This morning I attended session M02, which highlighted a new approval test standard available for evaluating and establishing the basis for "listed" systems as required by NFPA 68, Standard on Explosion Protection by Deflagration Venting. I can remember when the Committee on Explosion Protection Systems, responsible for NFPA 68 first considered this new technology in 1998 whereby an explosion could be vented indoors. The device generally consists of a flame arresting and particulate retention mesh along with a rupture membrane. The NFPA combustible dust standards include "particulate retention and flame arresting" devices (which is how these devices are denoted in NFPA 68) as a permitted control measure where combustible dust explosion hazards are determined to exist. For example, NFPA 654-2013, paragraph 7.1.4 provides the following; note 7.1.4.(6) includes the "flameless venting" device:
Dr. Jenny Chao, FM Global, and Armand Brandao, FM Approvals, reviewed the methodology used by the FM Approvals Standard 7730 (issued at the end of 2014) to evaluate these devices. NFPA 68 requires these devices be listed for their use. NFPA 68 is scheduled for revision in the Fall 2017 cycle; Public Inputs are being accepted for the standard until January 7, 2016. To view NFPA 68 in a read-only format go to www.nfpa.org/68. FM Approvals Standard 7730 is available from the FM Global web site.