§ 54.01-5 Definitions-(a) Unfired pressure vessel. An unfired pressure vessel is a tank containing gas, vapor, or liquid, or a combination thereof, under pressure, and not exposed to the products of combustion.

(b) Heat exchanger. A heat exchanger is a device usually consisting of a shell and tubes or coils by which heat is transferred from one substance to another.

§ 54.01-10 Plan approval. Manufacturers intending to fabricate unfired pressure vessels, heat exchangers, evaporators and similar appurtenances covered by the regulations in this part, to be installed on vessels subject to inspection by the Coast Guard, shall submit to the Officer in Charge, Marine Inspection, having jurisdiction over the vessel, detail plans in triplicate, which shall be fully descriptive of the pressure parts of such unfired pressure vessels. When due to location of the fabrication shop, such procedure would result in unnecessary delay in transmission, the plans may be forwarded directly to the Commandant (MMT), U. S. Guard, Washington 25, D. C. SUBPART 54.03-DESIGN AND CONSTRUCTION § 54.03-1 Materials. (a) Unfired pressure vessels and appurtenances covered by this part may be fabricated of material conforming to the specifications given in Part 51 of this subchapter and limited to the grades of material listed in table 52.05-10 (a) in Part 52 of this subchapter and table 54.03-10 (c) except as otherwise provided for in this part.

Coast

(b) Steel plate used for pressure parts of unfired pressure vessels may be of Class B material complying with the requirements of Subpart 51.04 or 51.22, except that unfired pressure vessels designed for pressures exceeding 700 pounds per square inch or temperatures exceeding 650° F. shall be constructed of Class A steel plate meeting the requirements of Subpart 51.04.

(c) (1) Arc- or gas-welded pressure vessels over 1 inch in thickness constructed of steel plate complying with Subpart 51.04 of this subchapter for grades C, D, E, F and G shall conform to the requirements for Class I welded pressure vessels.

(2) Where vessels constructed of these grades of steel plate do not exceed 1 inch

in thickness, the requirements for Class II welded pressure vessels shall apply and the vessels shall be stress-relieved as required by § 56.01-70 (h) of this subchapter.

(d) Carbon- and alloy-steel castings shall comply with the grades of material listed in table 52.05-10 (a) in Part 52 of this subchapter. The casting quality factor specified in § 52.05-13 of this subchapter shall be applied to the stresses given in table 52.05-10 (a).

(e) For electric resistance-welded pipe or tubing the stress values in table 52.05-10 (a) in Part 52 of this subchapter shall be substituted in the applicable design formulas for the factor SE.

(f) Unfired pressure vessels may be constructed of cast iron conforming to the applicable specifications of Part 51 of this subchapter under the following conditions:

(1) Cast iron shall not be used in the construction of shells and heads of pressure vessels where subject to steam pressures exceeding 30 pounds per square inch or where subject to gas or liquid pressures exceeding 125 pounds per square inch.

(2) The maximum allowable stress for cast iron as given in table 54.03-1 (f) shall be used in the applicable formula for unfired pressure vessels,

TABLE 54.03-1 (f)-MAXIMUM ALLOWABLE STRESS FOR CAST IRON

(g) Nonferrous materials may be used in the construction of unfired pressure vessels subject to the following conditions:

(1) The grade of material shall be as specified in Part 51 of this subchapter, and as given in table 54.03-10 (c).

(2) The pressure and temperature limitations for nonferrous materials shall be as given in § 55.07-1 (d) of this subchapter.

§ 54.03-5 Workmanship and design. (a) Equipment covered by this part and constructed of plates with riveted or welded joints shall conform to all the

All stresses refer to the annealed condition of the material, unless otherwise speci-
fied. For wrought material, the allowable 8 values are based upon one-fourth of the
minimum tensile strength or two-thirds of the minimum yield strength for tempera-
tures of 150° F. and below, whichever is lower; and upon creep stress or stress-rupture
at the higher temperatures. For cast material, the allowable 8 values are based upon
one-fifth of the minimum tensile strength for temperatures of 150° F and below; and
upon creep stress or stress-rupture at the higher temperatures.

1 The same stress may be employed for a temperature of 406° F. The minimum yield strength employed not included in the specification.

40,000

5,000

For temperatures of 100° F. and below, the following stress values may be used:
M1A, 3,350; GS11A, 4,000; GS11A (T4), 7,500.

The minimum tensile strength employed not included in the specification.
This material approved for tube sheets only.
'These stresses refer to the light drawn condition.
The same stress may be employed for 320° F.

To these stresses a casting quality factor of 80 percent shall be used. This is not
intended to apply to valves and fittings complying with A. 8. A. standards.
This stress is not permitted for temperatures exceeding 366° F.

requirements of Part 52 of this subchapter for such construction, except as provided otherwise in this part.

(b) Flanges cast integral with shells or heads shall have a fillet radius not less than the thickness of the necks to which they are attached.

(c) The corner radius of a cast unstayed dished head measured on the concave side of the head shall be not less than three times the thickness of the head, but in no case less than 6 percent of the outside diameter of the shell.

and

§ 54.03-10 Cylindrical shells heads. (a) The maximum allowable pressure of cylindrical shells and heads of unfired pressure vessels shall be determined by the applicable formulas given in Part 52 of this subchapter, except as provided otherwise in this part.

