The “highway drill jig” designed by Dr. David Rempel, Pam Susi, and Michael Cooper also is much easier on the construction laborers who are cutting these holes.
- Feb 02, 2012
The task of adding new concrete to a building’s foundation or making improvements to roads and bridges often involves horizontal drilling of many holes to house rebar. Handling the drill is punishing work for the laborer who does it, and the cutting also can expose him to airborne crystalline silica that will damage lung tissue if it is inhaled.
A new tool called a highway drill jig shows promise in reducing both exposures significantly. It was developed by Dr. David Rempel of the University of California San Francisco’s Division of Occupational and Environmental Medicine; Pam Susi of CPWR, The Center for Construction Research and Training; and Michael Cooper of The Lippy Group LLC in Berkeley, Calif., through research supported by CPWR. The result is shown in Alan Barr’s four-minute video of the trials and discussed in the February 2012 Journal of Occupational and Environmental Hygiene.
Rempel installed a shroud around the drill bit and a vacuum system for local exhaust ventilation to capture the silica dust. According to CPWR, the results were encouraging: “A conventional pneumatic rock drill produced levels of airborne crystalline silica 14 times over the exposure limit NIOSH recommends. The drill jig alone — presumably by distancing the worker from the work surface — reduced this to a mere six times the recommended exposure: better, but still hazardous. The combination of drill jig and LEV, however, brought the worker’s exposure levels down below the threshold established by NIOSH.”