Inspections and tests
The materials of every welded shell with the exception of cylinders, tubes, pressure drums and
cylinders as part of bundles of cylinders which are elements of a battery-vehicle or of a MEGC shall
be tested according to the method described in 6.8.5.
The basic requirements for the test pressure are given in 126.96.36.199.1 to 188.8.131.52.4 and the minimum test
pressures are given in the table of gases and gas mixtures in 184.108.40.206.5.
The first hydraulic pressure test shall be carried out before thermal insulation is placed in position.
When the shell, its fittings, piping and items of equipment have been tested separately, the tank shall
be subjected to a leakproofness test after assembly.
The capacity of each shell intended for the carriage of compressed gases filled by mass, liquefied
gases or dissolved gases shall be determined, under the supervision of an expert approved by the
competent authority, by weighing or volumetric measurement of the quantity of water which fills the
shell; the measurement of shell capacity shall be accurate to within 1%. Determination by a
calculation based on the dimensions of the shell is not permitted. The maximum filling masses
allowed in accordance with packing instruction P200 or P203 in 220.127.116.11 as well as 18.104.22.168.2 and
22.214.171.124.3 shall be prescribed by an approved expert.
Checking of the welds shall be carried out in accordance with the λ=1 requirements of 126.96.36.199.23.
By derogation from the requirements of 188.8.131.52.2, the periodic inspections shall take place:
at least after six years
at least after eight years
of service and thereafter at least every 12 years in the case of tanks intended for the carriage of
refrigerated liquefied gases.
The intermediate inspections according
to 184.108.40.206.3 shall be carried out at least
six years after each periodic inspection.
A leakproofness test or an intermediate inspection
according to 220.127.116.11.3 may be performed, at the request
of the competent authority, between any two successive
In the case of vacuum-insulated tanks, the hydraulic-pressure test and the check of the internal
condition may, with the consent of the approved expert, be replaced by a leakproofness test and
measurement of the vacuum.
If, at the time of periodic inspections, openings have been made in shells intended for the carriage of
refrigerated liquefied gases, the method by which they are hermetically closed before the shells are
returned to service shall be approved by the approved expert and shall ensure the integrity of the shell.
Leakproofness tests of tanks intended for the carriage of gases shall be performed at a pressure of not
- For compressed gases, liquefied gases and dissolved gases: 20% of the test pressure;
- For refrigerated liquefied gases: 90% of the maximum working pressure.
Holding times for tank-containers carrying refrigerated liquefied gases
The reference holding time for tank-containers carrying
refrigerated liquefied gases shall be determined on the
basis of the following:
(a) The effectiveness of the insulation system,
determined in accordance with 18.104.22.168.11;
b) The lowest set pressure of the pressure limiting
(c) The initial filling conditions;
(d) An assumed ambient temperature of 30 °C;
(e) The physical properties of the individual
refrigerated liquefied gas intended to be carried.
The effectiveness of the insulation system (heat influx in
Watts) shall be determined by type testing the tankcontainers.
This test shall consist of either:
(a) A constant pressure test (for example at atmospheric
pressure) during which the loss of refrigerated
liquefied gas is measured over a period of time; or
(b) A closed system test during which the rise in
pressure in the shell is measured over a period of
When performing the constant pressure test, variations
in atmospheric pressure shall be taken into account.
When performing either test corrections shall be made
for any variation of the ambient temperature from the
assumed ambient temperature reference value of 30 °C.
NOTE: ISO 21014:2006 "Cryogenic vessels —
Cryogenic insulation performance" details methods of
determining the insulation performance of cryogenic
vessels and provides a method of calculating the holding
Inspections and tests for battery-vehicles and MEGCs
The elements and items of equipment of each battery-vehicle or MEGC shall be inspected and tested
either together or separately before being put into service for the first time (initial inspection and test).
Thereafter battery-vehicles or MEGCs the elements of which are receptacles shall be inspected at not
more than five-year intervals. Battery-vehicles and MEGCs the elements of which are tanks shall be
inspected according to 22.214.171.124.6. An exceptional inspection and test shall be performed regardless of
the last periodic inspection and test when necessary according to 126.96.36.199.16.
The initial inspection shall include:
- a check of conformity to the approved type;
- a check of the design characteristics;
- an examination of the internal and external conditions;
- a hydraulic pressure test10 at the test pressure indicated on the plate prescribed in 188.8.131.52.10;
- a leakproofness test at the maximum working pressure; and
- a check of satisfactory operation of the equipment.
When the elements and their fittings have been pressure-tested separately, they shall be subjected
together after assembly to a leakproofness test.
10 In special cases and with the agreement of the expert approved by the competent authority, the hydraulic
pressure test may be replaced by a pressure test using another liquid or gas, where such an operation does not present
Cylinders, tubes and pressure drums and cylinders as part of bundles of cylinders shall be tested
according to packing instruction P200 or P203 in 184.108.40.206.
The test pressure of the manifold of the battery-vehicle or MEGC shall be the same as that of the
elements of the battery-vehicle or MEGC. The pressure test of the manifold may be performed as a
hydraulic test or by using another liquid or gas with the agreement of the competent authority or its
authorised body. By derogation from this requirement, the test pressure for the manifold of batteryvehicle
or MEGC shall not be less than 300 bar for UN No. 1001 acetylene, dissolved.