Document jy45M72RDmRyyN7Ra0mOkQ4OZ

Safe Practices Pampbfef No. Respiratory Protective Equipment Published by National Safety Council, Inc. 20 North Wacker Drive, Chicago 6 1. The hazards to life and health from working in certain dusts, fames, vapors, and gases have long been rec ognized, and it is generally agreed that employers should provide protection for workers exposed to these hazards. Pro gressive employers are making rapid progress in eliminating various dusts, fumes, vapors and gases through engi neering means, such as by the enclosure of processes, and by the installation of exhaust systems, but there are many op erations where it is necessary to provide the workers with suitable respiratory protective equipment 2. There are numerous types of res pirators on the market today that are known as gas masks, hose masks, oxy gen breathing apparatus, dust respira tors, chemical fume respirators, air-line masks, etc., but many industrialists do not understand their various character istics and differences. This pamphlet, therefore, has been prepared to serve as a guide for such persons. The data here in presented parallel the "American Standard Safety Code for the Protection of the Heads, Eyes, and Respiratory Organs," as well as the official publica tions of the United States Bureau of Mines. The latter of these two organ izations has established a testing and labeling service, and persons who buy such equipment are advised to purchase ,onIy those devices that have been so tested and labelled, and to use them only under the conditions for which they have been approved. 3. Another precaution that should be borne in mind is that some atmos pheres contain gases like hydrocyanic add gas that may be absorbed through the skin. Certain respirators will pro tect the lungs of persons in such atmos pheres, but it is obvious that no res pirator will protect against absorption of such gases through other exposed portions of the skin. Thij pamphlet is one of mote than 150 Safe Practices and Health Practice# Pam phlets. It is a compilation of experience in accident prevention. It ahoula not be assumed, however, tint it inlodo every acceptable procedure its the field covered. It most not be confused with federal, state or insurance requirements, or with the American Standard safety codes. Atten tion is called to the American Standard Safety Code for the Protection of the Heads, Eyes and Respiratory Organs of ' Industrial Workers, to which reference should be made; this code was formu lated under the sponsorship of the Na tional Bureau of Standards and under the procedure of the American Standards Association, 70 E, 45th St-, New York 17, N. Y. The suggestions contained in this pamphlet do not conflict with the requirements in the code. Additional copies of this pamphlet art available. Member price 35 cents each. Quantity and non-member prices on request. Types of Industrial Respiratory Equipment 4. There are two general classes of respiratory equipment: Courtesy, Mae Safety Appliance* Co. Figure 1. Self-contained oxygen breath ing apparatus provides respiratory pro tection for one hour in any atmosphere. (See paragraph 6.) I. Snpplied-air respiratory equipment. (See paragraph 5.) II. Air-purifying respirators. (See par agraph II.) But in each of these two classifications, there is a variety of types. Supplied-Air Equipment 5. In this classification there are four distinct types, plus three types adapted for abrasive-blasting opera tions: I. Self-contained oxygen breathing ap paratus. (See paragraph 6.) II. Hose mask with hand-operated Mower. (Type A snpplied-air res pirator.) (See paragraph 7.) * III. Hose mask without blower. (Type B snpplied-air respirator.) (See paragraph 8-) IV. Air-line respirator. (Type C sopplied-air respirator) (See para graph 9.) V. Abrasive - blasting respirators. (Types AE, BE, and CE snppliedair respirators.) (See paragraph 10.) 