When a fridge loses power or breaks down, its whole contents are at risk at once, so the guidance expects a plan before the failure: a protected supply, back-up storage, and an alarm that reaches a person when the building is empty. The one thing to remember: keep the door shut and the fridge switched on, and find the last reliable reading before deciding anything.
Why it matters
Why the plan has to come first
Failures rarely arrive at a convenient time, and the loss scales with what is in the fridge. UKHSA's Vaccine Update 338 (May 2023) reported that in 2022 unavoidable cold chain failures, such as power cuts, accounted for half of the value of vaccine wasted (£2.9 million), which is one reason holding less stock matters. The Green Book says to hold no more than two to four weeks' supply, a figure UKHSA's Vaccine Updates repeat (e.g. VU 374, August 2026). For flu vaccines and LAIV, UKHSA still recommends no more than two weeks.
Out of hours is where the damage grows. SPS notes that audible alarms can be missed when nobody is nearby (SPS on alerts), and a Friday evening failure may not be seen until Monday.
What the rules say
What each source asks for
For licence holders the duty to plan is there, even if no law names a power-failure plan. The Human Medicines Regulations 2012, reg 43 makes the GDP guidelines binding on wholesale dealers (43(1)) and requires the premises and equipment needed to maintain product quality (43(3)). EU GDP 3.3.1 asks for defined procedures "if the system fails or breaks down", and MHRA Guidance Note 6 asks applicants for details of "any business contingency plans". For vaccines, the Green Book says back-up facilities should be available if the fridge fails, and UKHSA's incident guidance expects every provider to have a written emergency storage plan for excursions and breakdowns. The Green Book also asks for at least one max/min thermometer that runs independently of mains power, so you can still measure when the power goes.
For medicines generally, SPS says every local temperature policy should include "contingency plans in the event of breakdown of temperature controls" (SPS). For wholesale, the MHRA Inspectorate blog, quoting the Green Guide, expects power-outage alarms on large commercial fridges and walk-in cold rooms, and the HPRA's IA-G0011 asks for out-of-hours alarm response. WHO's Supplement 7 says qualifying a new store should measure holdover time, how long it stays in range after power is lost, to inform emergency planning.
The HTA is most explicit: mortuaries need documented contingency plans for power failure, and hired temporary units should not be the only arrangement (HTA).
What good looks like
Before the failure
Prevention is mostly about the plug. The Green Book asks for a switchless socket or a clearly labelled plug, SPS lists a socket guard or fixed spur (SPS), and CQC's care home guidance also accepts a purpose-made socket cover (CQC).
Detection is the other half. SPS calls networked alerts by SMS, email or telephone "the most robust means of alerting users", because they reach people when nobody is on site. The South West ICARS toolkit adds a fridge check before weekends and bank holidays, and a logger download on the first morning back before any vaccine is given (SW ICARS toolkit). If a supplier hosts your monitoring, the MHRA's data integrity guidance expects business continuity in the contract, tested.
- Fridge leadBeforeIn place now
- Switchless socket, guard or labelled plug
- Back-up fridge or validated cool boxes named in the plan
- Max/min thermometer independent of mains power
- Alerts that reach a person out of hours
- Stock held to two to four weeks
- Whoever finds itWhen it failsFirst minutes
- Keep the door shut
- Leave it switched on, probes undisturbed
- Find the last reliable reading
- Tell the lead and the commissioner or RP
- Lead with pharmacist or RPAfterwardsSame day onwards
- Quarantine stock at +2 °C to +8 °C
- Assess it as an excursion
- Engineer check unless the cause was clearly the power
- Record what happened and review the plan
Drawn from the Green Book, the UKHSA vaccine incident guidance and SPS. Who owns each part is a local decision.
The first minutes of a failure
The Green Book's first instruction is to keep the door closed until you have assessed the situation and made a plan, and to tell the provider or commissioner and the immunisation lead. UKHSA's incident guidance adds: leave the fridge switched on with its probes undisturbed, and discard nothing until the SIT or health protection team has been consulted. Then establish the last reliable reading, the timing and the cause, quarantine the stock and record everything. From there it is an excursion like any other, assessed as set out on Temperature excursions.
Worked example
An illustrative power cut
This is an illustrative example in a community pharmacy whose fridge, when qualified, held its load below 8 °C for a measured 2 hours without power. Tuesday 19:40, after closing, a local power cut takes out the street. The on-call pharmacist gets a power-loss alert, then at 20:25 a high alarm: the fridge air has passed 8 °C, while the buffered load probe still reads 6.1 °C.
The first high alarm starts the plan. The door stays shut while she phones the network operator, who cannot confirm when power will return, and drives in. With no fix confirmed, the plan says move within 30 minutes of the air alarm, well before the load probe could reach 8 °C, so by 20:55 the stock is packed into validated cool boxes and on its way to the partner pharmacy named in the plan, whose spare capacity is agreed in writing. The load probe peaked at 6.8 °C. Power returns at 22:10.
Next morning she writes it up: the logger and cool box data downloaded, showing the air went out of range but the stock stayed within +2 °C to +8 °C throughout, each product checked against that record, and the move logged. The cause was clearly the power, not the fridge, so she records that rather than calling an engineer, and notes how long the load stayed below 8 °C for the next plan review.
Where it is unclear
Where the guidance stops short
Three gaps are worth knowing. The socket rule varies in strength: the Green Book accepts a labelled plug, the 2014 UKHSA protocol says switchless sockets are a must, and Public Health Scotland prefers a fixed spur. Nobody sets an escalation chain for out-of-hours alerts (our recommendation is below), and settings are expected to cover closed periods very differently (weekends and closed periods). And the MHRA's COVID-19 GDP flexibilities have never been formally withdrawn, so confirm with the GDP Inspectorate before relying on them (still live?).
In summary
The short version
- Protect the supply with a switchless socket, guard, fixed spur or labelled plug.
- Name your back-up storage in a written plan: what, where, and who moves the stock.
- Keep a max/min thermometer that works without mains power.
- Make sure an alarm reaches a person when nobody is in, and test it.
- Hold no more stock than you need: the Green Book says two to four weeks.
- When it fails: door shut, fridge on, probes undisturbed, last reliable reading found.
- Then assess it as an excursion, and review the plan.