or packing carton. It is good practice to use only NIOSH/MESA-approved equipment whenever possible. Mouthpiece-type chemical car tridge respirators (Figure 6) offer pro tection against intermittent exposure to light concentrations of gases and vapors or may be used for sclf-rcseuo in times of catastrophe. The mouth piece design promotes compactness ---such a respirator can be conven iently carried by the workman during all working hours or stored conven iently near the work location for im mediate availability. Chemical Cartridge Respirators ere non-cmcrgcncy respiratory protective devices and should never bo used in immediately dangerous atmospheres, except for cscapo purposes. However, to clarify this general statement, it wilt be well lo list four oilier major negative rule* which ap ply to Chemical Cartridge Respirators: A. Do not use Chemical Cartridge Resoirators lor protection against * 1.1^1 RSV 0005281 ~?A\ respiratory protection Figure 7--MSA BM-Mounl<t Respirator U a combination mtehanical-chamical Bltor respirator. gaseous material which is ax* tremcfy toxic in very small concen trations. Example: hydrogen cyan ide. A concentration of 100 parts per million is very dangerous within one hour. The toxicity is en tirely too great to chance the mini mum protection afforded by Chem ical Cartridge Respirators. B. Chemical Cartridge Respirators should not be used for exposures to harmful gaseous matter which cannot clearly be detected by odor. Example: methyl chloride and hydrogen sulphide. The for mer is odorless: and the latter, although foul smelling, paralyzes the olfactory nerves so quickly mat detection by odor is unreliable. C. Chemical Cartridge Respirators should not be used against any gaseous material in concentra tions which arc highly irritating to the eyes. Example; although a Chemical Cartridge Respirator can be made to atiord good res piratory protection against sullur dioxide in concentrations up to 500 parts per million, serious eye irritation begins in the range of between 20 and 30 parts per mil lion. and it is impossible to remain in an atmosphere containing 200 parts per million tor more than one minute without satisfactory eye protection. 0. Obviously, Chemical Cartridge Respirators cannot be used tor protection against gaseous mate rial which is not effectively stepped by chemical (ills utilized, regardless of concentration. Ex ample: carbon monoxide. The following is a partial list of gas eous material for which Chemical Cartridge Respirators should not be recommended for respiratory protec tion regardless of concentration or lime of exposure: 1. Acrolein 2. Aniline 3. Arsino 4. Bromine 5. Carbon disulfide 6. Carbon monoxido 7. Oimeihylaniline 8. Dimethyl sulfate 9. Hydrogen cyanide 10. Hydrogen fluoride It. Hydrogen Selenrdc 12. Hydrogen sulfide 13. Methanol 14. Methyl bromide 15. Methyl chloride 16. Methylene bisphcnyl isocyanate 17. Nickel carbanyt 18. Nitro compounds: Nitrobenzene Nitrogen oxides Nitroglycerine Nitromelhana 19. Ozone 20. Phosgene 21. Phosphine 22. Phosphorus trichloride 23.Si(bine 24. Sulfur chloride 25. To!uene diisocyanate 26. Vinyl chloride Nolo: The above list is far from complete and is ottered only as a guide to proper evaluation of the many contaminants found In Industry. Combination mechanical filter/ chemical titter respirators (Figure 7) utilize dust, mist, or fume filters with a chemical cartridge for dual or multiple exposure. Respirators with indepen dently replaceable mechanical filters ere sometimes used for this typo becauso the dust niter normally plugs before the chemical cartridge is ex* hauslcd. One combination mechan ical/chemical filter respirator em ploys a back-mounted filter element nd is especially well suited for spray painting end welding operations, whore the air contaminant is concen trated in front of the worker. RSV 0005282 7 Gas Masks * Application and Limitations Gas masks have been used effec tively for many years for respiratory protection against certain gases, vapors, and paniculate mailer which Othenviso might be harmful to tilo or health. They provido simplicity of op eration, compactness, coxa of maintenonco, nnd economy. However, be- eauso gns masks arc air-purifying devices, designed solely to remove specific contaminants from the air, it is essential thot their use be restricted to atmospheres which contain suffi cient oxygen to support life (a! least 10.5 percent by voiumo ol sea level) and which contain generally r.o more than 2'pcrecnl concentrations of toxic gases and vapors by voiumo. It is im perative thot the user assess the ex posure conditions carefully before selecting a specific mask for respira tory protection, it is recommended that instruments bo used where prac ticable in any situation to measure tho concentration of oxygen and harmful gases and vapors present in the at mosphere under tho various exposure and operating conditions. If (he spe cific exposure concentration* aro suspected of exceeding the specific limitations--only a self-contained breathing apparatus or a huso mask with blower should bo used. From n practical standpoint, gas masks aro generally cultjbto for ven tilated areas not subject to rapid change, but should never bo used in confined spaces below or above ground where oxygen deficiency and high gas concentrations may occur. Types of Gas Masks Various gas masks with conven tional-sized canisters are tested and approved by the U S. Bureau of Mines under Schedule 14 for respiratory pro tection against specific gases and vapors in concentrations up to 2 per cent by volume (3 percent ammonia), or as specified on the canister label (Figures 8. 