6. Self-contained oxygen -breathing apparatus. The wearer carries all of his equipment with him and is not de pendent upon the surrounding air not upon any other device or person. He receives oxygen from a container of com pressed oxygen. Such equipment can be used in any harmful or objectionable atmosphere and is particularly useful If the wearer must move about in an un restricted manner. (See Figure 1.) This makes it applicable especially in explor ing and rescue operations as in the min ing industry and in fire-fighting. It is not discussed in detail in this pamphlet; for-further information see N.S.C. Safe Practices Pamphlet No. M. 2, "Mine Rescue Work." 7. Hose mask with hand-operated blower. (Type A supplied-air respira tor.) This respirator has a tight-fitting face-piece to which is attached a large (Copyright, 1925,1929,193S, National Safety Council, Inc. All rights reserved. Printed in U. S. A.) Z--S.PJP. 64 SAFE PRACTICES PAMPHLET No. 64 The inlet should also have a device for has been properly modified or provided fastening or anchoring the end to a with additional equipment. Such changes fixed object in a zone of dean fresh air. consist primarily of adding a covering to This type of respirator is not .approved protect the head and shoulders against for use in atmospheres that are imme impact and abrasion by the rebounding diately harmful nor in those from which material. The windows inthe covering the wearer could not escape without the are shielded with glass or woven wire or aid of the device. The harness worn perforated sheet metaL Types AE, BE, by anyone using this respirator is so ar and CE supplied-air respirators are the ranged that a pull on the hose win not only types that are approved for use in exert a pull on the face-piece. The face- abrasive blasting operations. (See Fig piece may be of the full or Tissot-type, ure 3.) or half-mask, and an exhalation valve as well as a check valve are provided as cm Air-Purifying Respirators the type A supplied-air respirator. 11. There are 11 types of air-purify Conrty. X. t>. Bollard Co. Figure 2. Hose mule with hamlopetated blower proridcs rapintoty protection is any atmoapbere. (5ee paragraph 7.) diameter hose that offers low resistance to the air that passes through it Air is forced through the hose by a hand-op erated blower. The device as a whole is so arranged that the wearer can continue to breathe through it even though the blower ceases to operate. This is the only supplied-air respirator {except oxygen-breathing apparatus) that is ap proved for use in almost any atmos phere, even in an atmosphere that is im mediately dangerous to life. The sup ply-hose length should not exceed ISO feet from the blower to each man. Any one using this type of respirator also wears a body harness equipped with the necessary attachments for a life-line and for carrying the weight of the hose. Only full or Tissot-type face-pieces are used on such respirators. They form a pocket over the face and allow breath ing through the nose and mouth. An exhalation valve is provided in the facepiece to allow the escape of exhaled air and any excess of air delivered by the blower. A check valve is provided to allow flow of fresh air through the hose toward the face-piece only. (See Fig ure 2.) 9. Air-line respirator. (Type C sup plied-air respirator.) This type of respi rator is designed to protect workers against harmful or objectionable atmos pheres that are not immediately danger ous to life. In other words, it provides protection against' atmospheres that otherwise may cause harm only from continuous exposure. Air for this type of respirator is provided by either a mechanically - operated blower or a source of compressed-air. If air comes from a compressed-air system no inter nal lubricant should be used that could produce gases or mists that may be ob jectionable or injurious to health. (See paragraph 36.) If it is impracticable to follow this suggestion, suitable filters, temperature regulators and alarms should be installed in the system. A hand-operated detachable coupling should be provided in the hose so the wearer can easily and quickly attach or detach the hose at a point near the har ness. If the air pressure at any point in the system exceeds 25 pounds per square inch gage, a pressure-release mechanism should be installed that will prevent the pressure at the hose connec tion to the blower or manifold from ex ceeding 25 pounds per square inch gage. The air-supply line should not exceed 250 feet in length. The rate of air flow to the face-piece should not be less than 2 or more than 20 cubic feet per min ute. The body harness may be similar to that for type B. Any type of face- ing respirators. The first seven are chemical-filter respirators (usually called gas masks if filters ate contained in canisters; if filters are in cartridges, they are called cartridge-type chemicalfilter respirators); No. VIII is a combi nation chemical and mechanical-filter respirator; and the last three are me chanical-filter respirators. L Acid gas mask. (Type A chemicalfilter respirator.) (See paragraph 12} 21. Organic vapor gas mask. (Type B chemical-filter respirator.) (See paragraph 13.) HI. Ammonia gas mask. (Type C chemical - filter respirator.) (See paragraph 14.) IV. Carbon monoxide gas mask. (Type D chemical-filter respirator.) (See paragraph 15.) 