General provisions for the use of portable tanks for the carriage of refrigerated liquefied gases

This section provides general provisions applicable to the use of portable tanks for the carriage of refrigerated liquefied gases.

Portable tanks shall conform to the design, construction, inspection and testing requirements detailed in 6.7.4. Refrigerated liquefied gases shall be carried in portable tanks conforming to portable tank instruction T75 as described in and the portable tank special provisions assigned to each substance in Column (11) of Table A of Chapter 3.2 and described in

During carriage, portable tanks shall be adequately protected against damage to the shell and service equipment resulting from lateral and longitudinal impact and overturning. If the shell and service equipment are so constructed as to withstand impact or overturning it need not be protected in this way. Examples of such protection are provided in

Unless the name of the gas(es) being carried appears on the metal plate described in, a copy of the certificate specified in shall be made available upon a competent authority request and readily provided by the consignor, consignee or agent, as appropriate.

Empty portable tanks not cleaned and not gas-free shall comply with the same provisions as portable tanks filled with the previous substance.


Prior to filling the portable tank shall be inspected to ensure that it is authorized for the refrigerated liquefied gas to be carried and that the portable tank is not loaded with refrigerated liquefied gases which in contact with the materials of the shell, gaskets, service equipment and any protective linings, are likely to react dangerously with them to form dangerous products or appreciably weaken these materials. During filling, the temperature of the refrigerated liquefied gas shall be within the limits of the design temperature range.

In estimating the initial degree of filling the necessary holding time for the intended journey including any delays which might be encountered shall be taken into consideration. The initial degree of filling of the shell, except as provided for in and, shall be such that if the contents, except helium, were to be raised to a temperature at which the vapour pressure is equal to the maximum allowable working pressure (MAWP) the volume occupied by liquid would not exceed 98%.

Shells intended for the carriage of helium can be filled up to but not above the inlet of the pressure-relief device.

A higher initial degree of filling may be allowed, subject to approval by the competent authority, when the intended duration of carriage is considerably shorter than the holding time.

Actual holding time

The actual holding time shall be calculated for each journey in accordance with a procedure recognized by the competent authority, on the basis of the following:
(a) The reference holding time for the refrigerated liquefied gas to be carried (see (as indicated on the plate referred to in;
(b) The actual filling density;
(c) The actual filling pressure;
(d) The lowest set pressure of the pressure limiting device(s).

The actual holding time shall be marked either on the portable tank itself or on a metal plate firmly secured to the portable tank, in accordance with

Portable tanks shall not be offered for carriage:
(a) In an ullage condition liable to produce an unacceptable hydraulic force due to surge within the shell;
(b) When leaking;
(c) When damaged to such an extent that the integrity of the portable tank or its lifting or securing arrangements may be affected;
(d) Unless the service equipment has been examined and found to be in good working order;
(e) Unless the actual holding time for the refrigerated liquefied gas being carried has been determined in accordance with and the portable tank is marked in accordance with; and
(f) Unless the duration of carriage, after taking into consideration any delays which might be encountered, does not exceed the actual holding time.

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