Venting of Explosions | AIChE

Venting of Explosions


Ibarreta, A. F. - Presenter, Exponent, Inc.

Many industrial processes involve the use of combustible dusts or gases.  During processing, these materials may come in contact with air or an oxidizing atmosphere, leading to a potentially explosive atmosphere.  In many cases, explosion venting is the most cost-effective explosion protection option to mitigate the consequences of a potential deflagration.

Deflagrations inside equipment or structures can lead to a rapid rise in pressure inside an enclosure, leading to catastrophic failure of the structure.  Adequate venting of deflagrations requires proper sizing, placement and design of vents.  The National Fire Protection Association (NFPA) 68 Standard on Explosion Protection by Deflagration Venting provides guidance on proper vent panel design, implementation and maintenance, for both combustible dusts and gases.

This presentation provides an overview of deflagration hazards inside enclosures or vessels, and a tutorial of the requirements within the current version of the NFPA 68 standard.  The vented deflagration process is explained, which includes the pressure rise due to the expansion of the flame front and the pressure release due to flow through the vent.  The presentation works through sample calculations of the required size of explosion vents for different systems, and identifies cases where explosion venting may not be feasible. 

Attendees to the presentation are expected to gain a better understanding of the explosion hazards involved in the processing and handling of combustible dusts and flammable gases.  The presentation will explain the fundamental principles involved in venting of deflagrations and provide guidance for proper venting of deflagrations.