(b) The minimum thickness of shell plates, heads or dome plates, after flanging, shall be 1⁄2 inch, except that for riveted construction, the minimum thickness shall be 16 inch.

(c) The maximum allowable stresses for nonferrous materials shall be as given in table 54.03-10 (c).

§ 54.03-12 Cast-iron heads. (a) The maximum allowable pressure and minimum thickness of circular cast-iron blank spherically dished heads concave to the pressure shall be calculated by the following formulas:

P= maximum allowable pressure, in pounds per square inch.

T= thickness of dished portion of the head, in inches.

R= radius to which the head is dished measured on the concave side of the head, in inches (not to exceed the inside diameter of the shell to which the head is attached).

S maximum allowable tensile stress, as given in table 54.03-1 (f), in pounds per square inch.

(b) Cast-iron heads of semi-ellipsoidal form in which the inside depth of the head (one-half of the minor axis of the ellipse) is not less than one-quarter of the inside diameter of the shell to which the head is to be attached, shall have a thickness of at least that required for a cast-iron shell of the same diameter.

D= means gasket diameter for flanged attachments, or inside diameter of shell when bolted attachment is not employed, in inches.

(b) The minimum thickness of a fixed tube sheet shall be not less than 3⁄4 inch.

(c) Where tubes are welded or brazed to fixed tube sheets and no expansion joint is employed in the shell construction, consideration may be given by the Commandant to the use of a tube sheet of lesser thickness than required by formula (2) of this section.

(d) Floating tube sheets shall have a thickness not less than that required for a fixed tube sheet.

(e) U-tube tube sheets shall have a thickness of at least one and one-fourth times the thickness required for a fixed tube sheet.

(f) The pitch of tubes attached to tube sheets by expanding shall be not less than that given in table 54.03-15 (f).

TABLE 54.03-15 (1)-MINIMUM PITCH OF TUBES

P= maximum allowable pressure, in pounds per square inch.

S= maximum allowable stress, 80 percent of the values as given in table 52.05-10 (a), or 100 percent of the values as given in table 54.03-10 (c), in pounds per square inch. T= minimum thickness of the tube wall, in inches.

D= external diameter of the tube, in inches.

(b) Additional wall thickness above the minimum required by formula (2) of this section shall be provided as follows:

(1) When tubes act as stays, additional wall thickness shall be provided to carry the external load imposed upon the tubes.

(2) When tubes are expanded into the tube seats, at least one additional B. W. G. thickness shall be provided over a length at least equal to the width of the seat plus 1 inch.

(3) Bent tubes shall have the thickness increased when the radius is less than 5 times the outside diameter of the tube, to compensate for the reduction in wall thickness due to fabrication.

§ 54.03-25 Bolted flanged connections (a) Scope. (1) Bolted flanged

in Part 55 of this subchapter shall be used for connections to external piping and may be used for other flanged connections.

(2) Bolted flanged connections to pressure vessels and special flange designs other than those meeting the requirements of subparagraph (1) of this paragraph shall be designed in accordance with the requirements of this section.

(3) The regulations in this section may be applied to flanges having the gasket entirely within the inner edge of the bolt holes.

(4) This section shall not be construed to prohibit the use of other types of bolted flanged connections, such as flanges using full-face gaskets, or other means to provide effective restraint against flange deflection. Such designs may be used provided the design is acceptable to the Commandant.

(b) Material. (1) For temperatures not exceeding 450° F., commercial carbon-steel bolting material may be used for attaching heads, doors, covers, or flanges. Carbon-steel bolting and nut material shall comply with Subpart 51.49 of this subchapter. Bolting and nuts shall meet the minimum requirements of American Standard Coarse Thread Series. Nuts shall meet the requirements of American Standard Heavy Dimensions as given in Table 54.03-25 (b).

(2) For temperatures exceeding 450° F., high strength or alloy steel bolting and nut material complying with the requirements of Subpart 51.49 of this subchapter shall be employed. Nuts of the

blow classes shall not be used for mperatures exceeding the following: ass 1, 750° F.; classes 2 and 2H, 800° F.; ass 4, 900° F.; and class 3, 1,050° F. ›lting and nuts shall meet the minimum quirements of the American Standard eavy Dimensions and the American tandard Threads for High Strength olting as given in table 54.03-25 (b). 'ashers are not required but when used hall be of forged rolled steel.

[ (3) Studs continuously threaded or olts with the unthreaded portion reuced to the same diameter as that of he root of the thread, shall be employed hen the temperature exceeds 450° F. (4) Bolting shall have a length of read engagement of not less than the ormal thickness dimension of American tandard heavy nuts.

(5) In no case shall the size of a bolt e less than 1⁄2 inch in diameter.

(c) Bolt loads-(1) Operating bolt Dad. The minimum required operating olt load Wm shall be determined by ormula (1) under maximum operating onditions.

'm1=H+H=0.785 GP+ (26x3.14 GmP) (1) NOTE 1: Under maximum operating conitions the minimum required operating olt load Wm1 is the load required to resist he hydrostatic end force H exerted by the aximum internal pressure upon the area ounded by the mean diameter of the gasket, nd, in addition, maintain a compression

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