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(continued)
(3) For Class II piping, the type of joints shall be similar to Class I piping, with the following exceptions:
(i) Single-welded butt joints may be employed without the use of backing rings in all sizes provided that the weld is chipped or ground flush on the root side of the weld.
(ii) For services such as vents, overflows, and gravity drains, the backing ring may be eliminated and the root of the weld need not be ground.
(iii) Square-groove welds without edge preparation may be employed for butt joints in vents, overflows, and gravity drains where the pipe wall thickness does not exceed three-sixteenth inch.
(iv) The crimped or forged backing ring with continuous projection around the outside of the ring is acceptable only for Class II piping. The projection must be completely fused.
(4) Tack welds which become part of the finished weld, shall be made by a qualified welder. Tack welds made by an unqualified welder shall be removed. Tack welds which are not removed shall be made with an electrode which is the same as or equivalent to the electrode to be used for the first pass. Their stopping and starting ends must be properly prepared by grinding or other suitable means so that they may be satisfactorily incorporated into the final weld. Tack welds which have cracked shall be removed.
(5) (Reproduces 127.2(c)). When components of different outside diameters are welded together, the weld joint must be filled to the outside surface of the component having the larger diameter. There must be a gradual transition, not exceeding a slope of 1:3, in the weld between the two surfaces. To avoid unnecessary weld deposit, the outside surface of the component having the larger diameter must be tapered at an angle not to exceed thirty degrees with the axis of the pipe. (See Fig. 127.4.2.)
(6) (Modifies 127.4.2(d)). As-welded surfaces are permitted, however, the surface of welds must be sufficiently free from coarse ripple, grooves, overlaps, abrupt ridges and valleys to meet the following:
(i) The surface condition of the finished welds must be suitable for the proper interpretation of radiographic and other nondestructive examinations when nondestructive examinations are required by §56.95–10. In those cases where there is a question regarding the surface condition on the interpretation of a radiographic film, the film must be compared to the actual weld surface for interpretation and determination of acceptability.
(ii) Reinforcements are permitted in accordance with Table 56.70–15.
(iii) Undercuts must not exceed 1/32-inch and must not encroach on the minimum required section thickness.
(iv) If the surface of the weld requires grinding to meet the above criteria, care must be taken to avoid reducing the weld or base material below the minimum required thickness.
(7) The type and extent of examination required for girth butt welds is specified in §56.95–10.
(8) Sections of welds that are shown by radiography or other examination to have any of the following type of imperfections shall be judged unacceptable and shall be repaired as provided in paragraph (f) of this section:
(i) Any type of crack or zone of incomplete fusion or penetration.
(ii) Any slag inclusion or porosity greater in extent than those specified as acceptable set forth in PW–51 of section I of the ASME Code.
(iii) Undercuts in the external surfaces of butt welds which are more than 1/32-inch deep.
(iv) Concavity on the root side of full penetration girth butt welds where the resulting weld thickness is less than the minimum pipe wall thickness required by this subchapter. Weld reinforcement up to a maximum of 1/32-inch thickness may be considered as pipe wall thickness in such cases.
(c) Longitudinal butt welds. Longitudinal butt welds in piping components not made in accordance with the standards and specifications listed in 56.60–1 (a) and (b) must meet the requirements of paragraph 104.7 of ANSI-B31.1 and may be examined nondestructively by an acceptable method. Imperfections shall not exceed the limits established for girth butt welds except that no undercutting shall be permitted in longitudinal butt welds. See also §56.60–2(b).
(d) Fillet welds. (1) Fillet welds may vary from convex to concave. The size of a fillet weld is determined as shown in Figure 127.4.4A in ANSI B31.1. Fillet weld details for socket-welding components must meet §56.30–5(c) of this part. Fillet weld details for flanges must meet §56.30–10(c) of this part. Fillet weld details for flanges must meet §56.30–10 of this part.
(2) The limitations on cracks and undercutting set forth in paragraph (b)(8) of this section for girth welds are also applicable to fillet welds.
(3) Class I piping not exceeding 3 inches nominal pipe size and not subject to full radiography by §56.95–10 of this part may be joined by sleeves fitted over pipe ends or by socket type joints. Where full radiography is required, only butt type joints may be used. The inside diameter of the sleeve must not exceed the outside diameter of the pipe or tube by more than 0.080 inch. Fit between socket and pipe must conform to applicable standards for socket weld fittings. Depth of insertion of pipe or tube within the socket or sleeve must not be less than three-eighths inch. The fillet weld must be deposited in a minimum of two passes, unless specifically approved otherwise in a special procedure qualification. Requirements for joints employing socket weld and slip-on flanges are in §56.30–10 of this part.
(4) Sleeve and socket type joints may be used in Class II piping systems without restriction as to size of pipe or tubing joined. Applicable standards must be followed on fit. The fillet welds must be deposited in a minimum of two passes, unless specifically approved otherwise in a special procedure qualification. Requirements for joints employing socket weld and slip-on flanges are in §56.30–10 of this part.
