Loading (50 kb)...'
(continued)
(c) For several vessels or parts of vessels being welded in succession, the plate thickness of which does not vary by more than one-fourth inch, and which are made of the same grade of material, a test plate shall be furnished for each 50 feet of welding for Class I-L vessels or 150 feet of welding for Class II-L vessels. For each 50- or 150-foot increment of weld, as applicable, the test plates shall be prepared at the time of fabrication of the first vessel involving that increment.
(d) The test plates and any other test material from which toughness test specimens are cut shall be given the same heat-treatment as the production material they represent. Test specimens representing other material than the weld toughness test plates shall preferably be cut from a part of the vessel material but may be cut from like material that has been heat-treated within the temperature range specified by the producer in treating the actual vessel material.
(e) For nonpressure vessel type tanks and associated secondary barriers, as defined in §38.05–4, subchapter D (Tank Vessels) of this chapter, production toughness test plates shall be prepared in accordance with paragraphs (a) and (d) of this section. One set of toughness test plates shall be prepared for each 165 feet (50 meters) of production butt type welds.
§ 54.05-17 Weld toughness test acceptance criteria.
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(a) For Charpy V-notch impact tests the energy absorbed in both the weld metal and heat affected zone impact tests in weld qualification and production shall be:
(1) For weld metal specimens, not less than the transverse values required for the parent material.
(2) For heat affected zone specimens, when the specimens are transversely oriented, not less than the transverse values required for the parent material.
(3) For heat affected zone specimens, when the specimens are longitudinally oriented, not less than 1.5 times the transverse values required for the parent material.
(b) For drop-weight tests both specimens from each required set shall exhibit a no-break performance.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 73–254, 40 FR 40164, Sept. 2, 1975]
§ 54.05-20 Impact test properties for service of 0 °F and below.
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(a) Test energy. The impact energies of each set of transverse Charpy specimens may not be less than the values shown in Table 54.05–20(a). Only one specimen in a set may be below the required average and the value of that specimen must be above the minimum impact value permitted on one specimen only. See §54.05–5(c) for retest requirements.
Table 54.05-20(a)_Charpy v-notch impact requirements
------------------------------------------------------------------------
Minimum impact
value required Minimum impact
for average of value permitted
Size of specimen each set of 3 on one specimen
specimens foot- only of a set,
pounds \1\ foot-pounds
------------------------------------------------------------------------
10 x 10 mm........................ 20.0 13.5
10 x 7.5 mm....................... 16.5 11.0
10 x 5 mm......................... 13.5 9.0
10 x 2.5 mm....................... 10.0 6.5
------------------------------------------------------------------------
\1\ Straight line interpolation for intermediate values is permitted.
(b) Transversely oriented Charpy V-notch impact specimens of ASTM A 203 (incorporated by reference, see §54.01–1) nickel steels must exhibit energies not less than the values shown in §54.05–20 (a). Requirements for 9 percent nickel steels are contained in §54.25–20. Other nickel alloy steels, when specially approved by the Commandant, must exhibit a no-break performance when tested in accordance with the drop weight procedure. If, for such materials, there are data indicating suitable correlation with drop-weight tests, Charpy V-notch tests may be specially considered by the Commandant in lieu of drop-weight tests. If the drop-weight test cannot be performed because of material thickness limitations (less than one-half inch), or product shape, or is otherwise inapplicable (because of heat treatment, chemistry etc.) other tests or test criteria will be specified by the Commandant.
(c) Where sufficient data are available to warrant such waiver, the Commandant may waive the requirements for toughness testing austenitic stainless steel materials. Where required, austenitic stainless steels are to be tested using the drop-weight procedure and must exhibit a no-break performance. Where data are available indicating suitable correlation of Charpy V-notch results with drop-weight NDT or no-break performance, Charpy V-notch tests may be specially considered by the Commandant in lieu of dropweight tests. If the dropweight test cannot be performed because of material thickness limitations (less than one-half inch), or product shape, or is otherwise inapplicable (because of heat treatment, chemistry, etc.) other tests and/or test criteria will be specified by the Commandant.
[CGD 73–254, 40 FR 40164, Sept. 2, 1975, as amended by USCG–2000–7790, 65 FR 58460, Sept. 29, 2000]
§ 54.05-25 [Reserved]
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§ 54.05-30 Allowable stress values at low temperatures.
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(a) The Coast Guard will give consideration to the enhanced yield and tensile strength properties of ferrous and nonferrous materials at low temperature for the purpose of establishing allowable stress values for service temperature below 0 °F.
(b) The use of such allowable stress values must be specially approved by the Coast Guard for each application. Further information may be obtained by writing to the Coast Guard (G-MSE).
(c) Submittals must include information and calculations specified by the Coast Guard (G-MSE) to demonstrate that the allowable stress for the material cannot be exceeded under any possible combination of vessel loads and metal temperature.
