ISRP 2000 abstract

Presenter/author Title Abstract
Kovac, J.G.  NIOSH, PRL
Kravitz, J.H.  MSHA, PSHTC
Chemical bed degradation in self-contained self-rescuers  deployed in U.S. coal mines

In the aftermath of a mine fire or explosion, the atmosphere inside a mine may become oxygen deficient or filled with toxic gases. Under these circumstances, escape is nearly impossible unless a miner relies on a self-contained breathing apparatus, called a Self-Contained Self-Rescuer (SCSR). 

Since their introduction into U.S. underground coal mines in 1981, failures have been identified with a number of different models of SCSR’s . These failures are associated with life support performance, conditions-of-use, or age. All SCSR’s, regardless of specific design, have common components. One component, in particular, is a packed chemical bed, which functions either as a stand-alone scrubber, or as both an oxygen supply and carbon dioxide absorber. The life support performance of an SCSR depends on the general integrity of its chemical bed. As its chemical bed degrades, an SCSR’s overall life support performance also diminishes, sometimes to the point where it can no longer maintain the protective capacity for which it was approved or even to failure.

This paper discusses case histories of SCSR field failures due to chemical bed degradation in the context how these failures were discovered and what steps were taken to correct the problems and restore in-mine reliability, Failure rates are also estimated and a computer program is used to project what might happen to SCSR reliability if bed degradation in a population of SCSR’s goes undiscovered over a period of time.