(a) The minimum size of pipes connecting the water column to a boiler shall be one inch. For pressures of 400 pounds or over, lower water column connections to drums shall be provided with shields, sleeves, or other suitable means to reduce the effect of temperature differentials in the shells or heads. Water-glass fittings or gage cocks may be connected directly to the boiler.

1. (1) The design and material of a water column shall comply with the requirements of the ASME Code. Water columns made of cast iron in accordance with specification SA-278 may be used for maximum boiler pressures not exceeding 250 psi. Water columns made of malleable iron in accordance with specification SA-395 may be used for maximum boiler pressures not exceeding 350 psi. For higher pressures, steel construction shall be used.

2. (2) The steam and water connections to a water column or a water gage glass, including all pipe, fittings, valves, and drains, shall comply with the requirements of ASME and section 14-9.23 of this Subpart. These connections shall be such that they are readily accessible for internal inspection and cleaning. Some acceptable methods of meeting this requirement would be by providing a cross or fitting with a back outlet at each right angle turn to permit inspection and cleaning in both directions, or by using pipe bends or fittings of a type which does not leave an internal shoulder or pocket in the pipe connection and with a radius of curvature which will permit the passage of a rotary cleaner. The water column shall be fitted with a drain cock or drain valve with a suitable connection to the ashpit, or other safe point of waste, and if the water connection thereto has a rising bend or pocket which cannot be drained by means of the water-column drain, an additional drain shall be placed on this connection in order that it may be blown off to clear any sediment from the pipe. The water-column blowoff pipe shall be at least three-quarters inch pipe size.

   (c)

3. (1) When the gage glasses and gage cocks required by sections 14-9.16 and 14-9.18 of this Subpart are not connected substantially directly to the shell or drum of a boiler, a water column shall be used into which the gage glass and gage cocks shall be connected, excepted as modified by the ASME Code.
4. (2) The lower edge of the steam connections to a water column and the boiler shall not be below the highest visible water level in the water gage glass. There shall be no sag or offset in the piping which will permit the accumulation of water.
5. (3) The upper edge of the water connection to a water column and the boiler shall not be above the lowest visible water level in the gage glass. No part of this pipe connection shall be above the point of connection at the water column.

6. (4) An acceptable arrangement is indicated in Figure P-45.

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7. (5) No outlet connections, except for damper regulator, feedwater regulator, drains, steam gages, or apparatus of such form as does not permit the escape of an appreciable amount of steam or water therefrom, shall be placed on the pipes connecting a water column to a boiler.

8. (6) Where valves are installed between the water column and boiler, at least one steam gage shall be connected directly to the steam space of the boiler with one cock between the gage and boiler.

   Exception:

   Where a pipe in excess of 10 feet is used, a shutoff valve or cock arranged so that it can be locked or sealed open shall be installed and the pipe shall be of a size to permit blowing out.

9. (7) Water column drains shall be tested daily when the boiler is in operation.

(b)