[CGD 73–133R, 39 FR 9179, Mar. 8, 1974, as amended by CGD 82–063b, 48 FR 4781, Feb. 3, 1983; CGD 95–072, 60 FR 50462, Sept. 29, 1995; CGD 96–041, 61 FR 50727, 50728, Sept. 27, 1996]
Subpart 54.10—Inspection, Reports, and Stamping
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§ 54.10-1 Scope (modifies UG–90 through UG–103 and UG–115 through UG–120).
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(a) The inspection, tests, stamping, and reports for pressure vessels shall be as required by paragraphs UG–90 through UG–103 and UG–115 through UG–120 of the ASME Code except as noted otherwise in this subpart.
§ 54.10-3 Marine inspectors (replaces UG–90 and UG–91, and modifies UG–92 through UG–103).
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(a) Only marine inspectors shall apply the Coast Guard Symbol. They will not apply any other code symbol to pressure vessels.
(b) All pressure vessels not exempted under provisions of §54.01–15 shall be inspected by a marine inspector referring to procedures outlined in UG–92 through UG–103 of the ASME Code and §§50.30–10, 50.30–15, and 50.30–20 of this subchapter. The marine inspector will then stamp the vessel with the Coast Guard Symbol.
(c) Pressure vessels described in §54.01–5(c)(3), except pressure vessels in systems regulated under §58.60 of this chapter, must be visually examined by a marine inspector prior to installation. The marine inspector also reviews the associated plans and manufacturers' data reports. If, upon inspection, the pressure vessel complies with the applicable requirements in §54.01–5, the marine inspector stamps the pressure vessel with the Coast Guard Symbol.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 77–147, 47 FR 21810, May 20, 1982]
§ 54.10-5 Maximum allowable working pressure (reproduces UG–98).
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(a) The maximum allowable working pressure for a vessel is the maximum pressure permissible at the top of the vessel in its normal operating position at the operating temperature specified for that pressure. It is the least of the values found for maximum allowable working pressure for any of the essential parts of the vessel by the principles given in paragraph (b) of this section and adjusted for any difference in static head that may exist between the part considered and the top of the vessel. (See UA–60 (a) of the ASME Code.)
(b) The maximum allowable working pressure for a vessel part is the maximum internal or external pressure, including the static head thereon, as determined by the rules and formulas in this Division (ASME Code), together with the effect of any combination of loadings listed in UG–22 of the ASME Code (see §54.01–30) which are likely to occur, for the designated coincident operating temperature, excluding any metal thickness specified as corrosion allowance. (See UG–25 of the ASME Code.)
(c) Maximum allowable working pressure may be determined for more than one designated operating temperature, using for each temperature the applicable allowable stress value.
Note: Table 54.10–5 gives pictorially the interrelation among the various pressure levels pertinent to this part of the regulations. It includes reference to section VIII of the ASME Code for definitions and explanations.
Table 54.10-5_Pictorial Inter-Relation Among Various Pressure Levels With References to Specific Requirements
\1\
----------------------------------------------------------------------------------------------------------------
Pressures upon which
Pressure differential, psi \2\ Test pressures \3\ Relief device pressure relief device flow
settings capacity is based
----------------------------------------------------------------------------------------------------------------
Burst proof test (UG- ......................
101(m) of ASME Code).
Yield proof test (UG- ......................
101(j) of ASME Code).
Standard hydrostatic ......................
test (UG-99 of ASME
Code).
....................... ...................... Fire exposure, 120%
MAWP.
Pneumatic test (UG-100 ......................
of ASME Code).
....................... Rupture disk burst
(§ 54.15-13).
....................... ...................... Normal, 110% MAWP.....
----------------------------------------------------------------------------------------------------------------
Maximum allowable Maximum allowable Maximum allowable
working pressure working pressure working pressure
(MAWP), UG-98 and UA- (MAWP), UG-98 and UA- (MAWP), UG-98 and UA-
60(a) of ASME Code. 60(a) of ASME Code. 60(a) of ASME Code.
----------------------------------------------------------------------------------------------------------------
Design pressure, UG-21, Design pressure, UG-21 Design pressure, UG-21
and UA-60(b) of ASME and UA-60(b) of ASME and UA-60(b) of ASME
Code. Code. Code.
....................... Safety or relief value
setting (UG-133 of
ASME Code).
Operating pressure (UA- Operating pressure (UA- Operating pressure (UA-
60(f) of ASME Code). 60(f) of ASME Code). 60(f) of ASME Code).
----------------------------------------------------------------------------------------------------------------
\1\ For basic pressure definitions see § 52.01-3(g) of this subchapter.
\2\ For pressure differentials above 3,000 pounds per square inch (p.s.i.), special requirements may apply.
\3\ For the basis for calculating test pressures, see UA-60(e) of the ASME Code.
§ 54.10-10 Standard hydrostatic test (modifies UG–99).
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(a) All pressure vessels shall satisfactorily pass the hydrostatic test prescribed by this section, except those pressure vessels noted under §54.10–15(a).
