suitable plate affixed to the tank in a location adjacent to the gauging device.

(c) Dip tubes: A fixed length dip tube gauging device, when used, shall consist of a dip pipe of small diameter equipped with a valve at the outer end, and extending into the tank to a specified fixed length. On horizontallymounted cylindrical tanks, the fixed length to which the tube extends into the tank shall be such that the device will function to indicate when the liquid, at a point equidistant from the heads of the tank in a vertical plane containing the longitudinal axis of the tank, reaches the maximum level permitted by Parts 71 to 78 of this chapter. On spherical tanks and on vertically-mounted cylindrical tanks, the fixed length to which the tube extends into the tank shall be such that the device will function to indicate when the liquid at a point on the vertical axis of the tank in its normal position reaches the maximum level permitted by Parts 71 to 78 of this chapter.

[Order 20, 20 F. R. 8115, Oct. 28, 1955]

§ 78.325-21 Anchoring of tank. (a) Adequate hold-down devices shall be provided to anchor each cargo tank in a suitable manner that will not introduce undue concentration of stresses and shall be built to withstand loadings in any direction equal to the weight of the tank and attachments when filled with water. These devices on vehicles with frames shall incorporate turnbuckles of similar positive action devices for drawing the tank down tight on the frame of the motor vehicle.

(b) Stops and anchors: Suitable stops and anchors shall be attached to the motor vehicle and the tank to prevent movement between them due to starting, stopping and turning. These stops or anchors shall be installed so as to be readily accessible for inspection and maintenance except that lagging for lagged tanks is permitted to cover such stops and anchors.

(c) Anchoring integral tanks: Whenever any cargo tank is so designed and constructed that the cargo tank constitutes, in whole or in part, the stress member used in lieu of a frame, then such cargo tanks shall be designed so as to successfully and adequately withstand the stresses thereby imposed in addition to those created by the working pressure. [Order 20, 20 F. R. 8115, Oct. 28, 1955]

§ 78.330 Specification MC 310; cargo tanks. To be mounted on or to form part of tank motor vehicles for the transportation of corrosive liquids.

§ 78.330-1 Scope. (a) This specification is primarily designed to apply to cargo tanks of tank motor vehicles to be used for the transportation of corrosive liquids.

§ 78.330-2 Existing tank motor vehicles continuing in service-(a) Specification tank motor vehicles. Tank motor vehicles used for the transportation of corrosive liquids which shall have been in service prior to June 15, 1940, may be continued in service provided they have been designed and constructed in accordance with the requirements set forth in paragraphs T-117 (a), T-118 (a) and (b), T-120, T-121, T-122, T-123, and T-124, of Regulations for the Transportation of Explosives and Other Dangerous Articles on Public Highways by Motor Truck or Motor Vehicle, approved. adopted, and prescribed by order of this Commission dated November 6, 1934, and vacated on June 15, 1940.

(b) Existing nonspecification tank motor vehicles. Tank motor vehicles used for the transportation of corrosive liquids not meeting the requirements set forth in paragraph (a) of this section, which shall have been in service prior to June 15, 1940, may be continued in service provided they fulfill the requirements set forth under § 78.330-6 and are and can be maintained in safe operating condition, but in any event they shall be equipped with at least the accessories as specified in §§ 78.330-15 to 78.330-17, 78.330-18 (b), and 78.330-19.

§ 78.330-3 New tank motor vehicles. (a) Except as provided in § 78.330-4, every new tank motor vehicle acquired by a motor carrier on or after June 15, 1940, for the transportation of any corrosive liquid shall comply with the requirements of specifications MC 310 or MC 311. A certificate from the manufacturer of the cargo tank, or from a competent testing agency, certifying that each such tank is designed and constructed in accordance with the requirements of either specification, shall be procured, and such certificate shall be retained in the files of the carrier during the time that such tank is employed in the transportation of corrosive liquids by him. In lieu of this certificate, if the

motor carrier himself elects to ascertain if any such tank fulfills the requirements of either specification by his own test, he shall similarly retain the test data.

[Order 12, 18 F. R. 6782, Oct. 27, 1953]

§ 78.330-4 Novel tank motor vehicles, special authorization. (a) The Commission may, upon written request for such authorization by a motor carrier, authorize the use of limited numbers, and for limited times, of new tanks which fail to meet the requirements of this specification. In the event of such request for authorization, the carrier shall furnish those details concerning the design and construction of the tank as seem necessary for the determination of its ability safely to transport corrosive liquids.