8. Host mask without blower. (Type piece may be used except one that has B supplied-air respirator.) This type of a direct nose or mouth connection. respirator is similar to type A (see par agraph 7), but it has no blower nor any 10. Abrasive-blasting respirators. other source of air under pressure. The (Types AE, BE, and CE supplied-air hose should be not mote than 75 feet respirators.) Supplied-air respirators of long. The inlet to the hose should have the A, B, mid C types may be modified a terminal fitting or chamber that pro for use in abrasive blasting. The letter Cunrtmr, Baaghcra Carp. vides for drawing air through a screen E added to the regular-type letter indi made of corrosion-resistant material. cates that the regular-type respirator Psgate 3. Ahrasrre-blasting respirator of tf*Tair-line type. (See paragraph 10.) RESPIRATORY PROTECTIVE EQUIPMENT STV. 64--3 T3.~ Orgasnc~vapor'gas~wtskr~(type"' B chemical-filter respirators) provide protection against organic vapors such as aniline, benzene, ether, gasoline, etc., in concentrations not exceeding two per cent Black canisters are used for these respirators; they usually contain acti vated charcoal, (See Notes A, B, C, andD.) (See Figure 4.) Courtesr, Acme Protection aquip. Ca, Inc. Figure 4. Organic -vapor e*J mask for protection vgainst organic vapon. (See paragraph 15.) V. Combination acid gas and organic vapor gas mask. (Type AB chem ical-filter respirator.) (See para graph 16.) VI- Combination add gas, organic vapor, and ammonia gas mask. (Type ABC chemical-filter respi rator.) (Sec paragraph 17.) VH- Combination add gas, organic vapor, ammonia, and carbon monoxide gas made. (Type ABCD chemical -filter respirator-) (See paragraph 18.) VUL AS-gas respirator. (Type N respirator.) (See paragraph 19.) DC Type A mechanical-filter respirator. (See paragraph 20.) X Type B mechanical-filter respirator. (See paragraph 21.) XL Type C mechanical-filter respirator. (See paragraph 22.) 12. Add gas masks (type A chemi cal-filter respirators) provide protection against add gases such as hydrochloric add, hydrogei sulphide, sulphur diox ide, chlorine, etc., in concentrations not exceeding two per cent. The chemical filter is contained in a canister or car tridge that is colored white so it can easily be distinguished from other can isters used for other purposes. The chemical for this respirator usually con sists of soda lime or caustic soda fused on pumice granules. The time of pro tection decreases rapidly as the concen tration of gas increases. (See Notes A, B, C, and D.) 14. Ammonia gas masks (type C chemical-filter respirators) provide pro tection against ammonia in concentra tions not exceeding three per cent. Green canisters are used for these respirators; they usually contain silica gel or malic arid. The three per cent maximum con centration cannot be long endured by the wearers of this type of respirator because of the severe skin irritation from ammonia gas. (See Notes A, B, C, and D.) (See Figure 5) IS. Carbon monoside gas masks (type D chemical-filter respirators) provide protection against carbon maooxide in concentrations not exceeding two per cent- Blue canisters are used for these respirators; they usually contain "hopcaIite.', "Hopcalite" cata lyzes carbon monoxide with oxygen of the air to produce relatively harmless carbon.dioxide. These respirators pro tect in concentrations exceeding two per cent, but the air becomes noticeably wanner as the percentage of carbon monoxide encountered increases. (See Notes A, B, C, and D.) Courtage. Davis Kmergeney Xdutpment Co. Figure 6. Chemicsl-filtef requestor lor protection sgxiast sod gsses and organic vapors. (See paragraph 16.) 16. Combination add gas and or ganic vapor gas masks (combination type chemical-filter respirators AB) pro vide protection against arid gases and organic vapors in concentrations not ex ceeding two per cent arid gases and two per cent organic vapors. Yellow can isters are used with these respirators; they usually contain activated charcoal and soda lime. (See Notes A, B, C, and D.) (See Figure 6.) 