This article shall apply to the location, design, construction and operation of industrial baking and drying ovens which are heated with oil or gas fuel or which during operation contain flammable vapors from the products being baked or dried. It is the intent of this article to provide requirements for the operation of these ovens within certain limitations of control depending on oven design, paint formulation and ventilation requirements, the disregard of which may cause them to function in an unsafe manner, thereby becoming liable to destruction by fire or explosion.
A. 
Ovens, oven heaters and related equipment shall be located with due regard to the possibility of fire resulting from overheating 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.
B. 
Ovens shall be located at or above grade, or if in basements, at least 50% of the wall area of the room in which the oven is located shall be above grade.
C. 
Ovens shall be so located as to be readily accessible for inspection and maintenance and with adequate clearances to permit the proper functioning of explosion vents. Roofs and floors of ovens shall be sufficiently insulated and ventilated to keep temperatures at combustible ceilings and floors below 160° F.
D. 
Ovens shall be constructed of noncombustible materials throughout except where the maximum oven operating temperature is not over 160° F. The amount of insulation used in oven panel construction shall be enough to prevent the outside surface temperature from exceeding 160° F. or adequate guards shall be provided to protect personnel.
E. 
Ovens which may contain flammable air-gas mixtures shall be equipped with relief vents for freely relieving internal explosion pressures.
F. 
All ductwork shall be constructed of noncombustible material. Ducts shall be made tight throughout and shall have no openings other than those required for the proper operation and maintenance of the system. Ducts passing through combustible walls, floors or roofs shall have adequate insulation and clearances to prevent surface temperatures from exceeding 160° F. Exhaust ducts shall not discharge near doors, windows or other air intakes in a manner that will permit reentry of vapors into the building.
A. 
Ovens in which flammable or toxic vapors are liberated or through which products of combustion are circulated shall be ventilated by the introduction of a supply of fresh air and proper exhaust to outdoors. Such oven ventilation shall be arranged to provide vigorous and well distributed air circulation within the oven and to ensure that the flammable vapor concentration will be safely below the lower explosive limit at all times. Unless the oven is operated in accordance with specific approval specifying particular solvents and rate of ventilation, the rate of ventilation shall not be less than 10,000 cubic feet of fresh air per gallon of solvent evaporated in continuous-process ovens, and not less than 380 cubic feet per minute per gallon of flammable solvent evaporated in batch-process ovens.
B. 
Exhaust duct openings shall be located in the area of greatest concentration of vapors.
C. 
All exhaust shall be by mechanical means using power-driven fans.
A. 
Safety controls shall be sufficient in number and substantially constructed and arranged to maintain the required conditions of safety and prevent the development of fire and explosion hazards.
B. 
Ventilation controls, suitably interlocked, shall be provided which will ensure required ventilation of the system.
C. 
Fuel safety controls, suitably interlocked and arranged to minimize the possibility of dangerous accumulations of explosive air-fuel mixtures in the heating system, shall be provided.
D. 
Excess temperature controls shall be provided to maintain a safe operating temperature within the oven.
E. 
Conveyor interlocks shall be provided in conveyor ovens having a flammable vapor hazard so that the conveyor cannot move unless ventilating fans are operating and discharging the required amount of air.
Before any installation is made, plans are to be submitted to the Bureau of Fire Prevention for approval.