Proposal for certification tests and standards for closed-circuit breathing apparatus.
Pittsburgh, PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 99-144, (IC 9449), 1999 Aug; :1-12
Significant portions of the present Federal regulations for certification of closed-circuit breathing apparatus (42 CFR 84) are not quantitative. The human-subject testing portion of the regulations specifies activities rather than metabolic work rates; however, heavy human subjects have higher oxygen consumption, CO2 production, and ventilation rates than lighter human subjects performing the same activities. This means that apparatus certified using different human subjects have effectively passed different tests. In addition, apparatus performance is monitored only during selected intervals of testing, and always during rest, rather than during the entire performance period. Further, testing is arbitrarily terminated at specific rated durations, leaving unknown the performance during the remaining duration. Duration itself is misleading to users who believe that the apparatus will last a certain time no matter how much they weigh or how hard they work. The actual duration obtained from an apparatus, however, is highly variable, being inversely proportional to the work rate at which it is used. In this report, recommendations are made to (1) replace the present regulations for certification of closed-circuit breathing apparatus with quantitative tests specifying metabolic work rate rather than activity, (2) continuously monitor relevant physiological stressors, (3) continue testing until exhaustion of the oxygen source, and (4) classify closed-circuit breathing apparatus by quantity of usable oxygen, i.e., capacity, rather than by duration. Physiology-based stressor levels are suggested as well.
Mining-industry; Respirators; Standards; Testing-equipment; Regulations; Respiratory-protective-equipment; Quantitative-analysis; Quality-standards; Metabolic-rate; Humans; Body-mechanics; Oxygen-consumption; Work-capacity; Body-weight; Physiological-stress; Self-contained-breathing-apparatus; Respiration; Equipment-reliability; Materials-testing; Carbon-dioxide
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Numbered Publication; Information Circular
NTIS Accession No.
DHHS (NIOSH) Publication No. 99-144; IC-9449
National Institute for Occupational Safety and Health