9, 10). Each canister is specifically labeled and eolor coded 10 indicate (tie type of protection afforded (Figure 13). The Type N Gas Mask is the only one which protects against catbon monoxide (Figuro 10) with the exception of a self-rescue device designed for escape from car bon monoxide m underground mining Operations (Figure 11). NIOSH/MESA wifi accept for testing and approval vinyl chloride and certain chin-style macks undur 30 CFR Fart 11, Subpart t. Chin-type canisters, because of their smaller s<ze. should be limited lo concentrations not in excess of 0.5 percent by volume (Figure 12) Most canisters contain a fine' for the re moval of dust and other particulate matter, indicated by a gray or orange Stripe around the canister. Service Lite The service life of an oir-purilying device depends on the following factors: 1. The design. Including the qualify and amount of chemical till, packing uniformity and density. 2. Variable exposure conditions. In cluding concentration of contaminants In the air, breathing rate of the wearer, temperature and humidity. Generally, higher concentrations, breathing rates end humidity conditions adversely affect service life. Since the erposuro conditions are subject lo wide varia tion. it is most difficult to estimate the service fife of a gas mask canister. However, for guidance purposes, actual man tests performed under Bureau of Mines Schedule 14F stipu late the following minimum service re quirements at an average breathing rate of 25 liters per minute in concen trations of 2 per cent for most gases and vApors or 3 per cent ammonia: Industrial Size Canisters ................. 30 Minutes Type N. Canister Acid Gases ................15 Minutes Organic Vapors........2SMir>uics Ammonia ,15Minutes Carbon Monoxide ...30 Minutes Super Size Canisters, because of their greater volume of chemical fill, will last approximately twice as tong as the equivalent Industrial Size Can ister. Chin Style Canisters, because of their r.mr.ft size, should be used in concentrations />of in excess of 0.5 per cent. R$V 0005283 e m respiratory protection It must & emphasized, however, that thfl obpve times ere far guidance purposes only and are not to be taken as assured service life under actual exposure conditions which vary as slated. Canister* Replacement tt Is generally recommended that gas mask canisters used for emer gency purposes should be replaced alter u;>ch use. Specific indications for canister replacement and/or return to fresh nif an: %, if canisters with window indica tors show ihe specified color changes. 2. It nny leakage is detected by smell, last, eyes, nose or throat Irri tation. 3. tl high breathing resistance de velop*. 4 w me canfsfer shelf Ufa Is exceeded. Warning Signs Specific warning signs which re quire immediate rciurn to fresh ar arc: t. Uncomfortable heat in the In haled hir. (A properly operating canis ter will income wnrm on exposure to ceriain o^c* ot vaoors. but a canister which tn'comcs exiremely hot Indi cates th.M concentrations above the canister limit have been encountered.) 2. |i nmr.ea. dizziness or signs of distress dtwelop. Figure 1%---Color Code lor Cartridges and Gas Mask Canisters (ANSI K13.1-1S73) Atmospheric Contaminants to bo Protected Against Color Assigned Acid gases___________________________________________ Organic vapors White Ammon ia~gas ~~ ~ CarbonTnonoxidc gas " Black Green Acid gases and organic vapors Acid gases, ammonia, and organic vapors Blue "'fellow Ac7d gases, ammonia. cafponTnonoxido. and organic vapors Brown Olhervapors andgasesnot listed above __ * ""1~~ jRadioa'citve maieriats^texcept tn'Ium ancTnobfo gases)" * Red Olive Dusts, Imnosrir^'misTslother than radioactive materials)" Notes: Purple Orange vPa)poArpourrqple.stripe shat) be used to identify rad<oe(tve materials in combination with any S(2TY)*AVnporat noggpnst.rip* shaft be used to Identify dusts, fumes, and mists in combination with (3) wtierc label* only are colored to conform with this table, the canister or cartridge body shall bo gray or a ma'.ai esmsier or cartridge body m.ty be left tn Us n*tu*at metallic color. (4) The user shall r#i*r to ihc wording of the label to determine the type and degree of proteciion iho canisirr or cartridge will afford. RSV 0005284 \ . % ^ BM | |< -- Flour* 14. MSA Constant Flow