Frequently Asked Questions About Silica Dust Exposure, Answered



Frequently Asked Questions About Silica Dust Exposure, Answered

July 12, 2018 Shane Hedmond


OSHA's new crystalline silica dust exposure regulations officially went into effect on September 23, 2017.  Over the past 10 months, there has been plenty of confusion about the lung disease causing material. In the first 6 months after the effective date, OSHA's inspectors yielded 116 violations across the country.

 

I've personally given a dozen presentations on the silica dust regulations since last year and have read even more articles and supporting documents, but there is still plenty to learn. To help clear up some of the industry's most frequently asked questions, Jim Bohn, Director, Strategic Development for the Robert Bosch Tool Corporation has provided many excellent answers.


photo by MTA Capital Construction Mega Projects, CC BY 2.0



The following Q&A was provided by Bosch for industry education and all of the answers were contributed by Jim Bohn, unless otherwise noted. What other questions do you have about the silica dust regulations?  Tell us in the comment section below!


For even more information, you can review OSHA's Respirable Crystalline Silica standard 29 CFR 1926.1153.


Silica Dust Frequently Asked Questions

What if you’re working in a small area where the dust suction attachment won’t fit?


Dust exposure, regardless of the environment, must be controlled. If you’re in an environment where your power tool system is too big, then Table 1 will not be applicable and Paragraph D will take effect. This will require a company to conduct independent testing, with specific documentation on exposure levels and what steps a worker must take to stay below the PEL (0.5mg/m3: 50 micrograms per cubic meter) over a time-weighted eight-hour day.


Can you use tools from one brand and an attachment from a different brand?

Most tool brands have attachments that fit their tool(s) due to specific design elements of the tools (e.g., rotary hammer tube size variations, collar configuration on a grinder, etc.) Most attachments are brand specific. The exceptions are dust suction drilling attachments and universal collar dust shrouds.


Construction Junkie note: Other exceptions include SDS vacuum bits and Milwaukee's extremely inexpensive SDS+ collapsible Dust Trap ($19.99 on Ohio Power Tool).




Can a dust extractor (vacuum) from one brand be used with another brand of tools and attachments? 

Yes, but you do need to be sure that these three requirements are met:


Minimum of 25 CFM per 1" of grinder wheel,

Filter cleaning system (automatic or semi-automatic), and

99% filtration filter (HEPA is preferred).

Also, does a branded tool system require any other specification – refer to the appropriate Owners Manual.


What is the proper disposal procedure for concrete dust?

Every user who creates respirable silica dust must understand their responsibility in the collection and also disposal of silica dust. It’s highly recommended to use a fleece bag. These are usually multi-ply fabric bags that help manage air equilibrium and collect .3 microns or larger dust particles. It also contains a port-closing mechanism for containment after removing the bag from the vacuum canister’s port. Finally, it’s strong enough to withstand weight of dust collected and is not subject to tearing.


Will there be a special place for users to dispose of a full dust collection bag separate from a regular dumpster?

Take the bag (80% full) and place it in a standard garbage dumpster. Be careful that it’s not going to be exposed to potential damage if other items are placed in the same dumpster on top of it. The bag must not break open at any time. 




Are HEPA filers required in Table 1? 

“HEPA” filters are not required. The OSHA Silica Dust Regulation – Table 1, states that a filter needs to have 99% filtration to meet the guideline. Many non-HEPA filters meet this standard, but may not withstand the frequency of dust extractor filter cleaning that’s required due to fineness of silica dust clogging the filter (if not cleaned often). Use a HEPA filter 1) so OSHA agents know its filtration is rated 99% effective, 2) it offers greater durability versus a standard filter, and 3) saves money in the long term.


Construction Junkie note: OSHA's table 1 does specifically require that a HEPA-filtered vacuum be used when cleaning holes and when cleaning up in between passes of walk-behind milling machines and floor grinders when they are used indoors or in an enclosed area.


Is there a limit for length of a vacuum hose?

Bosch dust extractors can be used with either a 10 Ft. hose (which comes with the unit) or with a 16 Ft. hose (sold separately). Beyond 16 Ft. the expected efficiency of the dust extractor decreases greatly. Users may have dust control performance issues beyond 16 Ft.


What about jobsite dust from surrounding work areas? How can this be distinguished from cutting/grinding operations?

Dust generated in and around the jobsite must be compliant with the established control plan for that site. Anything levels that exceed the dust control plan should be reported immediately. It doesn’t matter who creates the dust, everyone must be safe from exposure.

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