All portable tanks intended for the carriage of flammable liquids shall be closed and be fitted with relief devices in accordance with 18.104.22.168 to 22.214.171.124.
For portable tanks intended for use only on land, open venting systems may be used if allowed according to Chapter 4.3.
NOTE: For Class 4.1 self-reactive substances, see 126.96.36.199.1.
Each substance shall have been tested and a report submitted to the competent authority of the country of origin for approval. Notification thereof shall be sent to the competent authority of the country of destination. The notification shall contain relevant transport information and the report with test results. The tests undertaken shall include those necessary:
(a) To prove the compatibility of all materials normally in contact with the substance during carriage;
(b) To provide data for the design of the pressure and emergency relief devices taking into account the design characteristics of the portable tank.
Any additional provision necessary for safe carriage of the substance shall be clearly described in the report.
The following provisions apply to portable tanks intended for the carriage of Type F organic peroxides or Type F self-reactive substances with a Self-Accelerating Decomposition Temperature (SADT) of 55 °C or more. In case of conflict these provisions prevail over those specified in Section 6.7.2. Emergencies to be taken into account are self-accelerating decomposition of the substance and fire-engulfment as described in 188.8.131.52.8.
The additional provisions for carriage of organic peroxides or self-reactive substances with a SADT less than 55 °C in portable tanks shall be specified by the competent authority of the country of origin. Notification thereof shall be sent to the competent authority of the country of destination.
The portable tank shall be designed for a test pressure of at least 0.4 MPa (4 bar).
Portable tanks shall be fitted with temperature sensing devices.
Portable tanks shall be fitted with pressure-relief devices and emergency-relief devices. Vacuum-relief devices may also be used. Pressure-relief devices shall operate at pressures determined according to both the properties of the substance and the construction characteristics of the portable tank. Fusible elements are not allowed in the shell.
The pressure-relief devices shall consist of spring-loaded valves fitted to prevent significant build-up within the portable tank of the decomposition products and vapours released at a temperature of 50 °C. The capacity and start-to-discharge pressure of the relief valves shall be based on the results of the tests specified in 184.108.40.206.1. The start-to-discharge pressure shall, however, in no case be such that liquid would escape from the valve(s) if the portable tank were overturned.
The emergency-relief devices may be of the spring-loaded or frangible types, or a combination of the two, designed to vent all the decomposition products and vapours evolved during a period of not less than one hour of complete fire-engulfment as calculated by the following formula:
q = heat absorption [W]
A = wetted area [m2]
F = insulation factor
= 1 for non-insulated shells, or
for insulated shells
K = heat conductivity of insulation layer [W. m-1. K-1]
L = thickness of insulation layer [m]
U = K/L = heat transfer coefficient of the insulation [W. m-2. K-1]
T =temperature of the substance at relieving conditions [K]
The start-to-discharge pressure of the emergency-relief device(s) shall be higher than that specified in 220.127.116.11.7 and based on the results of the tests referred to in 18.104.22.168.1. The emergency-relief devices shall be dimensioned in such a way that the maximum pressure in the portable tank never exceeds the test pressure of the tank.
NOTE: An example of a method to determine the size of emergency-relief devices is given in Appendix 5 of the "Manual of Tests and Criteria".
For insulated portable tanks the capacity and setting of emergency-relief device(s) shall be determined assuming a loss of insulation from 1% of the surface area.