Hi all, I'm wondering if someone can confirm that the use of a FFP1 dust mask to top up a hopper with garnet powder would be adequate? It generates little dust during the process (use of the actual power is different; we use it on a waterjet) which is just literally opening the bag up and pouring it in and takes a matter of minutes and done very infrequently. The only reason I've even enquiring about it really is because I know the garnet powder contains crystalline silica and whilst the MSDS advises using local guidelines for PPE, this more seems to relate to the use of the product when it i used for dry blast cleaning (which we don't, it's used for cut-outs and as I said, mixed with water). Thanks.

I agree with Kurdziel

Engineering control and RPE as a last resort. However FFP3 if you need RPE with silica.

Originally Posted by: chris42

To confirm this is filling the machine not emptying a dust bag?

The garnet will be a blast medium, so the granules will have some dust on them which when poured into the machine creates a small amount of dust above the opening it is filled into. Correct?

Assuming what I have put above is correct. If it will be mixed with water anyway, could the bag be opened and damped down with water, preventing any dust when tipped out? ( take care this does not add appreciably to the weight)

Chris

Hi Chris, yes, filling the machine; it has a mesh filter onto it that you pour the bag into (to stop other containminents getting into the machine). Not sure if damping it down would work, but as I said, the dust generation is very, very minimal and it's literally a couple of minutes process.

A Kurdziel/Bigmac1 - Thanks. I appreciate what you're saying, but I highly doubt I can convince my MD to fork out for an LEV system where there is little dispersion of the dust and it's a very short exercise. I think it's more likely that I just need to ensure the operators are wearing the right kind of RPE.

hmmm, I'm with the LEV peeps on this.  Emptying bags of  crystalline silica is going to form dust clouds whichever way you look at it.  The LTEL (EH40/2005) for respirable crystalline silica is 0.1mg/m³ and there is no STEL.  You need to have this measured whatever control you go with and I am quite sure they will recommend LEV and possibly dust masks for this task.

Originally Posted by: Svick1984

 I highly doubt I can convince my MD to fork out for an LEV system where there is little dispersion of the dust and it's a very short exercise.

Not sure that washes under the current sentencing guidelines - avoiding cost is construed as high culpability which in the case of gross negligence manslaughter would push the sentence towards 18 years imprisonment

EU 2017/2398 The Carcinogens and Mutagens Directive (Protection of Workers) established 0.1mg/m3 8hr TWA as a binding occupational exposure limit value for Respirable Crystalline Silica - this legislation is aimed at reducing risk to workers not giving employers an "up to" value

Svick

If you apply the precautionary principle and use (relatively expensive) FFP3 until you have some real data, it might help convince your MD of the benefits of ensuring that your air monitoring strategy is sufficiently robust!

Of course, you will also need to make sure that users get adequate training in face fit testing. That alone is likely to exceed the cost difference between FFP1 and FFP3 for the short time you need to use PPE pending the results of appropriate monitoring of the airborne levels of respirable and inhalable silica dust that is generated.