46 Cfr 52.01-110

Coast Guard, Dept. of Homeland Security § 52.01–110

wall thickness at least equal to stand- section except that float gages may be ard commercial pipe of the same di- substituted for gage glasses. ameter. Openings in dry pipes must be (c) Water columns. (Modifies PG–60.2.) as near as practicable to the drum out- The use of water columns is generally let and must be slotted or drilled. The limited to firetube boilers. Water col- width of the slots must not be less than umn installations shall be close hauled 6mm (0.25 in.). The diameter of the to minimize the effect of ship motion holes must not be less than 10mm (0.375 on water level indication. When water in.). Where dry pipes are used, they columns are provided they shall be must be provided with drains at each fitted directly to the heads or shells of end to prevent an accumulation of boilers or drums by 1 inch minimum water. size pipes with shutoff valves attached directly to the boiler or drums, or if [CGD 81–79, 50 FR 9432, Mar. 8, 1985, as amended by USCG–2003–16630, 73 FR 65161, necessary, connected thereto by a dis- Oct. 31, 2008] tance piece both at the top and bottom of the water columns. Shutoff valves § 52.01–110 Water-level indicators, used in the pipe connections between water columns, gauge-glass connec- the boiler and water column or be- tions, gauge cocks, and pressure tween the boiler and the shutoff valves, gauges (modifies PG–60). required by PG–60.6 of section I of the (a) Boiler water level devices. Boiler ASME Boiler and Pressure Vessel Code water level devices shall be as indi- for gauge glasses, shall be locked or cated in PG–60 of section I of the sealed open. Water column piping shall ASME Boiler and Pressure Vessel Code not be fitted inside the uptake, the (incorporated by reference; see 46 CFR smoke box, or the casing. Water col- 52.01–1) except as noted otherwise in umns shall be fitted with suitable this section. drains. Cast iron fittings are not per- (b) Water level indicators. (Modifies mitted. PG–60.1.) (1) Each boiler, except those (d) Gage glass connections. (Modifies of the forced circulation type with no PG–60.3.) Gage glasses and gage cocks fixed water line and steam line, shall shall be connected directly to the head have two independent means of indi- or shell of a boiler as indicated in para- cating the water level in the boiler graph (b)(1) of this section. When water connected directly to the head or shell. columns are authorized, connections to One shall be a gage lighted by the the columns may be made provided a emergency electrical system (See sub- close hauled arrangement is utilized so part 112.15 of subchapter J (Electrical that the effect of ship roll on the water Engineering) of this chapter) which level indication is minimized. will insure illumination of the gages (e) Gage cocks. (Modifies PG–60.4.) (1) under all normal and emergency condi- When the steam pressure does not ex- tions. The secondary indicator may ceed 250 pounds per square inch, three consist of a gage glass, or other accept- test cocks attached directly to the able device. Where the allowance pres- head or shell of a boiler may serve as sure exceeds 1724 kPa (250 psi), the gage the secondary water level indicator. glasses shall be of the flat type instead (2) See paragraph (d) of this section of the common tubular type. for restrictions on cock connections. (2) Gage glasses shall be in contin- (f) Pressure gages. (Modifies PG–60.6.) uous operation while the boiler is Each double-ended boiler shall be fitted steaming. with two steam gages, one on either (3) Double-ended firetube boilers end on the boiler. shall be equipped as specified in this (g) Salinometer cocks. In vessels oper- paragraph and paragraph (e) of this ating in salt water, each boiler shall be section except that the required water equipped with a salinometer cock or level indicators shall be installed on valve which shall be fitted directly to each end of the boiler. the boiler in a convenient position. (4) Externally fired flue boilers, such They shall not be attached to the as are used on central western river water gage or water column. vessels, shall be equipped as specified (h) High-water-level alarm. Each in paragraphs (b) (1) through (3) of this watertube boiler for propulsion must

