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OSHA 3079, 1993
No booklet can cover every situation in the workplace where respirators should be worn. Nonetheless, this booklet presents considerable information on respiratory equipment and complements the relevant safety and health regulations and manufacturers' requirements. Occupational Safety and Health Administration (OSHA) regulations governing the use of respirators in general industry are found in the Code of Federal Regulations (CFR) Title 29 Part 1910-134; those governing use in the construction industry are cited in 29 CFR Part 1926.103; and those for the maritime industry are in 29 CFR Parts 1915.152 and 1918.102. All are available in many libraries and from the Government Printing Office. Also, the CFR and this booklet refer to specifications issued by the American National Standards Institute, Inc. (ANSI), 11 West 42nd Street, New York, NY 10036.
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Hazards to the lungs are not always easy to detect. Some of the most common hazards are the lack of oxygen and the presence of harmful dusts, fogs, smokes, mists, fumes, gases, vapors, or sprays including substances that may cause cancer, lung impairment, other diseases, or death. Respirators help prevent the entry of harmful substances into the lungs during breathing. Some respirators also provide a separate supply of breathable air so work can be performed where there is inadequate oxygen or where greater protection is needed.
The prevention of atmospheric contamination at the worksite generally should be accomplished as far as feasible by engineering control measures, such as enclosing or confining the contaminant-producing operation, exhausting the contaminant, or substituting with less toxic materials. Historically, the industrial hygiene profession has sought to control hazardous air contamination through engineering means. When effective engineering controls are not feasible, while those controls are being installed, or during cleanup operations, however, appropriate respirators must be used. The user should be aware that respirators have their limitations and are not a substitute for effective engineering controls. Where respirators are necessary for health protection, specific procedures are necessary to overcome any potential deficiencies and to ensure the effectiveness of the equipment.
Employers are responsible for establishing an effective respiratory program. Different hazards require different respirators and employees are responsible for wearing the respirator and complying with the program.
The plant or company department of industrial hygiene, health physics, safety engineering or fire prevention should administer the program in liaison with the plant medical department. In small plants that have no such departments, the respirator program should be administered by an upper-level superintendent, foreman, or qualified person responsible to the principal manager. Responsibility for the program should rest with one person. The administrator must have sufficient knowledge of the subject to supervise the program properly.
Any respirator program should stress thorough training of all participants, especially the users who need to wear the respirators. Employees must be aware that the equipment does not eliminate the hazard. It the equipment fails, over- exposure will occur. To reduce the possibility of failure, equipment must fit properly and be maintained in a clean and serviceable condition.
Employers and employees must understand the equipment's purpose and its limitations. The equipment must not be altered or removed by the wearer even for a short time, despite the fact the wearer may find it uncomfortable.
An effective respirator program must cover the following factors:
In workplaces where respirators are used in potentially hazardous atmospheres present during normal operations or emergency situations, employers are required to have written operating procedures for the safe and proper use of respirators. Users must be familiar with these procedures as well as with available respirators and their limitations. In workplaces with no hazardous exposures, but where there is voluntary respirator use, a written program may not be necessary.
The effectiveness of a company's respirator program should be evaluated regularly at least annually and the written operating procedure modified as necessary to reflect the evaluation results. The use of a labor-management team may be effective for the periodic evaluation.
Choosing the right equipment involves several steps: determining what the hazard is and its extent, choosing equipment that is certified for the function, and ensuring that the device is performing the intended function. The proper selection of respirators must be made according to the guidance of American National Standards Institute (ANSI) publication, Practices for Respiratory Protection, ANSI Z88.2-1969. (A later edition of this standard, Z88.2-1980, has been issued by ANSI.)
Chemical and physical properties of the contaminant, as well as the toxicity and concentration of the hazardous material and the amount of oxygen present, must be considered in selecting the proper respirators. The nature and extent of the hazard, work rate, area to be covered, mobility, work requirements and conditions, as well as the limitations and characteristics of the available respirators also are selection factors.
