[More than 30 grams (approximately 1 ounce) of sample less than 420µm required; more than 300 grams (approximately 0.67 pounds) of sample less than 420 µm required if testing metal dusts.] ...

For purposes of testing, approval, and area classification, the Code groups various air mixtures and presents them in Sec. 500.6 of the 2011 NEC. As noted in 500.6(B)(1), Group E is defined as ...

Page 3 of 3. Combustible Dust Basics: How to Collect a Sample and What Does a Go/No-Go Test Mean? May 01, 2014; We've been blogging and writing a lot recently on the basics of combustible dust.