Industrial ovens and furnaces are used in many manufacturing processes. One use of industrial ovens is for drying and curing coatings on fabrics.
I investigated a fire loss involving a very large oven, 10 stories high, used for curing coatings on an industrial fabric. A young firefighter was burned in response to this fire, one of a string of many fires that had occurred involving the oven.
The investigation revealed that the fire occurred when a recirculation fan failed due to a broken shaft and therefore stopped circulating air. A gas burner that fired into this recirculation loop continued to operate and overheated the area due to the lack of airflow. This overheating ignited combustible residues that build up inside the oven and on its exterior due to leakage through the old ovens walls.
The fire spread up the walls due to this combustible residue, eventually to the location where the firefighter was injured. Prior to entering the forensic engineering profession, I spent many years designing industrial equipment including large industrial ovens. My experience with oven design and having seen many industrial ovens in the field told me that this incident should not have occurred.
NFPA 86, Standard for Ovens and Furnaces, is the widely acknowledged standard for the proper design and use of industrial ovens. Several of its provisions were not followed in the equipment installed at the subject site. The oven should have been equipped with air pressure switches on the recirculation fans that would have stopped the burner if the fan failed to operate. Also, a properly located high temperature limit switch would have sensed the abnormal elevated temperatures in the burner chamber and shut off the burner. I was also critical that a lack of ongoing cleaning at the plant allowed the accumulation of sufficient combustible residue to spread the fire. Finally, the oven lacked a fire extinguishing system that could have extinguished the fire prior to its spread. After my investigation, I testified at deposition about the above problems on behalf of the injured firefighter’s legal representatives. Shortly thereafter, the case settled on a favorable basis.
John Holecek, senior consulting engineer at Warren, is a licensed professional engineer in South Carolina, North Carolina, Alabama, Florida, Georgia, Ohio and Virginia and has both a Bachelor of Science in Mechanical Engineering and Master of Science in Mechanical Engineering from the University of South Carolina. A certified fire and explosion investigator by the National Association of Fire Investigators, John has more than 22 years experience in the design of industrial process equipment and is extremely knowledgeable in ICC, NFPA and OSHA codes and standards. He pairs more than 13 years of experience supervising manufacturing operations with deep knowledge in areas such as applied industrial heat transfer in oven design, industrial electrical process and motor control systems, material handling systems and fire protection systems. In addition he’s designed paint finishing systems, and commercial and consumer gas fired cooking appliances. John, who has more than 22 years’ experience managing outside contractors in site safety requirements and installation of industrial process equipment, is well versed in federal and state worker safety and environmental regulations.