Alr-Une Respirator. Figuro 15--*SA Osmond Flow Ak-Lino Respirator. Figure 15--tosttoo'* Abrasive Helmet. i Alr-Une Respirators AU-lino respirators shatt be used only In atmospheres not immediately dangerous to life or health or from which the wearer can escape without the uso of the respirator. This limita tion Is necessary because the air-line respirator is entirely dependent upon on air supply which is net carried by the wearer of the respirator. If the air Supply falls, the wearer is without respiratory protection and might not escape trom tho immediately danger ous atmosphere. Another limitation of air-line respirators is that the air-sup ply hose limits the wearer to a fixed distance from the air-supply source. The air-lino respirator is connected to a suitable compressed-air source by a hose of small inner diameter, and oir is delivered to the user continu ously or intermittently in sufficient vol ume to meet tho wearer's breathing requirements. Accessory equipment such ns pres sure regulators, pressure-relief valves. and air filters may ba necessary lo ensure that the air is at the proper pressure and quality tor breathing. Air-line respirators are furnished in many types, but there are three basic classes. There are constant flow, de mand flow, and pressure demand Ho*r, with the respirators equipped with half-masks or full facepieces, if eye protection is required, a full facepicco must be used. Constant flow units (Figuie 14) are normally used where there is an ample air supply such as provided by an air compressor. Demand type (Figure 1b) and pressure demand type (Figure 13) are generally used where only com pressed-air cylinders are available. NIOSH/tic54 approves air-line res pirators under 30 CFR Part 11, Sub- pert J, which has the foltov/ing sig nificant requirements. Toe maximum hose length for which approval Is granted is 300 feet, and the mnr.imum permissible inlet pressure is 125 pslg. Approval is sought for specific hose lengths and inlet pressures. With tho longest hose tength for which ap proval <a sought assembled to the res pirator and the lowest inlet pressure introduced to tho alr-suppiy hose, constant flow units must defiver at least four (4) cubic feet per minute (cfm) measured at the facepiece. The exhalation resistance at 65 liters per minute shall not exceed one (1) inch of water-column height. When helmets or hoods are used, the same requirements must be met except that the flow rate must be at least six (6) cubic feet per minute. For both typos of assemblies with the highest inlet pressure and shortest hose length, the maximum flow shall not exceed 15 cubic feel per minute. Constant Flow Air-Line Respirators with facepieces alone are used whsro respiratory protection only is needed. A hood can be added tor protection against sandblast or shot blast and frequently a helmet is used lor this application with a hood or cape fitted to it (Figure 16). Simitar units nro used also (or lead grinding (Figure 17). RSV 0005285 A respiratory protection gur* 1*--MSA Pressure Demand AJr* Lin* Respirator. Demand type air-fine respirators with half masks or tuil facepieces deliver air flow only during inhalation with exhalation to the atmosphere. Such respirators are normally used where the air supply is restricted to high pressure compressed sir cylin ders. A suitable pressure regulator is required to insure that the air is at the proper pressure for breathing. The same requirements for approval apply to the demand typo as to the constant flow units, except the minimum flow et a maximum resistance of two (2) inches of water-column height meas ured at the facepiece shall be el least four (4) cubic feci a minute and not more thnn fifteen (15) cubic feet a minute with alt hose length's within the Inlet pressure ranon for which approval is sough}. The exhalation resistance at 65 liters per minute shall not exceed one (1) inch of water. For those conditions where the pos sible Inward leakage caused by the negative pressure during inhalation always present in demand systems is unacceptable and thcro can't be the relatively high air consumption of the constant flow units, a pressure de mand air-line respirator (Figure 16) may be the best choice. It provides a positive pressure during both inhala tion and exhalation and must meet the same requirements for demand sys tems except that the static pressure in.the facepiece shall not exceed 1.5 inches of water, the exhalation resist ance at 85 liters per minute shall not exceed the static pressure in the face piece by more than 2.0 inches of water and that there be at least 4 CFM air flow during inhalation before t nega tive pressure is developed in Ihc lace* piece. The air supply is the responsibility of the user, and the air-line respirator is approved for us* only when it sup plies respirable air at the correct pres sure end flow. The compressed air shelf meet the most recent require* ments of Compressed Gas Associa* lion Specification G7.1 (ANSI 286.11973) (or