Vacuum Set-Up Helps Reduce Silica Dust

Journal: APRIL - MAY - JUNE 2005

Using a ventilated grinder to remove old mortar from masonry can protect workers from dangerous levels of crystalline silica dust, a study at the University of Iowa has found. The researchers, led by William Heitbrink, PhD, presented their draft recommendations for using the system in a new report for the Center to Protect Workers’ Rights.

Mortar removal, called tuckpointing, is one of the dustiest construction jobs. Workers who inhale the dust are at risk of developing silicosis, a disabling, permanent, and sometimes fatal lung disease. Because the need for better worker protections is urgent, the authors and CPWR decided to share some interim findings before the study is complete.

The dust control system is an industrial vacuum cleaner, hose, and hood (shroud) affixed to the grinder. The researchers tested different vacuum cleaner models and monitored dust levels near tuckpointers who were trying the vacuums. The ventilated grinders lowered workers’ silica exposures enough that they could wear a respirator with an assigned protection factor of 10. Such half-mask air-purifying respirators are much less heavy and bulky than the devices usually required for protection during tuckpointing.

The new system allows a clearer view of the work surface and reduces clean-up time. One company that has been using the ventilated grinder said the system they’ve used has not affected the rate of work, the report said.

The researchers warn that the ventilated grinders have limitations:

• Some of the vacuum cleaners can clog and quickly lose their ability to capture dust.

• Proper work practices are always needed for effective dust control.

• The equipment does not work well on uneven surfaces or on masonry missing a lot of mortar.

• Workers still need to wear respirators while tuckpointing with the ventilated grinders. The test data were collected during tuckpointing outdoors. During work indoors, much more protective respirators may be needed, even with the new system.

Exposure monitoring is needed to know which respirator is required. For more information on respiratory protection programs, see: http://www.osha.gov/SLTC/etools/respiratory/index.phpl.

The report, Protecting Tuckpointing Workers from Silica Dust: Draft Recommendations for a Ventilated Grinder, and a hazard alert on respirators for workers (in Spanish or English) are at www.cpwr.com or call CPWR at 301-578-8500.

Reprinted with permission from the Center to Protect Workers Right.