(b) The hydrostatic test pressure shall be at least one and one-half times the maximum allowable working pressure stamped on the pressure vessel, multiplied by the ratio of the stress value “S” at the test temperature to the stress value “S” at the design temperature for the materials of which the pressure vessel is constructed. The values for “S” shall be taken from Tables UCS 23, UNF 23, UHA 23, or UHT 23 of the ASME Code. The value of “S” at test temperature shall be that taken for the material of the tabulated value of temperature closest to the test temperature. The value of “S” at design temperature shall be as interpolated from the appropriate table. No ratio less than one shall be used. The stress resulting from the hydrostatic test shall not exceed 90 percent of the yield stress of the material at the test temperature. External loadings which will exist in supporting structure during the hydrostatic test should be considered. The design shall consider the combined stress during hydrostatic testing due to pressure and the support reactions. This stress shall not exceed 90 percent of the yield stress of the material at the test temperature. In addition the adequacy of the supporting structure during hydrostatic testing should be considered in the design.
(c) The hydrostatic test pressure shall be applied for a sufficient period of time to permit a thorough examination of all joints and connections. The test shall not be conducted until the vessel and liquid are at approximately the same temperature.
(d) Defects detected during the hydrostatic test or subsequent examination shall be completely removed and then inspected. Provided the marine inspector gives his approval, they may then be repaired.
(e) Vessels requiring stress relieving shall be stress relieved after any welding repairs have been made. (See UW–40 of the ASME Code.)
(f) After repairs have been made the vessel shall again be tested in the regular way, and if it passes the test, the marine inspector may accept it. If it does not pass the test, the marine inspector can order supplementary repairs, or, if in his judgment the vessel is not suitable for service, he may permanently reject it.
§ 54.10-15 Pneumatic test (modifies UG–100).
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(a) Pneumatic testing of welded pressure vessels shall be permitted only for those units which are so designed and/or supported that they cannot be safely filled with water, or for those units which cannot be dried and are to be used in a service where traces of the testing medium cannot be tolerated.
(b) Proposals to pneumatically test shall be submitted to the cognizant Officer in Charge, Marine Inspection, for approval.
(c) Except for enameled vessels, for which the pneumatic test pressure shall be at least equal to, but need not exceed, the maximum allowable working pressure to be marked on the vessel, the pneumatic test pressure shall be at least equal to 1.25 times the maximum allowable working pressure to be stamped on the vessel multiplied by the lowest ratio (for the materials of which the vessel is constructed) of the stress value “S” for the test temperature of the vessel to the stress value “S” for the design temperature (see UG–21 of the ASME Code). In no case shall the pneumatic test pressure exceed 1.25 times the basis for calculated test pressure as defined in UA–60(e) of the ASME Code.
(d) The pneumatic test of pressure vessels shall be accomplished as follows:
(1) The pressure on the vessel shall be gradually increased to not more than half the test pressure.
(2) The pressure will then be increased at steps of approximately one-tenth the test pressure until the test pressure has been reached.
(3) The pressure will then be reduced to the maximum allowable working pressure of the vessel to permit examination.
(e) Pressure vessels pneumatically tested shall also be leak tested. The test shall be capable of detecting leakage consistent with the design requirements of the pressure vessel. Details of the leak test shall be submitted to the Commandant for approval.
(f) After satisfactory completion of the pneumatic pressure test, the vessel may be stamped in accordance with §54.10–20. A marine inspector shall observe the pressure vessel in a loaded condition at the first opportunity following the pneumatic test. The tank supports and saddles, connecting piping, and insulation if provided shall be examined to determine if they are satisfactory and that no leaks are evident.
(g) The pneumatic test is inherently more hazardous than a hydrostatic test, and suitable precautions shall be taken to protect personnel and adjacent property.
§ 54.10-20 Marking and stamping.
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(a) Pressure vessels (replaces UG–116, except paragraph (k), and UG–118). Pressure vessels that are required by §54.10–3 to be stamped with the Coast Guard Symbol must also be stamped with the following information:
(1) Manufacturer's name and serial number.
(2) Coast Guard number, see §50.10–30 of this subchapter.
(3) Coast Guard Symbol, which is affixed only by the marine inspector.
(4) Maximum allowable working pressure __ kPa (__ psig) at __ °C (__ °F).
(5) Class.
(6) Minimum service temperature allowed, if below -18 °C (0 °F)
(7) Water capacity in liters (U.S. gallons), if a cargo carrying pressure vessel.
(b) Multichambered pressure vessels (replaces UG–116(k)). In cases where more than one pressure vessel is involved in an integral construction, as with a heat exchanger, the manufacturer may elect to class the component pressure vessels differently. In such cases he shall stamp the combined structures as required in paragraph (a) of this section with information for each pressure vessel. Where an item for stamping is identical for both vessels, as with name and address of manufacturer, it need not be duplicated. However, where differences exist, each value and the vessel to which it applies shall be clearly indicated.
