Md. Code Regs. 09.12.01.21

Current through Register Vol. 51, No. 22, November 1, 2024

Section 09.12.01.21 - Power Boiler - Existing Installation: Boiler Feed System

A. A boiler shall have a feed supply which permits it to be fed at any time while under pressure.

B. A boiler having more than 500 square feet of water-heating surface shall have at least two means of feeding, as follows:

(1) One means shall be an approved feed pump, injector, or inspirator;

(2) The other source may be directly from a water main, at a pressure 6 percent greater than the set pressure of the safety valve having the highest setting.

C. A boiler conforming to the ASME Code, PG-61.1, and fired by gaseous, liquid, or solid fuel in suspension may have a single feed supply provided that means are furnished for the immediate shutoff of heat input if the water feed is interrupted.

D. Feedwater shall be fed into a boiler so that it will not be introduced:

(1) Near a riveted joint of a shell or furnace sheet; or

(2) Directly against a surface exposed to:

(a) A product of combustion, or

(b) Direct radiation from the fire.

E. Feed Pipe.

(1) Feed pipe shall have a:

(a) Check valve near the boiler; and

(b) Valve or cock between the check valve and the boiler.

(2) When two or more boilers are fed from a common source, the branch to each boiler shall have a valve between the check valve and source of supply.

(3) The inlet of a globe valve on a feed pipe shall be under the disc of the valve.

F. Returns.

(1) When a return is fed back to a boiler by gravity, each return line shall have, as close as practicable to the boiler, a:

(a) Check valve; and

(b) Stop valve placed between the boiler and the check valve.

(2) It is recommended that no stop valve be placed in the supply and return pipe connection of a single boiler installation.

G. Deaerating Heater. When a deaerating heater is:

(1) Not used, the recommended minimum temperature for feedwater is 120°F to avoid creating localized stress.

(2) Used, the recommended minimum feedwater temperature is 215°F, so that dissolved gases can be released completely.

Md. Code Regs. 09.12.01.21

Regulations .21 adopted effective June 1, 1989 (16:10 Md. R. 1106)