17. Combination add gas, orgastic vapor, and ammonia .gas masks (combi nation type chemical-filter respirators ABC) provide protection against two per cent add gases, two per cent or ganic vapors, and two per cent am monia. Brown canisters are used with these respirators; they usually contain soda lime, activated charcoal, and silica gel As the number of gases encountered increases, the service time of the can isters decreases. (See Notes A, B, C, and D.) Cbartoxy. TokoUb IsdoxMea, Inc. FignreS. Amnwnix ga* mjok 'widxbefnial filter nrmtvlnrd fo nrattq. (See para graph 14.) IS. Cosnbination add gas, organic vapor, ammonia, and carbon monoxide gas masks (combination type chemicalfilter respirators ABCD) provide protec tion against two per cent add gases, two per cent organic vapors, three per cent antmrmia, and two per cent carbon monoxide. The canisters used with these 4--S.PJ?. 64 SAFE PRACTICES PAMPHLET No. 64 Note A: These chemical-filter respirators are provided with a body harness to support the weight of the canister. Note B: These chemical-filter respirators have check valves and exhala tion valves. Note C: No chemical-filter respirator will provide protection where the atmosphere is deficient m oxygen. Courtesy, Mine Safety Appliance* Co. Figure 7. All-gas respirator for protection against add gases, organic vapors, carbon monoxide, ammonia, imolrrs, dusts and mists. (See paragraph I?.) respirators usually contain soda lime, activated charcoal, silica gel and "hopcalite." (See Notes A, B, C, and D.) 19. All-gas respirators (type N res pirators) provide protection against combinations of add gases, organic vapors, ammonia, carbon monoxide, dusts, fumes, and mists if the concen trations do not exceed two per cent add gases, two per cent organic vapors, three per cent ammonia, and two per cent carbon monoxide. Red canisters are used with these respirators; they usually contain soda lime, activated charcoal, silica gd, hopcalite, and cotton wool filters. (See Note C.) (See Figure 7.) Note D: The resistance of a chemicalfilter respirator to a flow of air of 3 cubic feet par minute should not exceed 3 inches of water pressure and the resistance to exhalation should not exceed 1 inch of water. 20. Type A mechanical-filter respi rators provide protection against pnenmoconiosis-prodndng or nuisance dusts such as quartz, asbestos, iron ores, cement, limestone, gypsum, coal, coke, charcoal, wood, cellulose, flour and aluminum. They are not approved for protection against dusts whose main harmful constituents are metals or their compounds, such as antimony, arsenic, cadmium, chromium, lead, manganese, mercury, selenium, tellurium, thallium, uranium and vanadium, or against harmful smoke, gases and fumes. (See Notes and F.) (See Figures 8 to 12 inclusive.) Certain respirators of this type have been adapted by the manu facturers to provide protection against lead dust; others protect against pneu moconiosis-producing or nuisance dusts, also against lead dust. That is, such respirators protect against medianicallygenerated lead dust such as that gen erated in manufacturing storage bat teries; enameling; pottery making; rub ber compounding; sandpapering and chipping painted surfaces; paint mak ing; preparing litho-transfers; and min ing, nulling, and processing lead ores. These respirators are not approved for protection against the inhalation of lead fumes generated by heating and volatil izing lead, such as the fumes generated in lead burning and soldering, smelting, type founding, and fusing lead glaze and enamel; or protection against dusts of other poisonous metals or their com pounds, or harmful smokes, fumes or mists. (See Figures 13 and 14.) VWIUWO^I Figure 9. Mechanical-filter respirator for protection against pneumoconiosispfoducmg or nuisance dusts. (See paragraph 20.) 