Control of respirable dust and crystalline silica from breaking concrete with a jackhammer.

The Engineering and Physical Hazards Branch (EPHB) of the National Institute for Occupational Safety and Health (NIOSH) has been given the lead within NIOSH to study and develop engineering controls and assess their impact on reducing occupational illness. The objective of each of these studies has been to evaluate and document control techniques and to determine their effectiveness in reducing potential health hazards in a specific industry or for a specific process. The goal of the project reported in this article was to quantify the exposure reduction that could be achieved through the use of a water-spray attachment and two different tool-mounted local exhaust ventilation shrouds during concrete pavement breaking with jackhammers. In this case, the water-spray attachment consisted of a spray nozzle (of the type used with oil-burning furnaces) and associated hoses and fittings. Water was supplied by a pressurized tank mounted on the air-compressor trailer. The local exhaust ventilation (LEV) included an off-the-shelf shroud typically used with hand-held rock drills and a custom-made shroud. The same dust collector (one sold for use with the rockdrill hood) was used for both LEV attachments.