There are two basic classes of respirators: air purifying and atmosphere supplying. Air-purifying respirators use filters or sorbents to remove harmful substances from the air. They range from simple disposable masks to sophisticated devices. Air purifying respirators do not supply oxygen and may not be used in oxygen-deficient atmospheres or in ones that are immediately dangerous to life or health (IDLH). Atmosphere-supplying respirators are designed to provide breathable air from a clean air source other than the surrounding contaminated work atmosphere. They range from supplied-air respirators and self-contained breathing apparatus (SCBA's) to complete air-supplied suits.
The time needed to perform a given task, including the time necessary to enter and leave a contaminated area, is one factor that determines the type of respiratory protection needed. For example, a SCBA, gas mask, or air-purifying chemical-cartridge respirator provides respiratory protection for relatively short periods; whereas, a type of atmosphere-supplying respirator that supplies breathable air from an air compressor through an air line can provide protection for extended periods of time. Particulate filter air-purifying respirators can provide protection for long periods without the need of filter replacement only if the total concentration of atmospheric particulates is low. Where there are higher concentrations of contaminants, however, an atmosphere-supplying respirator such as the positive-pressure supplied-air respirator (SAR) offers the advantage of better protection and longer duration.
The use of SAR's also avoids the need to be concerned about the sensory warning properties of the airborne toxic materials, a factor that must be considered when using air-purifying respirators. SAR's also cause less discomfort than air-purifying respirators because the wearer need not overcome filter resistance when inhaling.
Air-purifying respirators present minimal interference with the wearer's movement. Atmosphere-supplying respirators, however, may restrict movement and present potential hazards. For example, SAR's with their trailing hoses, can limit the area the wearer can cover and may present a potential hazard where the trailing hose can come into contact with machinery. Similarly, an SCBA, a respirator that includes a back-mounted, compressed-air cylinder presents both a size and weight penalty. This may restrict climbing and movement in tight places, and carrying the added weight of the air cylinder presents an additional burden.
Another factor to consider when using respirators is the air supply rates. The wearer's work rate determines the volume of air breathed per minute. The volume of air supplied to meet the breathing requirements is of great significance when using atmosphere-supplying respirators such as self-contained and air-line respirators that use cylinders because this volume determines their operating life. The useful service life of these respirators under even moderate working conditions may be significantly less than under conditions of rest.
The peak airflow rate also is important in the use of a constant flow SAR. The air-supply rate should always be greater than the maximum amount of air being inhaled in order to maintain the respiratory enclosure under positive pressure.
Higher breathing resistance of air-purifying respirators under conditions of heavy work may result in distressed breathing. A person working in an area of high temperature or humidity is under stress. Additional stress resulting from the use of a respirator should be minimized by using one having a minimal weight and a minimal breathing resistance when these can be fitted properly to the wearer.
Some type of warning on the remaining service life is available for all SCBA's and for some chemical canister respirators. This may be a pressure gauge or timer with an audible alarm for SCBA's or a color end-of-service-life indicator on the cartridge or canister. The user should understand the operation and limitations of each type of warning device. Most other gas masks and chemical cartridge respirators have no indicator for the remaining service life. It is important, therefore, that new canisters and cartridges be used at the beginning of each work shift.
The following list presents a simplified version of characteristics and factors used for respirator selection. It does not specify the contaminant concentrations or particle size. Some OSHA substance-specific standards include more detailed information on respirator selection.
|Hazard Oxygen deficiency||Respirator|
|*Immediately dangerous to life or health||Any positive-pressure SCBA|
|Combination positive-pressure SAR with auxiliary self-contained air supply.|
|Not immediately dangerous to life or health||Any positive-pressure SCBA or supplied-air respirator.|
|Gas and vapor contaminants|
|*Immediately dangerous to life or health||Positive-pressure SCBA, Combination positive-pressure SAR, SAR with auxiliary self-contained air supply|
|Not immediately dangerous to life or health||Any positive-pressure SAR, Gas mask, Chemical cartridge respirator|
|*Particulate contaminants||Any positive-pressure SAR including abrasive blasting respirator, Powered air purifying respirator equipped with high-efficiency filters. Any air-purifying respirator with a specific particulate filter.|
|*Gaseous and particulate contaminants|
|*Immediately dangerous to life or health||Positive-pressure SCBA, Combination positive-pressure SAR with auxiliary self-contained air supply|
|Not immediately dangerous to life or health||Any positive-pressure supplied-air respirator, Gas mask, Chemical-cartridge respirator|
|*Escape from contaminated atmosphere that may be immediately dangerous to life or health||Any positive-pressure SCBA, Gas mask, Combination positive-pressure SAR with escape SCBA|
|*Firefighting||Any positive-pressure SCBA|
Note: "Immediately dangerous to life or health" is any condition that poses either an immediate threat to life or health or an immediate threat of severe exposure to contaminants, such as radioactive materials, which are likely to have adverse delayed effects on health.
