Silica Comparison: Wet vs. Dry vs. Vapour Blasting
How well does your machine protect you from respirable silica?
Permissible Exposure Limit (PEL) Test Parameters
Media: Medium recycled crushed glass
Blast Hose: 15 m (50 ft) x 38.1 mm (1.25 in) ID
Nozzle: #8 High Performance
Compressor: Doosan 425 CFM
Substrate: 1.22 m x 1.22 m (4 ft x 4 ft) Concrete Slab
Blasting Time per Test: 25 – 28 minutes
Graco retained a third party to perform an Industrial Hygiene Survey in order to evaluate potential exposures to respirable airborne dust and respirable silica during three separate blasting operations. Blasting parameters were kept constant for the three scenarios with the exception of the blasting equipment used and the usage of water. Blasting was performed on a 1.22 m x 1.22 m (4 ft x 4 ft) slab of concrete using medium crushed glass abrasive.
How long can you blast before hitting OSHA’s Respirable Silica Limit?
Occupational exposures to airborne contaminants are evaluated by comparing them to Permissible Exposure Limits (PELs) and Short-Term Exposure Limits (STELs) established by OSHA. PELs are time-weighted average (TWA) concentrations for a normal 8-hour workday or a 40-hour work week. STELs are 15-minute TWA concentrations that shall not be exceeded any time during the workday.
Third-Party Testing Reports
WATCH: Silica PEL Comparison