The Department of Labor has issued a rule reducing permissible exposure limit of respirable crystalline silica from 250 to 50 micrograms per cubic meter averaged over an eight hour work shift. This rule goes into effect for OSHA enforcement in the construction industry on June 23, 2017.
Complying with this rule will be a big challenge to construction in general. While precasters face challenges, they also have advantages against comparable building systems.
- Precast concrete is manufactured in a factory and shipped to a construction site for assembly. That means all manufacturing processes creating dust occur at our factories, not the job-site. We can apply engineering controls during manufacturing to capture dust in a factory setting under reproducible conditions rather than a job-site.
- Most openings are formed into our pieces rather than by cutting concrete. This means the additional dust from cutting openings at the job-site is not created.
- Precast concrete pieces are custom designed. We can adjust piece layout and add reinforcing to minimize the amount of cutting required at the job-site.
- Precast has a short construction duration. Coordination of subcontractors to prevent silica dust contamination between trades is likely to become a real concern. Our short construction duration means our crews create dust fewer days and have to be coordinated with the dust producing activities of other trades fewer days.
Tim Edland, P.E.
Research & Development Director