Why radon fan maintenance in schools matters:

Radon fan maintenance in schools is not just a technical task – it is central to how you safeguard pupils and staff and demonstrate legal compliance as an employer. Radon sumps, fans, pumps and PIV systems only keep radon low if they are working correctly and are regularly serviced, monitored and documented.

Radon is a naturally occurring radioactive gas that seeps into buildings from the ground and can accumulate to harmful levels, especially in radon-affected areas such as parts of the South West, Midlands and Wales. In the UK, the workplace action level is an annual average of 300 Bq/m³ (becquerels per cubic metre); above this, additional legal duties apply under the Ionising Radiations Regulations 2017 (IRR17).

For schools, this means radon is both a safeguarding and compliance issue. Your radon mitigation system – typically a radon sump and fan system,

sometimes supported by under-floor ventilation or positive input ventilation (PIV) – must be properly maintained throughout its life.

As an employer, your school or trust must assess and manage radon as a workplace hazard under the Health and Safety at Work etc. Act 1974 and the Management of Health and Safety at Work Regulations 1999. Where annual average radon levels exceed 300 Bq/m³, IRR17 applies and you must take action to reduce exposure, usually via engineered radon mitigation systems that are properly maintained and periodically re-measured.

Schools are workplaces, so the same health and safety law that applies to offices and factories also applies to classrooms, nurseries, sports halls and staff areas. You must carry out a suitable and sufficient risk assessment, and if radon is an identified hazard – for example because the school is in a radon-affected area or has occupied basements – you must test and manage the risk.

HSE guidance on radon in workplaces confirms that 300 Bq/m³ is the workplace action level. Above this, IRR17 is triggered and you must both notify HSE and implement measures to restrict exposure, such as installing radon sumps and fans or altering occupancy.

UK radon also highlights that duty holders in schools must ensure no individual is exposed to high levels of radon and promotes a national “Radon in schools” awareness and measurement campaign. Importantly, the duty is ongoing. Once you install a radon sump and fan system, you must keep it in efficient working order and verify that it continues to maintain radon below the action level through re-measurement at suitable intervals.

How do radon sump and fan systems protect pupils and staff?

A radon sump and fan system works by drawing radon-laden air from beneath the school building and safely exhausting it above roof level, preventing the gas from entering occupied rooms. In many UK schools that have tested above the workplace action level, such engineered radon mitigation systems are the standard, proven method for reducing radon levels for pupils and staff when correctly designed, installed and maintained. Radon is invisible, odourless and tasteless, so you will not know it is present without testing. In radon-affected areas, or where you have ground-contact rooms or basements that are regularly occupied, the only reliable way to assess risk is to place approved radon detectors for at least three months and analyse the annual average concentration.

Where results show radon above 300 Bq/m³, the usual engineering solution isa radon mitigation system such as a sub-slab depressurisation or radon sump and fan system. A sump is a small void created beneath the floor slab, connected by pipework to an externally mounted radon fan that runs continuously; the fan creates negative pressure in the soil under the building, intercepting radon before it enters classrooms and staff areas. Other measures can include under-floor ventilation and positive input ventilation (PIV) systems that dilute indoor radon by supplying filtered air from outside or from higher parts of the building. In practice, many schools use a combination of radon sumps, fans, pumps and PIV units, tailored to the layout and radon levels in different blocks and wings.

How often should a school service its radon fan and sump system?

As good practice, UK schools should arrange at least an annual service of each radon sump and fan system, alongside routine visual checks and radon re-measurement at intervals informed by HSE guidance and previous results. Even though radon fans are typically sealed-for-life units, their performance can degrade over time, so proactive servicing and clear records are essential to demonstrate that mitigation remains effective and compliant. To test or book a Service for your school, contact Radon Protection UK on 0800 978 8435.