Type I, Class D gaseous air. This currently requires that tho carbon monoxide level not exceed 20 peris per million (ppm), the carbon dioxide content not exceed 1000 ppm, and condensed hydrocarbons not exceed 5 milligrams per cubic meter. With internally lubricated piston- type compressors, overheating may produce carbon monoxide, so routine testing for carbon monoxide or the installation of constant monitoring analyzer Is desirable. Some air compressors are manufac tured specifically to provide respir able air. They use compression seal liquids such as water or diaphragms for delivering the air. The air supply hose (or which ap proval is grnnied must be used for the approval to be maintained. r$V 0005286 Hose Masks Hose masks, which supply outside aii to tho wearer through a length of hose, aro available either with or with out blowers. Those with blowers may be approved by NlOSH/MESA lor res piratory protection in any atmosphere regardless ot the degree of contam* motion or oxygen deficiency, provid ing clean, breathable air can be reached within Iho distance of the permissible hose length. (Up to SCO lect ol hose can be used on this typo o! equipment) The blower should always bo used with such unit.",. NlOSH/f/ESA will approve either hand-driven or motor/hand-driven blowers. The air hose must have a largo in side diameter, approximately one inch, so, in case Ot blower failure, the wearer can breathe through tho hose while escaping from the contaminated area; and it must be highly resistant to petroleum vapors as well as be able to withstand crushing weight That accounts for the heavy wire-reinforced construction ol hose-mask hoses. The entire hose-mask assembly. In cluding facepieces, harness, air hose, and blower, is usually packaged in a portable trunk (Tigure 1?). The blower operator serves also as a standby or guard, ready to aid the workman in case ol mishap. Hose masks without blowcis are used when unconlammated air can bo reached wilhm a distance ol 75 feet. Those units, however, carry only lim ited approval and cannot be used in almospht-ios immediately dnngmous to life or health. 30 CKt fail 11, Sub- part J, covets this class ol equipment. Self-Contained Apparatus . Self-contained breathing apparatus provide complete respiratory protec tion <n toxic gases and where thero Is oxygen deficiency, the wearer Js In dependent ol the surrounding ntmosphoto because he Is breathing with a system admitting no outside clr. Tho oxygen or air supply of tho apparatus iiseil takes caro of respiratory re quirements. Sell-contained breathing apparatus are divided into three basic types: oxygen cylinder rebroathing, demand or pressure demand, and settgenorot* Ing. Special forms of self-conlained breathing apparatus aie ovalicblo lor use underwnler. Such apparatus are generally referred to ns SCUBA (SelfContained Underwater Breathing Ap- RSV ..Y.?* , 000523? <>; -""Wa.  TTvT^r?'' respiratory protection Figure 10 -MeC--* Oxygen n#b<ethtng-Typ# Apparatus. paratus). The serf-contained breathing apparatus described in this booklet should never be used underwater. Oxygen Cylinder Rebrealhing Type The oxygen cylinder rebreathing lypos In use today are constant flow, ''lung-governed" lype which auto matically compensates lor the vary ing breathing demand of the user, or a combination of the two. It consists of a relatively small cylinder of com pressed oxygen, reducing and regu lating valves, n breathing bag. tacopiece or mouthpiece plus noseclip, and a chemical container to remove carbon dioxide from the exhaled breath. The self-generating typo uses the principle of rebreathing; but it has no mechanical operating components. The types of cylinder rebreathmg units now manufactured are approved by the Bureau or Mines or NlOSH/MESA for 45-minuto, two- (Figure 20), threeor tour-hour duration. They (unction in tho same manner and will be dis cussed together. The h:gh-prcssure oxygen from the cylinder Is reduced m pressure to a breathing level by means of a reduc ing and regulating vnlve. In some units there is a constant flow plus h lungcontrolled valve which adds any re quired additional flow. Other appa ratus have only an admission valve r.hich delivers the oxygen from the breathing b?g to the wert'cr's taco. Exhaled brenih passes down an other tube into the container holding the carbon dioxide-removing chem ical and then Uuough a cooler. Finally, tho purified exhalation flows into the breathing bag where il mixes with the Incoming oxygen from the cylinder. Tho rebreathing principle permits the most efficient utilization of tho oxygen supply. The exhaled breath contains both oxyge-n and carbon di oxide as the human body extracts only small pari ot tho oxygen in haled. As the user exhales into the con tainer, tho carbon dioxide is removed by the chemical and the oxygen which is left reused. That method of opera tion applies to alt oxygen cylinder re- breathing-lypo apparatus as werii as to the scll-gcnoraiing type. The oxygen