22. Type C mechanical-filter respi rators provide protection against die mist of chromic add as produced in chromium plating; the mist produced by spray coating with lead paint and vitre ous enamels. (See Notes E and F.) Note E: In all mechanical-filter respi rators having a rate of air flow of three cubic feet per minute, the resistance to the flow of air shall not exceed two inches of water pressure, and the resist ance to exhalation shall not ex ceed one inch of water pressure. Note F: No mechanical-filter respirator will provide protection where the atmosphere is deficient in oxygen. Respirator Maintenance 23. Practically all respirators have rubber and rubberized fabric in their Courtesy, Americas Optical Co Figure & Mechanical-filter respirator for protection against poenmoconiojis-prodoting ot tmionce dots. (See para- graph 20.) 21. Type B mechanical-filter respi rators provide protection against the fumes of metals such as aluminum, arsenic, antimony, cadmium, chromium, copper, iron, lead, magnesium, man ganese, mercury (except vapor), and zinc. (See Notes E and F.) Courtesy, B. 7. McDonald Co. Figure to. Mcrhaniral-filtcr respirator for protection against pncnmocociosis-producing or nuisance dusts. (See paragraph 20.) RESPIRATORY PROTECTIVE EQUIPMENT - 25.-- If-the-sarocjcspirator is.used hy. several persons, it is always advisable to dean and disinfect it after each per son has used it To dean a respirator, it may be washed with a brush and soap in warm water. Sterilizing may be ac complished in either of three ways: 64--5 a. Immerse for 10 minutes in a solution of 1 part of 40 per cent formaldehyde and 9 parts of water. b. Dip in a 3 per cent solution of carbolic acid or a 2 per cent solution of lysol. Courtesy, H, S. Cover Figure 1L. Mechanical-filter respirator for protection against pneumoconkwis-prodoEing or nuisance dusts. (See paragraph 2a) construction, and since heat, air, light, water and oil cause such substances to deteriorate, respirators should be stored in a cool dry place and protected from light and air as much as possible. Wood, fiber, or metal cases are provided with many respirators, and the respirators will last much longer if kept in such cases when not in actual use. 24. After a respirator has been used, it should be carefully wiped with a damp doth and dried before it is placed back in the case. Care should be taken to make sure there are no sharp folds or creases in the respirator when it is put away. c. Place in a moist atmosphere of anti septic gas, preferably formaldehyde, for 10 minutes at room temperature. The respirator should then be rinsed with water and hung up to dry in an inverted position. No attempt should be made to sterilize elastic head-bands, canisters and filters. 26. There should be a "time card" in each gas mask container, on which a record should be kept of the number of horn's and minutes that each canister is used. If there is any reason to believe that a canister is almost or entirely exhausted, a fresh canister, should be attached to the mask. 27. A timer should be used on the type N all-gas respirator; this has a hand that moves around a dial in about two hours of normal breathing, and one revolution indicates that a new canister should be attached even if the respirator has not been worn in contaminated air. Courtesy, Chicago Eye SSleW Ccl. Figure 13. Mechanics!-filter respirator for protection! against poeunwasoiosis-productng or nuisance data, *lo against lead dust. (See paragraph 20.) 30. In some organizations, one or more selected individuals are given the responsibility for maintaining all respi rator equipment in good condition. Use of Respirators 31. The man who is to wear a chem ical-filter respirator should test the face piece to make sure it fits and does not leak before he enters a gaseous loca tion. To do this, the respirator is put on and the head-hands adjusted until it fits dosely and comfortably. There should be no kinks in any of the tubes 28. Manufacturers deliver canisters with plugged seals covering the bottom valve, and with codes dosing the hose nipple unless the latter is attached to the face-piece. Canisters should be stored and used as directed by the can ister manufacturers. Courtesy, Standard Safety Equipment Co. Figure 12. Mechanical-filter respirator for protection against pnenmocooiosis-piodiictag or nuisance dusts. (Sec paragraph 20.) 29. Canisters should be protected, especially from possible absorption of dampness when not in use. If a canister has become saturated with moisture, it should not be used again. When a respi rator with a canister is stored for future use, the seal on the bottom opening of the canister should not be broken; if It has already been broken it should be dosed with the plug stopper furnished with the canister. Courtrey, Pulmoan Safety Equipment Corp. Figure 14. Methanind-filttr respirator for protection against pneutnoconiosia-producing or nuisance dusts, also against lead dust. (See paragraph 20.) 