Laboratory evaluation to reduce respirable crystalline silica dust when cutting cement roofing tiles using a masonry saw.
Valladares R; Sieber W; Kratzer J
American Industrial Hygiene Conference and Exposition, May 13-16, 2006, Chicago, Illinois. Fairfax, VA: American Industrial Hygiene Association, 2006 May; :32-33
Respirable crystalline silica dust exposure in residential roofers is a recently recognized hazard resulting from cutting cement roofing tiles. Roofers, cutting tiles using masonry saws, can be exposed to high concentrations of respirable dust. Silica exposures remain a serious threat to nearly two million U.S. workers. Although it is well established that respiratory diseases associated with exposure to silica dust are preventable, they continue to occur and cause disability or death. The effectiveness of a commercially available local exhaust ventilation (LEV) system and a water suppression system to reduce silica exposures were evaluated separately. The LEV system exhausted 500 cubic feet per minute (CFM), while the water suppression system supplied two gallons per minute (GPM) to the saw blade. Using a randomized block design, implemented under laboratory conditions, three trials were conducted (no control, water control, and ventilation control) on two types of cement roofing tiles using the same saw. Each treatment was replicated for a total of eight 30-sec runs per treatment per tile. Analysis of variance was performed using mean concentration levels from each run and control. The use of water controls and ventilation controls resulted in a statistically significant (p < 0.05) reduction of mean respirable dust concentrations for each tile. Mean concentrations using the water control were statistically significantly less than that of the ventilation control. The percentage reduction for respirable dust concentrations was 99% for the water control and 91 % for the LEY. Water is a good method for reducing crystalline silica exposures. However, water source and disposal requirements, water damage potential, surface discolorations, material expansion, cleanup, and other requirements make use of water in many situations problematic. LEV may be more desirable, but designing a system with a sufficient capture velocity that will control silica concentrations below occupational criteria might be difficult.
Workers; Work-environment; Dust-particles; Dust-exposure; Respiration; Respiratory-system-disorders; Respiratory-irritants; Pulmonary-system; Pulmonary-system-disorders; Pulmonary-function; Exposure-levels; Risk-factors; Respirators; Respiratory-equipment; Silicates; Silica-dusts; Dusts; Roofers; Hazards; Cements; Exposure-levels; Risk-factors; Ventilation; Ventilation-equipment; Ventilation-systems
American Industrial Hygiene Conference and Exposition, May 13-16, 2006, Chicago, Illinois