(b) When liquefied inflammable gases are to be transported at their boiling temperatures at or near atmospheric pressure, the Commandant may permit the use of alternate methods of storage if it is shown to his satisfaction that a degree of safety is obtained consistent with the minimum requirements of this part.

(c) The regulations covering the transportation in portable tanks of liquefied inflammable gases are contained in Parts 146 and 147 of Subchapter N (Explosives or Other Dangerous Articles on Board Vessels) of this chapter.

[CGFR 57-8, 22 F. R. 1484, Mar. 8, 1957]

§ 38.01-5 Certificate of inspectionTB/ALL. The certificate of inspection shall be endorsed for the carriage of liquefied inflammable gases as follows: Inspected and approved for the carriage of liquefied inflammable gases having vapor pressures not exceeding pounds per square inch gage at 115° F.

[CGFR 58-10, 23 F. R. 4671, June 26, 1958] SUBPART 38.05-DESIGN AND INSTALLATION OF CARGO TANKS

§ 38.05-1 Design and construction TB/ALL. (a) The cargo tanks shall meet the requirements for Class I or Class II arc welded unfired pressure vessels, and shall be fabricated, inspected and tested in accordance with the applicable requirements of Subchapter F (Marine Engineering) of this chapter, except as otherwise provided for in this part.

(b) Unlagged cargo tanks subject to atmospheric temperatures shall be designed for a pressure not less than the vapor pressure of the gas at 115° F., in pounds per square inch gage, but for not less than 30 pounds per square inch gage.

(c) Where cargo tanks are lagged as required by § 38.05-20, the tanks shall be designed for a pressure of not less than the vapor pressure of the gas at 105° F., in pounds per square inch gage, but for not less than 30 pounds per square inch gage.

(d) Refrigerated cargo tanks, in which the temperature is maintained below the normal atmospheric temperatures, shall be designed for a pressure of not less than the vapor pressure corresponding to the temperature of the liquid at which the system is maintained, plus 25 pounds per square inch gage.

(e) The shell and head thickness of cargo tanks shall be not less than 16 inch.

(f) Each tank shall be provided with not less than a 15-inch by 18-inch or 18inch diameter manhole, fitted with s cover located above the maximum liquid level and as close to the top of the tank as possible. Where access trunks are fitted to the tanks, the diameter of the trunks shall be not less than 30 inches.

CODIFICATION: In § 38.05-1, paragraphs (b). (c) and (e) were amended to read as set forth above by CGFR 57-29, 22 F. R. 4447, June 25, 1957.

(Water capacity, U. S. gallons)

(b) In addition to the markings required by paragraph (a) of this section, the following inscription shall be legibly marked on the tank or a corrosionresistant plate containing this inscription shall be securely attached thereon: This tank shall not contain a product having a vapor pressure in excess of p. s. 1. gage at 115° F.

(c) All tank inlet and outlet connections, except safety relief valves, liquid level gaging devices, and pressure gages, shall be labeled to designate whether they terminate in the vapor or liquid space. Labels of corrosion-resistant material may be attached to valves.

(d) All tank markings shall be permanently and legibly stamped in a readily visible position, and shall not be obscured by painting. If the tanks are lagged the markings attached to the tank proper shall be duplicated on a corrosion-resistant plate secured to the outside jacket of the lagging.

§ 38.05-10 Installation of cargo tanks-TB/ALL. (a) Cargo tanks shall be independent of the hull and shall be so arranged in the barge or vessel as to

provide a minimum clearance of not less than 24 inches on the vessel's side and not less than 15 inches on the vessel's bottom. Where more than one tank is installed in a vessel the distance between such tanks shall be not less than 15 inches unless otherwise approved by the Commandant. Alternate provisions may be made for moving such tanks to provide for adequate inspection and maintenance of the vessel's structure and tanks. See § 38.05-15 for additional requirements applicable only to tank barges.

(b) Tanks may be located in dry cargo holds or in other cargo tanks meeting the requirements for cofferdams, as prescribed in § 32.60-10 or § 32.65-15, and may be installed "on deck" or "under deck" with the tank protruding above deck. On installations where a portion of the tank extends above the weather deck, provision shall be made to maintain the weather tightness of the deck, except that vessels operating under an assigned load line for restricted routes or on protected inland waters may have tanks located in the holds of hopper type barges without the weather tightness of the deck being maintained.

