Radon Fan Maintenance in UK Schools: Why Servicing Your Sump System Protects Pupils and Staff

Sarah Clarke
4 days ago
11 min read

Author bio: Sarah Clarke is Director and Co-Founder of Radon Protection UK and has extensive experience helping schools, academies, NHS trusts and public-sector estates to measure, mitigate and manage radon. She leads teams delivering radon sump and fan installations, PIV systems, monitoring programmes and ongoing servicing, supporting duty holders with clear reporting and compliant radon management plans.

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. This blog explains your duties and sets out a practical servicing approach you can embed in your estates and health and safety plans.

What are my legal duties around radon in schools?

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. UKradon 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 in schools 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 is a 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 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.

HSE guidance notes that where radon levels have been reduced by engineered systems, re‑measurement periods may need to be “significantly more frequent” than the 10‑year interval that might be acceptable for low‑risk workplaces. For schools that have previously exceeded the action level and now rely on radon sumps and fans, an annual or biannual re‑test of key rooms is a robust, defensible approach.

BRE guidance on radon sumps explains that most sump fans are “sealed for life” and some have run for 20 years continuously, but it also emphasises the importance of checking that the fan is actually working and that radon levels remain low. In a school context, this translates into:

Building radon fan servicing into your planned preventative maintenance (PPM) schedule at least once every 12 months.
Carrying out termly or half‑termly visual and auditory checks (is the fan running, is there air movement at the outlet, are there unusual noises or vibrations?).
Ensuring an RPA or radon specialist reviews radon measurement results and advises on re‑test frequency, especially where IRR17 applies.

What should a radon fan service for a school include?

A school radon fan service should confirm that the sump and fan are mechanically and electrically sound, that the system is moving air as designed, that condensate management and exhaust discharge are correct, and that a clear record links the service to radon test results. This evidence supports your risk assessment, IRR17 duties and Ofsted‑ready compliance files.

A typical service visit from Radon Protection UK for a school sump and fan system will include:

Visual inspection of the external pipework, sump access and fan housing for damage, blockages or corrosion.
Verification that the fan is running continuously, with appropriate air movement at the outlet and no abnormal noise or vibration.
Checks that horizontal pipework slopes back to the sump so condensate drains correctly and does not collect in low points.
Confirmation that the exhaust point is safely located away from windows, doors and air intakes, and at a suitable height above ground level.
Electrical safety checks and confirmation that the fan is correctly fused and labelled, in line with BS 7671 and Building Regulations guidance.
Review of any associated PIV units or under‑floor ventilation fans where they are part of the same mitigation strategy.

What happens if a radon fan fails in term time?

If a radon fan fails in term time, radon levels in the affected block can rise back towards or above the pre‑mitigation level, meaning staff and pupils may again be exposed above the 300 Bq/m³ workplace action level. The school must treat this as a health and safety issue, take interim steps to reduce exposure, arrange urgent repair or replacement, and re‑measure radon to confirm effectiveness, documenting all actions.

In most schools, radon sumps and fans run silently in the background. Without monitoring or alarms, a failed fan can go unnoticed for months, especially if it fails during holidays. UKradon stresses the need to re‑test after any remedial work and to ensure radon levels remain low over time. For a school, that means you should not assume levels are safe just because a system was once commissioned.

If you suspect a fan has failed, you should:

Increase natural ventilation temporarily (opening windows and vents) and, where practicable, relocate activities from the most affected ground‑floor rooms or basements.
Arrange an urgent inspection by a specialist radon contractor to diagnose the fault and repair or replace the fan, pipework or controls.
Consider whether an IRR17 notification to HSE is required, particularly if you know or suspect levels have exceeded 300 Bq/m³ while occupied.
Commission re‑measurement using UKHSA‑validated radon detectors once the system is back in operation, to confirm that levels are back below the workplace action level.

Real‑world school scenarios (anonymised)

Primary school in a radon‑affected area – A rural primary school tested above 300 Bq/m³ in several classrooms and installed a radon sump and fan system. After commissioning, follow‑up testing confirmed levels had dropped well below the action level. The trust now has an annual servicing contract and re‑tests key rooms every two years so governors can evidence that mitigation remains effective.

Secondary school with an unnoticed fan failure – A secondary school in a high‑radon area installed a sump and fan system but had no structured maintenance plan. A later re‑measurement as part of a wider estates project revealed levels had rebounded; investigation showed the fan had failed months earlier. The school had to implement urgent repairs, re‑testing and improvements to its radon management plan to satisfy health and safety auditors.

How can your school prove it is managing radon risk?

radon protection uk ltd testing radon levels

Your school or trust can demonstrate it is managing radon risk by maintaining a written radon risk assessment, test results, mitigation design records, commissioning reports, ongoing radon fan servicing logs and re‑measurement data linked to each building. This documentation shows that governors and senior leaders have identified radon, acted to control it and are checking that controls remain effective in line with HSE and UKradon guidance.