(c) Stamping data (replaces UG–117). Except as noted in paragraph (d) of this section, the data shall be stamped directly on the pressure vessel. The data shall be legibly stamped and shall not be obliterated during the service life of the pressure vessel. In the event that the portion of the pressure vessel upon which the data is stamped is to be insulated or otherwise covered, the data shall be reproduced on a metal nameplate. This plate shall be securely attached to the pressure vessel. The nameplate shall be maintained in a legible condition such that it may be easily read.
(1) Those parts of pressure vessels requiring Coast Guard shop inspection under this part which are furnished by other than the shop of the manufacturer responsible for the completed vessel shall be stamped with the Coast Guard Symbol, the Marine Inspection Office identification letters (see §50.10–30 of this subchapter) and the word “Part”, the manufacturer's name and serial number, and the design pressure.
(d) Thin walled vessels (Modifies UG–119). In lieu of direct stamping on the pressure vessel, the information required by paragraph (a) of this section shall be stamped on a nameplate permanently attached to the pressure vessel when the pressure vessel is constructed of—
(1) Steel plate less than one-fourth inch thick; or
(2) Nonferrous plate less than one-half inch thick.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9977, June 17, 1970; CGD 72–206R, 38 FR 17226, June 29, 1973; CGD 77–147, 47 FR 21810, May 20, 1982]
§ 54.10-25 Manufacturers' data report forms (modifies UG–120).
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(a) The Manufacturers' data report form, as provided by the Coast Guard, shall be completed in duplicate and certified by the manufacturer for each pressure vessel required to be shop inspected under these regulations. The original of this form shall be delivered to the Coast Guard inspector.
(b) Data forms for those parts of a pressure vessel requiring inspection, which are furnished by other than the shop of the manufacturer responsible for the completed unit, shall be executed in triplicate by the manufacturer of the parts. The original and one copy shall be delivered to the Coast Guard inspector who shall forward one copy of the report to the Officer in Charge, Marine Inspection, having cognizance over the final assembly. These partial data reports, together with the final inspection and tests, shall be the final Coast Guard inspector's authority to apply the Coast Guard symbol and number. A final data report shall be executed by the manufacturer or assembler who completes the final assembly and tests.
(c) If a pressure vessel is required to be inspected in accordance with §54.10–3(c), the manufacturer's data reports required by UG–120 must be made available to the Coast Guard inspector for review prior to inspection of the pressure vessel.
(Approved by the Office of Management and Budget under control number 2130–0181)
[CGFR 69–127, 35 FR 9977, June 17, 1970 as amended by CGD 77–147, 47 FR 21810, May 20, 1982]
Subpart 54.15—Pressure-Relief Devices
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§ 54.15-1 General (modifies UG–125 through UG–136).
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(a) All pressure vessels built in accordance with applicable requirements in Division 1 of section VIII of the ASME Code must be provided with protective devices as indicated in UG–125 through UG–136 except as noted otherwise in this subpart.
(b) The markings shall be in accordance with this chapter for devices covered by §54.15–10.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 88–032, 56 FR 35822, July 29, 1991]
§ 54.15-3 Definitions (modifies UA–60).
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(a) Definitions applicable to this subpart are in §52.01–3 of this subchapter.
§ 54.15-5 Protective devices (modifies UG–125).
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(a) All pressure vessels must be provided with protective devices. The protective devices must be in accordance with the requirements of UG–125 through UG–136 of the ASME Code except as modified in this subpart.
(b) An unfired steam boiler evaporator or heat exchanger (see §54.01–10) shall be equipped with protective devices as required by §54.15–15.
(c) All pressure vessels other than unfired steam boilers shall be protected by pressure-relieving devices that will prevent the pressure from rising more than 10 percent above the maximum allowable working pressure, except when the excess pressure is caused by exposure to fire or other unexpected source of heat.
(d) Where an additional hazard can be created by exposure of a pressure vessel to fire or other unexpected sources of external heat (for example, vessels used to store liquefied flammable gases), supplemental pressure-relieving devices shall be installed to protect against excessive pressure. Such supplemental pressure-relieving devices shall be capable of preventing the pressure from rising more than 20 percent above the maximum allowable working pressure of the vessel. The minimum required relief capacities for compressed gas pressure vessels are given under §54.15–25. A single pressure-relieving device may be used to satisfy the requirements of this paragraph and paragraph (c) of this section, provided it meets the requirements of both paragraphs.
(e) Pressure-relieving devices should be selected on the basis of their intended service. They shall be constructed, located, and installed so that they are readily accessible for inspection and repair and so arranged that they cannot be readily rendered inoperative.
(f) Where pressure-indicating gages are used, they shall be chosen to be compatible with the pressure to be indicated. The size of the visual display, the fineness of graduations, and the orientation of the display will be considered. In no case shall the upper range of the gage be less than 1.2 times nor more than 2 times the pressure at which the relieving device is set to function.
(g) The Commandant may authorize or require the use of a rupture disk in lieu of a relief or safety valve under certain conditions of pressure vessel use and design. See §54.15–13.
(h) Vessels that are to operate completely filled with liquid shall be equipped with liquid relief valves unless otherwise protected against overpressure.
