OSHA Respiratory Protection Program
Many different types and levels of inhalation hazards exist on a hazardous waste site. Waste site workers need to thoroughly understand the different types of respiratory equipment available, protection factors, and fit testing so they can select the best respirator for the hazards they will encounter.
Respiratory Protection Program - 29 CFR 1910.134
Under 29 CFR 1910.134 hands-on hazwoper training methods should be used. OSHA requires employers to have a respiratory protection program that covers all employees whose job requires the use of respirators.
This program must meet the following requirements:
1. Written standard operating procedures covering the selection and use of respirators must be established.
2. Respirators will be selected based on hazards to which the worker is exposed.
3. The user will be instructed and trained in the proper use of respirators and their limitations.
4. Respirators must be regularly cleaned and disinfected. Those used by more than one worker must be thoroughly cleaned and disinfected after each use.
5. Respirators will be stored in a convenient, clean, and sanitary location.
6. Respirators used routinely will be inspected during cleaning. Worn or deteriorated parts will be replaced.
7. Appropriate surveillance of work area conditions and degree of employee exposure or stress shall be maintained.
8. A local physician will determine if a user is physically able to perform the work and use the equipment. This medical status should be reviewed periodically (suggested annually). See Lesson on Medical Surveillance for more details.
9. The user should be properly fit tested and taught how to check facepiece fit before each use. See the section on fit testing at the end of this lesson. 10. The effectiveness of the program should be evaluated on a regular basis.
Selection of Respiratory Equipment
Respiratory protection is of primary importance since inhalation is one of the major routes of exposure to chemical toxicants. Respiratory protective devices (i.e., respirators) consist of a facepiece connected to either an air source or an air-purifying device.
Positive and Negative Pressure Airflow
Different types of airflow may influence the selection of a respirator:
• Positive Pressure Airflow.
• Negative Pressure Airflow.
Positive-pressure respirators maintain a positive pressure in the facepiece during both inhalation and exhalation. The two main types of positive-pressure respirators are pressure-demand or continuous flow.
Pressure-Demand In pressure-demand respirators, a pressure regulator and an exhalation valve on the mask maintain the mask's positive pressure, except possibly during high breathing rates. If a leak develops in a pressure-demand respirator, the regulator sends a continuous flow of clean air into the facepiece, preventing penetration by contaminated ambient air.
Continuous-Flow Continuous-flow respirators including some supplied air respirators (SARs) and all powered air-purifying respirators (PAPR), send a continuous stream of air into the facepiece at all times. With SARs the continuous flow of air prevents infiltration (i.e., invasion) by ambient air but uses the air supply much more rapidly than with pressure demand respirators. Powered air-purifying respirators (PAPRs) are operated in a positive-pressure continuous flow mode utilizing filtered ambient air. However, maximal (i.e., highest) breathing rates may create a negative pressure in the facepiece of a PAPR.
Negative-Pressure Airflow Negative-pressure respirators draw air into the facepiece via the negative pressure created by user inhalation. The main disadvantage of negative-pressure respirators is that if any leaks develop in the system (i.e., a crack in the hose or an ill fitting mask or facepiece), the user draws contaminated air into the facepiece during inhalation. When atmosphere-supplying respirators are used, only those operated in the positive-pressure mode are recommended for work at hazardous waste-sites.
Atmosphere-Supplying Respirators Atmosphere-supplying respirators are respirators with an air source and consist of two types: - Self-Contained Breathing Apparatus (SCBA), which supplies air from a source carried by the user, and - Supplied Air Respirator (SAR), which supplies air from a source located some distance away and connected to the user by an air line hose. Supplied air respirators are sometimes referred to as air line respirators.
Air-Purifying Respirators Air-purifying respirators (APRs), on the other hand, do not have a separate air source. Instead, they utilize ambient (i.e., surrounding) air which is "purified" through a filter before inhalation.
Types of APR face pieces Different types of facepieces are available for use with the various types of respirators. The types generally used at hazardous waste sites are full facepiece masks and half masks. Full facepiece masks cover the face from the hairline to below the chin, providing eye protection. Half masks cover the face from below the chin to over the nose and do not provide eye protection. Federal regulations require the use of respirators that have been tested and approved by the Mine Safety and Health Administration (MSHA) and NIOSH. Testing procedures are described in 29 CFR 1910.134 Appendix A. Approval numbers are clearly written on all approved respiratory equipment. However, not all respiratory equipment that is marketed is approved. Periodically, NIOSH publishes a list, entitled NIOSH Certified Equipment List, of all approved respirators and respiratory components.
Protection Factor The level of protection that can be provided by a respirator is indicated by the respirator's protection factor. The Assigned Protection Factor (APF) is determined experimentally by measuring facepiece seal and exhalation valve leakage. The number indicates the relative difference in concentrations of substances outside and inside the facepiece. For example, the protection factor for full facepiece air-purifying respirators is 50. This means, theoretically, that workers wearing these respirators should be protected in atmospheres containing chemicals at concentrations that are up to 50 times higher than the appropriate limits (PELs, TLVs, etc.). This may be referred to as the maximum use limit (M.U.L.). One source of protection factors for various types of atmosphere supplying (SCBA and SAR) and air-purifying respirators can be found in American National Standards Institute standard ANSI Z88.2-1980.