Service equipment shall be so arranged as to be protected against the risk of being wrenched off or
damaged during handling and carriage. When the connection between the frame and the tank or the
jacket and the shell allows relative movement, the equipment shall be so fastened as to permit such
movement without risk of damage to working parts. The external discharge fittings (pipe sockets,
shut-off devices), the stop-valve and its seating shall be protected against the danger of being
wrenched off by external forces (for example using shear sections). The filling and discharge devices
(including flanges or threaded plugs) and any protective caps shall be capable of being secured against
Each filling and discharge opening in portable tanks used for the carriage of flammable refrigerated
liquefied gases shall be fitted with at least three mutually independent shut-off devices in series, the
first being a stop-valve situated as close as reasonably practicable to the jacket, the second being a
stop-valve and the third being a blank flange or equivalent device. The shut-off device closest to the
jacket shall be a quick closing device, which closes automatically in the event of unintended
movement of the portable tank during filling or discharge or fire engulfment. This device shall also be
possible to operate by remote control.
Each filling and discharge opening in portable tanks used for the carriage of non-flammable
refrigerated liquefied gases shall be fitted with at least two mutually independent shut-off devices in
series, the first being a stop-valve situated as close as reasonably practicable to the jacket, the second a
blank flange or equivalent device.
For sections of piping which can be closed at both ends and where liquid product can be trapped, a
method of automatic pressure relief shall be provided to prevent excess pressure build-up within the
Vacuum insulated tanks need not have an opening for inspection.
External fittings shall be grouped together so far as reasonably practicable.
Each connection on a portable tank shall be clearly marked to indicate its function.
Each stop-valve or other means of closure shall be designed and constructed to a rated pressure not
less than the MAWP of the shell taking into account the temperature expected during carriage. All
stop-valves with a screwed spindle shall be closed by a clockwise motion of the handwheel. In the
case of other stop-valves the position (open and closed) and direction of closure shall be clearly
indicated. All stop-valves shall be designed to prevent unintentional opening.
When pressure-building units are used, the liquid and vapour connections to that unit shall be
provided with a valve as close to the jacket as reasonably practicable to prevent the loss of contents in
case of damage to the pressure-building unit.
Piping 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 a suitable material.
To prevent leakage due to fire, only steel piping and welded joints shall be used between the jacket
and the connection to the first closure of any outlet. The method of attaching the closure to this
connection shall be to the satisfaction of the competent authority or its authorized body. Elsewhere
pipe joints shall be welded when necessary.
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 525 °C. The joints shall not decrease the strength of the
tubing as may happen when cutting threads.
The materials of construction of valves and accessories shall have satisfactory properties at the lowest
operating temperature of the portable tank.
The burst pressure of all piping and pipe fittings shall be not less than the highest of four times the
MAWP of the shell or four times the pressure to which it may be subjected in service by the action of
a pump or other device (except pressure-relief devices).