Effect of test exercises and mask donning on measured respirator fit.

Quantitative respirator fit test protocols are typically defined by a series of fit test exercises. A rationale for the protocols that have been developed is generally not available. There also is little information available that describes the effect or effectiveness of the fit test exercises currently specified in respiratory protection standards. This study was designed to assess the relative impact of fit test exercises and mask donning on respirator fit as measured by a controlled negative pressure and an ambient aerosol fit test system. Multiple donnings of two different sizes of identical respirator models by each of 14 test subjects showed that donning affects respirator fit to a greater degree than fit test exercises. Currently specified fit test protocols emphasize test exercises, and the determination of fit is based on a single mask donning. A rationale for a modified fit test protocol based on fewer, more targeted test exercises and multiple mask donnings is presented. The modified protocol identified inadequately fitting respirators as effectively as the currently specified Occupational Safety and Health Administration (OSHA) quantitative fit test protocol. The controlled negative pressure system measured significantly (p < 0.0001) more respirator leakage than the ambient aerosol fit test system. The bend over fit test exercise was found to be predictive of poor respirator fit by both fit test systems. For the better fitting respirators, only the talking exercise generated aerosol fit factors that were significantly lower (p < 0.0001) than corresponding donning fit factors.

Development of an on-site, behavior-based safety audit for the residential construction industry.

The purpose of this study was to describe the development and implementation of an on-site, behavior-based safety audit based on a safety program designed specifically to reduce injuries and fatalities in the residential construction industry. The audit was used to assess safety hazards and safety compliance on residential construction work sites. Safety behaviors were scored as all-or-none. A high score was related to high safety compliance. A total of 195 audits were performed on residential construction companies from varying trades. Analysis of mean total scores indicated that companies that had received some form of safety training scored significantly higher than companies that had not received any (P<0.01). Analysis of mean total scores between company trades indicated that masonry/stucco application companies had significantly lower scores than most other trades represented (P<0.01). Challenges in designing, administering and analyzing the safety audits are discussed.