Engineering Control Technologies to Reduce Occupational Silica Exposures in Masonry Cutting and Tuckpointing

Abstract

SYNOPSISObjectives. A number of tasks in construction generate worker overexposures to respirable crystalline silica dust, which is a significant contributor to occupational mortality and morbidity. This study evaluated the performance of commercially available engineering controls used in dusty construction tasks commonly performed by bricklayers.Methods. Local exhaust ventilation (LEV) controls for a portable abrasive cutter and for tuckpointing grinders were examined at a bricklayers' training center, as were two stationary wet saws. Personal breathing zone air samples were collected with and without the use of LEV or water suppression during simulated concrete block cutting, brick cutting, and tuckpointing.Results. Compared with the use of no exposure control during block and brick cutting, the portable LEV unit significantly reduced mean respirable quartz exposures by 96% for block cutting and 91% for brick cutting (p,0.01). The use of stationary wet saws was also associated with 91% reductions in exposure (p,0.01). For tuckpointing, the reductions in mean respirable quartz concentrations were between 91% and 93% with the LEV controls (p,0.05). Conclusions.Reductions of up to 96% in mean respirable quartz concentration were observed between control and no-control scenarios. These reductions with commercially available off-the-shelf tools demonstrate the effectiveness of engineering control interventions to reduce crystalline silica exposures in construction. Strategies to further improve control performance and approaches for increasing control interventions in construction are needed.

Occupational demands and health effects for bricklayers and construction supervisors: A systematic review

“…Information from other sources, however, is needed to fill the existing gaps and to enable the goal-oriented approach typical of the job-specific WHS. In addition to information from literature published after the time frame of this review [e.g., Faber et al, 2009;Meeker et al, 2009;Hess et al, 2010], other methods such as a questionnaire survey, must be used in order to supplement and validate the evidence from the literature.…”

In-depth survey report: removing mortar with a powered chisel with on-tool local exhaust ventilation, International Union of Bricklayers and Allied Craftworkers Southern Ohio-Kentucky Regional Training Center, Batavia, Ohio.

“…In comparison, the mean PBZ respirable quartz concentration for the chisel tested here was 0.11 mg/m 3 . That represents a 77% reduction compared to one of the LEV-equipped grinders and a 67% reduction compared to the other LEV-equipped grinder in the Meeker et al [2009] study. However, even with that reduction, if the powered chisel with on-tool LEV was used for a full shift and dust levels remained constant and consistent with those observed in this study, the highest quartz concentration measured during use of the chisel, 0.16 mg/m 3 would be about 3 times the OSHA PEL and NIOSH REL.…”

“…For example, Meeker et al [2009] [Meeker et al 2009]. In comparison, the mean PBZ respirable quartz concentration for the chisel tested here was 0.11 mg/m 3 .…”

The power of local action in occupational health: the adoption of local exhaust ventilation in the Chicago tuckpointing trade

“…Researchers at NIOSH and CPWR began publishing research related to silica and engineering controls for silica beginning in 2003. [14][15][16][17][18][19][20] Research on a variety of LEV systems which involved measurement of silica exposure among tuckpointers using grinders, with and without controls, continued into the current decade. These studies have led to published recommendations for improving LEV design, focusing on grinder shrouds, minimum air flows needed for effective dust capture and ease of use.…”

“…By the first decade of the new millennium, ample research demonstrated that silica exposures were pervasive in construction and that effective engineering controls were available. [14][15][16][17][18][19][20] In 1992, NIOSH Director Dr. J. Donald Millar developed a national program to eradicate silicosis, which he described as "an occupational obscenity." Joint prevention efforts on the part of OSHA, NIOSH, and the Mine Safety and Health Administration kicked off a national public education campaign in 1996 with the theme -Silica: It's not just dust and NIOSH Alerts were published and disseminated widely.…”