§ 78.330-5 Marking of cargo tanks(a) Metal identification plate. On the right side, near the front, and in a place readily accessible for inspection, there shall be on every cargo tank a metal plate. This plate shall be permanently affixed by means of soldering, brazing, welding, or other suitable means; and upon it shall be marked by stamping, embossing, or other means of forming letters into or on the metal of the plate itself in the manner illustrated below, at least the information indicated below. The plate shall not be so painted as to obscure the markings thereon.

Carrier's Serial Number 1
Manufacturer's Name*
Date of Manufacture 2

ICC MC 310*

1 Carriers are not required to number their tanks serially; any designation regularly used by the carrier to identify the tanks may be put in this space.

2 In the event the identity of the tank manufacturer or the date of manufacture is not known and cannot be ascertained, the spaces indicated shall be marked "MAKE UNKNOWN" and/or "DATE OF MANUFACTURE UNKNOWN."

3 Substitute "ICC SPEC-T-118," or "ICC 7.5-S-1," or "NO SPECIFICATION," as appropriate.

Every

(b) Nonspecification tanks. cargo tank not complying with the requirements set forth in § 78.330-2 or with the requirements of §§ 78.330-1 to 78.330-7, incl., shall be tested at least once in every calendar year, and shall successfully fulfill the requirements set forth under § 78.330-7. No two such required tests shall be closer together than 6 months.

(c) Specification tanks. Every cargo tank complying with the requirements set forth in § 78.330-2 (a) or §§ 78.330-1 to 78.330-7 incl. shall be tested at least once in every 5-year period. If tested no oftener than once every 5 years, at least one such test shall be made in the last year of any such 5year period. The time of reckoning of such testing of such cargo tanks shall be from the time of the last test made in accordance with the requirements set forth under § 78.330-7; and if no such tests have ever been made, such tanks shall be tested within 6 months after June 15, 1940.

(d) Novel cargo tank. Every cargo tank which shall have been authorized by this Commission to transport corrosive liquids under the provisions of § 78.330-4 shall be tested under requirements specifically set forth in the terms of such authorization.

(e) Testing following accidents. Every cargo tank capable of suitable repair

following any accident in which a tank motor vehicle may have been involved shall be retested in accordance with the requirements set forth under § 78.330-7 if the cargo tank has itself been damaged in a manner likely to affect the safety of operation of the motor vehicle, or if the damage to the tank motor vehicle is such as to make the safety of the cargo tank uncertain.

(f) Special testing required by the Commission. Upon the showing of probable cause of the necessity for retest, the Commission may, in its discretion, cause any cargo tank to be retested in accordance with the requirements of § 78.330-7 at any time.

§ 78.330-7 Method of testing-(a) Test for leaks; cargo tanks. Every cargo tank shall be tested by completely filling the tank and dome with water or other liquid having a similar viscosity, the temperature of which shall not exceed 100° F. during the test, and applying a pressure of 11⁄2 times designed working pressure but not less than 10 pounds per square inch gauge. The tank must hold the prescribed pressure for at least 10 minutes without leakage or evidence of distress. All closures shall be in place while test is made, and the pressure shall be gauged at the top of tank.

(b) Test for distortion or failure. Every cargo tank shall be tested by the pressures prescribed in paragraph (a) of this section and shall withstand such pressures without undue distortion or other indication of impending failure. If there is undue distortion, or if failure impends or occurs, the cargo tank shall not be returned to service unless a suitable repair is made. The suitability of the repair shall be determined by the same method of test.

§ 78.330-8 Must comply with A. S. M. E. Code. (a) Tanks built under this specification shall be designed and constructed in accordance with and fulfill all requirements of section VIII of the Code for Unfired Pressure Vessels of the American Society of Mechanical Engineers, 1940 edition, which is hereinafter referred to as "the Code."

(b) When divided into compartments. When the interior of the tank is divided into compartments, each compartment shall be designed, constructed, tested, and retested as a separate tank.

