Silicosis in the lab??? 1

[GTSLABS]

I have worked in a geotechnical laboratory atmosphere for over 17 years. I do have mild asthma but the dust has never really bothered me. I recently purchased a Surface Grinder to grind flat rock core specimens. I have a shop
vac attached to the grinding wheel housing to collect the majority of the dust and plan on installing a second unit
on the opposite side of the housing for better evacuation of dust. I am also considering a misting nozzle to assist in dust reduction.

I want to protect myself and employees from Silicosis.
What is the adequate filter size to use on a conventional shop vac if possible. Or do I need to go to an industrial unit?

Are any other laboratories using general or specialized dust collection systems JUST for the lab?

Thanks
Steven

 

[Mccoy]

GISLABS,
risk of silicosis is conventionally related to the respirable quartz concentration of 0.05 mgm-3 (ACGIH treshold level value). By definition, the particle size for respirable dust has a median value of 4-5 microns (according to different conventions), so most air filters today, which collect sub-micron particles, should do.
The design of dust control system is related to many factors, including size of the shop, type and amount of particulates produced, humidity of filtered air. Please note that some systems do not work well w/ wet air, and those which are better suited to filter wet particles are called "scrubbers". You might want to have a look at this site:

http://www.engcollab.com

which features a few illustrative articles.
Your concern for silicosis might well be legitimate.
Grinding most igneous rocks and sandstones is a potential serious source of airborne respirable quartz. I do not have notice of samples taken in soil testing labs, though in some instances i suspect risk of silicosis might be real.
Grinding and cutting quartz-rich material definitively exposes to silicosis in buiders and stone workers.
If you'd like to know the situation in your lab the only way is by personal air samplers installed on workers performing typical duties (just make sure some dry soil is being worked), and successive XRD analysis - pretty much costly. The site for more info on silicosis is:

http://www.cdc.gov/niosh