A report from NFPA looks at recent oven, furnace and dryer explosions — in particular, explosions in curing ovens, electric arc furnaces and grain dryers. The report — prepared by Fire Protection Research Foundation and the National Fire Protection Association — will be used by the technical committee responsible for the industrial ovens and furnaces standard, NFPA 86, as it begins works on the next revision cycle of this important code.

Though NFPA 86 has required explosion-relief on specific ovens and furnaces for more than 90 years, it was felt that they were incomplete and inconsistent with NFPA 68, Standard on Explosion Protection by Deflagration Venting.

The survey was designed to identify several key pieces of information:

• The type of ovens, furnaces, or dryers that are experiencing explosions.
• The causes and subsequent outcomes of the explosions.
• The type of explosion protection installed on the system that exploded (and its effectiveness).
• The impact of the explosion on people and property.
• Additional data to substantiate the redirection of explosion-relief guidelines within NFPA 86.

The leading cause of explosions, according to survey respondents, is human error. Failure of a safeguard, a safeguard not installed, unforeseen hazard and poor process design were other causes listed.

“The most important result from the survey, from the perspective of explosion relief is the relatively large percentage of incidents in which the oven/furnace/dryer was significantly damaged or had to be replaced, indicating either that explosion venting was missing or was ineffective in these cases,” say the authors, Sreenivasan Ranganathan  Sean Gillis, in the report.

NFPA 86, Standard for Ovens and Furnaces, provides standardized methods to minimize fire and explosion hazards of ovens and furnaces used for industrial processing of materials, and it includes requirements for proper explosion ventilation methods for new ovens and furnaces.

Read the full report here.