cylinder must be re filled and tho carbon dioxide-remov ing chemical replaced alter each uso. As is true of all respiratory protective equipment, training in proper uso ond maintenance is essential for tho most efficient operation. HSV 0005288 Demand-Type Apparatus Demand-type apparatus are avail able In different models for specific applications. All consist of a highpressure cylinder, a demand regu lator connecied either directly or by a high-pressure hoso to the cylinder, a tacepicce and breathing tube as sembly with exhalation valve, and a method of mounting the complete ap paratus on (he body. In uso, the wearer turns on the cylinder valve alter put ting on the facepiece, inhales lo ob tain desired air llov/ through the de mand regulator lo ll>n facepiece, and then exhales through a valve in ihe (accpicee to the surrounding atmos phere. The term "demand regulator" means that the air flow is oh inhala tion demand, automatically regulat ing itself to the desired level to com pensate lor variations In breathing needs. AH demand apparatus arc relatively Inefficient when competed wilh the rc* breathing type, because the exhaled oxygen Is released lo ihe atmosphere Instead of being reused. Of parlicuiar application to some industries is a short-duration unit known as an "escape mask" (Figure 21). It is normally worn by a worker at times when he is in an area where a potentially toxic atmosphere, above the capacity of a gas mask, exists. Areas to which high-pressuro gases are piped fall into this category. An other type of short-durnton unit (Fig ure 22) is put on at the time escape is necessary. A work mask type of apparatus (Figure 23) is used for planned main tenance work. It is not fin emergency apparatus as if requires setting up some auxiliary equipment (or use. it has a connecting hose which limits the free movement of the wearer to the length of the hose. The apparatus is actually a two-fold unit: 1. A self-contained apparatus with which the wearer can move freely about by using a small cylinder to leave the toxic atmosphere--cither routinely or in the failure of the main breathing supply. 2. Thera la a provision for connect ing a hose to the demand regulator so that the wearer can breathe during the work period from a targe cylinder which has a pressure regulator at tached to provide low pressure for the connecting hose. Manifold as semblies ean be provided to permit more than one worker to work from a common breathing source. It is im perative that tho emergency cylinder be used with this type of apparatus; otherwise, a failure of the supply from the largo cylinder would expose ihe wearer to the toxic atmosphere. Warning Device Demand-type apparatus depend upon watching pressure gauge to Figure 24--Audi-Larm'* warning tfeviee. RSV 0005.289 /*r- .>%, !^ Figure 15 Hr CubTM iS-uwnvie enfL Flew* M--Afe Mathr* SO-minwM unil peratm. |tm whn the breathing supply has dropped lo a point where the user must return to fresh air. Except for escape'typo or work mask-type units, self-actuating warning device Is re quired for NlOSH/MCSA approval. The warning device can either be audible (Figure 24} or uso increased breathing resistance to alert the wearer to return to fresh air, but H must be self-actuating. The apparatus shown in Figura 25 Is approved by NtOSH/MESA for 15 minutes and mat shown in Figure 26 Is approved for 30 minutes under 30 CFR Pari 11. Subpat H. lor entry into and escape from Irrcspirabtc atmos pheres. These service Me ratings are based on tests on men performing moderate to heavy work m each of the diMorent types of work tests or breathmg machine tests at a rate of 40 liters per mmuto. The user should not expect to obtain me exact rated serv ice Mu on each use. The work bemg pc'tormud may bo more or less siren- uous (Man Hut used m tho tests. Whore work is moru strenuous, the duration may be shorter. Thu duration of the apparatus will depend upon factors such as: (a) the degree of physical activity of the user; (b) the physical condition of the user; (c) the degree to which the user's breathing is increased by ex citement. fear, or other emo tional factors; (d) the degree of training or ex perience which the user has had with this Of similar equipment; (e) whether or not the cylinder is fully charged at the start of the work period; (0 the possible presence In the compres-cd air of carbon di oxide concentration* greater thjn the 0 04 percent noimalty found <n atmospheric air; (g) the atmospheric pressure; If used in a pressurized tunnel or caisson si 2 atmospheres (15* psi gauge), the duration will be one half as tong as when used at 1 atmosphere, and 3 ctmcs- pheiot v/itf be one-third as long; (h) the condition of the apparatus. Three-, five-, or tcrwnlnule-duroiio-i units can be approved for escape onfy. Combination apparatus, combin ing an escape unit with an air-line respirator, are approved also. Pressure demand apparatus (Fig ure 27) using the same principle as described previously under pressure