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FAQ’s of Hazardous Dust Testing (DHA)

Written by Rachelle Andreasen | 03.08.18

By Rachelle Andreasen, Dust Project Manager, Fauske & Associates, LLC

A state of the art dust testing lab will frequently receive a number of questions from a variety of industries. Combustible or hazardous dusts exist in most industries including pharmaceuticals, food, cosmetics, metals, papers/pulp, petrochemical, agricultural, manufacturing, wood, plastics/polymers... 

Many plant managers or facility safety experts are not sure where to start when it comes to possible hazardous dusts.  Some aren't sure if there are enough dusts to warrant a collector? Some see dusts and don't know if that "tiny" bit is hazardous or combustible? Some know they need a dust collector, but what kind?  If there's an existing collector, is it efficient?  How often should it be checked?   

Here are a few other questions we frequently answer and a video below that shows you how to collect a combustible dust sample.   

Q: Where is the best place to collect material for testing?

A: Typically, the finest and driest material present within the facility presents the greatest hazard.  With this being said, it is recommended that the material be collected from the dust collector filter, elevated surfaces within the facility, or the dust collector bin.  If finer material cannot be collected, and you know that finer material may be generated in the process, it is recommended that you request particle size reduction prior to testing. 

Q: Can I use historical data to design my dust collector?

A: No, it is not recommended to use historical/literature values to design a dust collector or to size explosion protection.  Historical values are a good reference to identify if your material has a trend of being explosible and/or combustible, but there are so many other factors that play a role in ensuring your specific facility has data that truly represents the material within your process.  It is important to consider the characteristics such as particle size distribution, particle morphology, and moisture content.

Q: How much material do I need to submit for the Explosion Severity test?

A: Typically we recommend that at minimum of 500 g (1 lb) is submitted for the Kst test; however, depending on the density of your material more material may be needed.  It is also recommended that additional material be sent if particle size reduction is requested.

Q: How long does it take to get results?

A: Explosion Severity (Kst) testing is one of the most labor intensive dust testing services we offer.  Depending on how the sample behaves during testing, a typical Kst test can take anywhere from 4 to 6 hours.  However, depending on the nature of the material and the clean-up involved, testing may take longer.  For example, if the material being tested generates hazardous decomposition products, additional safety procedures are followed.  

Hazardous dust /or combustible dust hazard analysis (DHA) is a painless but important step in plant management and facility safety. There are no dumb questions.  Whether meeting new OSHA, NFPA or NEP standards or just taking precautionary steps, get your dust tested.  See our helpful videos on dust collection or specific tests such as MIE, MIT and LIT, Go/No Go Testing and more. 

Watch this video to learn how to collect a combustible dust sample.