La. Admin. Code tit. 55 § V-5025

Current through Register Vol. 50, No. 11, November 20, 2024

Section V-5025 - Safety Valves

A. The use of weighted-lever safety valves or safety valves having either the seat or disk of cast-iron are prohibited; valves of this type of construction shall be replaced by direct, spring-loaded, pop-type valves that conform to the requirements of ASME Code, Section I.

B. Each boiler shall have at least one ASME/NB stamped and certified safety valve, and if it has more than 500 square feet of water-heating surface, or an electric power input of more than 1100 KW, it shall have two or more safety valves of the same type.

C. The valve or valves shall be connected to the boiler, independent of any other steam connection and attached as close as possible to the boiler without unnecessary intervening pipe or fittings. Where alteration is required to conform to this requirement, owner or user shall be allowed reasonable time in which to complete the work as permitted by the chief inspector.

D. No valves of any description shall be placed between the safety valve and the boiler nor on the escape pipe, if used. When an escape pipe is used, it shall be at least the full size of the safety valve discharge and fitted with an open drain to prevent water lodging in the upper part of the safety valve or in the escape pipe. When an elbow is placed on a safety valve escape pipe, it shall be located close to the safety valve outlet or the escape pipe shall be anchored and supported securely. All safety discharges shall be so located or piped as to be carried clear from walkways or platforms.

E. The safety valve capacity of each boiler shall be such that the safety valve or valves will discharge all the steam that can be generated by the boiler without allowing the pressure to rise more than 6 percent above the highest pressure to which any valve is set, and in no case to more than 6 percent above the maximum allowable working pressure.

F. One or more safety valves on every boiler shall be set at or below the maximum allowable working pressure. The remaining valves may be set within a range of 3 percent above the maximum allowable working pressure, but the range of setting of all the safety valves on a boiler shall not exceed 10 percent of the highest pressure to which any valve is set.

G. When boilers of different maximum allowable working pressures with minimum safety valve settings varying more than 6 percent are so connected that steam can flow toward the lower pressure units, the latter shall be protected by additional safety valve capacity, if necessary, on the lower pressure side of the system. The additional safety valve capacity shall be based upon the maximum amount of steam which can flow into the lower pressure system.

H. In those cases where the boiler is supplied with feed water directly from water mains without the use of feeding apparatus (not to include return traps), no safety valve shall be set at a pressure greater than 94 percent of the lowest pressure obtained in the supply main feeding the boiler.

I. The relieving capacity of the safety valves on any boiler shall be done by one of the three following methods and, if found to be insufficient, additional valves shall be provided:

1. by making an accumulation test, which consists of shutting off all other steam discharge outlets from the boiler and forcing the fires to the maximum. The safety valve capacity shall be sufficient to prevent a rise of pressure in excess of 6 percent of the maximum allow-able working pressure. This method should not be used on a boiler with a super heater or reheater;

2. by measuring the maximum amount of fuel that can be burned and computing the corresponding evaporative capacity (steam generating capacity) upon the basis of the heating value of this fuel. These computations shall be made as outlined in the Appendix of the ASME Code, Section I;

3. by measuring the maximum amount of feed water that can be evaporated. When either of the methods outlined in two or three is employed, the sum of the safety valve capacities shall be equal to or greater than the maximum evaporative capacity (maximum steam generating capacity) of the boiler.

J. Repairs to safety and safety-relief valves shall be conducted only by holders of the National Board VR Certificate of Authorization, or by owner/users that have obtained the state certificate of authorization to repair safety and safety-relief valves.

La. Admin. Code tit. 55, § V-5025

Promulgated by the Department of Public Safety, Office of the State Fire Marshal, LR 33:1357 (July 2007).

AUTHORITY NOTE: Promulgated in accordance with R.S. 23:531 and R.S. 51:1424.