demand air-line respirators arc ap proved and used where the toxicity is such that the potential back leak of domand apparatus Is not tolerable. Under Subport H all demand-type ap paratus have met tests conducted at -- 25*F, although low-temperature components such as nosecups to re duce logging may be added it needed. Under tho latest Approval require ments, the manufacturer selects the minimum temperature for which ho seeks approval. RSV 0005290 15 System. apparatm. Recharging Cylinders There are several methods for refill ing or recharging high pressure air or oxygen cylinders. Compressors are sometimes used, but the simplest and most convenient method is to cascade from large supply to small apparatus cylinders. Such a system is shown in Figure 23. Self-Generating Apparatus The sell-generating type apparatus has a nominal service life of one hour (Figure 29). This one hour service life is based on specific test procedures and in use a lesser or longer protec tion period may result based on the user and his level of exertion. This apparatus dillers from conven tional cylinder rebreathing apparatus in that ii utilizes a chcrnic.il canister which evolves oxygen and removes the exhaled carbon dioxide in accord ance with breathing requirements. kt eliminates high pressure cylinders, regulating valves, and other mechan ical components. The canister, which contains potas sium superoxide, evolves oxygen when contacted by the moisture and carbon d'Oxicle m the exhaled breath, and retains tho carbon diOM-'u and moisture. Retaining moisture is im portant as it aids m preventing lens logging. In use, the self-generating unit-operatea as other rebreathing apparatus 'except that the wearer, using the can ister, makes his own oxygen instead of drawing from a compressed gas cyl inder. The outstanding features of this type are its simplicity of construction and use, and lesser need for mainte nance when compared with high pres sure apparatus. NIOSH/MESA 30 CFR Part 11, Sub part H. covers self-contained breath ing apparatus. Except for some spe cial application equipment not cov ered by the Approval Schedule, all setl-contained breathing apparatus should bear Bureau ol Mines or NIOSH/MESA approval. ftSV 0005291 i( Use of Spectacles and Audible Communications Certain facepieces enable the wearer to also wear prescription spectacles without disturbing the facepiece seal (Figure 30). Most respiratory protective equip* ment can be furnished with a speak* Ing diaphragm mounted in the face* piece. Without such a speaking dia* phragm, audible communication be* tween wearers of respiratory protec* five equipment is inadequate at best and at times may bo impossible. Face* pieces wilh on exhalation valve pro* vide some measure of voice trans* mission through Ihis valve, and even those without exhalation valves permit an extremely limited transmission through the facepiece. However, a much greater degreo of audible trans* mission is provided by the modern, scientifically designed speaking dia* phragm, thus enabling voice com* municaiion belwcon wearers of such equipment whore otherwise visible communication might be tho only mothod possible. Also, sound-powered telephone equipment (Figure 31) ean be used with facepieces equipped v/ith a speaking diaphragm or In some models built into the facepiece. Such equipment provides audible communi* cation for long distances over a con* necting cable but reouires no power source other than human voice. The usual installation of these instruments provides a transmitter mounted in the facepiece and earphones mounted in a head harness for each user of re spiratory protective equipment who it lo be connected to the system. . The person who is to direct tho op erations of those wilh respiratory pro tection <s located in fresh air with a handset similar to that used with tele phones. The connecting coble ir. con veniently mounted on a reel to provide rapid winding and unwinding. Voice Amplification Unit Another type of voice transmission equipment that ean bo used with tacopieces containing a speaking dia phragm is Ihe battery-powered ampli fication unit (Figure 32). These devices arc particularly effective in overcom ing high background noise levels and enable mask wearers to communicate with other workers. rSV 0005292 17 'J !1 Figure J3--0tiffins for selecting respiratory prulecthre Jctteti. (Based en Bureaa ol Mints Information Circular 7792. Numbers In parentheses refer 1o Bureas of Mines Schedules; letters In parentheses rater to Subpart ol HIOSH/MSSA SO CfR Part 11.) respiratory protection Training For safe us* of any respiratory pro* tective device. it is essential that the user be properly instructed in its se lection, use and maintenance. Both supervisors and workers shall bo so Instructed by competent persons. Minimum training shall include iho following: 1. Instruction In the nature of the hazard, whether acute, chronic, or both, and an honesl appraisal of what may happen If the proper device is not used. 2. Explanation of why moro posltlvo control is not Immediately feasi ble. This shall include recognition that every reasonable effort is being made to reduce or eliminate the need for respiratory protection. 