Monday, April 22, 2024

Dust Collection/Explosion Venting/Valve

Schwelke, Eric

Here are the responses from my original query:

On Sep 4, 2016, at 8:07 PM, Schwelke, Eric > wrote:
Hope you all are enjoying your Labor Day weekend.

Our dust collection system in our fabrication area has reached the end of its life and we are looking to replace the unit and all the ductwork. We were presented with a few different quotes and have been informed that we should test our “dust” for explosiveness. If it is, we have been advised to follow the NFPA/OSHA protocols to protect against such an incident happening. Of course, the explosion venting/valve system is more than twice the $$$ than the system without.

For those of you who do in-house fabrication, have you ever had your ‘dust’ tested? Also, have you ever been audited by OSHA regarding same?



That is ridiculous because you neither manufacture explosives nor deal with grain dust. What you want to do is collect from the floor also to pick up harmful chemicals, most of which drop, then pick up under and behind your laminations so vapors do not pass by your face.

I just installed a system in my office. Did it myself, but the 2 bids I got made no mention of this. By the way, I bought a used system on Craigslist and have a significant amount of Nordfab ductwork and connectors left over if you are interested in buying some. The stuff is bulletproof.

I know nothing of your OSHA/NFPA protocols but offer this comment. We have a ducted dust extractor which is installed outside. The outside unit (fan and collector) has an “explosion” window in it. It is a plastic membrane which forms part of the outer wall of the extractor and it is designed to “blow out” should there be a fire/explosion etc in the extractor. We have never had our dust examined/tested for flammability or explosiveness but we are very careful to only grind or sand metals and materials which produce sparks, while the dust extractor is turned off.


Just run a static ground wire inside all ductwork.


I’d say you will have better response if you were to be more specific on size and fabrication specifics as it really depends.


I am in Tennessee and OSHA has indeed taken a keen interest in our industry. The inspectors that visited our facilities said that so much manufacturing had left the states that they were “forced” to start looking at the service industries like ours to have something to do. Can you believe that? So instead of reducing the size of the department, they simply look for other businesses to harass. I would definitely go through the testing. The fines are astronomical. For example, if you are caught with a respirator in your facility without the right paperwork documenting proper training or you have a beard, fines can be $5k. We have had to install guards on the Troutman to keep clothes and hair from getting caught in them. We actually had to install signs on the air compressor that say not for personal use or for blowing off clothing. OK so what are you supposed to use it for then? Signs on glue pots so people won’t drink it – no I’m not making this stuff up. Yadda yadda yadda. It goes on and on. These guys can shut your doors and have the might of the fed government behind them. Complete your due diligence it’s cheaper than the fines.

I worked for the VA system for over 10 yrs and have never heard of this and had OSHA audits regularly, my advice, has your dust ever exploded? Just be mindful of what is going into your dust collection system, foam dust, wood dust which is explosive, metal shavings which could be hot enough to cause a fire, Exc. I now work for private sector and like I said have not had a problem. Just my two cent, I would look at what you had, what your future fabrication is going to be and decide from that.


Flammable aerosols are fine non reacted carbon molecules. Examples include .. . .

-Powdered sugar

-Coal dust

-Fine saw dust

-Charcoal dust

-Powered cheese (think old school Mac and cheese) -flour -etc

Non flammable aerosols include

– carbon dust

-plaster dust

-Crepe and cork dust -> unless you are magically grinding your dust extra fine. I believe that you would have to take cork dust and freeze it with liquid nitrogen then run it in a ball mill for sometime before it would be fine enough to aerosolize and flashburn. Etc. Volatile chemicals can explode in a dust collector if the concentration is high enough. But you would have to be vacuuming up spilled thinner or gasoline with a dust collector to get the concentrations high enough. So, unless your orthotics and prosthetics laboratory is doubling as a meth lab The person telling you to get your dust tested either has something to sell you or has too much time on their hands.


Never tested – however is your ducting all metal or plastic/pvc? “spark’ in ungrounded systems is the usual suspect and is combated by running grounding wire through the ducts from the metal on the collector to the metal on the tools so no static builds and jumps through the ducts.

I just put in a system but that didn’t come up at all. I would be very interested in replies. sorry I wasn’t any help

No and no. We have built two different systems and use a standard cyclone vacuumed system with pvc schedule 40 ducting.

Eric Schwelke CPO LPO, Director
Kessler O & P Services
11 Microlab Road
Livingston, NJ 07039
Direct Tel: 973 863 4231
Direct Fax: 717 635 3920
“Success in Motion”

[] Top-ranked by U.S.News & World Report for the 23rd consecutive year, Kessler Institute is the only rehabilitation hospital in New Jersey to be named to the prestigious list of “America’s Best Hospitals” and is the leading center of its kind in the East.
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