29/10/2008

Control of Hazardous Dust During Tuckpointing

Construction workers are exposed to hazardous dust when grinding or cutting
mortar or cement from between the bricks of old buildings. An US-American
National Institute for Occupational Safety and Health (NIOSH) document
summarizes findings that construction workers hazardous dust exposures can be
reduced using tool-mounted local exhaust ventilation and work practices.

Workers who use grinders to remove deteriorated mortar between bricks
(tuckpointing) may be exposed to crystalline silica at concentrations up to 100
times the NIOSH recommended exposure limit (REL) of 50 g/m3 lung disease. In
addition, exposure to crystalline silica has been linked to lung cancer, kidney
disease, reduced lung function, and other disorders. No effective treatment
exists for silicosis, but it can be prevented by controlling workers exposure
to dust containing crystalline silica.

As brick buildings get older, the mortar between the bricks starts to fall
apart and needs to be replaced to prevent water intrusion into the building.
Before replacing the mortar, to inch of the old mortar is removed by using a
grinder. The grinder breaks up the mortar and turns it into airborne dust that
may contain crystalline silica. The crystalline silica dust released during
tuckpointing operations is very hard to control. The dust may be carried
throughout the workplace. When workers use compressed air to clean their
clothes, tools, and equipment, even more dust is added to the air.

NIOSH has identified and discusses the following control measures to reduce
worker exposure to hazardous dust during tuckpointing:

  • Vacuum Cleaners

  • Hose

  • Shroud and Grinder

  • Work Practices

  • Respirators


More info


AplusA-online.de - Source: National Institute for Occupational Safety and Health (NIOSH)