Thermal insulation

If tanks intended for the carriage of liquefied gases are equipped with thermal insulation, such
insulation shall consist of either:
- a sun shield covering not less than the upper third but not more than the upper half of the tank
surface and separated from the shell by an air space at least 4 cm across; or
- a complete cladding, of adequate thickness, of insulating materials.

Tanks intended for the carriage of refrigerated liquefied gases shall be thermally insulated. Thermal
insulation shall be ensured by means of a continuous sheathing. If the space between the shell and the
sheathing is under vacuum (vacuum insulation), the protective sheathing shall be so designed as to
withstand without deformation an external pressure of at least 100 kPa (1 bar) (gauge pressure). By
derogation from the definition of "calculation pressure" in 1.2.1, external and internal reinforcing
devices may be taken into account in the calculations. If the sheathing is so closed as to be gas-tight, a
device shall be provided to prevent any dangerous pressure from developing in the insulating layer in
the event of inadequate gas-tightness of the shell or of its items of equipment. The device shall prevent
the infiltration of moisture into the heat-insulating sheath. For type testing of the effectiveness of the
insulation system, see

Tanks intended for the carriage of liquefied gases having a boiling point below -182° C at atmospheric
pressure shall not include any combustible material either in the thermal insulation or in the means of
The means of attachment for vacuum insulated tanks may, with the approval of the competent
authority, contain plastics substances between the shell and the sheathing.

By derogation from the requirements of shells intended for the carriage of refrigerated
liquefied gases need not have an inspection opening.

Items of equipment for battery-vehicles and MEGCs

Service and structural equipment shall be configured or designed to prevent damage that could result
in the release of the pressure receptacle contents during normal conditions of handling and carriage.
When the connection between the frame of the battery-vehicle or MEGC and the elements allows
relative movement between the sub-assemblies, the equipment shall be so fastened as to permit such
movement without damage to working parts. Manifold piping leading to shut-off valves shall be
sufficiently flexible to protect the valves and the piping from shearing, or releasing the pressure
receptacle contents. The filling and discharge devices (including flanges or threaded plugs) and any
protective caps shall be capable of being secured against unintended opening.

In order to avoid any loss of content in the event of damage, the manifolds, the discharge fittings (pipe
sockets, shut-off devices), and the stop-valves shall be protected or arranged from being wrenched off
by external forces or designed to withstand them.

The manifold shall be designed for service in a temperature range of -20° C to +50° C.
The manifold shall be designed, constructed and installed so as to avoid the risk of damage due to
thermal expansion and contraction, mechanical shock and vibration. All piping shall be of suitable
metallic material. Welded pipe joints shall be used wherever possible.
Joints in copper tubing shall be brazed or have an equally strong metal union. The melting point of
brazing materials shall be no lower than 525ºC. The joints shall not decrease the strength of tubing as
may happen when cutting threads.

Except for UN No.1001 acetylene, dissolved, the permissible maximum stress σ of the manifolding
arrangement at the test pressure of the receptacles shall not exceed 75% of the guaranteed yield
strength of the material.
The necessary wall thickness of the manifolding arrangement for the carriage of UN No.1001
acetylene, dissolved shall be calculated according to an approved code of practice.
NOTE: For the yield strength, see
The basic requirements of this paragraph shall be deemed to have been complied with if the following
standards are applied: (Reserved).

By derogation from the requirements of, and, for cylinders, tubes,
pressure drums and bundles of cylinders (frames) forming a battery-vehicle or MEGC, the required
closing devices may be provided for within the manifolding arrangement.

If one of the elements is equipped with a safety valve and shut-off devices are provided between the
elements, every element shall be so equipped.

The filling and discharge devices may be affixed to a manifold.

Each element, including each individual cylinder of a bundle, intended for the carriage of toxic gases,
shall be capable of being isolated by a shut-off valve.

Battery-vehicles or MEGCs intended for the carriage of toxic gases shall not have safety valves,
unless the safety valves are preceded by a bursting disc. In the latter case, the arrangement of the
bursting disc and safety valve shall be satisfactory to the competent authority.

When battery-vehicles or MEGCs are intended for carriage by sea, the requirements of
shall not prohibit the fitting of safety valves conforming to the IMDG Code.

Receptacles which are elements of a battery-vehicle or MEGC intended for the carriage of flammable
gases shall be combined in groups of not more than 5 000 litres which are capable of being isolated by
a shut-off valve.
Each element of a battery-vehicle or MEGC intended for the carriage of flammable gases, when
consisting of tanks conforming to this Chapter, shall be capable of being isolated by a shut-off valve.
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