20 CAR § 880-1010 – Feed piping check valve requirements

(a)
1. (1) The feed pipe shall be provided with a check valve near the boiler and a valve or cock between the check valve and the boiler, and when two (2) or more boilers are fed from a common source, there shall also be a globe or regulating valve on the branch to each boiler between the check valve and the source of supply.
2. (2) A typical arrangement is shown in the ASME code.
3. (3) Wherever globe valves are used on feed piping, the inlet shall be under the disk of the valve.
(b) When the supply line to a boiler is divided so as to feed a drum in more than one (1) place or to feed more than one (1) drum, it is recommended that each such branch line be equipped with a stop-and-check valve even though the common source is equipped as required above.
(c) If a boiler is equipped with duplicate feed arrangements, each such arrangement shall be equipped as required by the ASME code, as adopted.
(d) A combination stop-and-check valve in which there is only one (1) seat and disk, and a valve stem is provided to close the valve when the stem is screwed down, shall be considered only as a stop valve, and a check valve shall be installed as otherwise provided.
(e) Where an economizer or other feedwater-heating device is connected directly to a boiler without intervening valves, the feed valves and check valves required shall be placed on the inlet of the economizer or feedwater-heating device.
(f)
1. (1)
  1. (A) For boilers having a water heating surface of not more than one hundred square feet (100 ft²), the feed connection to the boiler shall not be smaller than one-half-inch pipe size.
  2. (B) For a water heating surface of more than one hundred square feet (100 ft²), the feed connection to the boiler shall not be less than three-fourths-inch pipe size.
2. (2) High-temperature water boilers shall be provided with a means of adding water to the boiler or to the system under pressure.
3. (3) A forced flow steam generator with no fixed steam and waterline shall be provided with a source of feeding capable of supplying water to the boiler at a pressure not less than the expected maximum sustained pressure at the boiler inlet.