(c) All cargo tanks shall be installed with the manhole openings and fittings located above the weather deck.

(d) Tanks shall be supported in steel saddles and securely anchored in place. Each tank shall be so supported as to prevent the concentration of excessive loads on the supporting portion of the shell. The design shall show the manner in which the tanks are to be installed, supported and secured in the barge or vessel and shall be approved prior to installation.

(e) No strength welding employed in the attachment of supports, lugs, fittings, etc., shall be done on tanks that require and have been stress-relieved unless authorized by the Commandant.

§ 38.05-15 Cargo tanks on bargesB/ALL. Cargo tanks having a capacity of not more than 60,000 gallons may form part of the structure of a tank barge where adequate provision is made to prevent damage to tanks in the event of collision or grounding. Sides of all tank barges shall be fitted with suitable guards as an added precaution against the cargo tanks becoming damaged as a result of collision.

§ 38.05-20 Lagging-TB/ALL. (a) Lagged tanks shall be covered with an incombustible insulation material of a thickness to provide a thermal conductance of not more than 0.075 B. t. u. per square foot per degree Fahrenheit differential in temperature per hour. The insulation material shall be of an approved type complying with the requirements of Subpart 164.009 of Subchapter Q (Specifications) of this chapter, and shall be given a vapor-proof coating with fire-retardant material acceptable to the Commandant. Tanks exposed to the weather shall have the insulation and the vapor-proof coating covered with a removable sheet metal jacket of not less than 0.083 inch thickness and flashed around all openings so as to be weathertight.

§ 38.05-25 Refrigerated systems— TB/ALL. (a) Where refrigerated systems are installed to maintain the temperature of the liquid below atmospheric, at least two complete refrigeration plants automatically regulated by pressure variations within the tanks shall be provided, each to be complete with the necessary auxiliaries for proper operation. The capacity of each refrigeration compressor shall be sufficient to maintain the vapor pressure in the tanks during the peak atmospheric temperature conditions below the pressure for which the tanks are designed.

(b) An alternate arrangement may consist of three compressors, any two of which shall be capable of maintaining the vapor pressure in the tanks during peak atmospheric temperature conditions below the pressure for which the tanks are designed, the third compressor acting as a standby unit.

(c) Refrigerated tanks shall be insulated in conformance with the requirements of § 38.05-20.

SUBPART 38.10-PIPING, VALVES, FITTINGS AND ACCESSORY EQUIPMENT

§ 38.10-1 Valves, fittings and accessories-TB/ALL. (a) All valves, flanges, fittings, and accessory equipment shall be of a type suitable for use with liquefied petroleum gases, and shall be made of steel or Grade A malleable iron conforming to the requirements of Part 51 of Subchapter F (Marine Engineering) of this chapter. All fittings shall be of not less than 300-pound standard, provided that in refrigerated tank systems designed for pressures less than 150

p. s. i., 150-pound standard may be permitted. Welded fittings shall be used wherever possible and the number of pipe joints shall be held to a minimum. Screwed joints in the cargo liquid and vapor lines are prohibited. Unless otherwise indicated herein, the pressure rating of valves, fittings and accessories shall be not less than the maximum pressure for which the tank is designed.

(b) Valve seat material, packing, gaskets, etc. shall be resistant to the action of the liquefied petroleum gas in the liquid phase. All flange and manhole cover gasket material shall be noncombustible and capable of withstanding a temperature of 1,000° F. without failure.

(c) Each tank shall be provided with the necessary fill and discharge liquid and vapor shut-off valves, safety relief valves, liquid level gaging devices, thermometer well and pressure gage, and shall be provided with suitable access for convenient operation. Connections to tanks installed below the weather deck shall be made to a trunk or dome extending above the weather deck. Tanks installed on hopper barges shall have all pipe connections attached to the top of the tanks. Connections to the tanks shall be protected against mechanical damage and tampering. Other openings in the tanks, except as specifically permitted by this subchapter, are prohibited. [Paragraph (c) amended by CGFR 57-29, 22 F. R. 4447, June 25, 1957]

(d) All connections to tanks, except safety relief valves and liquid level gaging devices, shall have manually operated shutoff valves located as close to the tank as possible.

