Silica Dust in the Construction Industry:
A Guide to Respirable Crystalline Silica
About Silica Dust
Silica Health Effects
Symptoms of Inhaled Silica
Silicosis: A non-reversible lung disease.
Chronic obstructive pulmonary disease (COPD)
How Does Silica Get Into The Lungs?
Silica Exposure in Common Construction Work Practices
What kind of work practices cause silica exposure? Below are many common work practices used today in the construction industry that create silica exposure.
Each of these work practices can potentially expose workers to respirable crystalline silica at levels 10X to 200X above the OSHA PEL.
The OSHA PEL Explained
What Contractors Need to Know About the OSHA PEL
Silica is an important topic in the construction industry with the new rule passed by OSHA, which reduced the permissible exposure limit (PEL) to 50 micrograms of respirable crystalline silica per cubic meter of air (μg/m3), averaged over an 8-hour day.
The new rule requires employers to use engineering controls to limit worker exposure, develop a written exposure control plan, and train workers on silica risks, among other requirements.
The new OSHA PEL was approved in 2016, with employers in the construction industry required to comply by June 23, 2017.
What does all this mean to the average contractor? We’ve created this silica dust resource page for contractors and industry professionals to help answer that question.
Using this page you’ll:
1) Understand OSHA PEL in simple terms
2) Know how to inexpensively test your silica exposure
3) Understand your options for controlling silica dust
What is the OSHA PEL?
‘Permissible Exposure Limit’ is the legal limit established by OSHA for worker exposure to silica. In simple terms, how much dust a worker is legally allowed to breath over an eight hour period.
The PEL is determined by three factors: Air, Dust and Time. For us to understand the PEL we need to have a better grasp of each factor.
AIR: The first Factor in the OSHA PEL
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.
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 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
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.
DUST: The Second Factor in the OSHA PEL
How much silica dust is in the air I breathe, and what are my exposure levels?
This depends on a number of factors:
Using masonry as an example, our studies have shown up to 9 million micrograms of respirable crystalline silica can be released into the environment in a single common paver cut. That’s enough silica dust to exceed 40 years worth of exposure within the OSHA PEL.
For the average contractor, this means you should understand the exposure levels created by the common work practices on your jobs. To accurately measure your exposure levels you need to perform air monitoring tests, an easy and inexpensive process (details below).
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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.
TIME: The Third Factor in the OSHA PEL
The Time Factor
Time is the third and final factor used to calculate the PEL. Once we know how much air is being breathed, how much dust is contained within that air, and how much of that dust is respirable silica, we still need to factor the amount of time that air and dust is being inhaled.
We can use what we’ve learned so far to determine the total maximum silica exposure for a person over an eight-hour period. Since a worker breathes 16.8m3 of air in eight hours, and the OSHA PEL is 50μg/m3, the total maximum exposure for eight hours is 840μg (16.8m3 * 50μg).
16.8m3 of air x 50μg of Silica =
840µg in 8 hours TWA
Time Weighted Average (TWA)
Using this chart, it shows that dependent upon the silica content in the breathing zone, an operator can perform a task that could be 200 micrograms or even 400 micrograms per cubic meter and still stay under an 8 hour TWA as long as the exposure in the other 6-7 hours per day is in clean air.
So you see, this allows us to go in for a limited time, 1 hours, 2 hours, 3 hours, into a dusty environment and still keep our 8 hour TWA below safe limits.
To know what your exposure levels are, you will still need to do air monitoring for tasks that might be above 50mc per cm but this still gives you many options for tasks that are required for a short duration of the day.
Know our exposure level, and use the time weighted average to work to your benefit.
Testing Your Silica Dust Exposure
If you’re cutting at an exposure level of 200ug/m3 , you can cut for two hours and still be within the OSHA PEL. In this case your total exposure is 840ug.
Education and Silica Dust Solutions
Silica dust is a major problem affecting the construction industry. One thing we know is it won’t go away by ignoring it.
With the new OSHA rule being enforced June 2017, contractors will have two choices: a) address the problem proactively through education and informed decisions, or b) wait until the problem comes to you in the form of a citation, lawsuit, or serious health issues.
What can you do about it? Start with education.
Silica Education
The fact is a majority of those affected by the silica dust problem know very little about it, or even that there is a problem. That’s why the solution must start with education. Use this page and the resources linked below to educate yourself and your workers about silica.
Know the Hazard
Understand the hazard and risks associated with silica exposure.
Know the Standards
Understand the OSHA PEL and what it means to you, your business and your workers.
Know Your Exposure
Understand how to use air monitoring to measure silica exposure levels and understand the results.
Know Your Options
Understand your options, including tools, work practices and educational resources for controlling silica exposure on your job sites.
iQ Power Tools and the War on Silica Dust
iQ Power Tools manufactures the world’s first and only power tools with integrated dust collection technology for the concrete, masonry, hardscape and tile industries. As contractors for over 30 years, we dealt with dust problems and breathed the dust ourselves for years.
Our goal is to see the construction industry 100% dust free. We aim to achieve that goal through education and the development of professional tools and technology to eliminate silica dust from job sites.
Know the standard. Know your exposure. Know your options.
And take action.
Resources
iQ ’s OSHA Silica Standard 2016 Webinar
http://www.masoncontractors.org/education/on-demand/osha-silica-2016-what-does-it-mean-to-me/
OSHA Table One
https://www.osha.gov/silica/SilicaConstructionRegText.pdf
Work Practice Options
http://plan.silica-safe.org
Galson Labs
http://www.galsonlabs.com
iQ Power Tools
iQ Power Tools manufactures a comprehensive range of premium power tools with integrated dust collection systems for the concrete, masonry, hardscape and tile sectors.
The company was founded by third-generation masons Joel and Paul Guth, who have logged over 30 years each in the masonry industry. Decades of experience taught them about dust problems; their company started out creating tools to solve their own problems only to realize these same issues affected all contractors…mess, money and a threat to the health and safety of the industry.
iQ Power Tools envisions a future where their innovation helps create a 100% dust-free environment: jobsites are safer, work practices are healthier, and the construction industry becomes even more sustainable.
