Advantages and Disadvantages
Now let's discuss the relative advantages and disadvantages of SCBAs, SARs, and APRs. When atmosphere-supplying respirators are used, only those operated in the positive-pressure mode are recommended for work at hazardous waste sites.
Maintenance and Care of Respirators
Self-Contained Breathing Apparatus (SCBA)
- Advantages: SCBAs provide the highest available level of protection against airborne contaminants and oxygen deficiency and under strenuous work conditions.
- Disadvantages: They are bulky, heavy (up to 35 pounds). They have finite air supply that limits work duration. They may impair movement in confined spaces.
Positive-Pressure Supplied-Air Respirator (SAR) (Also Called Air-Line Respirator)
- Advantages: SARs enable longer work periods than a SCBAs. They are less bulky and heavy than a SCBA. SAR equipment weighs less than 5 pounds (or around 15 pounds if escape SCBA protection is included). They protect against most airborne contaminants.
- Disadvantages: SARs are not approved for use in atmospheres immediately dangerous to life or health (IDLH) or in oxygen-deficient atmospheres unless equipped with an emergency egress unit such as an escape-only SCBA that can provide immediate emergency respiratory protection in case of air-line failure. MSHA/NIOSH certification limits hose length to 300 feet (90 meters). As the length of the hose is increased, the minimum approved air flow may not be delivered at the facepiece. The air line is vulnerable to damage, chemical contamination, and degradation. Decontamination of hoses may be difficult. The worker must retrace steps to leave work area. SARs require supervision/monitoring of the air supply line.
Air-Purifying Respirator (Including Powered Air-Purifying Respirators (PAPRs)
- Advantages: APRs enhance mobility. They are lighter in weight than an SCBA. Generally weighs 2 pounds (1 kg) or less (except for PAPRs).
- Disadvantages: APRs cannot be used in IDLH or oxygen-deficient atmospheres (less than 19.5 percent oxygen at sea level). They provide a limited duration of protection, and it may be hard to gauge the safe operating time in field conditions. APRs only protect against specific chemicals and up to specific concentrations and require monitoring of contaminant and oxygen levels. APRs can only be used:
- against gas and vapor contaminants with adequate warning properties, or
- for specific gases or vapors if the service is known and a safety factor is applied or if the unit has an ESLI (end-of-service-life indicator).
Knowledge Check Choose the best answer for the question.
1-5. What is an advantage of the self-contained breathing apparatus (SCBA)?
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