(e) Seal welds (reproduces 127.4.5). (1) Where seal welding of threaded joints is performed, threads shall be entirely covered by the seal weld. Seal welding shall be done by qualified welders.
(2) The limitation on cracks and undercutting set forth in §56.70–15(b)(8) for girth welds are also applicable to seal welds.
(f) Weld defect repairs (reproduces 127.4.11). (1) All defects in welds requiring repair must be removed by a flame or arc-gouging, grinding, chipping, or machining. Repair welds must be made in accordance with the same procedures used for original welds, or by another welding process if it is a part of a qualified procedure, recognizing that the cavity to be repaired may differ in contour and dimensions from the original joint. The types, extent, and method of examination and limits of imperfections of repair welds shall be the same as for the original weld.
(2) Preheating may be required for flame-gouging or arc-gouging certain alloy materials of the air hardening type in order to prevent surface checking or cracking adjacent to the flame or arc-gouged surface.
(g) Welded branch connections (reproduces 127.4.8). (1) Figure 127.4.8A, Figure 127.4.8B, and Figure 127.4.8C of ANSI-B31.1 show typical details of branch connections with and without added reinforcement. However, no attempt has been made to show all acceptable types of construction and the fact that a certain type of construction is illustrated does not indicate that it is recommended over other types not illustrated. See also Figure 56.70–15(g) for additional pipe connections.
(2) Figure 127.4.8D of ANSI-B31.1 shows basic types of weld attachments used in the fabrication of branch connections. The location and minimum size of these attachment welds shall conform to the requirements of this paragraph. Weld sizes shall be calculated in accordance with 104.3.1 of ANSI-B31.1, but shall not be less than the sizes shown in Figure 127.4.8D and F of ANSI-B31.1.
(3) The notations and symbols used in this paragraph and in Figure 127.4.8D and F of ANSI-B31.1 are as follows:
Figure 56.70–15(g)—Acceptable types of welded pipe connections
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tn=nominal thickness of branch wall less corrosion allowance, inches.
tc=the smaller of 1/4 inch or 0.7tn.
te=nominal thickness of reinforcing element (ring or saddle), inches (te=0 if there is no added reinforcement).
tmin=the smaller of tn or te.
tw=dimension of partial penetration weld, inches.
(4) Branch connections (including specially made integrally reinforced branch connection fittings) which abut the outside surface of the run wall, or which are inserted through an opening cut in the run wall, shall have opening and branch contour to provide a good fit and shall be attached by means of full penetration groove welds except as otherwise permitted in paragraph (g)(7) of this section. The full penetration groove welds shall be finished with cover fillet welds having a minimum throat dimension not less than tc. The limitation as to imperfection of these groove welds shall be as set forth in 127.4.2(e) of ANSI-B31.1 for girth welds.
(5) In branch connections having reinforcement pads or saddles, the reinforcement shall be attached by welds at the outer edge and at the branch periphery as follows:
(i) If the weld joining the added reinforcement to the branch is a full penetration groove weld, it shall be finished with a cover fillet weld having a minimum throat dimension not less than tc the weld at the outer edge, joining the added reinforcement to the run, shall be a fillet weld with a minimum throat dimension of 0.5 te.
(ii) If the weld joining the added reinforcement to the branch is a fillet weld, the throat dimension shall not be less than 0.7 tmin. The weld at the outer edge joining the outer reinforcement to the run shall also be a fillet weld with a minimum throat dimension of 0.5 te.
(6) When rings or saddles are used, a vent hole shall be provided (at the side and not at the crotch) in the ring or saddle to reveal leakage in the weld between branch and main run and to provide venting during welding and heat treating operations. Rings or saddles may be made in more than one piece if the joints between the pieces have strength equivalent to ring or saddle parent metal and if each piece is provided with a vent hole. A good fit shall be provided between reinforcing rings or saddles and the parts to which they are attached.
(7) Branch connections 2 in. NPS and smaller that do not require reinforcement may be constructed as shown in Fig. 127.4.8F of ANSI-B31.1. This construction is limited to use in Class I and II piping systems at a maximum design temperature of 750 °F. or a maximum pressure of 1025 psi.
(h) Heat treatment. Heat treatment for welds shall be in accordance with subpart 56.85.
Table 56.70-15_Reinforcement of Girth and Longitudinal Butt Welds
------------------------------------------------------------------------
Maximum thickness (in inches) of
reinforcement for design temperature
--------------------------------------
Thickness (in inches) of base 0 °F
metal Below 0 and above
°F or 350° to but less
above 750 750 °F than 350
°F °F
------------------------------------------------------------------------
Up to \1/8\, inclusive........... \1/16\ \3/32\ \3/16\
Over \1/8\ to \3/16\, inclusive.. \1/16\ \1/8\ \3/16\
Over \3/16\ to \1/2\, inclusive.. \1/16\ \5/32\ \3/16\
Over \1/2\ to 1, inclusive....... \3/32\ \3/16\ \3/16\
Over 1 to 2, inclusive........... \1/8\ \1/4\ \1/4\
Over 2........................... \5/32\ (\1\) (\1\)
------------------------------------------------------------------------
\1\ The greater of \1/4\ in. or \1/8\ times the width of the weld in
inches.
