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Proposal for certification tests and standards for closed-circuit breathing apparatus.

Authors
Kyriazi-N
Source
NIOSH 1999 Aug; :1-12
NIOSHTIC No.
20000248
Abstract
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.
Keywords
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
Contact
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
CAS No.
124-38-9
Publication Date
19990801
Document Type
Numbered Publication; Information Circular
Fiscal Year
1999
NTIS Accession No.
PB2000-100638
NTIS Price
A03
Identifying No.
(NIOSH) 99-144; IC-9449
ISSN
1066-5552
NIOSH Division
PRL
Source Name
National Institute for Occupational Safety and Health
State
PA
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