WHERE IS SILICA FOUND?

This first thing to understand is where you might encounter silica dust on the job site.

Crystalline silica is generally found in concrete, brick and stone products, as well as man made stone and other masonry materials. This means the rule covers a pretty large group of trades from roadwork, decorative concrete, counter top installation and more. Due to health issues related to silica dust, OSHA has reduced the Permissible Exposure Level, or PEL, for silica dust to 50 micro grams per square meter in an 8 hour time weighted average.

So, what does all this mean? The 8 hour time weighted average part is a bit too complicated to get into here, but, what can be said simply is the new standard is basically 1/5^th of what was previously allowed for construction.

CONSTRUCTION STANDARDS AND OPTIONS

OSHA is issuing two standards. One for construction and the other for general industry and maritime. In this post we'll be focusing on the construction standard.

The rule provides two options for construction.

Option 1 is in short to control the dust with your own measures, then measure the amount of silica dust that workers are exposed to. If it's at or above the action level of 25 micro grams per square meter over an 8 hour time weighted average, you must find better ways to protect workers from crystalline silica dust exposure. Measuring PEL can be complicated. It involves placing special monitoring devices on workers and then sending the monitors off to a laboratory for testing and/or providing medical testing for workers on a regular basis.

So basically, you have to say “I have my own way to control the dust” then take the time and expense to test your idea

Option 2 is to simply follow the dust control methods found in Table 1 of the new rules construction standards.

If your idea to control PEL works, you're set! If not, you have to start all over again until you get it right. That's why following Table 1 may be the better option.

TABLE 1

Table 1 shows dust control methods for many common job site operations. According to OSHA's fact sheet, employers who follow table 1 correctly are not required to measure employees exposure to silica and are not subject to the PEL.

For tools like stationary masonry saws, hand saws and rig mounted core saws or drills, table 1 requires the use of a tool equipped with an Integrated Water Delivery System that continuously feed water to the blade or bit. This is almost always followed up with the instruction to operate and maintain the tool in accordance with manufacturers instructions to minimize dust emissions.

Other tasks have different requirements and options. Things like cutting fiber cement board, tuck pointing, dowel drilling concrete and using handheld and stand mounted drills must use a commercially available dust route and a dust collector. There are other tools listed that have the option of using either IWDS or dust collection. Along with the requirement to use a dust collector in many of the operations, table 1 also places requirements on the dust collector itself. The following statement appears in the table almost everywhere a dust collector is called for:

“(the) Dust collector must provide the air flow recommended by the tool manufacturer, or greater, and have a filter with 99% or greater efficiency and a filter-cleaning mechanism.”

To more clearly define what that statement means, let's look at the text preceding table 1 to gain some insight.

Let's first take a look at what is written about filter efficiency. It shows us that OSHA had originally considered requiring HEPA filters which provide a filter efficiency of 99.97% at 0.3 microns because they believed they offered better protection from silica dust. However, they found two problems.

One, too many HEPA filters clog quickly, making the level of filtration irrelevant. And, two, there were more filters that were close to HEPA available so that the standard could be more easily implemented.

The dust collection systems we offer at Rental Tools Online use HEPA filters as we feel they provide the best protection for our customers. In addition they also feature an Electromagnetic Pulse Filter Cleaning System (EPFCS) that vibrates both filters to remove dust and prevents them from becoming clogged.

The rule went into effect on June 23^rd, 2016 and construction businesses must be compliant by June 23^rd 2017. Hopefully this post as given you a better sense of what you may need to do to keep yourself in compliance.