Notes: 1. For double welded butt joints, this limitation on
reinforcement given above applies separately to both inside and
outside surfaces of the joint.
2. For single welded butt joints, the reinforcement limits given above
apply to the outside surface of the joint only.
3. The thickness of weld reinforcement is based on the thickness of the
thinner of the materials being joined.
4. The weld reinforcement thicknesses must be determined for the higher
of the abutting surfaces involved.
5. For boiler external piping use the column titled ``Below 0 °F. or
above 750 °F.'' for weld reinforcement thicknesses.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9978, June 17, 1970; CGD 73–254, 40 FR 40165, Sept. 2, 1975; CGD 77–140, 54 FR 40614, Oct. 2, 1989; 55 FR 39969, Oct. 1, 1990; CGD 95–012, 60 FR 48050, Sept. 18, 1995]
§ 56.70-20 Qualification, general.
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(a) Qualification of the welding procedures to be used, and of the performance of welders and welding operators, is required, and shall comply with the requirements of the ASME Boiler and Pressure Vessel Code (section IX) except as modified by part 57 of this subchapter.
(b) Each butt-welded joint of Class I of Class I-L piping shall be marked with the welder's identification symbol. Dies shall not be used to mark the pipe where the pressure exceeds 600 pounds per square inch or the temperature exceeds 750 °F. or in Class I-L systems.
Subpart 56.75—Brazing
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§ 56.75-5 Filler metal.
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(a) The filler metal used in brazing must be a nonferrous metal or alloy having a melting point above 1,000°F. and below that of the metal being joined. The filler metal must meet and flow freely within the desired temperature range and, in conjunction with a suitable flux or controlled atmosphere, must wet and adhere to the surfaces to be joined. Prior to using a particular brazing material in a piping system, the requirements of §56.60–20 of this part should be considered.
(b) The brazing material used shall have a shearing strength of at least 10,000 pounds per square inch. The maximum allowable working pressure for brazing piping shall be determined by this part.
(c) (Reproduces 128.1.2.) Fluxes that are fluid and chemically active at the brazing temperature shall be used when necessary to prevent oxidation of the filler metal and the surfaces to be joined and to promote free flowing of the filler metal.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 77–140, 54 FR 40615, Oct. 2, 1989]
§ 56.75-10 Joint clearance (reproduces 128.2.2).
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(a) The clearance between surfaces to be joined shall be no larger than is necessary to insure complete capillary distribution of the filler metal; between 0.002–inch minimum and 0.006-inch maximum.
(b) [Reserved]
§ 56.75-15 Heating (reproduces 128.2.3).
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(a) The joint shall be brought to brazing temperature in as short a time as possible to minimize oxidation.
(b) [Reserved]
§ 56.75-20 Brazing qualification.
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(a) The qualification of the performance of brazers and brazing operators, shall be in accordance with the requirements of part C, section IX of the ASME Code and part 57 of this subchapter.
(b) Manufacturers shall perform those tests required by paragraph (a) of this section prior to performing production brazing.
§ 56.75-25 Detail requirements.
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(a) Pipe may be fabricated by brazing when the temperature to which such connections may be subjected does not exceed 425 °F. (For exception refer to §56.30–30(b)(1).)
(b) (Reproduces 128.2.1.) The surfaces to be brazed shall be clean and free from grease, oxides, paint, scale, and dirt of any kind. Any suitable chemical or mechanical cleaning method may be used to provide a clean wettable surface for brazing.
(c) After the parts to be joined have been thoroughly cleaned the edges to be brazed shall be given an even coating of flux prior to heating the joint as a protection against oxidation.
§ 56.75-30 Pipe joining details.
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(a) Silver brazing. (1) Circumferential pipe joints may be either of the socket or butt type. When butt joints are employed the edges to be joined shall be cut or machined square and the edges shall be held closely together to insure a satisfactory joint.
(b) Copper-alloy brazing. (1) Copper-alloy brazing may be employed to join pipe, valves, and fittings. Circumferential joints may be either of the butt or socket type. Where butt joints are employed, the included angle shall be not less than 90° where the wall thickness is three-sixteenths of an inch or greater. The annular clearance of socket joints shall be held to small clearances which experience indicates is satisfactory for the brazing alloy to be employed, method of heating, and material to be joined. The annular clearance shall be shown on drawings submitted for approval of socket joints.
(2) Copper pipe fabricated with longitudinal joints for pressures not exceeding that permitted by the regulations in this subchapter may have butt, lapped, or scarfed joints. If of the latter type, the kerf of the material shall be not less than 60°.