6--SJP-P. 64 SAFE PRACTICES PAMPHLET No. 64 -or~ho9e.-Re9staace-to natural-breath -aear-the-icc-machine-or- ammonia- pip^- -nre~to~ wcar~meni may otdaHggr flHfflT ing should be very slight. The intake mg. Instead, it is better to place it just lives; they think they are super-men to the canister should be dosed with the inside or outside one of the exit doors and "can take it" without protection. palm of the hand, and suction exerted so anyone can reach it quickly without Usually the attitude of such men can with the lungs until the face-piece col exposing himself unnecessarily to the be changed if someone in authority in lapses. The face-piece should remain ammonia gas. the organization will honestly make an collapsed far about IS seconds. If the respirator is tight, the wearer can pro ceed, but he should enter the gas cau tiously to see that the canister is active: If the respirator leaks or if the canister is used up, as indicated by odor, taste, or eye, nose or throat irritation, the wearer should immediately return to fresh air and ascertain the cause. If the canister is used up a new one should be attached, care being exercised to make sure that the right canister is se lected for the gas to be encountered. 35. It is recommended that a safety belt and life-line he used in every case where the wearer of a respirator enters a confined irrespirahle atmosphere. A man'should be stationed outside to tend the life-line and to act in an emergency. In many cases, he should be provided with suitable respiratory protective equipment so he can put it on if it be comes necessary for him to go into the same iixespirable atmosphere to assist his co-worker. effort to do it He should explain why specific types of respirators are neces sary under certain conditions, show the men how to fit the respirators in proper position, and explain their operation. Then, after every possible effort has been made to convince such men that respirators are essential, the job be comes one of laying down certain shop rules and enforcing than through super vision--and discipline, if necessary, as a last resort Special cate should be used when the respirator is worn in gases or vapors that have no warning properties. 32. Each person who learns to use a supplied-air respirator or a chemicalfilter respirator should first undergo a physical examination, especially as to the condition of the heart and lungs. 33. When respirators with hose con nections are used, care must be exer cised to prevent injury to the hose; for instance, it should not be permitted to lie in water or oiL 34. If respirators are provided for emergency use, they should be kept handy to the place where the emergency may be created. For instance, at least cme type C chemical-filter respirator should be available in an ice plant for use in case of ammonia leak. The respi Use of Compressed Air 36. If compressed sir is used for air line respirators, special filters or other means should be provided to prevent contamination of the air with oil, mois ture, carbon monoxide, and other un desirable contaminants. Carbon monox ide is not likely to be created in com pressed air equipment except under un usual circumstances, such as if any part of the equipment becomes considerably overheated. Thus, it is necessary to check the compressed air-equipment fre quently to prevent overheating. (See paragraph 9.) Getting Workers to Wear Respirators 37. Some workers consider respi ACKNOWLEDCMENT This pamphlet was prepared by the Industrial Division, National Safety Council, in cooperation with engineers of the D. S. Bureau of Mines, representative members of the sectional committee for the "Safety Code for the Protection of the Heads, Eyes and Respiratory Or gans of Industrial Workers," and various manufacturers of respiratory protective equipment. It has been reviewed by the Safe Practices Conference Committee arid approved by the Executive Com mittee of the Council. The respirators illustrated in tins pamphlet have aU been approved by the U. S. Bureau of Mines; limited space makes it impossible to illustrate aU respirators that have been so approved. rator, however, should sot be kept too rators a nuisance, not realizing that fail- Rtp. --3M I i I i