(i) The protective devices required under paragraph (a) of this section shall be installed directly on a pressure vessel except when the source of pressure is external to the vessel, and is under such positive control that the pressure in the vessel cannot exceed the maximum allowable working pressure at the operating temperature except as permitted in paragraphs (c) and (d) of this section.
(j) Pressure-relieving devices shall be constructed of materials suitable for the pressure, temperature, and other conditions of the service intended.
(k) The opening through all pipes and fittings between a pressure vessel and its pressure-relieving device shall have at least the area of the pressure-relieving device inlet, and in all cases shall have sufficient area so as not to unduly restrict the flow to the pressure-relieving device. The opening in the vessel shall be designed to provide direct and unobstructed flow between the vessel and its pressure-relieving device.
(l) Safety devices need not be provided by the pressure vessel manufacturer. However, overpressure protection shall be provided prior to placing the vessel in service.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 88–032, 56 FR 35822, July 29, 1991; CGD 95–012, 60 FR 48049, Sept. 18, 1995]
§ 54.15-10 Safety and relief valves (modifies UG–126).
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(a) All safety and relief valves for use on pressure vessels or piping systems shall be designed to meet the protection and service requirements for which they are intended and shall be set to relieve at a pressure which does not exceed the “maximum allowable working pressure” of the pressure vessel or piping system. Relief valves are not required to have huddling chambers for other than steam service. In addition, safety valves used on vessels in which steam is generated shall meet §52.01–120 of this subchapter except §52.01–120(a)(9). For steam service below 206 kPa (30 psig), bodies of safety valves may be made of cast iron. Safety relief valves used in liquefied compressed gas service shall meet subpart 162.017 or 162.018 in subchapter Q (Specifications) of this chapter as appropriate.
(b) Pilot-valve control or other indirect operation of safety valves is not permitted unless the design is such that the main unloading valve will open automatically at not over the set pressure and will discharge its full rated capacity if some essential part of the pilot or auxiliary device should fail. All other safety and relief valves shall be of the direct spring loaded type.
(c) Safety and relief valves for steam or air service shall be provided with a substantial lifting device so that the disk can be lifted from its seat when the pressure in the vessel is 75 percent of that at which the valve is set to blow.
(d) Safety and relief valves for service other than steam and air need not be provided with a lifting device although a lifting device is desirable if the vapors are such that their release will not create a hazard.
(e) If the design of a safety or relief valve is such that liquid can collect on the discharge side of the disk, the valve shall be equipped with a drain at the lowest point where liquid can collect (for installation, see UG–134 of section VIII of the ASME Code).
(f) Cast iron may be employed in the construction of relief valves for pressures not exceeding 125 pounds per square inch and temperatures not exceeding 450 °F. Seats or disks of cast iron are prohibited.
(g) The spring in a relief valve in service for pressures up to and including 250 pounds per square inch shall not be reset for any pressure more than 10 percent above or 10 percent below that for which the relief valve is marked. For higher pressures, the spring shall not be reset for any pressure more than 5 percent above or 5 percent below that for which the relief valve is marked.
(h) The rated relieving capacity of safety and relief valves for use on pressure vessels shall be based on actual flow test data and the capacity shall be certified by the manufacturer in accordance with one of the following:
(1) 120 percent of the valve set pressure for valves rated in accordance with Compressed Gas Association Standard S–1.2.5.2.
(2) 110 percent of the valve set pressure for valves rated in accordance with UG–131 of section VIII of the ASME Code.
(3) 103 percent of the valve set pressure for steam in accordance with PG–69 of the ASME Code.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 81–79, 50 FR 9436, Mar. 8, 1985]
§ 54.15-13 Rupture disks (modifies UG–127).
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(a) Paragraph UG–127 of the ASME Code provides for the use of rupture disks in series with spring loaded safety or relief valves.
(b) For certain pressure vessels containing substances which may render a relief or safety valve inoperative, or where the installation of a valve is considered impractical, the Commandant may authorize or require the use of a rupture disk in parallel with or in lieu of a spring loaded safety or relief valve. These rupture disks shall:
(1) Comply with the general provisions of §54.15–5 except as noted otherwise in this section;
(2) Have a capacity for discharge such that the volume of release is sufficient to prevent the internal pressure from exceeding 120 percent of the “maximum allowable working pressure” with the pressure vessel exposed to fire conditions (see §54.15–25); and,
(3) Operate at a pressure level which does not produce fatigue failure of the disk. The normal maximum operating pressure multiplied by 1.3 shall not exceed the nominal disk burst pressure. (Notice that this restriction for protection of the rupture disk will usually require operation below the “maximum allowable working pressure” of the pressure vessel and therefore should be considered in design.)
(c) All disks shall be oriented so that if rupture occurs, the disk fragments and pressure vessel discharge will be directed away from operating personnel and vital machinery.
§ 54.15-15 Relief devices for unfired steam boilers, evaporators, and heat exchangers (modifies UG–126).
