Glossary

The empty container is stabilized at +18°C and loaded with warm-packs that have been stabilized at the same temperature for a minimum of 24 hours. Warm life is measured from the moment when the container is closed, until the temperature of the coldest point inside the vaccine storage compartment first reaches 0°C at a constant ambient temperature of -20°C.

A coolant-pack typically stabilized at room temperature, up to a recommended maximum of +24°C. Warm water-packs are used for the transport of freeze-sensitive vaccines during exposure to sub-zero ambient temperatures.

A flat, leak proof, plastic container, filled with tap water, complying generally with specification PQS/E005/IP01.

The maximum weight and number of water-packs that can be fully frozen, in one batch, during a 24-hour freezing cycle.

The maximum weight and number of fully frozen water-packs that can remain fully frozen at the end of freezing capacity testing.WHO Collaborating CentreWHO Collaborating Centres are institutions designated by the WHO Director-General to form part of an international collaborative network carrying out activities in support of WHO’s programmes at all levels. 

The worst-case temperature in refrigerators is to be the lowest temperature measured during testing and the worst-case temperature in freezers is to be the highest temperature measured during testing. The reading must refer to a point lying within the zone allocated for the storage of vaccines.