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have an audible and a visible high- (5) In the event the maximum steam water-level alarm. The alarm indica- generating capacity of the boiler is in- tors must be located where the boiler is creased by any means, the relieving ca- controlled. pacity of the safety valves shall be checked by an inspector, and, if deter- [CG FR 68–82, 33 FR 18815, Dec. 18, 1968, as amended by CGD 81–79, 50 FR 9433, Mar. 8, mined to be necessary, valves of in- 1985; CGD 83–043, 60 FR 24772, May 10, 1995; creased relieving capacity shall be in- USCG–2003–16630, 73 FR 65161, Oct. 31, 2008] stalled. (6) (Modifies PG–67.) Drum safety § 52.01–115 Feedwater supply (modifies valves shall be set to relieve at a pres- PG–61). sure not in excess of that allowed by Boiler feedwater supply must meet the Certificate of Inspection. Where for the requirements of PG–61 of section I any reason this is lower than the pres- of the ASME Boiler and Pressure Ves- sure for which the boiler was originally sel Code (incorporated by reference; see designed and the revised safety valve 46 CFR 52.01–1) and § 56.50–30 of this sub- capacity cannot be recomputed and chapter. certified by the valve manufacturer, one of the tests described in PG–70(3) of [USCG–2003–16630, 73 FR 65161, Oct. 31, 2008] section I of the ASME Boiler and Pres- § 52.01–120 Safety valves and safety re- sure Vessel Code shall be conducted in lief valves (modifies PG–67 through the presence of the Inspector to insure PG–73). that the relieving capacity is sufficient (a)(1) Boiler safety valves and safety at the lower pressure. relief valves must be as indicated in (7) On new installations the safety PG–67 through PG–73 of section I of the valve nominal size for propulsion boil- ASME Boiler and Pressure Vessel Code ers and superheaters must not be less (incorporated by reference; see 46 CFR than 38mm (11⁄2 in.) nor more than 52.01–1) except as noted otherwise in 102mm (4 in.). Safety valves 38mm (11⁄2 this section. in.) to 114mm (41⁄2 in.) may be used for (2) A safety valve must: replacements on existing boilers. The (i) Be stamped in accordance with safety valve size for auxiliary boilers PG–110 of section I of the ASME Boiler must be between 19mm (3⁄4 in.) and and Pressure Vessel Code; 102mm (4 in.) NPS. The nominal size of (ii) Have its capacity certified by the a safety valve is the nominal diameter National Board of Boiler and Pressure (as defined in 56.07–5(b)) of the inlet Vessel Inspectors; opening. (iii) Have a drain opening tapped for (8) Lever or weighted safety valves not less than 6mm (1⁄4 in.) NPS; and now installed may be continued in use (iv) Not have threaded inlets for and may be repaired, but when renew- valves larger than 51mm (2 in.) NPS. als are necessary, lever or weighted (3) On river steam vessels whose boil- safety valves shall not be used. All ers are connected in batteries without such replacements shall conform to the means of isolating one boiler from an- requirements of this section. other, each battery of boilers shall be (9) Gags or clamps for holding the treated as a single boiler and equipped safety valve disk on its seat shall be with not less than two safety valves of carried on board the vessel at all times. equal size. (10) (Modifies PG–73.2.) Cast iron may (4) (Modifies PG–70.) The total rated be used only for caps and lifting bars. relieving capacity of drum and super- When used for these parts, the elon- heater safety valves as certified by the gation must be at least 5 percent in valve manufacturer shall not be less 51mm (2 inch) gage length. Nonmetallic than the maximum generating capac- material may be used only for gaskets ity of the boiler which shall be deter- and packing. mined and certified by the boiler man- (b)(1) (Modifies PG–68.) Superheater ufacturer. This capacity shall be in safety valves shall be as indicated in compliance with PG–70 of section I of PG–68 of section I of the ASME Boiler the ASME Boiler and Pressure Vessel and Pressure Vessel Code except as Code. noted otherwise in this paragraph.

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