So now you’re aware of OSHA’s more stringent regulations on silica dust exposure, you’ve tested the job sites in question, you’ve discovered that the levels of airborne silica dust don’t meet the new standard, and now you need to do something about it. There’s good news and bad news.
The bad news: OSHA penalties are severe and selecting the best remedy can be confusing.
The good news: this guide will help you discern the best silica-removal method possible in your journey to be crystalline silica free (or at least OSHA compliant).
Let’s dive right in.
Water, Vacuum, Compressed Air or Fan?
Generally speaking, water is the best way to suppress airborne silica dust at the source. Utilizing this method, a nozzle is attached to a power tool and provides a stream of water at the point of cutting, grinding, drilling, etc. However, sometimes using water isn’t a viable option. In these situations, the best alternative is to use an industrial vacuum or dust collector.
It’s important to note that compressed air or dry sweeping should be avoided. These methods are a sure-fire way to release more silica dust into the air and increase exposure. Similarly, fans are not effective dust control devices when used as the sole control method and should not be used as the primary method for managing dust.
Silica Dust States
The first thing you need to know when deciding the best way to reduce silica dust is what state the dust is in:
- New silica dust – this is dust made at the time of cutting, drilling, grinding, etc.
- Silica dust buildup – dust that has built up over time and now blankets the job site (or portions of it)
- Airborne silica dust – dust that has been released into the air through agitation
Each of these dust states has a corresponding method of removal:
- Fresh silica dust: water spout/vacuum integrated directly onto the power tool
- Silica dust buildup: HEPA shop vacuums
- Airborne silica dust: industrial dust collectors and ventilation systems
1) New Silica Dust
The best way to contain and remove silica dust is at the source. Whether from cutting, grinding, crushing or drilling, capturing the dust before it’s released into the air greatly reduces the risk of silica dust exposure. However, not any vacuum can be used. In order to effectively collect crystalline silica dust, the vacuum needs to be equipped with a HEPA filter. A true HEPA filter can trap 99.97% of all airborne particles larger than 0.3 microns (0.001 mm, or about 0.000039 in.), making it perfect for silica dust removal.
For smaller jobs (for example, those that use handheld masonry saws, grinders, and rotary hammers), the best way to collect silica dust at the source is by using a vacuum-assisted power tool. This system allows the silica dust to be safely collected while the operator simultaneously performs the task at hand. Utilizing a portable shop vacuum (like Industrial Vacuum’s HEPA-filter-equipped Vactagon Shop Vacs) and the right attachment, your power tool’s natural motion will feed most of the silica dust directly into the vacuum. In most cases, here are the items you will need:
- Industrial shop vacuum – 100 CFM or more will give best results
- HEPA filter – in conjunction with a pre-filter or cyclonic separator (which remove larger particles that can overload or even clog the filter) will improve vacuum efficiency and extend the service life of the HEPA filter, which are quite expensive.
- Vacuum hose – if using a 100 CFM vacuum, a one- to two-inch diameter hose will be needed. Any larger and the airflow velocity will be reduced. Also avoid excessively long hoses, which increase air flow resistance.
- Dust collector attachment for power tool – be sure to use an appropriately sized collector for your power tool.
Decontaminate worker clothes
OSHA also recommends worker clothes and uniforms be cleaned frequently to prevent the transfer of silica dust from work areas into break rooms, other parts of the facility, and (most importantly) the home. HEPA shop vacs are an easy way to remove excess dust from clothes and uniforms, so you should position one at the exits of every silica work areas to allow your workers to decontaminate their clothes before leaving.
Mobile Industrial Vacuums
For bigger jobs (i.e., those using truck-mounted drilling rigs, crawlers or other vehicles for drilling into rock, concrete, or soil) that release large amounts of crystalline silica dust, a more powerful vacuum is needed to protect workers in the immediate vicinity of the drilling rig. In most cases, here are the items you will need:
- Trailer-mounted industrial vacuum - The Hurricane line of trailer mounted vacuums are ideal for the remote or changing job site locations. Concrete cutting or demolition on highways or bridges as well as rock drilling or mining. We have a Hurricane model to safely capture your silica dust emissions.
- Vacuum hose
2) Silica Dust Buildup
If you haven't been collecting silica dust at the source, chances are it has built up around the work area (i.e., on equipment, on top of high surfaces, ventilation ducts, etc.). Although not airborne, built-up silica dust still poses a risk. For instance, if agitated the dust can become airborne and then inhaled. What's more, dust accumulations present other safety risks in the form of combustible dust fires and explosions. Hence, collecting silica dust buildup is just as important as collecting new silica dust.
It’s important to reiterate that compressed air or dry sweeping should be avoided; you’ll need to use the right vacuum to collect the dust. Again, the best method for built up dust is a HEPA shop vacuum, or for larger jobs, either a skid-mounted or trailer-mounted industrial vacuum (with integrated HEPA filters). Equipped with the right hose and accessories, industrial vacuum cleaners can be used to easily accomplish difficult cleaning challenges, such as removing large quantities of dust from hard-to-reach areas (or larger areas in general). In most cases, here are the items you will need:
- HEPA shop vac - for smaller cleanup jobs.
- Skid-mounted industrial vacuums - for large cleanup jobs. Facilities that are in need of a central vacuum system for safe cleanup of silica dust can rely on a Hurricane skid mounted stationary electric vacuum. For safe, efficient collection of the dust to a central location in your foundry or factory.
- Trailer-mounted industrial vacuums - for large cleanup jobs. The Hurricane trailer mounted vacuums are ideal for facilities with multiple buildings or locations that need silica dust clean up. The mobile Hurricane can be moved with a truck, fork truck or bobcat to reach all of your clean up areas.
- HEPA filter
- Vacuum hose
3) Airborne Silica Dust
If airborne dust containing silica is generated, mechanical ventilation or dust collection system with an air flow sufficient to remove airborne contaminants from workers' breathing zone should be provided. The air flow of the mechanical ventilation system should be 50-100 cubic feet per minute per square foot of face area (0.25 m3/s per square meter of face area) depending on the application.
- Stationary industrial dust collector - The Filt-Aire electric stationary Dust Collectors are ideal for ventilating entire buildings or rooms to capture the airborne silica dust. They can also be used with a piping system to capture airborne dust at the source, such as a grinder, transfer belt or other dust emitting machinery.
- Portable industrial dust collector - The Filt-Aire mobile diesel Dust Collectors are most commonly used on Frac sites, rock crushing or drilling projects or while cutting or demolishing concrete on roads and bridge decks. With several sizes available from 2,000 cfm to 60,000 cfm we have a Filt-Aire model to meet your needs.
Deciding Which Machine You Need
Even with all this information, variables remain that need to be taken into account before selecting a silica dust control method.
For instance, just because you have a large workspace, a more powerful dust collector isn't necessarily the best solution. If only one corner of the entire workspace is the source of silica dust then you'll only need a dust collector powerful enough to clean the smaller area -- not a larger unit to cover the entire area.
To make sure you make the right investment, we urge you to contact one of our specialists who will guide you to finding the right vacuum or dust collector (or both, if need be) for your particular situation.