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Manikin-Based Performance Evaluation of Elastomeric Respirators against Combustion Particles
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2013
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Source: J Occup Environ Hyg. 10(4):203-212
Details:
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Alternative Title:J Occup Environ Hyg
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Description:Objective:
To investigate the effects of faceseal leakage, breathing flow and combustion material on the overall (none size-selective) penetration of combustion particles into P-100 half and full facepiece elastomeric respirators used by firefighters.
Methods:
Respirators were tested on a breathing manikin exposed to aerosols produced by combustion of three materials (wood, paper, and plastic) in a room-size exposure chamber. Testing was performed using a single constant flow (inspiratory flow rate = 30 L/min) and three cyclic flows (mean inspiratory flow rates = 30, 85, and 135 L/min). Four sealing conditions (“unsealed”, “nose-only sealed”, “nose & chin sealed”, and “fully sealed”) were examined to evaluate the respirator faceseal leakage. The total aerosol concentration was measured inside (Cin) and outside (Cout) of the respirator using a condensation particle counter. The total penetration through the respirator was determined as a ratio of the two (P = Cin / Cout).
Results:
Faceseal leakage, breathing flow type and rate, and combustion material were all significant factors affecting the performance of the half mask and full facepiece respirators. The efficiency of P-100 respirator filters met the NIOSH certification criteria (penetration ≤0.03%); it was not significantly influenced by the challenge aerosol and flow type, which supports the current NIOSH testing procedure utilizing a single challenge aerosol and a constant air flow. However, contrary to the NIOSH total inward leakage (TIL) test protocol assuming that the result is independent on the type of the tested aerosol, this study revealed that the challenge aerosol significantly affects the particle penetration through unsealed and partially sealed half mask respirators. Increasing leak size increased the total particle penetration. The findings of this study point to some limitations of the existing TIL test in predicting protection levels offered by half mask elastomeric respirators.
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Source:
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Pubmed ID:23442086
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Pubmed Central ID:PMC6758539
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