Indiana Administrative Code
Title 675 - FIRE PREVENTION AND BUILDING SAFETY COMMISSION
Article 30 - INDIANA BOILER AND PRESSURE VESSEL RULES
Rule 10 - Existing Installations of Heating Boilers
Section 10-14 - Installation of safety and relief valves

(a) Safety valves shall be connected to a heating boiler with the spindle vertical if possible, either directly to a tapped or flanged opening in the boiler, to a fitting connected to the boiler by a close nipple, to a Y base, to a valveless steam pipe between adjacent boilers, or to a valveless header connecting steam outlets on the same boiler.

(b) Relief valves shall be connected to the top of a heating boiler, with spindle vertical if possible, either directly to a tapped or flanged opening on the boiler, to a fitting connected to the boiler by a close nipple, to a Y base, or to a valveless header connecting water outlets on the same boiler.

(c) When a Y base is used, the inlet area shall not be less than the combined outlet areas. When the size of the boiler requires a safety valve or relief valve larger than four and one-half (41/2) inches in diameter, two (2) or more valves having the required combined capacity shall be used.

(d) No shut-off of any description shall be placed between the safety or relief valve and the boiler, or on discharge pipes between such valves and the atmosphere. Safety and relief valves shall not be connected to an internal pipe in the boiler.

(e) When a discharge pipe is used, its cross-sectional area shall be not less than the cross-sectional area of the valve or aggregate area based on the nominal diameters of the valves with which it connects, and the discharge pipe shall be fitted with an open drain to prevent water from lodging in the upper part of the valve or in the pipe. When an elbow is placed on a safety or relief valve discharge pipe, it shall be supported so that no stress is placed on the valve body. The discharge from a safety or relief valve shall be directed to a safe location.