Back to the Grind: Using Grinders according to Table 1 the OSHA Silica Regulation

A lot of contractors use grinders, typically between 4" and 5," for making quick cuts.  Or, if you're doing restoration work, you're using them a LOT.  

 4.5" ginder used with a shroud for cutting mortar

4.5" ginder used with a shroud for cutting mortar

There's still a lot of you contractors out there that still don't know what to do to get rid of the dust to be in compliance, so here's a few little tidbits to get you going when using a grinder, whether for small, quick cuts or for restoration and mortar removal:

Can you cut wet?  

If you can, do it.  Then don't worry about the vacuum system.  

Here's an alternative to using a grinder for small cuts or tuckpointing:  5" Masonry Wet Saw.  It might not work for all situations but it could be a good alternative in some cases to avoid using a vacuum.

 5" Masonry Wet Saw

5" Masonry Wet Saw

Can't cut wet?

Now you've got to figure out the vacuum system.  

Grinders used for mortar removal:

  • Your vacuum must have 25 CFM (cubic feet per minute) or greater of airflow per inch of wheel diameter.  

For example- if you're running a 5' angle grinder for tuckpointing, your vacuum must be rated by the manufacturer at 125 CFM.

  • Your vacuum must have a filter with 99% or greater efficiency (HEPA) and a cyclonic pre-separator or filter-cleaning mechanism. 

Here are a few examples of vacuums that can meet that standard:  12 Gallon Xtract Vac and Cordless/Corded 2.1 Gallon HEPA Filter Dry Dust Extractor/Vacuum

 12 Gallon Xtract Vac

12 Gallon Xtract Vac

  • Make sure your tool, grinder in this case, has the correct shroud to attach to the vacuum hose.  It is important to understand that most shrouds are not universal.  Most manufacturers have not made shrouds for every grinder they make.  Always use and maintain your tools according to your manufacturer's instructions.  
  • No matter how long you are removing mortar, you will still have to require your employees to wear a respirator.  
    • Under 4 hours- they must wear a APF 10 (N-95)
    • Over 4 hours- they must wear a APF 25 
 https://www.osha.gov/Publications/3352-APF-respirators.pdf

https://www.osha.gov/Publications/3352-APF-respirators.pdf

 https://www.osha.gov/Publications/3352-APF-respirators.pdf

https://www.osha.gov/Publications/3352-APF-respirators.pdf

  • Train your employees to use these every time they are tuckpointing.  They'll also need to know how to use this correctly.  Like any safety products, they only are good if they actually use them.  Change is hard for most so you'll have to be persistent to ensure they are following the new standard.

Grinders used for cutting (other than mortar removal):

  • Just like with tuckpointing, your vacuum must have 25 CFM (cubic feet per minute) or greater of airflow per inch of wheel diameter.  

For example- if you're running a 5' angle grinder for cutting materials, your vacuum must be rated by the manufacturer at 125 CFM.

  • Your vacuum must have a filter with 99% or greater efficiency (HEPA) and a cyclonic pre-separator or filter-cleaning mechanism. 

Here are a few examples of vacuums that can meet that standard:  12 Gallon Xtract Vac and Cordless/Corded 2.1 Gallon HEPA Filter Dry Dust Extractor/Vacuum

 Cordless-Corded 2.1 Gal HEPA Vac

Cordless-Corded 2.1 Gal HEPA Vac

  • Make sure your tool, grinder in this case, has the correct shroud to attach to the vacuum hose.  It is important to understand that most shrouds are not universal.  Most manufacturers have not made shrouds for every grinder they make.  Always use and maintain your tools according to your manufacturer's instructions.
  • When used properly, this system stays within Table 1 and no respirator is necessary except for when using it indoors or in an enclosed area for more than 4 hours.  
  • If you are indoors using it for more than 4 hours, you'll need to have your employee wear a APF 10 (a N-95 dust mask- see above) and follow all of the necessary regulations for this.

 

  • Train your employees to use these every time they cut with a grinder.  This will be a big adjustment for most.  They'll also need to know how to use this correctly.  Like any safety products, they only are good if they actually use them.

Another alternative is to do testing.  If you think the task you're doing is below the PEL, you can choose to do testing on the specific test at hand.  Be sure that you follow the regulation for testing procedures, which can be quite complicated.

Also check out additional resources pertaining to silica:

 

If you have questions, or if Spec Rents can help you in any way, please contact us.  Check out our silica solutions for additional information.

Post by:  Elizabeth "Liz" Graves, Sales Manager at Spec Rents, LLC.  Contact Liz at lizg@specrents.com

Source: https://www.osha.gov/silica/Table1sect1926...