46 CFR §52.01-35

1. (a)To determine the appropriate part of the regulations where requirements for miscellaneous boiler types, such as donkey, fired thermal fluid heater, heating boiler, etc., may be found, refer to table 1 to § 54.01-5 of this subchapter.
2. (b)Fired vessels in which steam is generated at pressures exceeding 103 kPa gage (15 psig) must meet the requirements of this part.