scope:

This standard shall apply to Class A, Class B, Class C, and Class D ovens, dryers, and furnaces; thermal oxidizers; and any other heated enclosure used for processing of materials and related equipment.

The terms ovens, dryers, and furnaces are used interchangeably and shall also apply to other heated enclosures used for processing of materials.

Within the scope of this standard, a Class A, Class B, or Class C oven is any heated enclosure operating at approximately atmospheric pressure and used for commercial and industrial processing of materials.

A ClassA oven shall be permitted to utilize a low-oxygen atmosphere.

This standard shall apply to bakery ovens and Class A ovens, in all respects, and where reference is made to ANSI Z50.1, Bakery Equipment - Safety Requirements, those requirements shall apply to bakery oven construction and safety.

This standard shall apply to atmosphere generators and atmosphere supply systems serving Class C furnaces and to furnaces with integral quench tanks or molten salt baths.

This standard shall apply to Class D ovens and furnaces operating above ambient temperatures to over 5000°F (2760°C) and at pressures normally below atmospheric to 10⁻⁸ torr (1.33 × 10⁻⁶ Pa).

This standard shall not apply to the following:

(1) Coal or other solid fuel-firing systems

(2) Listed equipment with a heating system(s) that supplies a total input not exceeding 150,000 Btu/hr (44 kW)

(3) Fired heaters in petroleum refineries and petrochemical facilities that are designed and installed in accordance with API STD 560, Fired Heaters for General Refinery Services, 2007; API RP 556, Instrumentation and Control Systems for Fired Heaters and Steam Generators, 1997; and API RP 2001, Fire Protection in Refineries, 2005.

(4) Fluid heaters where either of the following conditions exists:

(a) Fluid is flowing under pressure in tubes or pipes and is indirectly heated by combustion of liquid gas fuel or an electrical source.

(b) Fluid is heated indirectly by products of combustion of liquid or gas fuel flowing through tubes (firetube).

Purpose.

This standard provides the requirements for furnaces to minimize the fire and explosion hazards that can endanger the furnace, the building, or personnel.