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 184.108.40.206.3 and 220.127.116.11.4, 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
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 18.104.22.168.8.1) (as
indicated on the plate referred to in 22.214.171.124.1);
(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 126.96.36.199.2.
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
(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 188.8.131.52 and the portable tank is marked in accordance
with 184.108.40.206.2; and
(f) Unless the duration of carriage, after taking into consideration any delays which might be
encountered, does not exceed the actual holding time.
Forklift pockets of portable tanks shall be closed off when the tank is filled. This provision does not
apply to portable tanks which according to 220.127.116.11.4, need not be provided with a means of closing
off the forklift pockets.
General provisions for the use of UN multiple-element gas containers (MEGCs)
This section provides general requirements applicable to the use of multiple-element gas containers
(MEGCs) for the carriage of non-refrigerated gases referred to in 6.7.5.
MEGCs shall conform to the design, construction, inspection and testing requirements detailed in
6.7.5. The elements of MEGCs shall be periodically inspected according to the provisions set out in
packing instruction P200 of 18.104.22.168 and in 22.214.171.124.
During carriage, MEGCs shall be protected against damage to the elements and service equipment
resulting from lateral and longitudinal impact and overturning. If the elements and service equipment
are so constructed as to withstand impact or overturning, they need not be protected in this way.
Examples of such protection are given in 126.96.36.199.4.
The periodic testing and inspection requirements for MEGCs are specified in 188.8.131.52. MEGCs or
their elements shall not be charged or filled after they become due for periodic inspection but may be
carried after the expiry of the time limit.