3. A discussion ol why this Is the proper typo o( unit (or the particular purpose. 4. A discussion of the device's capabilities and llminiions, 5. Instruction and training In actual use (especially a respiratory protec tive device lor emeiycncy use) and close and frequent supervision to assure that it continues to be property used. 6. Classroom and field training to recognize and cope with emergency situation*. Training shall provido the men an opportunity to handle the device, have it lilted properly, test its faccpiccc* lo-facc soai, wear it in normal air for long familiarity period.'and, finally, to wear it in a test atmosphara. Respiratory protective dsvieea should never be worn when a satis factory face seal cannot be obtained. There are many conditions which may prevent a satisfactory fact seal such as excessively long sideburns, a beard, temples on glasses, or an unusually structured face. Inspection, Maintenance and Repair of Respiratory Protective Equipment Proper inspection, maintenance, and repair of respiratory protective equipment is mandatory to insure success of any respiratory protection program. The precise nature of the program will vary widely based on variables as plant size and the equip ment involved. However, the goal Is to maintain the equipment in u condi tion providing the fame effectiveness it had when manufactured. Inspection: All equipment must bo inspected periodically before use and after each use. For equipment used only for emergencies the period be tween inspections con bo as individ ually desired, but should be no more than one month. A record shall be kept of aft inspection* by date with the results tabulated. There ore many dilfetrnces in the types ol equipment usrd and between the same types of equipmcnl made by different manu facturers. The best rule Is to follow precisely the recommendations of the manufacturer. Maintenance: All respiratory pro tective equipment shell bo cleaned and disinfected after each use. Other maintenance include* replacement of disposable element* such as fitters and cartridges whenever such re placement la necessary. Repair: Replacement of other than disposable parts and any repair shall be done only by personnel with ade quate training to Insuro the equip ment la functionally sound atier the work la accomplished. Only pans sup plied by the manufacturer for the product being repaired shall be used. Medical Surveillance Workers should never be assigned to any operations requiring respira tory protection until a physician has determined that they aro capable physically and psychologically to per form the work using the respiratory protective equipment. Mnny plants hovo prosmpfoymont physical txnmnnlions which Aid in such evaluation, but additional checks may be neces sary to determine suitability for a spociftc assignment. Should an employee have exposure to certain toxic materials periodic ex aminations such as a urinalysis or bioassay may bo necessary even though Iho worker wears the proper respira tory protective couiomenu RSV 0005294 10 uuJ of Mines Approval Schedules Tho Bureau of Mines, U.S. Depart ment of Uio Interior, prepared a senes Approval Schedules sotting forth Oe minimum requirements that vari ous typos of respiratory protective equipment should <*t*et to be. eon- sidored safo and ? ^cy lor uso in certain hazards or untoaithfuf con ditions. Provisions weft mada for lasting and approving the following types of respiratory protective doviccs: Self- Contained Breathing Apparatus (Schedule 13), Supplied-Air Respira tors (Schedule 19),Gas Masks (Sched ule 14), Mechanical Filter Respirators (Schedule 21). Chemical Cartridge Respirators (Schedule 23). Those devices were tested at iht Bureau of Mines at Pittsburgh, Pennsy'vania. With the exception of certain sec tions of Schedule 13, Bureau of Minoa approvals of respiratory pro tective doviccs were based upon per formance tests rather than upon spec ifications as to how the devices must be built. This policy allows manufac turers wide latitude of choice in de sign and allowed the Bureau to ap prove changes and improvements in the doviccs without frequent revision of the Schedules. Each Schedule con tains a statement to tho effect thai: (1) the device must be constructed, in all of Its peris, of materials suitable for the purpose Ihcy must serve, and (2) the design, mechanical construction, durability, and workmanship must be satisfactory from the standpoint of safety of the wearer, freedom oi move ment, field and dearness of vision, fit of the facepiece, and comfort under cl! conditions of use. This statement gavo the Bureau of Mines certain dis cretionary powers that permit the denial of approval ol a device that may meet tho performance requirements of the specific Schedule