(c) Brazing, general. (1) Heat shall be applied evenly and uniformly to all parts of the joint in order to prevent local overheating.
(2) The members to be joined shall be held firmly in place until the brazing alloy has set so as to prevent any strain on the joint until the brazing alloy has thoroughly solidified. The brazing shall be done by placing the flux and brazing material on one side of the joint and applying heat until the brazing material flows entirely through the lap and shows uniformly along the seam on the other side of the joint. Sufficient flux shall be used to cause the brazing material to appear promptly after reaching the brazing temperature.
Subpart 56.80—Bending and Forming
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§ 56.80-5 Bending.
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Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design, and substantially free of buckles. Such bends shall meet the design requirements of 102.4.5 and 104.2.1 of ANSI-B31.1. This shall not prohibit the use of bends designed as creased or corrugated. If doubt exists as to the wall thickness being adequate, Class I piping having diameters exceeding 4 inches shall be nondestructively examined by the use of ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a screwed plug extending outside the pipe covering. The nondestructive method shall be employed where the design temperature exceeds 750 °F. Prior to the use of nondestructive method of examination by the above procedure, it shall be demonstrated by the user, in the presence of a marine inspector on specimens similar to those to be examined, that consistent results, having an accuracy of plus or minus 3 percent, can be obtained.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9979, June 17, 1970]
§ 56.80-10 Forming (reproduces 129.2).
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(a) Piping components may be formed (swaging, lapping, or upsetting of pipe ends, extrusion of necks, etc.) by any suitable hot or cold working method, providing such processes result in formed surfaces which are uniform and free of cracks or other defects, as determined by methods of inspection specified in the design.
§ 56.80-15 Heat treatment of bends and formed components.
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(a) (Reproduces 129.3.1.) Carbon steel piping which has been heated to at least 1,650 °F. for bending or other forming operations shall require no subsequent heat treatment.
(b) Ferritic alloy steel piping which has been heated for bending or other forming operations shall receive a stress relieving treatment, a full anneal, or a normalize and temper treatment, as specified by the design specification before welding.
(c) (Reproduces 129.3.3.) Cold bending and forming of carbon steel having a wall thickness of three-fourths of an inch and heavier, and all ferritic alloy pipe in nominal pipe sizes of 4 inches and larger, or 1/2-inch wall thickness or heavier, shall require a stress relieving treatment.
(d) (Reproduces 129.3.4.) Cold bending of carbon and ferritic alloy steel pipe in sizes and wall thicknesses less than specified in 129.3.3 of ANSI-B31.1 may be used without a postheat treatment.
(e) (Reproduces 129.3.5.) For other materials the heat treatment of bends and formed components shall be such as to insure pipe properties that are consistent with the original pipe specification.
(f) All scale shall be removed from heat treated pipe prior to installation.
(g) (Reproduces 129.3.6.) Austenitic stainless steel pipe that has been heated for bending or other forming may be used in the “as-bent” condition unless the design specification requires post bending heat treatment.
[CGFR 68–62, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9979, June 17, 1970; CGD 73–254, 40 FR 40166, Sept. 2, 1975]
Subpart 56.85—Heat Treatment of Welds
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§ 56.85-5 Heating and cooling method (reproduces 131.1).
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(a) Heat treatment may be accomplished by a suitable heating method which will provide the desired heating and cooling rates, the required metal temperature, metal temperature uniformity, and temperature control.
§ 56.85-10 Preheating.
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(a) The minimum preheat temperatures listed in Table 56.85–10 for P-number materials groupings are mandatory minimum pre-heat temperatures. Preheat is required for Class I, I-L, I-N, II-N and II-L piping when the ambient temperature is below 50 °F.
(b) (Modifies 131.2.2.) When welding dissimilar materials the minimum preheat temperature may not be lower than the highest temperature listed in Table 56.85–10 for any of the materials to be welded or the temperature established in the qualified welding procedure.
(c) (Reproduces 131.2.3.) The preheat temperature shall be checked by use of temperature-indicating crayons, thermocouples, pyrometers, or other suitable methods to assure that the required preheat temperature is obtained prior to and uniformly maintained during the welding operation.
Table 56.85-10_Preheat and Postheat Treatment of Welds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Preheat required Post heat treatment requirement (1)(2)
------------------------------------------------------------------------------------------------------------------------
Time cycle
-----------------------
ASME Sec IX Nos. Minimum Minimum wall and Minimum
Minimum wall temperature other Temperature Hour per time
(3)(4) (inch) (5)(6)(°F) (3)(4)(17)(inch) (7)(8)(9)(10)(11)(12)(°F)(inch) inch of within
wall range
(3)(4) (hour)
--------------------------------------------------------------------------------------------------------------------------------------------------------
P-1(16)........................ All.............. 50 (for .30 C. Over \3/4\ in..... 1,100 to 1,200 (minimum) (maximum)... 1 1
maximum or less)
(13).