Full facepieces, half masks, quarter masks and even the different brands of the same type of respirator marketed, have different fit characteristics. No one respirator will fit everyone. Employers will find it advantageous to purchase several brands of each type in various sizes to ensure proper fit for all workers who must wear one.
Corrective glasses worn by employees also present a problem when fitting respirators. Special mountings are available to hold corrective lenses inside full facepieces. If corrective lenses are needed, the facepiece and lenses must be fitted by a qualified individual to provide good vision, comfort, and proper sealing.
The user must receive fitting instructions including demonstrations and practice in how to wear the respirator, how to adjust it, and how to determine if it fits properly.
Although respirators are designed for maximum efficiency, they cannot provide protection without a tight seal between the facepiece and the face of the wearer. Consequently, beards and other facial hair can substantially reduce the effectiveness of a respirator. The absence of dentures can seriously affect the fit of a facepiece. To ensure proper respiratory protection, a facepiece must be checked each time the respirator is worn. This can be accomplished by performing. either a positive-pressure or negative pressure check. Detailed instructions for performing these tests can be found in the ANSI standard.
The effectiveness of the fit of the facepiece can be tested two ways: qualitatively and quantitatively.
Qualitative fit testing involves the introduction of a harmless odorous or irritating substance into the breathing zone around the respirator being worn. If no odor or irritation is detected by the wearer, a proper fit is indicated.
Quantitative fit testing offers more accurate, detailed information on respirator fit. It involves the introduction of a harmless aerosol to the wearer while he or she is in a test chamber. While the wearer performs exercises that could induce facepiece leakage, the air inside and outside the facepiece is then measured for the presence of the harmless aerosol to determine any leakage into the respirator.
All respirators must be inspected for wear and deterioration of their components before and after each use. Special attention should be given to rubber or plastic parts that can deteriorate. The facepiece, especially the face seal surface, headband, valves, connecting tube, fittings, and canister must be in good condition. A respirator inspection must include a check of the tightness of the connections.
Emergency use respirators and SCBA's must be inspected at least monthly. Air and oxygen cylinders must be fully charged according to the manufacturer's instructions. Regulator and warning devices must be checked to ensure their proper function. Records must be kept of inspection dates and findings.
Chemical cartridges and gas mask canisters must be replaced as necessary to provide complete protection. The manufacturer's recommendations must be followed. Mechanical filters must be replaced as necessary to avoid high resistance to breathing.
Repairs must be made only by experienced persons using parts specifically designed for the respirator. The manufacturer's instructions should be consulted for any repair, and no attempt should be made to repair or replace components or make adjustments or repairs beyond the manufacturer's recommendations.
A respirator that has been used must be cleaned and disinfected before it is reissued. Emergency-use rescue equipment must be cleaned and disinfected immediately after each use.
Respirators must be stored to protect against dust, sunlight, heat, extreme cold, excessive moisture, or damaging chemicals. Protection against any mechanical damage also should be provided. Respirators should be stored so that facepieces and exhalation valves will rest in a normal position to prevent the rubber or plastic from reforming into an abnormal shape.
Respirators may be washed in a detergent solution and then disinfected by immersion in a sanitizing solution. Cleaners, sanitizers that effectively clean the respirator and contain a bactericidal agent are commercially available. The bactericidal agent frequently used is a quaternary ammonium compound. Strong cleaning and sanitizing agents and many solvents can damage rubber or elastomeric respirator parts. Such materials must be used with caution or after consultation with the respirator manufacturer.
