VANCOUVER – When it comes to silica, not all vacuums are created equal.
Shalinda Shafie, an MSc candidate at the University of British Columbia, addressed the recent BC Construction Safety Alliance’s (BCCSA) Health and Safety conference with a session titled “Study on the Use of Dust-Extraction Vacuums in the BC Construction Industry”. She looked at the various types of vacuums available to mitigate the presence of silica and explained their effectiveness.
“The study is looking at all the different factors that affect the performance of vacuums because we don’t really know how well they’re performing when they’re on actual construction sites,” Shafie said.
“There’s quite substantial differences in the performance of vacuum cleaners both when they’re brand new and also after they’ve been use don a construction site for a while. Like any other piece of equipment if you don’t maintain it the performance goes downhill,” Ed Chesser from the UBC School of Population and Public Health said.
“We’re encouraging people to get vacuum cleaners that are easy to maintain and can learn to maintain them properly, because more air flow means less dust for the guy working the tools. If you don’t have much airflow at all you have clouds of duct flying even though you have a vacuum cleaner system connected and that’s not healthy,” Chesser said.
Awareness of the effects of silica on human respiration goes back millennia to the time of the Romans and Pliny the Elder, Chesser said, and locally in Vancouver silica’s harmful nature was known for more than 30 years.
“But it’s been very slow to grow and spread,” he added. “There are a few pioneers who have been using vacuum cleaners well for quite a while, and a lot of others who haven’t.”
Some companies such as Ocean in the United States and WorkSafeBC have emphasized the importance of vacuuming silica, Chesser added, “and I think we can thank the epidemiologists partly for recognizing its causing lung cancer as well as silicosis and there’s other studies that show it causes asthma problems and various other issue for people so we understand now the importance of controlling it better than we used to.”
Shafie noted that one of the key takeaways from her study was the need for companies to make an effort to know exactly what vacuums they are using and how to maintain them, as well as the importance of training.
“We have people who are just picking up a vacuum and not really learning how to use it before they start using it, they might not maintain it properly and that causes further issues down the road,” she said.
BCCSA provided funding for research and helped arrange study sites, Shafie said, but didn’t need to use the association’s existing silica tools.
“Earlier researchers helped create that tool. Not being contractors, we don’t have a need to go directly into it and figure out how to control silica dust,” Chesser said.
Shafie and Chesser also demonstrated a simple device that can be used to test vacuum cleaner air pressure.
“This is two feet of two-inch plastic pipe, a pressure gauge and sensor connected into it. We connect the vacuum cleaner hose into one end, and it measures the amount of pressure difference the vacuum cleaner creates as it drags the air through. That pressure difference is proportional to the square root of the air flow, so we can calculate from that pressure difference how much air flow that vacuum cleaner is pulling through the hose,” Chesser said.
“I’d like to see all construction sites equipped with an airflow measuring device like this, so they can check for themselves how well their vacuum cleaner is working and obviously if it isn’t providing the right airflow get it fixed or get a better vacuum,” he added.
Any unskilled tradesperson could put a similar device together, Chesser joked, as he had recently done so himself.