P-1(16)........................ All.............. 175 (for over .30 ......do.......... ......do............................. 1 1
C.) (13) and
wall thickness
over 1 in.
P-3(15)........................ All walls........ 175.............. Over \1/2\ in..... 1,200 to 1,350 (minimum) (maximum)... 1 1
P-4(15)........................ Up to \3/4\ in 300.............. Over \1/2\ in or 1,330 to 1,400 (minimum) (maximum)... 1 1
inclusive. over 4 in nom.
size or.
Over \3/4\ in.... 400.............. Over .15 C.
maximum.
P-5(15) (less than 5 cr.)...... Up to \3/4\ in 300.............. Over \1/2\ in or 1,300 to 1,425 (minimum) (maximum)... 1 1
inclusive. over 4 in. nom.
size or.
Over \3/4\ in.... 400.............. Over 0.15 C.
maximum.
P-5(15) (5 cr. and higher)..... Up to \3/4\ 300.............. All walls......... ......do............................. 1 2
inclusive.
Over \3/4\ in.... 400.............. Over 0.15 C.
maximum.
P-6............................ All walls........ 300 (14)......... All walls......... 1,400 to 1,500 (minimum) (maximum)... 1 2
P-8............................ ......do......... None required.... ......do.......... None required........................
--------------------------------------------------------------------------------------------------------------------------------------------------------
For P–7, P–9A, P–9B, P–10C and other materials not listed the Preheat and Postheat Treatment is to be in accordance with the qualified procedure.
Notes Applicable To Table 56.85–10:
(1) Not applicable to dissimilar metal welds.
(2) When postheat treatment by annealing or normalizing is used, the postheat treatment temperatures must be in accordance with the qualified welding procedure.
(3) Wall thickness of a butt weld is defined as the thicker of the two abutting ends after end preparation including I.D. machining.
(4) The thickness of socket, fillet, and seal welds is defined as the throat thicknesses for pressure and nonpressure retaining welds.
(5) Preheat temperatures must be checked by use of temperature indicating crayons, thermocouple pyrometers, or other suitable method.
(6) For inert gas tungsten arc root pass welding lower preheat in accordance with the qualified procedure may be used.
(7) The maximum postheat treatment temperature listed for each P number is a recommended maximum temperature.
(8) Postheat treatment temperatures must be checked by use of thermocouple pyrometers or other suitable means.
(9) Heating rate for furnace, gas, electric resistance, and other surface heating methods must not exceed: (i) 600 °F per hour for thicknesses 2 inches and under.
(ii) 600 °F per hour divided by 1/2 the thickness in inches for thickness over 2 inches.
(10) Heating route for induction heating must not exceed:
(i) 600 °F per hour for thickness less than 1 1/2 inches (60 and 400 cycles).
(ii) 500 °F per hour when using 60 cycles and 400 °F per hour when using 400 cycles for thicknesses 1 1/2 inches and over.
(11) When local heating is used, the weld must be allowed to cool slowly from the postheat treatment temperature. A suggested method of retarding cooling is to wrap the weld with asbestos and allow to cool in still air. When furnace cooling is used, the pipe sections must be cooled in the furnace to 1000 °F and may then be cooled further in still air.
(12) Local postheat treatment of butt welded joints must be performed on a circumferential band of the pipe. The minimum width of this band, centered on the weld, must be the width of the weld plus 2 inches.
Local postheat treatment of welded branch connections must be performed by heating a circumferential band of the pipe to which the branch is welded. The width of the heated band must extend at least 1 inch beyond the weld joining the branch.
(13) 0.30 C. max applies to specified ladle analysis.
(14) 600 °F maximum interpass temperature.
(15) Welding on P–3, P–4, and P–5 with 3 Cr max. may be interrupted only if—
(i) At least 3/8 inch thickness of weld is deposited or 25 percent of welding groove is filled, whichever is greater;
(ii) The weld is allowed to cool slowly to room temperature; and
(iii) The required preheat is resumed before welding is continued.
(16) When attaching welding carbon steel non-pressure parts to steel pressure parts and the throat thickness of the fillet or partial or full penetration weld is 1/2 in. or less, postheat treatment of the fillet weld is not required for Class I and II piping if preheat to a minimum temperature of 175 °F is applied when the thickness of the pressure part exceeds 3/4 in.
(17) For Class I-L and II-L piping systems, relief from postweld heat treatment may not be dependent upon wall thickness. See also §§56.50–105(a)(3) and 56.50–105(b)(3) of this chapter.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9980, June 17, 1970; CGD 72–104R, 37 FR 14234, July 18, 1972; CGD 72–206R, 38 FR 17229, June 29, 1973; CGD 73–254, 40 FR 40166, Sept. 2, 1975; CGD 77–140, 54 FR 40615, Oct. 2, 1989]
§ 56.85-15 Postheat treatment.
