AIR
How much do I breathe?
Air Intake Factors
The first factor in calculating the PEL is air. How much air does a person breathe? The answer depends on a number of factors.
• Height
• Weight
• Fitness Level
• Activity
For the construction industry we’re going to make an assumption that the average adult male employee works at a moderate activity level. Looking at this chart, we’ll use 35 liters per minute, an activity level right between a brisk walk and mowing the lawn.
1 min = 35 liters
The average adult male working at a moderate activity level inhales 16.8 cubic meters of air over the course of an 8-hour work day.
The Math
As a visual reference, Joel is standing in the middle of a 16.8-meter cube that represents the quantity of air inhaled in during an 8 hour workday.
1 min = 35 liters
1 hour = 2100 liters
2100 liters/hour x 8 hours =
16,800 liters per day
Or 16,800 liters ÷ 1000 liters
= 16.8 m3
Air Monitoring
Air monitoring uses a battery-operated vacuum attached to an operator’s shirt collar, collecting air samples right where the operator breathes. The results will tell us the exposure level for specific work practices. Once we know exposure level, we can calculate time.
What does this mean to you? It means that to know where you stand, you need to do air monitoring to learn what your exposure levels are. This is an inexpensive and relatively easy process for average contractors. Once you learn your exposure levels, you can decide what options are best-suited to control silica exposure on your job sites.
For more information and an inexpensive way to get this done, please contact www.galsonlabs.com. Their typical silica cartridge test is about $35 and the vacuum to run with the cartridge is free to use if you test with galson labs.