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(a) An approved safety valve set to relieve at a pressure not exceeding the “maximum allowable working pressure” of the shell shall be fitted to all unfired steam boilers and evaporators except for evaporators of the atmospheric type designed for vapor discharge direct to a distiller with no shutoff valve in the discharge line. The distiller connected to atmospheric evaporators shall be fitted with a vent to prevent a buildup in pressure. In no case shall the vent be less than 1 1/2 inches in diameter. Evaporators operating between atmospheric pressure and 15 p.s.i.g., may use a rupture disc as an alternative to the safety valve.
(b) Safety valves for use on pressure vessels in which steam or pressure is generated shall comply with the requirements of §54.15–10. Rupture discs used in lieu of these safety valves, as provided for in paragraph (a) of this section, shall comply with the requirements of §54.15–13.
(c) The relieving capacity of evaporator safety valves required by paragraph (a) of this section shall be at least equal to the capacity of the orifice fitted in the steam supply to the evaporator. The orifice capacity shall be determined in accordance with the formula in paragraph (c) (1) or (2) of this section as appropriate:
(1) Where the set pressure of the evaporator shell safety valve is 58 percent or less than the setting of the safety valve in the steam supply:
W=51.45AP
(2) Where the set pressure of the evaporator shell safety valve exceeds 58 percent of the setting of the safety valve on the steam supply:
W=105.3Av P1(P-P1)
where:
W=The required orifice capacity, in pounds per hour.
A=Cross-sectional area of rounded entrance orifice, in square inches. The orifice shall be installed near the steam inlet or the coils or tubes and where no orifice is employed the area used in the formula shall be that of the inlet connection or manifold.
P=Set pressure of steam supply safety valve, in pounds per square inch, absolute.
P1=Set pressure of evaporator shell safety valve, in pounds per square inch, absolute.
(d) The relieving capacity of safety valves on unfired steam boilers shall not be less than the maximum generating capacity of the unfired steam boiler as certified by the manufacturer.
(e) On new installations and where the orifice size of an existing unfired steam boiler or evaporator is increased, an accumulation test shall be made by closing all steam outlet connections except the safety valves for a period of five minutes. When conducting the accumulation test, the water shall be at the normal operating level and the steam pressure shall be at the normal operating pressure, and while under this test the pressure shall not rise more than 6 percent above the safety valve setting.
(f) A heat exchanger with liquid in the shell and the heating medium in the tubes or coils, shall be fitted with a liquid relief valve meeting the requirement of §54.15–5.
(g)(1) A heat exchanger with steam in the shell and liquid in the tubes or coils at a pressure exceeding that in the shell, shall have a liquid relief valve fitted to protect the shell against excess pressure.
(2) The discharge capacity of such relief valves shall be calculated on the basis of the discharge from one tube using the difference in pressures between that in the shell and that in the tubes and shall be not less than that determined by the following formula:
Q=29.81KD2v P1-P2
where:
Q=Required relief valve discharge capacity, in gallons per minute, based on relief valve set pressure.
P1=Pressure in the tube or coils, in pounds per square inch.
P2=Set pressure of the shell relief valve, in pounds per square inch.
D=Internal diameter of the largest tube or coil, in inches.
K=Coefficient of discharge=0.62.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 72–206R, 38 FR 17226, June 29, 1973]
§ 54.15-25 Minimum relief capacities for cargo tanks containing compressed or liquefied gas.
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(a) Each tank shall be fitted with one or more safety relief valves designed, constructed, and flow tested in accordance with subpart 162.017 or 162.018 in subchapter Q (Specifications) of this chapter. Valves conforming to specification subpart 162.017 shall be limited to use on tanks whose maximum allowable working pressure is not in excess of 10 pounds per square inch. With specific approval of the Commandant, such valves may be connected to the vessel in lieu of being directly fitted to the tanks.
(b) The discharge pressure and the maximum overpressure permitted shall be in accordance with §54.15–5.
(c) The rate of discharge for heat input of fire must meet the following formula:
Q=FGA0.82
where:
Q=minimum required rate of discharge in cubic meters (cubic feet) per minute of air at standard conditions 15 °C and 103 kPa (60 °F and 14.7 psia).
F=fire exposure factor for the following tank types:
F=1.0 for tanks without insulation located on the open deck.
F=0.5 for tanks on the open deck having insulation that has approved fire proofing, thermal conductance, and stability under fire exposure.
F=0.5 for uninsulated independent tasks installed in holds.
F=0/2 for insulated independent tanks in holds or for uninsulated independent tanks in insulated holds.
F=0.1 for insulated independent tanks in inerted holds or for uninsulated independent tanks in inerted, insulated holds.
F=0.1 for membrane and semi-membrane tanks.
G=gas factor of:
where:
L=latent heat of the material being vaporized at the relieving conditions, in Kcal/kg (Btu per pound).
C=constant based on relation of specific heats (k), Table §54.15–25(c) (if k is not known, C=.606(315)).
Z=compressibility factor of the gas at the relieving conditions (if not known, Z=1.0).
