R 408.18181 Ovens.

Rule 8181. (1) With the exception of a range or cabinet type oven without moving parts installed before November 16, 1974, a combustible fueled oven shall be provided devices to protect against all of the following hazards: (a) Ignition failure. (b) Abnormal fuel pressure. (c) Combustion air failure. (d) Electrical power failure. (e) Exhaust system failure. (f) Excessive temperature. (2) Preventilation purge shall be arranged in the safety control circuit and set so as to require operation of the exhaust and recirculating fans to provide not less than 4 complete oven heating chamber air changes with fresh air before the burner ignition system may be operated and fuel turned on. (3) If a combustible fuel is used that is heavier than air, a bottom exhaust system shall be provided and used during the purge cycle. (4) A direct-fired oven installed after November 16, 1974, shall be equipped with relief vents for freely relieving internal explosion pressures. The vents shall be proportioned in the ratio of their area to the area of explosion containing volume of the oven which shall be not less than 1 square foot of relief area to 30 cubic feet of oven volume. (5) All safety controls shall be inspected not less than monthly as prescribed in Table 1 “Safety Control Inspection Guide for Washers and Ovens” of R 408.18142(5).