§ 52.01–115 46 CFR Ch. I (10–1–00 Edition)
under all normal and emergency condi- ceed 250 pounds per square inch, three tions. The secondary indicator may test cocks attached directly to the consist of a gage glass, or other accept- head or shell of a boiler may serve as able device. Where the allowance pres- the secondary water level indicator. sure exceeds 1724 kPa (250 psi), the gage (2) See paragraph (d) of this section glasses shall be of the flat type instead for restrictions on cock connections. of the common tubular type. (f) Pressure gages (modifies PG–60.6). (2) Gage glasses shall be in contin- Each double-ended boiler shall be fitted uous operation while the boiler is with two steam gages, one on either steaming. end on the boiler. (3) Double-ended firetube boilers (g) Salinometer cocks. In vessels oper- shall be equipped as specified in this ating in salt water, each boiler shall be paragraph and paragraph (e) of this equipped with a salinometer cock or section except that the required water valve which shall be fitted directly to level indicators shall be installed on the boiler in a convenient position. each end of the boiler. They shall not be attached to the (4) Externally fired flue boilers, such water gage or water column. as are used on central western river (h) High-water-level alarm. Each vessels, shall be equipped as specified watertube boiler for propulsion must in paragraphs (b) (1) through (3) of this have an audible and a visible high- section except that float gages may be water-level alarm. The alarm indica- substituted for gage glasses. tors must be located where the boiler is (c) Water columns (modifies PG–60.2). controlled. The use of water columns is generally [CG FR 68–82, 33 FR 18815, Dec. 18, 1968, as limited to firetube boilers. Water col- amended by CGD 81–79, 50 FR 9433, Mar. 8, umn installations shall be close hauled 1985; CGD 83–043, 60 FR 24772, May 10, 1995] to minimize the effect of ship motion on water level indication. When water § 52.01–115 Feedwater supply (modifies columns are provided they shall be PG–61). fitted directly to the heads or shells of Boiler feedwater supply must meet boilers or drums by 1 inch minimum the requirements of PG–61 of the ASME size pipes with shutoff valves attached Code and § 56.50–30 of this subchapter. directly to the boiler or drums, or if [CGD 81–79, 50 FR 9433, Mar. 8, 1985] necessary, connected thereto by a dis- tance piece both at the top and bottom § 52.01–120 Safety valves and safety re- of the water columns. Shutoff valves lief valves (modifies PG–67 through used in the pipe connections between PG–73). the boiler and water column or be- (a)(1) Boiler safety valves and safety tween the boiler and the shutoff valves relief valves must be as indicated in required by PG–60.6 of the ASME Code PG–67 through PG–73 of the ASME for gage glasses, shall be locked or Code except as noted otherwise in this sealed open. Water column piping shall section. not be fitted inside the uptake, the (2) A safety valve must: smoke box, or the casing. Water col- (i) Be stamped in accordance with umns shall be fitted with suitable PG–110 of the ASME Code; drains. Cast iron fittings are not per- (ii) Have its capacity certified by the mitted. National Board of Boiler and Pressure (d) Gage glass connections (modifies Vessel Inspectors; PG–60.3). Gage glasses and gage cocks (iii) Have a drain opening tapped for shall be connected directly to the head not less than 6mm (1⁄4 in.) NPS; and or shell of a boiler as indicated in para- (iv) Not have threaded inlets for graph (b)(1) of this section. When water valves larger than 51mm (2 in.) NPS. columns are authorized, connections to (3) On river steam vessels whose boil- the columns may be made provided a ers are connected in batteries without close hauled arrangement is utilized so means of isolating one boiler from an- that the effect of ship roll on the water other, each battery of boilers shall be level indication is minimized. treated as a single boiler and equipped (e) Gage cocks (modifies PG–60.4). (1) with not less than two safety valves of When the steam pressure does not ex- equal size.
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(4) (Modifies PG–70.) The total rated 51mm (2 inch) gage length. Nonmetallic relieving capacity of drum and super- material may be used only for gaskets heater safety valves as certified by the and packing. valve manufacturer shall not be less (b)(1) (Modifies PG–68.) Superheater than the maximum generating capac- safety valves shall be as indicated in ity of the boiler which shall be deter- PG–68 of the ASME Code except as mined and certified by the boiler man- noted otherwise in this paragraph. ufacturer. This capacity shall be in (2) The setting of the superheater compliance with PG–70 of the ASME safety valve shall not exceed the design Code. pressure of the superheater outlet (5) In the event the maximum steam flange or the main steam piping beyond generating capacity of the boiler is in- the superheater. To prevent damage to creased by any means, the relieving ca- the superheater, the drum safety valve pacity of the safety valves shall be shall be set at a pressure not less than checked by an inspector, and, if deter- that of the superheater safety valve mined to be necessary, valves of in- setting plus 5 pounds minimum plus creased relieving capacity shall be in- approximately the normal load pres- stalled. sure drop through the superheater and (6) (Modifies PG–67). Drum safety associated piping, including the con- valves shall be set to relieve at a pres- trolled desuperheater if fitted. See also sure not in excess of that allowed by § 52.01–95(b) (1). the Certificate of Inspection. Where for (3) Drum pilot actuated superheater any reason this is lower than the pres- safety valves are permitted provided sure for which the boiler was orginially the setting of the pilot valve and super- designed and the revised safety valve heater safety valve is such that the capacity cannot be recomputed and superheater safety valve will open be- certified by the valve manufacturer, fore the drum safety valve. one of the tests described in PG–70(3) of the ASME Code shall be conducted in (c)(1) (Modifies PG–71.) Safety valves the presence of the Inspector to insure shall be installed as indicated in PG–71 that the