T=temperature in degrees K=(273 + degrees C) (R=(460 + degrees F)) at the relieving conditions (120% of the pressure at which the pressure relief valve is set).
M=molecular weight of the product.
A=external surface area of the tank in m 2 (sq. ft.) for the following tank types:
For a tank of a body of revolution shape:
A=external surface area.
For a tank other than a body of revolution shape:
A=external surface area less the projected bottom surface area.
For a grouping of pressure vessel tanks having insulation on the vessel's structure:
A=external surface area of the hold without the projected bottom area.
For a grouping of pressure tanks having insulation on the tank:
A=external surface area of the pressure tanks excluding insulation, and without the projected bottom area. 1
1 Figure 54.15–25(c) shows a method of determining the side external surface area of a grouping of vertical pressure tanks.
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Table 54.15-25(c)_Constant C
------------------------------------------------------------------------
k C
------------------------------------------------------------------------
1.00.......................................... .606 (315)
1.02.......................................... .611 (318)
1.04.......................................... .615 (320)
1.06.......................................... .620 (322)
1.08.......................................... .624 (324)
1.10.......................................... .628 (327)
1.12.......................................... .633 (329)
1.14.......................................... .637 (331)
1.16.......................................... .641 (333)
1.18.......................................... .645 (335)
1.20.......................................... .649 (337)
1.22.......................................... .652 (339)
1.24.......................................... .658 (341)
1.26.......................................... .660 (343)
1.28.......................................... .664 (345)
1.30.......................................... .667 (347)
1.32.......................................... .671 (349)
1.34.......................................... .674 (351)
1.36.......................................... .677 (352)
1.38.......................................... .681 (354)
1.40.......................................... .685 (356)
1.42.......................................... .688 (358)
1.44.......................................... .691 (359)
1.46.......................................... .695 (361)
1.48.......................................... .698 (363)
1.50.......................................... .701 (364)
1.52.......................................... .704 (366)
1.54.......................................... .707 (368)
1.56.......................................... .710 (369)
1.58.......................................... .713 (371)
1.60.......................................... .716 (372)
1.62.......................................... .719 (374)
1.64.......................................... .722 (376)
1.66.......................................... .725 (377)
1.68.......................................... .728 (379)
1.70.......................................... .731 (380)
1.72.......................................... .734 (382)
1.74.......................................... .736 (383)
1.76.......................................... .739 (384)
1.78.......................................... .742 (386)
1.80.......................................... .745 (387)
1.82.......................................... .747 (388)
1.84.......................................... .750 (390)
1.86.......................................... .752 (391)
1.88.......................................... .755 (392)
1.90.......................................... .758 (394)
1.92.......................................... .760 (395)
1.94.......................................... .763 (397)
1.96.......................................... .765 (398)
1.98.......................................... .767 (399)
2.00.......................................... .770 (400)
2.02.......................................... .772 (401)
2.20.......................................... .792 (412)
------------------------------------------------------------------------
(c–1) For an independent tank that has a portion of the tank protruding above the open deck, the fire exposure factor must be calculated for the surface area above the deck and the surface area below the deck, and this calculation must be specially approved by the Commandant (G-MSE).
(d) In determining the total safety valve relieving capacity, the arrangement and location of the valves on the tank will be evaluated. The valves shall be placed so that a number of valves sufficient to provide the required relieving capacity shall always be in communication with the cargo vapor phase. The possible motions which the tank may see in its intended service and attendant changes in cargo liquid level will be considered. Shut off valves shall not be installed between the vessel and the safety relief valves. Manifolds for mounting multiple relief valves may be fitted with acceptable interlocking shut off valves so arranged that the required capacity of discharge will be “lined up” at all times.
(e)(1) Each safety relief valve shall be tested in the presence of a marine inspector before being placed in service except as noted otherwise in paragraph (e)(2) of this section. The test shall satisfactorily show that the valve will start to discharge at the required minimum pressure.
(2) Each safety relief valve fitted with a breaking pin and rupture disk need not be tested in the presence of a marine inspector before being placed in service. In lieu thereof, a certificate shall be furnished with the valve attested to by the manufacturer that the test requirements of paragraph (e)(1) of this section have been met.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 74–289, 44 FR 26007, May 3, 1979; CGD 82–063b, 48 FR 4781, Feb. 3, 1983; CGD 95–072, 60 FR 50462, Sept. 29, 1995; CGD 96–041, 61 FR 50728, Sept. 27, 1996; USCG–2004–18884, 69 FR 58346, Sept. 30, 2004]
Subpart 54.20—Fabrication by Welding
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§ 54.20-1 Scope (modifies UW–1 through UW–65).
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(a) Pressure vessels and vessel parts that are fabricated by welding shall be as required by paragraphs UW–1 through UW–65 of section VIII of the ASME Code except as noted otherwise in this subchapter.
(b) [Reserved]
§ 54.20-2 Fabrication for hazardous materials (replaces UW–2(a)).
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(a) Pressure vessels containing hazardous materials as defined in §150.115 of this chapter must be of the class and construction required by subchapter D, I, O, or, when not specified, of a class determined by the Commandant.
