PPE CASE - Point-of-Use Assessment for Self-Contained Self-Rescuers Randomly Sampled from Mining Districts: Third Phase
NPPTL Report Number P2019-0101
Sample Period: February 2013 to December 2014
Gary Walbert and Bill Monaghan
National Institute for Occupational Safety and Health
National Personal Protective Technology Laboratory
An ongoing Long-Term Field Evaluation (LTFE) study, carried out jointly by the National Personal Protective Technology Laboratory (NPPTL), a laboratory in the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA), evaluates the long-term field performance and reliability of self-contained self-rescuer (SCSR) units deployed in U.S. underground coal mines. The LTFE study provides performance, reliability, and user maintenance compliance data on field-deployed SCSR units.
This report presents findings from the third phase long-term random (LTR3) testing of SCSR units that was conducted between February 2013 and December 2014. Prior to collection, MSHA provided a copy of the SCSR inventory from which NIOSH compiled a statistically-significant random list of 620 SCSR units to target for collection. NIOSH returned 319 SCSR units to the laboratory when the collection effort ended. Three hundred ten (310) SCSR units that passed the manufacturers’ recommended visual inspections were subsequently tested using an automated breathing and metabolic simulator (ABMS). The tests performed in this study are not approval tests; however, products that exhibit any suspected nonconforming characteristics during their inspection and testing at NPPTL are identified. A certified product investigation process (CPIP) may subsequently be opened to determine the impact of observed performance degradation or potential nonconformance of deployed SCSR units. It was not necessary to open a CPIP audit for SCSR nonconformance issues in this phase of the LTFE study.
Twenty-five of the targeted SCSR units failed the manufacturers’ recommended visual inspections either at the mine or at NIOSH. LTR3 sample test results suggest that SCSR units that pass the manufacturers’ recommended inspection criteria and breathing and metabolic simulation (BMS) testing can be relied upon to provide life support for mine escape. Although deployment in the mining environment caused some performance degradation in most of the SCSRs tested during LTR3, all retained their ability to preserve life in the event of an emergency.
As in the first phase long-term random (LTR1) SCSR unit collection efforts, NIOSH failed to collect 100 of each NIOSH-approved SCSR model deployed in United States underground coal mines. A revised strategy to meet this study design goal is being formulated and will be enacted for future LTFE collection phases in order to retain the desired statistical validity of the study.
NIOSH  PPE CASE: self-contained self-rescuer long-term field evaluation: third phase random sampling results. By Walbert G, Monaghan W, and Coyne J. Pittsburgh, PA U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, NPPTL Report Number P2019-0101.