yet may be ex tremely uncomfortable to wenr, flim- i'Af built, or constructed of materials that are not suitable for conditions the device will encounter in service. Tho submission of respiratory pro- (active devices to the Bureau ol Mines was entirely voluntaty on the part of the manufacturer. The Bureau had no regulatory power requiring (hat all respiratory protective equipment be submitted fui approval looting Itacted merely as an Impnrlial testing agency thai xciveef by making available to thn public a list ol respiratory protective devices that have met definite per formance requirements. A manufacturer could visit or com municate with the Bureau ol Mines it Pittsburgh to obtain criticisms of pro posed designs or to d>ssuss test re quirements in connection with a dovico to bo submitted. No charge was made for this, consultation, and no wrilton report made to the manufacturer. Tho Bureau of Minos approval ap plies only to the device as a unit and not to its Integral parts. For instance, suppose that approval had been granted to four manufacturers, A. B, C. and 0. on lour antirely different gas masks of the same type. An assembly of A s canister harness, B's canister, C's check vatv*. and O'* facepiece would not constitute an approved as sembly. even though these individual items are parts of approved gas masks. This approval of complete devices ap- * plies throughout tho entire Bureau of Minos approval system and is not peculiar to those Schedules thai doal with respiratory protective equipment. All approved devices must bear the approval labol issued lo the manufac turers by tho Bureau. Thcso labels contain much mote information than the bare fact that the device has been approved by the Bureau of Mines. They give the limitations of tho ap proval. Hsl tho approval markings on the parts that mane up the approved assembly, and have statements re garding special precautions that should bo taken in the uso of (he de vice. The approval labels should be studied carefully so that tho devices may be used in an approved manner. Even though a device is approved, if it is used improperly or under condi tions other than thoso covered by the approval label, the approval is invali dated. Bureau of Mines approvals wero issued with the understanding that the manufacturer would make his de vice according to drawings, designs and specimens that he submitted to the Bureau and that had been con sidered and included m the approval. If ho desired to make any changes in the design of a permissible device, he had to first obtain the Bureau's ap proval of Urc change Thu Bureau Checked approved equipment that is on the market from lime to lime to as certain whether- or not it conformed to the approved device in physical makeup end performance. From tho preceding m'ormalion, it is clear that Bureau ol Mines approval is truly significant as A safeguard iu tho purchaser ol respir*)1? PrlClivo equipment and will ensuro to him that euch equipment Is dependable and salt. NIOSH/MCSA Approvals Recently, testing lor approval was transferred from tho Bureau of Mines lo tho Toiling and Certification Lab oratory (TCU of iho National Institute for Occupational Safety and Health (NIOSH) at Morgantown. West Virginia. The current opproval requirements re outlined in Codo of Federal Regu lations, Title 30, Part 11, usually re ferred to as 30 CFR Part 11. and are similar to those of the Bureau of Mines. However, additional devices, such as chin-type get masks, various types of chemical eartridgerespirators other than organic vapor types, and pesticide respirators, are covered by the Subparts of 30 CFR Part 11. Alt approvals are issued jointly by NIOSH end tho Mining Enforcement and Safety Administration (MESA). The Subparts of 30 CFR Pari 11 correspond to the Bureau of Mines Approval Schedules. Bureau of Mines Schedule 13 (Breathing Apparatus) la Subpart H; Schedule 14 (Gas Masks) Is Subpart t; Schedule 19 (Alr-Lina Respirators end Hose Masks) Is Sub part J; Schedule 21 (Oust Fume, and Mist Respirators) Is Subpart K; and Schedule 23 (Chemical Cartridge Res pirator?) la Subpart L. A new Subpart M covers pesticldo respirators and gas masks with the approvals granted at appropriate under either Subpart I or L Such devices were previously Ifsted by the Department of Agricul ture. Bureau of Mines approval numbers were BM with the appropriate Ap proval Schedule Number and the ap proval number in sequence. For ex ample. a demand-type breathing ap paratus would be DM 13E-10, etc. Under tho NIOSH/MESA joint ap proval, the letters "TC" (meaning Testing and Certification) are used rather than "BM" with the balance ol the approval number being the same. For example, tho breathing apparatus referred to above now bears approval number TC 13F-29. Since alt approvals are now jolM NIOSK/MESA, all devices recently ap proved or approved in the future will be NlOSH/MESA joint approvals with the TC prefix. 20 - ---i . jwi.. M'J! f* turn' JUi.v ju*. J1. RSV 0005295 uo.u