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Combustible Dust Flame Propagation and Quenching in Pipes and Ducts

Fire Protection Research Foundation report: “Combustible Dust Flame Propagation and Quenching in Pipes and Ducts"
Authors: Alexander Ing, National Fire Protection Association
Date of issue: December 2018


A technical basis is required for determining when pipes or ducts are too small in diameter to permit the propagation of combustible dust deflagrations. This must be evaluated considering the characteristics of the equipment system (pipe/duct diameter and length), properties of the combustible dust, and operating conditions (pressure, temperature, flow rate, etc.). The knowledge will permit establishing rational protection requirements in NFPA’s various combustible dust fire and explosion prevention standards. There is also a lack of knowledge around conditions influencing the explosion propagation through piping, especially small diameter piping. Having a clear understanding of experimental testing data would allow analysis to see what conditions and parameters will affect the explosion propagation and also point out where there are knowledge gaps.

This comprehensive literature review project seeks to identify the parameters affecting flame propagation involving combustible dusts within pipes and ducts, and seeks to determine the conditions under which a combustible dust flame will not propagate (i.e., will quench) within a piping or ductwork system. The following tasks have been carried out for this project:

  1. Identify the conditions under which combustible dust deflagration will not propagate within a piping or duct work system.
  2. Identify the factors (pipe diameter, pipe length, dust type, and dust concentration) affecting the explosion propagation through pipes from relevant literatures.
  3. Identify the gaps from previous studies in the literature and in previous data compilations.
  4. Prepare a final report based on the information gathered from tasks 1, 2 and 3.