relieving capacity is sufficient of the ASME Code except as noted oth- at the lower pressure. erwise in this paragraph. (7) On new installations the safety (2) The final setting of boiler safety valve nominal size for propulsion boil- valves shall be checked and adjusted ers and superheaters must not be less under steam pressure and, if possible, than 38mm (11⁄2 in.) nor more than while the boiler is on the line and the 102mm (4 in.). Safety valves 38mm (11⁄2 steam is at operating temperatures, in in.) to 114mm (41⁄2 in.) may be used for the presence of and to the satisfaction replacements on existing boilers. The of a marine inspector who, upon ac- safety valve size for auxiliary boilers ceptance, shall seal the valves. This must be between 19mm (3⁄4 in.) and regulation applies to both drum and 102mm (4 in.) NPS. The nominal size of superheater safety valves of all boilers. a safety valve is the nominal diameter (3) The safety valve body drains re- (as defined in 56.07–5(b)) of the inlet quired by PG–71 of the ASME Code opening. shall be run as directly as possible (8) Lever or weighted safety valves from the body of each boiler safety now installed may be continued in use valve, or the drain from each boiler and may be repaired, but when renew- safety valve may be led to an inde- als are necessary, lever or weighted pendent header common only to boiler safety valves shall not be used. All safety valve drains. No valves of any such replacements shall conform to the type shall be installed in the leakoff requirements of this section. from drains or drain headers and they (9) Gags or clamps for holding the shall be led to suitable locations to safety valve disk on its seat shall be avoid hazard to personnel. carried on board the vessel at all times. (d)(1) (Modifies PG–72.) The operation (10) (Modifies PG–73.2). Cast iron may of safety valves shall be as indicated in be used only for caps and lifting bars. PG–72 of the ASME Code except as When used for these parts, the elon- noted in paragraph (d)(2) of this sec- gation must be at least 5 percent in tion.
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(2) (Modifies PG–73). The lifting de- (6) All oil-burning boilers shall be vice required by PG–73.1.3 of the ASME provided with oiltight drip pans under Code shall be fitted with suitable re- the burners and elsewhere as necessary lieving gear so arranged that the con- to prevent oil draining into the bilges. trols may be operated from the fire- (c) Boiler uptakes. (1) Where dampers room or engineroom floor. are installed in the uptakes or funnels, the arrangement shall be such that it [CGFR 68–82, 33 FR 18815, Dec. 18, 1968, as will not be possible to shut off the gas amended by CGD 81–79, 50 FR 9433, Mar. 8, 1985] passages from the operating boilers. (2) Each main power boiler and auxil- § 52.01–130 Installation. iary boiler shall be fitted with a sepa- rate gas passage. (a) Foundations. (1) Plans showing de- tails of proposed foundations and sup- § 52.01–135 Inspection and tests (modi- port for boilers and the proposed means fies PG–90 through PG–100). of bracing boilers in the vessel shall be (a) Requirements. Inspection and test submitted for approval to the Officer in of boilers and boiler pressure parts Charge, Marine Inspection, in the dis- shall be as indicated in PG–90 through trict where the installation is being PG–100 of the ASME Code except as made. noted otherwise in this section. (2) Provision shall be made in founda- (b) The inspections required by PG–90 tions for expansion of the boilers when through PG–100 of the ASME Code heated. shall be performed by the ‘‘Authorized (3) Boilers shall be provided with Inspector’’ as defined in PG–91 of the chocks to prevent movement in the ASME Code. The Authorized Inspector event of collision unless a bolted or riv- shall hold a valid commission issued by eted construction satisfactorily pro- the National Board of Boiler and Pres- vides for this contingency. sure Vessel Inspectors. After installa- (b) Protection of adjacent structure. (1) tion, boilers will be inspected for com- Boilers shall be so placed that all parts pliance with this part by the ‘‘Marine are readily accessible for inspection Inspector’’ as defined in § 50.10–15 of and repair. this subchapter. (2) In vessels having a double bottom (c) Hydrostatic test (modifies PG–99). or other extensive surfaces directly Each new boiler shall be hydrostatical- below the boiler, the distance between ly tested after installation to 11⁄2 times such surface and a boiler shall in no the maximum allowable working pres- case be less than 18 inches at the low- sure as indicated in PG–99 of the ASME est part. Code. Before the boilers are insulated, (3) In certain types of vessels where accessible parts of the boiler shall be the boiler foundation forms the ashpit, emptied, opened up and all interior sur- such foundations shall be efficiently faces shall be examined by the marine ventilated, except in cases where the inspector to ascertain that no defects ashpit is partially filled with water at have occurred due to the hydrostatic all times. test. (4) The pans of oil-burning, watertube (d) Operating tests. In addition to hy- boilers shall be arranged to prevent oil drostatic tests prescribed in paragraph from leaking into the bilges and shall (c) of this section, automatically con- be lined with firebrick or other heat re- trolled auxiliary boilers must be sub- sisting material. jected to operating tests as specified in (5) The distance between a boiler and §§ 61.30–20, 61.35–1, 61.35–3, 62.30–10, 63.15– a compartment containing fuel oil 9, 63.25–3, and 63.25–5 of this chapter, as shall not be less than 24 inches at the appropriate, or as directed by the Offi- back end of a boiler and 18 inches else- cer in Charge, Marine Inspection, for where, except that for a cylindrical propulsion boilers, These tests are to part of a boiler or a knuckle in the cas- be performed after final installation. ing of a water-tube boiler, these dis- [CGFR 68–82, 33 FR 18815, Dec. 18, 1968, as tances may be reduced to 18 inches, amended by CGFR 69–127, 35 FR 9976, June 17, provided all parts are readily acces- 1970; CGD 81–79, 50 FR 9433, Mar. 8, 1985; CGD sible for inspection and repair. 88–057, 55 FR 24236, June 15, 1990]
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