Most applications for industrial burners fit the definition of a "furnace" or "oven." One definition of "furnace" is the convective or
radiative transfer of thermal energy from combustion to the product's enclosure. Combustion safety cannot be overemphasized
due to the potential for significant hazards. Therefore, national standards were established that all industrial ovens and furnaces
must comply with. One of these standards is NFPA #86: Standard for Ovens and Furnaces.
NFPA #86 covers the safe operation of ovens and furnaces, specifically mentioning explosion protection, proper ventilation,
equipment location, and more.
It is suitable for a variety of applications, including electric arc furnaces and low oxygen systems.
Let’s focus on the combustion safety of direct gas stoves.
Safe practices save lives.
Prevent explosion
The root cause of furnace explosions is the accumulation of fuel and oxygen in the furnace and its airways and pipes, which then
ignites. The severity of the explosion is a function of the amount of fuel and the fuel/air ratio at the critical moment.
Today's BMS (Burner Management System) are controlled by digital devices programmed to monitor and adjust gas flow and purge
timing, minimum ignition valve settings at start-up, and flame and fuel conditions during operation. When the BMS detects a fault
condition, it cuts off the main fuel supply, forcing the burner to shut down.
The standard requires that BMS controllers "shall be listed for intended service." Insurance underwriting of covered equipment
verifies compliance. NFPA #86 also requires that control logic be protected from unauthorized changes and that security logic be
stored in non-volatile memory.
Burner system restart
Any trip triggered by the BMS will require a trained operator to correct the fault before restarting the burner. Purge removes any
flammable gases that may have accumulated before the burner is started or restarted. The standard requires a volume of air to
pass through that is 4 times the enclosure volume to ensure a safe restart.