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(a) Where pressure retaining components having different thicknesses are welded together as is often the case when making branch connections, the preheat and postheat treatment requirements of Table 56.85–10 apply to the thicker of the components being joined. Postweld heat treatment is required for Classes I, I-L, II-L, and systems. It is not required for Class II piping. Refer to §56.50–105(a)(3) for exceptions in Classes I-L and II-L systems and to paragraph (b) of this section for Class I systems.
(b) All buttwelded joints in Class I piping shall be postweld heated as required by Table 56.85–10. The following exceptions are permitted:
(1) High pressure salt water piping systems used in tank cleaning operations; and,
(2) Gas supply piping of carbon or carbon molybdenum steel used in gas turbines.
(c) All complicated connections including manifolds shall be stress-relieved in a furnace as a whole as required by Table 56.85–10 before being taken aboard ship for installation.
(d) (Reproduces 131.3.2.) The postheat treatment method selected for parts of an assembly shall not adversely affect other components. Heating a fabricated assembly as a complete unit is usually desirable; however, the size or shape of the unit or the adverse effect of a desired heat treatment on one or more components where dissimilar materials are involved, may dictate alternative procedures such as heating a section of the assembly before the attachment of others, or local circumferential band heating of welded joints in accordance with §56.85–15(j)(3) and note (12) of Table 56.85–10.
(e) (Reproduces 131.3.3.) Postheat treatment of welded joints between dissimilar metals having different postheat requirements shall be that established in the qualified welding procedure.
(f)–(h) [Reserved]
(i) (Reproduces 131.3.4.) For those materials listed under P-No. 1, when the wall thickness of the thicker of the two abutting ends, after end preparation, is less than three-fourths inch, the weld need not be postheat treated. In all cases, where the nominal wall thickness is 3/4 in. or less, postheat treatment is not required.
(j) (1)–(2) [Reserved]
(3) In local postheat treatment the entire band must be brought up to uniform specified temperature over the complete circumference of the pipe section, with a gradual diminishing of the temperature outward from the edges of the band.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 72–206R, 38 FR 17229, June 29, 1973; CGD 73–254, 40 FR 40167, Sept. 2, 1975]
Subpart 56.90—Assembly
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§ 56.90-1 General.
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(a) The assembly of the various piping components, whether done in a shop or as field erection, shall be done so that the completely erected piping conforms with the requirements of the regulations in this subchapter and with the specified requirements of the engineering design.
§ 56.90-5 Bolting procedure.
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(a) All flanged joints shall be fitted up so that the gasket contact faces bear uniformly on the gasket and then shall be made up with relatively uniform bolt stress. Bolt loading and gasket compression need only be verified by touch and visual observation.
(b) (Reproduces 135.2.2.) In bolting gasketed flanged joints, the gasket shall be properly compressed in accordance with the design principles applicable to the type of gasket used.
(c) Steel to cast iron flanged joints shall be assembled with care to prevent damage to the cast iron flange in accordance with §56.25–10.
(d) (Reproduces 135.2.4.) All bolts shall be engaged so that there is visible evidence of complete threading through the nut or threaded attachment.
§ 56.90-10 Threaded piping (reproduces 135.4).
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(a) Any compound or lubricant used in threaded joints shall be suitable for the service conditions and shall not react unfavorably with either the service fluid or the piping materials.
(b) Threaded joints which are to be seal welded shall be made up without any thread compound.
(c) Backing off to permit alignment of pipe threaded joints shall not be permitted.
Subpart 56.95—Inspection
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§ 56.95-1 General (replaces 136).
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(a) The provisions in this subpart shall apply to inspection in lieu of 136 of ANSI-B31.1.
(b) Prior to initial operation, a piping installation shall be inspected to the extent necessary to assure compliance with the engineering design, and with the material, fabrication, assembly and test requirements of ANSI-B31.1, as modified by this subchapter. This inspection is the responsibility of the owner and may be performed by employees of the owner or of an engineering organization employed by the owner, together with the marine inspector.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9979, June 17, 1970]
§ 56.95-5 Rights of access of marine inspectors.
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Marine inspectors shall have rights of access to any place where work concerned with the piping is being performed. This includes manufacture, fabrication, assembly, erection, and testing of the piping or system components. Marine inspectors shall have access to review all certifications or records pertaining to the inspection requirements of §56.95–1, including certified qualifications for welders, welding operators, and welding procedures.
§ 56.95-10 Type and extent of examination required.
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(a) General. The types and extent of nondestructive examinations required for piping must be in accordance with this section and Table 136.4 of ANSI-B31.1. In addition, a visual examination shall be made.
(1) 100 percent radiography 1 is required for all Class I, I-L, and II-L piping with wall thickness equal to or greater than 10 mm (.375 in.).
(2) Nondestructive examination is required for all Class II piping equal to or greater than 18 inches nominal diameter regardless of wall thickness. Any test method acceptable to the Officer in Charge, Marine Inspection may be used.
(3) Appropriate nondestructive examinations of other piping systems are required only when deemed necessary by the Officer in Charge, Marine Inspection. In such cases a method of testing satisfactory to the Officer in Charge, Marine Inspection must be selected from those described in this section.