(b) Class III pressure vessels must not be used for the storage or stowage of hazardous materials unless there is specific authorization in subchapters D, I, or O.
[CGD 77–147, 47 FR 21810, May 20, 1982]
§ 54.20-3 Design (modifies UW–9, UW–11(a), UW–13, and UW–16).
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(a) Fabrication by welding shall be in accordance with the provisions of this part and with part 57 of this subchapter.
(b) Welding subject to UW–11(a) of the ASME Code shall be modified as described in §54.25–8 for radiographic examination.
(c) A butt welded joint with one plate edge offset, as shown in Figure UW–13.1(k) of the ASME Code, may only be used for circumferential joints of Class II and Class III pressure vessels.
(d) Attachment welds for nozzles and other connections shall be in accordance with UW–16 of the ASME Code. When nozzles or connections are made to pressure vessels, as shown in Figure UW–16.1 (a) and (c) of the ASME Code, and are welded from one side only, backing strips shall be used unless it can be determined visually that a full penetration weld has been achieved.
(e) When fabricating by welding the minimum joint requirements shall be as specified under the column headed “minimum joint requirements” in Table 54.01–5(b) for various classes of pressure vessels.
(f) Joints in Class II or III pressure vessel cargo tanks must meet the following:
(1) Category A and B joints must be type (1) or (2).
(2) Category C and D joints must have full penetration welds extending through the entire thickness of the vessel wall or nozzle wall.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 77–147, 47 FR 21810, May 20, 1982; CGD 85–061, 54 FR 50964, Dec. 11, 1989]
§ 54.20-5 Welding qualification tests and production testing (modifies UW–26, UW–28, UW–29, UW–47, and UW–48).
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(a) Performance and procedure qualification. No production welding shall be done until welding procedures and welders have been qualified in accordance with part 57 of this subchapter.
(b) Tests. Production tests are required in accordance with §57.06–1 of this subchapter.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9977, June 17, 1970]
Subpart 54.23—Fabrication by Brazing
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§ 54.23-1 Scope (modifies UB–1).
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(a) Fabrication by brazing shall be in accordance with the provisions of this part and with part 57 of this subchapter.
[CGFR 69–127, 35 FR 9977, June 17, 1970]
Subpart 54.25—Construction With Carbon, Alloy, and Heat Treated Steels
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§ 54.25-1 Scope.
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(a) The carbon, alloy, and heat treated steels used in construction of pressure vessels and parts shall be as indicated in section VIII of the ASME Code except as noted otherwise in this subpart.
§ 54.25-3 Steel plates (modifies UCS–6).
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(a) The steels listed in UCS–6(b) and UCS–6(c) of the ASME Code will be allowed only in Class III pressure vessels (see Table 54.01–5(b)).
§ 54.25-5 Corrosion allowance (replaces UCS–25).
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(a) The corrosion allowance shall be as required in §54.01–35 in lieu of requirements in UCS–25 of the ASME Code.
§ 54.25-7 Requirement for postweld heat treatment (modifies UCS–56).
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(a) Postweld heat treatment is required for all carbon and low alloy steel Class I, I-L, and II-L vessels regardless of thickness. (Refer to Table 54.01–5(b) for applicable requirements.)
(b) Cargo tanks which are fabricated of carbon or low alloy steel as Class II pressure vessels, designed for pressures exceeding 100 pounds per square inch gage and used in the storage or transportation of liquefied compressed gases shall be postweld heat treated regardless of thickness.
[CGFR 69–127, 35 FR 9977, June 17, 1970]
§ 54.25-8 Radiography (modifies UW–11(a), UCS–57, UNF–57, UHA–33, and UHT–57).
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(a) Full radiography is required for all Class I and Class I-L vessels regardless of thickness. (Refer to Table 54.01–5(b) for applicable requirements.)
(b) Class II-L vessels shall be spot radiographed. The exemption provided in UW–11(c) of the ASME Code does not apply. (Refer to Table 54.01–5(b) for applicable requirements.)
(c) Each butt welded joint in a Class II or III pressure vessel cargo tank must be spot radiographed, in accordance with UW–52, regardless of diameter or thickness, and each weld intersection or crossing must be radiographed for a distance of at least 10 thicknesses from the intersection.
[CGFR 68–82, 33 FR 18828, Dec. 18, 1968, as amended by CGD 85–061, 54 FR 50964, Dec. 11, 1989]
§ 54.25-10 Low temperature operation—ferritic steels (replaces UCS–65 through UCS–67).
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(a) Scope. (1) This section contains requirements for pressure vessels and nonpressure vessel type tanks and associated secondary barrier, as defined in §38.05–4 and §154.7 of this chapter, and their parts constructed of carbon and alloy steels which are stressed at operating or hydrostatic test temperatures below 0 °F.
(2) The service temperature is the minimum temperature of a product atwhich it may be contained, loaded and/or transported. However, the service temperature shall in no case be taken higher than given by the following formula: (continued)