Sec.29-232-59. Boiler feeding and feed piping

All boilers shall have a feed supply which will permit the boilers being fed at any time while under pressure. A boiler having more than five hundred square feet of water heating surface shall have at least two means of feeding, one of which shall be an approved feed pump, injector or inspirator. Where a source of feed directly from pressure mains is available at sufficient pressure to feed the boiler against a pressure three percent greater than the release pressure of the safety valve with the highest release setting, this may be considered one of the means. For boilers that are fired with solid fuel not in suspension, and for boilers whose setting or heat source can continue to supply sufficient heat to cause damage to the boiler if the feed supply is interrupted, one such means of feeding shall be steam operated. A boiler fired by gaseous, liquid or solid fuel in suspension may be equipped with a single means of feeding water provided means are furnished for the shutting off of its heat input prior to the water level reaching the lowest permissible level established by the code. The feed water shall be introduced into the boiler in such manner that it will not be discharged close to riveted joints of shell or furnace sheets or directly against surfaces exposed to gases at high temperatures, or direct radiation from the fire.

The feed piping to the boiler shall be provided with a check valve near the boiler and a valve or cock between the check valve and the boiler. When two or more boilers are fed from a common source, there shall also be a valve on the branch to each boiler between the check valve and course of supply. Whenever a globe valve is used on feed piping, the inlet shall be under the disc of the valve. In all cases where returns are fed back to the boiler by gravity, there shall be a check valve and stop valve on each return line, the stop valve to be placed between the boiler and the check valve and both shall be located as close to the boiler as is practicable. Where deaerating heaters are not employed, it is recommended that the temperature of the feed water be not less than 120°F to avoid the possibility of setting up localized stress. Where deaerating heaters are employed, it is recommended that the minimum feed water temperature be not less than 215°F so that dissolved gases may be thoroughly released.

(Effective August 25, 1987)