(b) Visual examination. Visual examination consists of observation by the marine inspector of whatever portions of a component or weld are exposed to such observation, either before, during, or after manufacture, fabrication, assembly or test. All welds, pipe and piping components shall be capable of complying with the limitations on imperfections specified in the product specification under which the pipe or component was purchased, or with the limitations on imperfections specified in §56.70–15(b) (7) and (8), and (c), as applicable.
(c) Nondestructive types of examinations—(1) 100 Percent radiography. Where 100 percent radiography 1 is required for welds in piping, each weld in the piping shall be completely radiographed. If a butt weld is examined by radiography, for either random or 100 percent radiography, the method used shall be as follows:
1 Where for some reason, such as joint configuration, radiography is not applicable, another approved examination may be utilized.
(i) X-ray or gamma ray method of radiography may be used. The selection of the method shall be dependent upon its adaptability to the work being radiographed. The procedure to be followed shall be as indicated in PW–51 of section I of the ASME Code.
(ii) If a piping component or a weld other than a butt weld is radiographed, the method used shall be in accordance with UW–51 of section VIII of the ASME Code.
(2) Random radiography. Where random radiography 1 is required, one or more welds may be completely or partially radiographed. Random radiography is considered to be a desirable means of spot checking welder performance, particularly in field welding where conditions such as position, ambient temperatures, and cleanliness are not as readily controlled as in shop welding. It is to be employed whenever an Officer in Charge, Marine Inspection questions a pipe weld not otherwise required to be tested. The standards of acceptance are the same as for 100 percent radiography.
(3) Ultrasonic. Where 100 percent ultrasonic testing is specified, the entire surface of the weld being inspected shall be covered using extreme care and careful methods to be sure that a true representation of the actual conditions is obtained. The procedures to be used shall be submitted to the Commandant for approval.
(4) Liquid penetrant. Where liquid penetrant examination is required, the entire surface of the weld being examined shall be covered. The examination shall be performed in accordance with appendix VIII to section VIII of the ASME Code. The following standards of acceptance shall be met:
(i) All linear discontinuities and aligned penetrant indications revealed by the test shall be removed. Aligned penetrant indications are those in which the average of the center-to-center distances between any one indication and the two adjacent indications in any straight line is less than three-sixteenths inch. All other discontinuities revealed on the surface need not be removed unless the discontinuities are also revealed by radiography, in which case the pertinent radiographic specification shall apply.
(5) Magnetic particle. Where magnetic particle testing is required, the entire surface of the weld being examined shall be covered. The testing shall be performed in accordance with appendix VI to section VIII of the ASME Code. The following standards of acceptance are required for welds. All linear discontinuities and aligned indications revealed by the test shall be removed. Aligned indications are those in which the average of the center-to-center distances between any one indication and the two adjacent indications in any straight line is less than three-sixteenths inch. All other revealed discontinuities need not be removed unless the discontinuities are also revealed by radiography, in which case the requirements of paragraph (c)(1) of this section shall be met.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 72–206R, 38 FR 17229, June 29, 1973; CGD 78–108, 43 FR 46546, Oct. 10, 1978; CGD 77–140, 54 FR 40615, Oct. 2, 1989; CGD 95–028, 62 FR 51202, Sept. 30, 1997; USCG–2000–7790, 65 FR 58460, Sept. 29, 2000]
Subpart 56.97—Pressure Tests
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§ 56.97-1 General (replaces 137).
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(a) Scope. The requirements in this subpart apply to pressure tests of piping in lieu of 137 of ANSI-B31.1. Those paragraphs reproduced are so noted.
(b) Leak tightness. It is mandatory that the design, fabrication and erection of piping constructed under the regulations in this subchapter demonstrate leak tightness. Except where otherwise permitted in this subpart, this requirement must be met by a hydrostatic leak test prior to initial operations. Where a hydrostatic test is not practicable, a pneumatic test (§56.97–35) or initial service leak test (§56.97– 38) may be substituted if approved by the Commandant.
(1) At no time during the hydrostatic test may any part of the piping system be subjected to a stress greater than 90 percent of its yield strength (0.2 percent offset) at test temperature.
(2) Pneumatic tests may be used in lieu of the required hydrostatic test (except as permitted in paragraph (b)(3) of this section), only when—
(i) Piping subassemblies or systems are so designed or supported that they cannot be safely filled with water; 1 or
1 These tests may be made with the item being tested partially filled with water, if desired.
(ii) Piping subassemblies or systems are to be used in services where traces of the testing medium cannot be tolerated and, whenever possible, the piping subassemblies or system have been previously hydrostatically tested to the pressure required in §56.97–30(e).
(3) A pneumatic test at a pressure not to exceed 25 psig may be applied before a hydrostatic or a pneumatic test as a means of locating major leaks. The preliminary pneumatic test must be carried out in accordance with the requirements of §56.97–35.
