Summer Backup Power Checklist for Critical Sites

Hot weather is not just a comfort issue. For many organisations, it can become an operational risk.

During periods of high temperature, facilities, estates and operations teams often focus on keeping people safe and buildings usable. That should always be the priority. But there is another important area to consider: whether critical power systems are ready if mains power is disrupted.

The Met Office has warned that high temperatures can affect heat-sensitive systems and equipment, with possible disruption to power and other essential services. For sites that rely on generators, UPS systems, controls, fuel supplies and emergency procedures, summer is a sensible time to review readiness.

This practical checklist is designed to help teams identify common weak points before they become bigger problems.

Why hot weather can create power resilience risks

Backup power is often associated with winter storms, high winds and grid disruption. But summer conditions can create their own challenges.

High temperatures can place additional pressure on electrical equipment, cooling systems, UPS batteries, plant rooms and site infrastructure. At the same time, demand for cooling, ventilation, refrigeration and process equipment may increase.

For critical sites, this raises important questions:

• Will the standby generator start and support the required load?
• Are UPS batteries in good condition?
• Is the plant room or UPS room becoming too warm?
• Is fuel level and fuel quality confirmed?
• Are the right people clear on what happens if mains power is lost?
• Is emergency generator hire or refuelling access planned in advance?

A short check during hot weather can help prevent a much larger issue during an outage.

1. Keep equipment cool

Cooling and ventilation are especially important during periods of hot weather.

Generator rooms, UPS rooms, switchrooms, battery areas, control panels and other plant spaces all need suitable conditions to operate reliably. If airflow is restricted, equipment can run hotter than intended, increasing the risk of alarms, reduced performance or avoidable faults.

Areas to review include:

• Are ventilation grilles clear?
• Are generator room air inlets and outlets unobstructed?
• Are UPS systems operating within suitable room conditions?
• Are battery areas becoming too warm?
• Are filters, louvres or vents blocked by dust, debris or stored items?
• Is any temporary equipment affecting airflow?
• Are alarms or temperature warnings being monitored?

It is also worth checking whether plant rooms have changed over time. Storage, temporary works, added equipment or blocked access routes can all affect airflow and maintenance access.

2. Test backup power readiness

A generator start test is useful, but it does not always prove the full system will perform during a real power failure.

During hot weather, facilities and maintenance teams should review the wider backup power system, including the generator, controls, fuel supply, batteries, transfer equipment and any linked UPS systems.

Generator checks to consider include:

• Latest service date
• Alarm history
• Coolant level and condition
• Oil level
• Starter battery condition
• Battery charger operation
• Control panel status
• Fuel level
• Fuel condition
• Signs of leaks or damage
• Airflow around the set
• Load bank test history
• Automatic Transfer Switch operation
• Remote monitoring or telemetry status

If your site has not recently tested the generator under load, it may be worth arranging a load bank test. This can help confirm how the generator performs under controlled conditions, rather than relying only on a short start-up test.

3. Review UPS systems and batteries

UPS systems are often the first line of defence when power quality drops or mains power is lost. They support critical loads while generators start, stabilise or come online.

However, UPS batteries are affected by age, load and temperature. Warmer environments can reduce battery life and affect confidence in runtime.

UPS checks to consider include:

• Battery age
• Recent battery test results
• UPS load percentage
• Expected runtime
• Room temperature
• Ventilation and cooling
• Alarm history
• Bypass status
• Maintenance history
• Whether critical loads have changed since the system was installed

For many sites, the UPS is treated as a background system until there is a problem. Summer is a useful time to check whether it is still suitable for the current site load and risk profile.

4. Confirm fuel and refuelling access

Fuel is a simple but critical part of backup power resilience.

A generator can only support the site if there is enough usable fuel and a practical way to refuel if the outage continues. This is especially important for sites that support healthcare, water, refrigeration, data, security, manufacturing or other essential operations.

Fuel and access checks to consider include:

• Current fuel level
• Fuel quality
• Tank condition
• Signs of water contamination
• Refuelling access
• Delivery restrictions
• Site opening hours
• Security access
• Out-of-hours contacts
• Safe tanker access
• Local parking or access limitations

For high-risk sites, it is worth confirming the expected run time and whether emergency refuelling arrangements are realistic.

5. Check your emergency response plan

Backup power is not just about equipment. It also depends on people, process and timing.

A useful emergency plan should answer:

• Who receives the alarm?
• Who attends site?
• Who has access?
• Who contacts the service provider?
• Which loads are critical?
• What happens if the generator does not start?
• What happens if the UPS runtime is shorter than expected?
• Is emergency generator hire available?
• Is there a connection point for temporary power?
• Are site drawings and key documents accessible?
• Are contact details up to date?

During periods of hot weather, response times and access can also be affected by travel disruption, staff availability and increased demand across multiple sites. Planning ahead makes a difference.

Summer backup power checklist

Use this quick checklist as a starting point.

Generator

• Service history reviewed
• Alarms checked
• Coolant and oil levels confirmed
• Starter batteries checked
• Fuel level confirmed
• Fuel quality reviewed
• Load bank test history checked
• Automatic Transfer Switch operation reviewed
• Remote monitoring status checked

UPS

• Battery condition reviewed
• Load percentage checked
• Runtime expectations confirmed
• Room temperature checked
• Cooling and ventilation reviewed
• Alarm history checked
• Bypass status reviewed
• Maintenance history confirmed

Site and plant room

• Ventilation routes clear
• Air inlets and outlets unobstructed
• Switchrooms and battery areas checked
• Access routes clear
• Site drawings available
• Emergency contacts updated
• Key staff briefed

Fuel and emergency response

• Fuel level confirmed
• Fuel quality checked
• Refuelling route confirmed
• Out-of-hours access agreed
• Emergency hire requirement reviewed
• Connection point availability checked
• Response procedure understood
• Critical loads identified

When should you arrange a professional review?

A professional review is worth considering if:

• The generator has not been serviced recently
• The UPS battery set is ageing
• The site load has changed
• The generator has not been load bank tested
• The fuel has not been tested
• There are recurring alarms
• The site has no clear emergency procedure
• Temporary generator access has not been planned
• The site supports critical operations, healthcare, water, data, refrigeration, security or life safety systems

In many cases, small remedial actions can reduce risk significantly.

How P&I Group can help

P&I Group supports critical sites across the UK with generator, UPS, hire, service and maintenance solutions.

Our team can support with:

• Generator servicing and maintenance
• UPS servicing and battery testing
• Load bank testing
• Fuel testing, polishing and management
• Emergency generator hire
• Temporary power planning
• Generator connection points
• ATS and control system support
• Site surveys and resilience reviews
• CPD sessions for consultants and engineers

If you are reviewing site readiness during hot weather, our team can help identify practical steps to improve resilience.

Speak to P&I Group

Hot weather can expose weaknesses that have been sitting quietly in the background.

A short review today can help reduce the risk of a much bigger problem later.

Contact P&I Group to discuss generator servicing, UPS testing, emergency power planning or temporary generator hire.

Frequently asked questions