§ 78.330-9 Material. (a) As specified in paragraphs U-12, U-13, and U-20 of the A. S. M. E. Code for Unfired Pressure Vessels, 1949 Edition, no revisions. Tanks may be constructed of ferrous materials listed in Table U-2 including the stainless steels or of nickel or nickel alloys as listed in Table U-3 of the Code. Use of other materials listed in Table U-3 may be authorized by the Commission upon submission of satisfactory supporting data.

(b) Lining. Except as provided in paragraph (c) of this section, cargo tanks must be lined and the material used for lining each cargo tank subject to this specification shall be homogeneous, nonporous, imperforate when applied, not less elastic than the metal of the tank proper, and substantially immune to attack by the commodities transported therein. It shall be of substantially uniform thickness, and it shall be directly bonded or attached by other equally satisfactory means. Joints and seams in the lining shall be made by fusing the material together, or by other equally satisfactory means. The interior of the tank shall be free from scale, oxidation, moisture, and all foreign matter during the lining operation.

(c) Conditions under which tanks need not be lined. Tanks need not be lined as provided in paragraphs (b) of this section, if:

(1) the material of the tank is substantially immune to attack by the materials to be transported therein.

(2) the material of the tank is thick enough to withstand 10 years' normal service without being reduced at any point to less thickness than that specified in § 78.330-10 corresponding to its capacity, or

(3) the chemical reaction between the material of the tank and the commodity to be transported therein is such as to allow the tank to be properly passified or neutralized as set forth elsewhere in this appendix; or

(4) for the transportation of hydrofluoric acid of sixty percent (60%) or higher concentration, they be passified in the following or an equally effective method: By filling the tank to not less than ninety percent (90%) of its capacity with hydrofluoric acid of fifty-eight

percent (58%) strength and allowing it to stand at least forty-eight (48) hours at a temperature of eighty degrees Fahrenheit (80° F.), then seven (7) hours at one hundred forty degrees Fahrenheit (140° F.), the internal pressure being maintained at atmospheric pressure the meanwhile.

[15 F. R. 8372, Dec. 2, 1950, as amended by Order 14, 19 F. R. 3265, June 3, 1954]

§ 78.330-10 Thickness of metal. (a) The minimum thickness of metal for cargo tanks shall be as follows:

tests-(a)

§ 78.330-12 Pressure Tanks. Each completed cargo tank shall be tested before being put into transportation service by completely filling the tank and dome with water or other liquid having a similar viscosity, the temperature of which shall not exceed one hundred degrees Fahrenheit (100° F.) during the test, and applying a pressure of one and one-half (12) times the working pressure of the tank (minimum pressure, ten pounds per square inch (10 lbs./sq. in.) gauge). The tank shall be capable of holding the prescribed pressure for at least ten (10) minutes without leakage, evidence of impending failure, or failure. All closures shall be in place while the test is made, and the pressure shall be gauged at the top of the tank.

§ 78.330-13 Marking of cargo tanks by metal plates. (a) Every cargo tank designed and constructed in accordance with this specification shall be marked on a metal plate with the designation "ICC-MC 310" as set forth in § 78.330-5 (a), together with the other markings

therein specified. In addition, the test markings shall be painted on the tank in the manner prescribed in § 78.330-5 (b).

No

§ 78.330-14 Tank outlets-(a) bottom outlets. No tanks, except those used for shipments of sludge acid or alkaline corrosive liquids, may have bottom discharge outlets.

(b) Bottom outlets. Bottom outlets shall be of metal not subject to rapid deterioration by the lading, and each shall be provided with a valve or plug at its upper end and a liquid-tight closure at its lower end. Every such valve or plug shall be such as to insure against unseating due to stresses or shocks incident to transportation.

chambers.

(c) Bottom wash-out Tanks may be equipped with bottom washout chambers. Bottom wash-out chambers shall be of metal not subject to rapid deterioration by the lading and shall be provided with a liquid-tight closure at its lower end. If used for loading or unloading, they shall be equipped with a valve or plug at the upper end.

[15 F. R. 8372, Dec. 2, 1950, as amended by Order 27, 21 F. R. 7611, Oct. 4, 1956]

§ 78.330-15 Venting, gauging, loading, and air inlet devices. (a) When installed, venting, gauging, loading, and air inlet devices, including their valves, shall be provided with adequate means for their secure closure; and means shall also be provided for the closing of pipe connections of valves.

