§ 52.01-110 Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60).

(a) Boiler water level devices. Boiler water level devices must be as indicated in PG-60 of Section I of the ASME BPVC (incorporated by reference; see § 52.01-1) except as noted otherwise in this section. (b) Water level indicators. (Modifies PG-60.1.) (1) Each boiler, except those of the forced circulation type with no fixed water line and steam line, must have two independent means of indicating the water level in the boiler connected directly to the head or shell. One must be a gage lighted by the emergency electrical system (See subpart 112.15 of subchapter J of this chapter). The secondary indicator may consist of a gage glass, or other acceptable device. Where the allowance pressure exceeds 1724 kPa (250 psig), gage glasses must be of the flat type instead of the common tubular type. (2) Gage glasses must be in continuous operation while the boiler is steaming. (3) Double-ended firetube boilers must be equipped as specified in this paragraph (b) and paragraph (e) of this section except that the required water level indicators must be installed on each end of the boiler. (4) Externally fired flue boilers, such as are used on central western river vessels, must be equipped as specified in paragraphs (b)(1) through (3) of this section except that float gages may be substituted for gage glasses. (c) Water columns. (Modifies PG-60.2.) The use of water columns is generally limited to firetube boilers. Water column installations must minimize the effect of ship motion on water level indication. Water columns must be fitted directly to the heads or shells of boilers or drums, or if necessary, connected thereto by a distance piece both at the top and bottom of the water columns. Shutoff valves used in the pipe connections between the boiler and water column must be locked or sealed open. Water column piping must not be fitted inside the uptake, the smoke box, or the casing. Water columns must be fitted with suitable drains. Cast iron fittings are not permitted. (d) Gage glass connections. (Modifies PG-60.3.) Gage glasses and gage cocks must be connected directly to the head or shell of a boiler as indicated in paragraph (b)(1) of this section. (e) Gage cocks. (Modifies PG-60.4.) (1) When the steam pressure does not exceed 250 psi, three test cocks attached directly to the head or shell of a boiler may serve as the secondary water level indicator. (2) [Reserved] (f) Salinometer cocks. In vessels operating in saltwater, each boiler must be equipped with a salinometer cock or valve. They must not be attached to the water gage or water column. (g) High-water-level alarm. Each watertube boiler for propulsion must have an audible and a visible high-water-level alarm. The alarm indicators must be located where the boiler is controlled.