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The National Institute for Occupational Safety and Health,
National Personal Protective Technology Laboratory, has undertaken a study to
determine how well self-contained self-rescuers (SCSRs), deployed in accordance
with Federal regulations (30 CFR 75.1714), hold up in the underground
environment with regard to both physical damage and aging. This report presents
findings regarding laboratory-tested SCSRs in the seventh phase of testing from
May 1999 to August 2000. The SCSRs were tested on human subjects and on a
breathing and metabolic simulator. The results indicate that most of the
apparatus, if they pass their approved inspection criteria, perform
satisfactorily. The deployed CSE SR-100s, however, exhibited significantly
higher inhaled carbon dioxide (CO2) levels than new units, as they did in the
previous two phases. Several Draeger OXY K-Pluses that rattled when shaken were
found to have potassium superoxide (K02) particles throughout the breathing
circuit, including the mouthpiece. Draeger investigated the problem and
developed a shake test to detect damaged units. The durations of new Ocenco
M-20s were statistically significantly longer than those of deployed units,
although only by 2 min.
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