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In-depth survey report: control of respirable dust and crystalline silica from grinding concrete at Messer Construction , Newport, Kentucky and Baker Concrete Construction, Dayton, Ohio, report no. CT-247-21.

Echt-A; Shulman-S
NIOSH 2002 Aug; :1-9
When construction workers use hand-held grinders to smooth poured concrete surfaces after forms are removed, they risk overexposure to respirable dust and crystalline silica. A previous study at a stadium construction site revealed TW A respirable crystalline silica exposures that ranged from 56 to 830 microg/m3 (the NIOSH REL is 50 microg/m3) and TW A respirable dust concentrations ranging from 0.38 to 6.9 mg/m3. Silicosis is an occupational respiratory disease caused by inhaling respirable crystalline silica dust. Silicosis is irreversible, often progressive (even after exposure has ceased), and potentially fatal. Exposure to crystalline silica dust occurs in many occupations, including construction. Because no effective treatment exists for silicosis, prevention through exposure control is essential. The study described here compared the exposures during the use of off-the-shelf local exhaust ventilation shrouds with that of no shroud. The aim was to quantify the exposure reduction that could be achieved through the use of shrouds, and to compare shroud effectiveness. Two grinders from different manufacturers were studied, at three study sites. Two shrouds were evaluated for each type of grinder for a total of four shrouds. The grinder with no control varied ftom site to site, since this was furnished by the employer; The same vacuum cleaner was used to provide exhaust air flow at both sites. An aerosol photometer was paired with an SKC aluminum cyclone to measure respirable dust exposures in the cement mason's breathing zone. With 95% confidence, the results indicated at least 90% reduction due to the controls for each of the four shrouds at an average flow rate of 122 cfm. Results indicate little difference between the reductions in the different grinder/shroud pairings. This study demonstrated effective control can be achieved for hand-held grinding of concrete.
Silica-dusts; Respirable-dust; Concretes; Construction; Construction-equipment; Construction-industry; Construction-materials; Construction-workers; Control-technology; Grinding-equipment; Engineering-controls; Silicosis; Environmental-control-equipment; Exposure-limits; Exhaust-systems; Exhaust-ventilation; Ventilation; Region-4; Region-5
7631-86-9; 14808-60-7
Publication Date
Document Type
Control Technology; Field Studies
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
NIOSH Division
Priority Area
Disease and Injury; Asthma and Chronic Obstructive Pulmonary Disease; Research Tools and Approaches; Control Technology & Personal Protective Equipment
SIC Code
Source Name
National Institute for Occupational Safety and Health