§ 78.330-16 Shear section. (a) There shall be provided between each shut-off valve seat and discharge faucet a shear section which will break under strain, unless the discharge piping is so arranged as to afford equivalent protection, and leave the shut-off valve seat intact in case of accident to the discharge faucet or piping.

§ 78.330-17 Protection of valves. (a) Draw-off valves and fittings of cargo tanks projecting beyond the frame, or if the vehicle be frameless, beyond the shell, at the rear, shall be adequately protected by steel bumpers or other equally effective devices, against collision.

§ 78.330-18 Fixtures, reinforcements, and other attachments not specified. (a) All external attachments to any

cargo tank shall be made of materials specified in "the Code" and constructed and attached as therein specified.

(b) Heater coils. Heater coils, when installed, shall be so constructed that the breaking off of their external connections will not cause leakage of contents of tanks.

§ 78.330-19 Closures for manholes. (a) The manhole cover shall be designed to provide a secure closure of the manhole. All covers, not hinged to the tanks, shall be attached to the outside of the dome by at least 8 inch chain or its equivalent. All joints between manhole covers and their seats shall be made tight against leakage of vapor and liquid by use of gaskets of suitable material not subject to attack by the corrosive liquid to be transported in the tank.

§ 78.331 Specification MC 311; cargo tanks. To be mounted on or to form part of tank motor vehicles for the transportation of corrosive liquids. [Order 12, 18 F. R. 6782, Oct. 27, 1953]

§ 78.331-1 Scope. (a) This specification is primarily designed to apply to cargo tanks of tank motor vehicles to be used for the transportation of corrosive liquids.

[Order 12, 8 F. R. 6782, Oct. 27, 1953]

§ 78.331-2 Existing tank motor vehicles continuing in service-(a) Specification tank motor vehicles. Tank motor vehicles used for the transportation of corrosive liquids which shall have been in service prior to June 15, 1940, may be continued in service provided they have been designed and constructed in accordance with the requirements set forth in paragraphs T-117 (a), T–118 (a) and (b), T-120, T-121, T-122, T-123, and T-124, of Regulations for the Transportation of Explosives and Other Dangerous Articles on Public Highways by Motor Truck or Motor Vehicle, approved, adopted, and prescribed by order of this Commission dated November 6, 1934, and vacated on June 15, 1940.

(1) Tank motor vehicles used for the transportation of corrosive liquids which shall have been in service prior to December 31, 1953, may be continued in service provided they have been designed and constructed in accordance with the requirements of specification MC 310 of

the Regulations for the Transportation of Explosives and Other Dangerous Articles.

(b) Existing nonspecification tank motor vehicles. Tank motor vehicles used for the transportation of corrosive liquids not meeting the requirements set forth in paragraph (a) of this section, which shall have been in service prior to June 15, 1940, may be continued in service provided they fulfill the requirements set forth under § 78.331-6 and are and can be maintained in safe operating condition, but in any event they shall be equipped with at least the accessories as specified in §§ 78.330-15, 78.330-16, 78.330-17, 78.330-18 (b), and 78.330-19 of specification MC 310 or §§ 78.331-11 (d) and (e), 78.331-15 and 78.331-17 of this specification.

(c) Qualification of existing tank motor vehicles which conform to Specification MC 311. Tank motor vehicles used for the transportation of corrosive liquids which shall have been in service prior to December 31, 1953, and which meet all of the construction requirements of this specification may be continued in service provided such cargo tanks are marked ICC MC 311X on the plate required by § 78.331-5.

[Order 12, 18 F. R. 6782, Oct. 27, 1952, as amended by Order 16, 19 F. R. 6275, Sept. 29, 1954]

§ 78.331-3 New tank motor vehicles. (a) Except as provided in § 78.331-4 every new tank motor vehicle acquired by a motor carrier on or after December 31, 1953, for the transportation of any corrosive liquid shall comply with the requirements of specifications MC 311 or MC 310. A certificate from the builder of the cargo tank, or from a competent testing agency, certifying that each such tank is designed and constructed in accordance with the requirements of either specification, shall be procured, and such certificate shall be retained in the files of the carrier during the time that such tank is employed in the transportation of corrosive liquids by him. The certificate shall indicate that the cargo tank has successfully passed the test requirements.

[Order 16, 19 F. R. 6275, Sept. 29, 1954]

§ 78.331-4 Novel tank motor vehicles, special authorization. (a) The Commission may, upon written request for such