Industrial Ovens

This chapter regulates the installation and operation of industrial ovens and furnaces, requiring compliance with NFPA 86 and other referenced codes.

2101 — General

2101.1 Scope. This chapter shall apply to the installation and operation of industrial ovens and furnaces. Industrial ovens and furnaces shall comply with the applicable provisions of NFPA 86, the International Fuel Gas Code, International Mechanical Code and this chapter. The terms" ovens" and "furnaces" are used interchangeably in this chapter.

2101.2 Permits. Permits shall be required as set forth in Sections 105.6 and 105.7.

2102 — Definitions

2102.1 Definitions. The following words and terms shall, for the purposes of this chapter and as used elsewhere in this code, have the meanings shown herein.

FURNACE CLASS A. An oven or furnace that has heat utilization equipment operating at approximately atmospheric pressure wherein there is a potential explosion or fire hazard that could be occasioned by the presence of flammable volatiles or combustible materials processed or heated in the furnace.

Note: Such flammable volatiles or combustible materials can, for instance, originate from the following: Paints, powders, inks, and adhesives from finishing processes, such as dipped, coated, sprayed and impregnated materials. The substrate material. Wood, paper and plastic pallets, spacers or packaging materials. Polymerization or other molecular rearrangements. Potentially flammable materials, such as quench oil, water-borne finishes, cooling oil or cooking oils, that present a hazard are ventilated according to Class A standards.

Note: Such flammable volatiles or combustible materials can, for instance, originate from the following:

Paints, powders, inks, and adhesives from finishing processes, such as dipped, coated, sprayed and impregnated materials.
The substrate material.
Wood, paper and plastic pallets, spacers or packaging materials.
Polymerization or other molecular rearrangements.

Potentially flammable materials, such as quench oil, water-borne finishes, cooling oil or cooking oils, that present a hazard are ventilated according to Class A standards.

FURNACE CLASS B. An oven or furnace that has heat utilization equipment operating at approximately atmospheric pressure wherein there are no flammable volatiles or combustible materials being heated.

FURNACE CLASS C. An oven or furnace that has a potential hazard due to a flammable or other special atmosphere being used for treatment of material in process. This type of furnace can use any type of heating system and includes a special atmosphere supply system. Also included in the Class C classification are integral quench furnaces and molten salt bath furnaces.

FURNACE CLASS D. An oven or furnace that operates at temperatures from above ambient to over 5,000°F (2760°C) and at pressures normally below atmospheric using any type of heating system. These furnaces can include the use of special processing atmospheres.

2103 — Location

2103.1 Ventilation. Enclosed rooms or basements containing industrial ovens or furnaces shall be provided with combustion air in accordance with the International Mechanical Code and the International Fuel Gas Code, and with ventilation air in accordance with the International Mechanical Code.

2103.2 Exposure. When locating ovens, oven heaters and related equipment, the possibility of fire resulting from over-heating or from the escape of fuel gas or fuel oil and the possibility of damage to the building and injury to persons resulting from explosion shall be considered.

2103.3 Ignition source. Industrial ovens and furnaces shall be located so as not to pose an ignition hazard to flammable vapors or mists or combustible dusts.

2103.4 Temperatures. Roofs and floors of ovens shall be insulated and ventilated to prevent temperatures at combustible ceilings and floors from exceeding 160°F (71°C).

Worked example

Scenario: A manufacturing plant plans to install an industrial oven in a newly enclosed room in its basement.

Explanation: The design must ensure the basement room provides combustion air in accordance with the International Mechanical Code and International Fuel Gas Code, and ventilation air in accordance with the International Mechanical Code, to prevent the accumulation of hazardous fumes and ensure proper combustion.

2104 — Fuel Piping

2104.1 Fuel-gas piping. Fuel-gas piping serving industrial ovens shall comply with the International Fuel Gas Code. Piping for other fuel sources shall comply with this section.

2104.2 Shutoffvalves. Each industrial oven or furnace shall be provided with an approved manual fuel shutoff valve in accordance with the International Mechanical Code or the International Fuel Gas Code.

2104.2.1 Fuel supply lines. Valves for fuel supply lines shall be located within 6 feet (1829 mm) of the appliance served. Exception: When approved and the valve is located in the same general area as the appliance served.

2104.2.1 Fuel supply lines. Valves for fuel supply lines shall be located within 6 feet (1829 mm) of the appliance served.