(e) Excess flow valves, where required by this section, shall close automatically at the rated flow of vapor or liquid as specified by the manufacturer. The piping, including valves, fittings and appurtenances protected by an excess flow valve, shall have a greater capacity than the rated flow of the excess flow valve.

(f) Liquid level gaging devices which are so constructed that outward flow of tank contents shall not exceed that passed by a No. 54 drill size opening, need not be equipped with excess flow valves.

(g) Pressure gage connections need not be equipped with excess flow valves if the openings are not larger than No. 54 drill size.

(h) Excess flow valves may be designed with a bypass not to exceed a No. 60 drill size opening to allow equalization of pressure.

(i) Prior to disconnecting shore lines, the pressure in the liquid and vapor lines shall be relieved to the atmosphere through suitable valves installed at the loading header.

(j) Relief valves shall be fitted in liquid lines which may be subject to excessive pressure caused by liquid full condition and the escape from the relief valves shall be piped to the venting system.

(k) A pressure gage shall be located at the highest practicable point. A thermometer well, where fitted, shall terminate in the liquid space and be attached to the shell by welding with the end of the fitting being provided with a gastight screwed plug or bolted cover.

§ 38.10-5 Filling and discharge pipes-TB/ALL. (a) Filling connections shall be provided with one of the following:

(1) A combination back pressure check valve and excess flow valve; or

(2) One double or two single back pressure check valves; or

(3) A positive shut-off valve in conjunction with either an internal back pressure check valve or an internal excess flow valve.

(b) All other liquid and vapor connections to tanks, except filling connections, safety relief valves, liquid level gaging devices and pressure gages described in § 38.10-1, shall be equipped with automatic excess flow valves; or in lieu thereof, may be fitted with quick closing internal stop valves, which, except during filling and discharge operations, shall remain closed. The control mechanism for such valves shall be provided with a secondary remote control of a type acceptable to the Commandant. In addition, such control mechanism shall be equipped with a fusible plug, designed to melt between 208° F. and 220° F., which will cause the internal stop valve to close automatically in case of fire.

(c) The excess flow, internal stop, or back pressure check valves shall be located on the inside of the tank or outside where the piping enters the tank. In the latter case, installation shall be made in such a manner that any undue strain will not cause breakage between the tank

and excess flow, back pressure check, or internal stop valve.

(d) Where the filling and discharge connections are made through a common nozzle at the tank, and the connection is fitted with a quick-closing internal stop valve as required by paragraph (b) of this section, the back pressure check valve or excess flow valve is not required, provided, however, a positive shut-off valve is installed in conjunction with the internal stop valve.

§ 38.10-10 Cargo piping-TB/ALL. (a) All piping, valves, and fittings shall be designed for a working pressure of not less than the vapor pressure of the gas at 115° F., or the maximum pressure to which the system may be subjected. In the case of piping on the discharge side of the liquid pumps or vapor compressors, the design pressure shall be not less than the pump or compressor discharge relief valve setting; or, provided the piping is not fitted with relief valves, the design pressure shall not be less than the total discharge head of the pump or compressor.

(b) Piping subject to tank pressure shall be seamless drawn steel or electric resistance welded steel.

(c) Where necessary, provision shall be made for expansion and contraction of piping by means of seamless steel pipe expansion bends. Suitable means shall be provided for controlling the expansion in the piping system. Special consideration will be given for the use of packless type bellows or corrugated expansion joints. Slip type expansion joints are prohibited.

(d) Piping shall be provided with adequate support to take the weight of the piping off the valves and fittings and to prevent excessive vibration.

§ 38.10-15 Safety relief valves-TB/ ALL. (a) Each tank shall be fitted with one or more safety relief valves designed, constructed and flow-tested for capacity in conformance with Subpart 162.018 of Subchapter Q (Specifications) of this chapter.

