NFPA 86: Standard for Ovens and Furnaces establishes the minimum safety requirements for equipment that uses heat to process materials. The standard is designed to prevent fires, explosions, and hazardous operating conditions in industrial heating systems. Although there are many updates in the most recent edition, these two mandatory annual requirements directly affect combustion equipment in use by most heat treating operations: Safety Train Verifications and Radiant Tube Integrity Inspections.
The annual Safety Train Verification requirement focuses on confirming that each component of the fuel safety train is present and functioning correctly. (Often in older furnace installations, components like gas line drip legs or wye strainers were omitted) Combustion systems rely on a sequence of valves, switches, regulators, and interlocks that must function in a precise way for safe furnace operation. These devices can drift out of adjustment, wear mechanically, or fail electrically over time. Verifying the gas safety train annually ensures that all protective devices respond when necessary. This procedure confirms valve functionality, switch setpoints, regulator performance, and the integrity of wiring and interlocks. The goal is to identify any signs of degradation of the gas safety train before it becomes a safety hazard.
Radiant Tube Integrity Inspections are now another required annual check. Radiant tubes operate in severe thermal environments that can lead to cracking, oxidation, warping, or weld deterioration. A tube that loses integrity can leak products of combustion into the furnace chamber, which can contaminate products, affect temperature uniformity, and create unsafe operating conditions. Loss of integrity can occur through thermal cycling, corrosion, or mechanical stress. The annual inspection ensures that any failing tubes are identified before they compromise safety or performance.
Three common ways to perform Radiant Tube inspections are the use of digital combustion technology, pressure testing, and visual inspection. Digital combustion technology uses furnace atmosphere and O₂ data to identify failing tubes. This method significantly reduces downtime and manpower, improves safety, and increases accuracy. Pressure testing includes furnace shutdown, tube sealing and pressurization, pressure verification, and final seal removal and reassembly. Visual inspection requires furnace shutdown and multi-day cooling, confined space entry with elevated risk, and offers limited accuracy due to restricted access, typically identifying only major cracks in cold tubes.
It has been observed through industry interactions that many heat treaters have not yet come into compliance with these updated NFPA 86 requirements because of the long-standing belief that their equipment was effectively grandfathered in. Historically, older furnaces and ovens were not always required to meet new verification or inspection criteria. That is no longer true. Due to the grandfather clause being eliminated, every furnace or oven, regardless of installation date, must comply with the current standard.
Failure to comply with the annual requirements can have significant consequences. Noncompliance increases exposure to safety incidents, unplanned outages, and equipment damage. Insurance carriers and auditors are placing greater emphasis on documented conformance to NFPA 86, and missing these verifications can affect coverage or lead to corrective actions. In the event of an incident, lack of compliance presents substantial liability.
PSNERGY provides resources that help heat treaters and metal processors meet these requirements efficiently. We offer detailed guidance, inspection procedures, and combustion technology for Safety Train Verifications and Radiant Tube Integrity Checks, along with service options for facilities that need support. These resources assist operators in building compliant, safe, and reliable operations.
For more information on the recent edition of NFPA 86, visit: https://www.nfpa.org/
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