Exception: When approved and the valve is located in the same general area as the appliance served.

2104.3 Valve position. The design of manual fuel shutoff valves shall incorporate a permanent feature which visually indicates the open or closed position of the valve. Manual fuel shutoff valves shall not be equipped with removable handles or wrenches unless the handle or wrench can only be installed parallel with the fuel line when the valve is in the open position.

Worked example

Scenario: A bakery is installing a new large-scale bread oven that uses natural gas and also has a small liquid propane backup system.

Explanation: The natural gas piping for the oven must comply with the International Fuel Gas Code. The piping for the liquid propane backup system, as another fuel source, must comply with the specific requirements of IFC Chapter 21, Section 2104, in addition to any other applicable codes for LP gas.

2105 — Interlocks

2105.1 Shut down. Interlocks shall be provided for Class A ovens so that conveyors or sources of flammable or combustible materials shall shut down if either the exhaust or recirculation air supply fails.

Worked example

Scenario: A paint curing oven (Class A) uses a conveyor system to move freshly painted parts through the oven, where solvents are evaporated.

Explanation: The oven system must include interlocks that automatically shut down the conveyor and stop the supply of painted parts (flammable materials) if either the oven's exhaust fan or recirculation air supply fails. This prevents the accumulation of flammable vapors and reduces fire or explosion risk.

2106 — Fire Protection

2106.1 Required protection. Class A and B ovens which contain, or are utilized for the processing of, combustible materials shall be protected by an approved automatic fire-extinguishing system complying with Chapter 9.

2106.2 Fixed fire-extinguishing systems. Fixed fire-extinguishing systems shall be provided for Class C or D ovens to protect against such hazards as overheating, spillage of molten salts or metals, quench tanks, ignition of hydraulic oil and escape of fuel. It shall be the user's responsibility to consult with the fire code official concerning the necessary requirements for such protection.

2106.3 Fire extinguishers. Portable fire extinguishers complying with Section 906 shall be provided not closer than 15 feet (4572 mm) or a maximum of 50 feet (15 240 mm) or in accordance with NFPA 10. This shall apply to the oven and related equipment.

Worked example

Scenario: A Class B industrial oven is used to heat-treat plastic components, which are combustible materials.

Explanation: Because the oven processes combustible materials and is a Class B oven, it is required to have an approved automatic fire-extinguishing system. This system must comply with the specific requirements outlined in IFC Chapter 9.

2107 — Operation and Maintenance

2107.1 Furnace system information. An approved, clearly worded, and prominently displayed safety design data form or manufacturer's nameplate shall be provided stating the safe operating condition for which the furnace system was designed, built, altered or extended.

2107.2 Oven nameplate. Safety data for Class A solvent atmosphere ovens shall be furnished on the manufacturer's name-plate. The nameplate shall provide the following design data:

The solvent used. The number of gallons (liters) used per batch or per hour of solvent entering the oven. The required purge time. The oven operating temperature. The exhaust blower rating for the number of gallons (liters) ofsolvent per hour or batch at the maximum operating temperature. Exception: For low-oxygen ovens, the maximum allowable oxygen concentration shall be included in place of the exhaust blower ratings.

The solvent used.
The number of gallons (liters) used per batch or per hour of solvent entering the oven.
The required purge time.
The oven operating temperature.
The exhaust blower rating for the number of gallons (liters) ofsolvent per hour or batch at the maximum operating temperature.

Exception: For low-oxygen ovens, the maximum allowable oxygen concentration shall be included in place of the exhaust blower ratings.

2107.3 Training. Operating, maintenance and supervisory personnel shall be thoroughly instructed and trained in the operation of ovens or furnaces.

2107.4 Equipment maintenance. Equipment shall be maintained in accordance with the manufacturer's instructions.

Frequently asked questions

What codes apply to industrial ovens?

Industrial ovens and furnaces must comply with NFPA 86, the International Fuel Gas Code, the International Mechanical Code, and IFC Chapter 21.

What are the ventilation requirements for rooms containing industrial ovens?

Enclosed rooms or basements with industrial ovens must provide combustion air as per the International Mechanical Code and International Fuel Gas Code, and ventilation air as per the International Mechanical Code.

When do industrial ovens require automatic fire protection?

Class A and B ovens that contain or are used to process combustible materials must be protected by an approved automatic fire-extinguishing system complying with Chapter 9.