Persons assigned to tasks that require the use of a respirator must be physically able to perform the work while using the respirator. The local physician must determine what health and physical conditions are pertinent. The respirator user's medical status must then be reviewed periodically.
When respirators are worn in toxic atmospheres, the individual must be provided appropriate laboratory tests. These may include urine, blood, or fecal analysis and other techniques to determine the intake and excretion of toxic substances. The findings of these tests, when correlated with other exposure data, such as air sampling data for wearers of such equipment, can serve as an indication of the effectiveness of the program. Positive evidence of exposure must be followed up with appropriate surveillance of work area conditions to determine if there is any relationship to inadequate respiratory protection or a need for additional engineering controls.
Surveillance must be maintained of the conditions in the work area and of the degree of worker exposure or stress (combination of work rate, environmental conditions, and physiological burdens of wearing a respirator). Changes in operating procedures, temperature, air movement, humidity, and work practices may influence the concentration of a substance in the work area atmosphere. These factors necessitate periodic monitoring of the air contaminant concentration. Testing must continue to ensure that the contaminant exposure has not risen above the maximum protective capability of the respirators being used.
Employees using SCBA'S, or SAR's with auxiliary SCBA'S, in confined spaces where the environment is or may be immediately dangerous to life or health must wear safety harnesses and lifelines. A second person equipped with complete protective gear must be standing by ready to help if the first worker gets into trouble. Communications (visual, voice, or signal line) must be maintained with all persons present. Precautions must be taken so that, in the event of an accident, one person will be unaffected and have the proper rescue equipment to assist the others in an emergency situation.
Compressed air, compressed oxygen, liquid air, and liquid oxygen used for respiration must be of high purity. Oxygen must meet the requirements of the United States Pharmacopoeia for medical or breathable oxygen. Breathable air must meet at least the requirement for Grade D breathable air described in Compressed Gas Association (CGA) Commodity Specification G-7. 1-1966. (A later edition of this specification, G-7.1-1989, has been issued by CGA.) Compressed oxygen must not be used in open circuit SCBA's or SAR's that have previously used compressed air. Oxygen must never be used with air-line respirators.
Breathable air may be supplied to respirators from cylinders or air compressors. For testing cylinders, see Shipping Container Specifications of the Department of Transportation (49 CFR Part 178).
Containers of breathable gas must be clearly marked. (See American National Standards Institute Method of Marking Portable Compressed Gas Containers to Identify the Material Contained, ANSI Z48.1/CGA C-4-1988; Federal Specification BB-A-1034a, June 21, 1968, Air, Compressed for Breathing Purposes; or Interim Federal Specification GG-B-00675b, April 27, 1965, Breathing Apparatus Self Contained.) Further details on the sources of compressed air and its safe use will be found in the Compressed Gas Association's pamphlet G-7.1-1989.
The compressor for supplying air must be equipped with the necessary safety devices and alarms. Compressors must be constructed and situated to avoid any entry of contaminated air into the system and must be equipped with suitable in- line, Air purifying sorbent beds and filters installed to ensure air quality. The system also must have a receiver of sufficient capacity to enable the wearer to escape from a contaminated atmosphere in the event of compressor failure and alarms to indicate compressor failure and overheating. If an oil-lubricated compressor is used, it must have a high-temperature or carbon monoxide alarm or both. If only the high-temperature alarm is used, the air from the compressor must be tested frequently for carbon monoxide.
Air-line couplings must be incompatible with outlets for other gas systems to prevent accidental servicing of air-line respirators with nonrespirable gases or oxygen.
Respiratory protective devices must be approved jointly by the Mine Safety and Health Administration of the Department of Labor, and the National Institute for Occupational Safety and Health of the Department of Health and Human Services, for the contaminant or situation to which the employee is exposed.
When planning a program to control occupational illness caused by breathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, vapors, or sprays, the primary objective should be to prevent such atmospheric contamination. Respirators must be used while effective engineering controls, if they are feasible, are being installed. If engineering controls are not feasible, employers must provide respirators, and employees must wear them when it is necessary to protect their health. The equipment issued to the employee must be properly selected, used, and maintained for a particular work environment and contaminant, and employees must be trained in all aspects of the respiratory protection program.