Choosing a fridge or freezer

Cold chain medicines should be stored in a specialist medicines fridge or freezer. In larger organisations, walk-in cold stores may be used and the principles below for fridges apply equally to cold stores. Domestic fridges and freezers are not recommended for storage of medicines in healthcare settings.

Medicines fridges have fan-assisted cooling and do not have ice compartments or salad drawers, which ensures that the operating temperature is as uniform as possible within the storage compartment. Do not use a laboratory fridge: these are usually designed to operate across a different temperature range (1-10°C).

Freezers may be fan assisted or use direct cooling. Medicines or laboratory freezers that are designed for the temperature range of the medicines to be stored are suitable, for example -15 to -25°C, <-40°C or Ultra Low -60 to -90°C.

Considerations

When choosing a fridge or freezer, consider the quantity of medicines to be stored. Purchase a fridge or freezer that is large enough to fit all the stock and still allow room for air movement. More than one fridge or freezer may be needed, either for space reasons, because they will be used for different purposes, or for contingency. For example, Pharmacy Aseptic units often have a dedicated fridge for chilling down products that have been prepared at room temperature.

Desirable features

The following features may be desirable and are often standard on medicines refrigerators and freezers:

• in-built digital temperature display
• adjustable temperature set point, with controls that are protected from accidental changes
• audible door-open alarm
• audible high and low temperature alarm. Sometimes these can be set by the user
• in-built “wandering” probe for load temperature monitoring
• in-built temperature recording system that can be downloaded, e.g. using a SD card or USB stick. These are especially useful when the fridge or freezer will not be attached to a remote building management system
• glass doors to enable stock to be viewed without the need to open the door. This will protect the stock from temperature fluctuations but may allow the transmission of UV light into the fridge. If the medicines need to be protected from light, select a glass door that has low UV transmission
• door lock. Pass-code locks may be preferable to locks that require keys, which may be misplaced
• for single door fridges and freezers, a door that may be hung with a left or right hinge
• auto-defrost function
• a port for temperature monitoring probes for freezers. This is so that the thermometer or datalogger can sit outside the freezer if it is unable to withstand freezing temperatures itself

Selecting a higher specification fridge or freezer with additional features may reduce on-going costs of monitoring and may reduce the likelihood of temperature excursions with consequent wastage of medicines.

Setting up a fridge or freezer

Installing the fridge or freezer

Refrigerators and freezers should be installed following the manufacturer’s instruction:

• position the fridge or freezer in a location with good air clearance all round and away from heat sources
• adjust the feet so that the door swings closed when left ajar
• there may be a need to allow the coolant to settle before first switching it on
• protect the fridge or freezer from being accidentally turned off. Sometimes it is possible to have a fridge or freezer wired into a spur by an electrician. Alternatively, a warning label or a socket guard could be used
• install any necessary additional temperature monitoring equipment and add the new fridge or freezer to the local temperature monitoring arrangements

Refer to our series of articles on temperature monitoring for further advice.

Getting ready to use the fridge or freezer

Choose a suitable temperature set point by referring to the manual:

• fridges operate between 2 and 8°C so a mid-way set point of 5°C is usually appropriate
• freezers should be set, ensuring that the range is appropriate for the medicines to be stored. Some models may need to be adjusted by a service engineer

Set the upper and lower alarms, if installed.

Depending on the value and the criticality of the medicines, it may be necessary to temperature map the fridge or freezer before use.

Monitor the performance of the fridge or freezer closely for the first few days to ensure that it is performing correctly.

Using a fridge or freezer

Pharmacy fridges rely on the movement of chilled air around the chamber, so it is important not to add so much stock that air movement is impeded. Keep stock away from the interior walls and bottom of the fridge, and off the floor of walk-in cold stores. Small cartons may be packed into a mesh box or tray but avoid the use of solid trays or insulating material such as polystyrene.

Freezers without fans do not rely so much on air movement, but it is still important not to overstock to avoid developing cold and warm spots. When removing or adding stock ensure the door is open for a brief as possible time whilst still permitting good stock rotation.

Fridges and freezers should be included in of “end of shift” checklists: check that the fridge is switched on and that the temperature is within range.

Monitoring a fridge or freezer

All fridges and freezers should be monitored continuously. Refer to our series of articles on temperature monitoring for more information and advice about how to choose a suitable temperature monitoring strategy for your local needs.

It is not always possible to avoid a fridge or freezer going slightly out of range during a working day while stock is being added and removed. Whenever this happens, monitor the temperature closely until it returns back into range. If it doesn’t, follow our guidance on managing temperature excursions.

Fridge care and maintenance

Fridges and freezers must be maintained if they are to continue to be effective.

Fridges

There should be a local programme of cleaning and inspection that includes:

• wipe the door seals and door seal contact points
• check for damage to the door seals
• clean the drain hole
• dust the external condenser coils, if accessible

Freezers

There should be a local programme of cleaning and inspection that includes:

• check for ice build up, especially around the door seals, and defrost if necessary
• check for damage to the door seals
• dust the external condenser coils, if accessible.

The frequency of cleaning should be determined locally and sufficient to keep the fridge or freezer visually clean and free from significant ice build-up at all times.

An annual service and calibration programme should be undertaken by a specialist in refrigeration, and periodic portable appliance testing should be performed in line with organisational policy.

Useful resources

Our quick reference guide produced to support the COVID-19 vaccine programme summarises the key points on how to set up and monitor your fridge.

• Refrigerators for Covid-19 vaccine storage - Quick reference guide 23.12.20 · PDF · 632 KB

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