V8

(1) Substances stabilized by temperature control shall be forwarded in such manner that the

control temperatures indicated in 2.2.41.1.17 and 2.2.41.4 or in 2.2.52.1.16 and

2.2.52.4, as appropriate, are never exceeded.

(2) The means of temperature control chosen for the transport operation depends on a

number of factors such as:

- the control temperature(s) of the substance(s) to be carried;

- the difference between the control temperature and the expected ambient

temperature;

- the effectiveness of the thermal insulation;

- the duration of the transport operation; and

- the safety margin to be allowed for delays en route.

(3) Suitable methods to prevent the control temperature from being exceeded are listed

below, in ascending order of effectiveness:

R1 Thermal insulation, provided that the initial temperature of the substance(s) is

sufficiently below the control temperature;

R2 Thermal insulation and coolant system, provided that:

- an adequate quantity of non-flammable coolant (e.g. liquid nitrogen or

solid carbon dioxide), allowing a reasonable margin for possible delay, is

carried or a means of replenishment is assured;

- liquid oxygen or air is not used as coolant;

- there is a uniform cooling effect even when most of the coolant has been

consumed; and

- the need to ventilate the transport unit before entering is clearly indicated

by a warning on the door(s);

R3 Thermal insulation and single mechanical refrigeration, provided that for

substances with a flash-point lower than the sum of the emergency temperature

plus 5 °C explosionproof

electrical fittings, EEx IIB T3, are used within the

cooling compartment to prevent ignition of flammable vapours from the

substances;

R4 Thermal insulation and combined mechanical refrigeration system and coolant

system, provided that:

- the two systems are independent of one another; and

- the requirements of methods R2 and R3 above are met;

R5 Thermal insulation and dual mechanical refrigeration system, provided that:

- apart from the integral power supply unit, the two systems are

independent of one another;

- each system alone is capable of maintaining adequate temperature

control; and

- for substances with a flash-point lower than the sum of the emergency

temperature plus 5 °C explosionproof

electrical fittings, EEx IIB T3, are

used within the cooling compartment to prevent ignition of flammable

vapours from the substances.

(4) Methods R4 and R5 may be used for all organic peroxides and self-reactive substances

and polymerizing substances.

Method R3 may be used for organic peroxides and self-reactive substances of Types C,

D, E and F and, when the maximum ambient temperature to be expected during carriage

does not exceed the control temperature by more than 10 °C, for organic peroxides and

self-reactive substances of Type B and polymerizing substances.

Method R2 may be used for organic peroxides and self-reactive substances of Types C,

D, E and F and polymerizing substances when the maximum ambient temperature to be

expected during carriage does not exceed the control temperature by more than 30 °C.

Method R1 may be used for organic peroxides and self-reactive substances of Types C,

D, E and F and polymerizing substances when the maximum ambient temperature to be

expected during carriage is at least 10 °C below the control temperature.

(5) Where substances are required to be carried in insulated, refrigerated or mechanicallyrefrigerated

vehicles or containers, these vehicles or containers shall satisfy the

requirements of Chapter 9.6.

(6) If substances are contained in protective packagings filled with a coolant, they shall be

loaded in closed or sheeted vehicles or closed or sheeted containers. If the vehicles or

containers used are closed they shall be adequately ventilated. Sheeted vehicles and

containers shall be fitted with sideboards and a tailboard. The sheets of these vehicles

and containers shall be of an impermeable and non-combustible material.

(7) Any control and temperature sensing devices in the refrigeration system shall be readily

accessible and all electrical connections shall be weatherproof. The temperature of the

air inside the transport unit shall be measured by two independent sensors and the

output shall be recorded so that any change in temperature is readily detectable. When

substances having a control temperature of less than +25 °C are carried, the transport

unit shall be equipped with visible and audible alarms, powered independently of the

refrigeration system and set to operate at or below the control temperature.

(8) A back-up refrigeration system or spare parts shall be available.

NOTE: This provision V8 does not apply to substances referred to in 3.1.2.6 when substances

are stabilized by the addition of chemical inhibitors such that the SADT is greater than 50 °C.

In this latter case, temperature control may be required under conditions of carriage where the

temperature may exceed 55 °C.