Note: Compressed gas is hazardous when used as a testing medium. It is, therefore, recommended that special precautions for protection of personnel be taken whenever gas under pressure is used as the test medium.
(4) The hydrostatic test of the piping system, when conducted in accordance with the requirements of this part, is acceptable as the test for piping subassemblies and may also be used in lieu of any such test required by the material specification for material used in the piping subassembly or system provided the minimum test pressure required for the piping system is met, except where the installation would prevent performing any nondestructive examination required by the material specification to be performed subsequent to the hydrostatic or pneumatic test.
[CGD 73–254, 40 FR 40167, Sept. 2, 1975]
§ 56.97-5 Pressure testing of nonstandard piping system components.
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(a) All nonstandard piping system components such as welded valves and fittings, nonstandard fittings, manifolds, seacocks, and other appurtenances must be hydrostatically tested to twice the rated pressure stamped thereon, except that no component should be tested at a pressure causing stresses in excess of 90 percent of its yield strength.
(b) Items for which an accepted standard appears in Table 56.60–1(b) need not be tested as described in paragraph (a) of this section, but need only meet the test required in the applicable standard.
[CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 77–140, 54 FR 40615, Oct. 2, 1989]
§ 56.97-25 Preparation for testing (reproduces 137.3).
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(a) Exposure of joints. All joints including welds must be left uninsulated and exposed for examination during the test.
(b) Addition of temporary supports. Piping systems designed for vapor or gas may be provided with additional temporary supports, if necessary, to support the weight of the test liquid.
(c) Restraint or isolation of expansion joints. Expansion joints must be provided with temporary restraint, if required for the additional pressure load under test, or they must be isolated from the test.
(d) Isolation of equipment not subjected to pressure test. Equipment that is not to be subjected to the pressure test must be either disconnected from the piping subassembly or system or isolated by a blank flange or similar means. Valves may be used if the valve with its closure is suitable for the proposed test pressure.
(e) Treatment of flanged joints containing blinds. Flanged joints at which blinds are inserted to blank off other equipment during the test need not be tested.
(f) Precautions against test medium expansion. If a pressure test is to be maintained for a period of time and the test medium in the system is subject to thermal expansion, precautions must be taken to avoid excessive pressure. A small relief valve set to 1 1/3 times the test pressure is recommended during the pressure test.
[CGD 73–254, 40 FR 40167, Sept. 2, 1975]
§ 56.97-30 Hydrostatic tests (reproduces 137.4).
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(a) Provision of air vents at high points. Vents must be provided at all high points of the piping subassembly or system in the position in which the test is to be conducted to purge air pockets while the component or system is filling.
(b) Test medium and test temperature. (1) Water will be used for a hydrostatic leak test unless another medium is approved by the Commandant.
(2) The temperature of the test medium will be that of the available source unless otherwise approved by the Commandant upon review of the metallurgical aspects of the piping materials with respect to its brittle fracture properties.
(c) Check of test equipment before applying pressure. The test equipment must be examined before pressure is applied to ensure that it is tight and that all low-pressure filling lines and other items that should not be subjected to the test pressure have been disconnected or isolated by valves or other suitable means.
(d) Examination for leakage after application of pressure. Following the application of the hydrostatic test pressure for a minimum of 10 minutes (see §56.97–30(g)), examination for leakage must be made of all joints, connections and of all regions of high stress, such as regions around openings and thickness-transition sections.
(e) Minimum required hydrostatic test pressure. Except as otherwise permitted in §56.97–30(f) or §56.97–40, piping systems must be subjected to a hydrostatic test pressure that at every point in the system is not less than 1.5 times the maximum allowable working pressure.
(f) Maximum permissible hydrostatic test pressure. (1) When a system is tested hydrostatically, the test pressure must not exceed the maximum test pressure of any component such as vessels, pumps, or valves in the system.
(2) At no time during the hydrostatic test may any part of the piping system be subjected to a stress greater than 90 percent of its yield strength (0.2 percent offset) at test temperature.
(g) Hydrostatic test pressure holding time. The hydrostatic test pressure must be maintained for a minimum total time of 10 minutes and for such additional time as may be necessary to conduct the examination for leakage required by §56.97–30(d).
[CGD 73–254, 40 FR 40167, Sept. 2, 1975]
§ 56.97-35 Pneumatic tests (replaces 137.5).
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(a) General Requirements. When a pneumatic test is performed, it must be conducted in accordance with the requirements of this section.
(b) Test medium and test temperature. (1) The gas used as the test medium must not be flammable.
(2) The temperature of the test medium will be that of the available source unless otherwise approved by the Commandant upon review of the metallurgical aspects of the piping materials with respect to its brittle fracture properties.
(c) Check of test equipment before applying pressure. The test equipment must be examined before pressure isapplied to ensure that it is tight and that all items that should not be subjected to the test pressure have been disconnected or isolated by valves or other suitable means. (continued)