(b) Each safety relief valve shall be set to start to discharge at a pressure not in excess of the design pressure of the tank.

(c) (1) The safety relief valves shall have a combined relieving capacity sufficient to prevent a rise of pressure in the tank of more than 20 percent above the maximum allowable pressure when all

Q=minimum required rate of discharge, in cubic feet per minute of standard air at 120 percent of the maximum set pressure of the safety relief valve. Discharge measured at 60° F. and atmospheric pressure (14.7 p. s. 1. a.)

A total external surface area of the tank, in square feet.

=T(DXU) for cylindrical tanks with hemispherical heads,

=rD(U+0.3D), for cylindrical tanks with spherically dished or semi-ellipsoidal heads,

=D3, for spherical tanks.

D=outside diameter of the tank, in feet. U external overall length of the tank, in feet.

(2) The minimum rates of discharge of safety relief valves for lagged tanks insulated in conformance with the requirements of § 38.05-20 need only be 50 percent of the capacity required for uninsulated tanks.

(d) Safety relief valves shall be attached to the tank near the highest point of the vapor space. Shutoff valves shall not be installed between the tanks and safety relief valves, except manifolds for mounting multiple safety relief valves may be fitted with acceptable interlocking shutoff valves so arranged at all times as to permit the required capacity discharge through the open safety relief valves.

(e) Each safety relief valve shall be tested in the presence of an inspector before being placed in service. The tests shall satisfactorily indicate that the safety relief valves will start to discharge at a pressure not in excess of the maximum allowable pressure of the tank.

§ 38.10-20 Liquid level gaging devices-TB/ALL. (a) Each tank shall be fitted with a liquid level gaging device of approved design to indicate the maximum level to which the tank may be filled with liquid at temperatures between 20° F. and 130° F.

(b) Liquid level gaging devices may be of the following types: rotary tube, slip tube, fixed tube, magnetic, automatic float, or similar types approved by the Commandant.

(c) All gaging devices shall be arranged so that the maximum liquid level for butane, mixtures of butane and propane, or propane, to which the tank may be filled is readily determinable. The maximum gallonage capacity as required by § 38.15-1 shall be marked on the tank, system name plate, or gaging device.

(d) Gaging devices that require bleeding of the product to the atmosphere, such as the rotary tube, fixed tube and slip tube, shall be so designed that the bleed valve maximum opening is not larger than a No. 54 drill size, unless provided with excess flow valve.

(e) Automatic float continuous reading tape gages, and similar types, shall be fitted with a shutoff valve located as close to the tank as practicable, which shall be designed to close automatically in the event of fracture of the external gage piping. An automatic float gage shall always be used in conjunction with a fixed tube device.

(f) Gaging devices shall have a design pressure of at least 250 pounds per square inch.

(g) Length of fixed tube device shall be designed to indicate the maximum level to which the tank may be filled. based on the volume of the product at 40° F. at its maximum permitted filling density for unlagged tanks and at 50° F. for lagged tanks. The maximum volume of the liquid at 60° F. may be obtained by determining the volume of the liquid at 40° F. or 50° F. for unlagged or lagged tanks, using the filling densities given in § 38.15-1 and correcting the liquid volumes at these temperatures to 60° F. by applying the volume correction factors in table 38.10-20 (g).

TABLE 38.10-20 (g)-VOLUME CORRECTION FACTORS

(i) Gage glasses of the columnar type are prohibited.

(j) Flat sight glasses may be used in the design of automatic float continuous reading tape gages: Provided, That such glasses shall be made of heat-treated, high strength material of not less than 1⁄2 inch in thickness and adequately protected by a metal cover.

SUBPART 38.15-SPECIAL CARGO HANDLING

REQUIREMENTS

§ 38.15-1 Filling densities-TB/ALL. The "filling density" is defined as the percent ratio of the weight of the gas in a tank to the weight of water the tank will hold at 60° F. The filling densities shall not exceed the ratios indicated in the table 38.15-1.

NOTE: Increase in filling densities to provide for seasonal changes and refrigeration of cargo may be considered by the Commandant upon presentation of factual evidence that safe operation can be effected.

shall be set