The burial compartment has isothermal insulation such that the overall coefficient of heat transmission is no more than 0.7 watts per square metre per degree Kelvin.
For an ambient temperature of 30° C, the burial compartment’s cooling system must enable an internal temperature of between 0° C and 7° C to be reached in no more than one hour, and then maintained between these values for at least nine hours.
Any installation of a device for producing cold by evaporation or sublimation of a refrigerant in the burial compartment is prohibited. Vehicles put into service before 1 November 1994 may nevertheless retain such devices until 1 September 2000, provided that the vehicle has undergone a compliance inspection under the conditions set out in article D. 2223-114.
When cold production is provided by a mechanical unit mounted in the body of the vehicle, the cooling of the condenser is designed to prevent the intake of air that has already circulated in the compartment or of exhaust gases and to ensure that the hot air is evacuated outside the vehicle.
The interior temperature of the burial compartment is permanently measured by a thermometer, the probe of which is placed in the evaporator suction system and the display of which is prominently installed on the outside of the compartment.