HSE recommends that employers keep records of radon measurements, actions taken and the timing of any re‑measurement, especially in workplaces where mitigation systems are in use. UK radon’s “Radon in schools” campaign materials highlight the expectation that duty holders can show they have considered radon, arranged testing where required and followed up results appropriately.

In practice, this means your school’s radon file (physical or digital) should include:

A radon risk assessment referencing relevant legislation (HSWA 1974, Management Regulations, IRR17 where applicable).
Maps or screenshots showing whether the school lies in a radon‑affected area.
Original test instructions, detector deployment plans and accredited laboratory reports.
Mitigation design drawings and specifications for radon sump and fan systems, PIV units and under‑floor ventilation.
Commissioning records showing pre‑ and post‑mitigation radon levels.
Planned maintenance schedules, service reports and any incident or fault logs for radon fans and pumps.
A clear re‑measurement timetable and evidence that testing is being repeated at appropriate intervals.

Practical radon management for multi‑academy trusts

For multi‑academy trusts, a centralised radon policy and estate‑wide register of tests, mitigation systems and servicing dates is the most efficient way to manage risk. Standardising procedures, suppliers and re‑measurement intervals ensures consistency across schools and enables trustees to evidence compliance collectively.

Trusts with sites in radon‑affected areas should:

Use the UK Health Security Agency’s radon map to identify higher‑risk schools by postcode and prioritise them for testing.
Develop a trust‑wide radon management policy setting out when to test, who is responsible, how mitigation decisions are made and how servicing is scheduled.
Maintain a central register of all sump and fan systems, PIV units and radon monitors, including installation dates, fan models, and service / replacement history.
Align radon fan servicing and re‑measurement with other statutory inspections (e.g. gas safety, electrical testing, fire alarms) to make best use of closures and caretaker time.
Work with a specialist partner such as Radon Protection UK to provide consistent advice, reporting and training for site teams.

Planning radon fan maintenance around the school year

The most practical approach is to schedule intrusive radon sump and fan servicing during school holidays or inset days, while building in quick visual checks during term time. By aligning servicing with your financial year and other compliance tasks, you can minimise disruption, manage costs and still show that radon mitigation is being actively maintained.

Many schools schedule initial radon testing and any remedial works in the autumn and spring terms, when buildings are closed overnight and heating patterns are typical. Once systems are in place, summer or Easter holidays are ideal for more extensive fan replacements, pipework modifications or additional PIV installations.

Short, planned term‑time visits can then focus on low‑disruption checks, such as confirming fans are running, logging readings from any installed radon monitors and reviewing the condition of external pipework and fixings. For MATs, grouping servicing by region can also deliver economies of scale and support consistent standards across schools.

Why partner with Radon Protection UK for school radon servicing?

Radon Protection UK specialises in radon testing, mitigation and ongoing servicing for schools, academies and public‑sector estates. By partnering with a specialist, your school gains access to experienced engineers, RPA advice, clear reporting and proactive maintenance plans that keep radon levels low and give governors, trustees and Ofsted confidence that risks are being managed.

Radon Protection UK works across England, Wales, Scotland and Northern Ireland, supporting schools in both radon‑affected regions and lower‑risk areas that still require risk assessment and reassurance testing. Typical services for education settings include:

Radon risk assessment and estate‑wide screening programmes.
Radon testing in schools using UKHSA‑validated detectors and clear, school‑friendly reporting.
Design and installation of radon sump and fan systems, pumps, under‑floor ventilation and PIV systems tailored to existing buildings.
Commissioning and re‑testing to demonstrate reductions below the workplace action level of 300 Bq/m³.
Planned radon fan maintenance in schools, including annual servicing, call‑outs and replacement planning.
Ongoing monitoring strategies, including integration of digital radon monitors in higher‑risk areas where appropriate.

By embedding radon fan maintenance in your broader health and safety and estates strategies, and by working with a dedicated radon specialist, your school can move from one‑off projects to a confident, long‑term approach that protects pupils, staff and visitors.

FAQs: radon fans and UK schools

Do all UK schools need to test for radon?

All schools must consider radon in their health and safety risk assessment, but testing is prioritised for buildings in radon‑affected areas and for schools with occupied basements. HSE and UKradon advise that duty holders should check the UK radon map and, where radon is an identified hazard, carry out three‑month measurements using validated detectors.

What happens if our school’s radon fan stops working?

If a radon fan stops working, radon levels can rise back towards or above the pre‑mitigation level, potentially exceeding the 300 Bq/m³ workplace action level again. You should treat this as a maintenance incident, increase natural ventilation where possible, arrange urgent inspection and repair, and re‑test with validated detectors to confirm levels are back under control.

How often should we retest radon levels after installing a sump and fan?

After installing a sump and fan, you should re‑measure radon to confirm the system is effective and then repeat measurements at intervals informed by risk and previous results. HSE suggests more frequent re‑measurement where engineered controls are used; for many schools, an annual or biannual re‑test of key rooms is a defensible standard.

What is the legal radon action level for schools in the UK?

For schools as workplaces, the key threshold is the workplace action level of 300 Bq/m³ as an annual average, above which IRR17 applies and employers must take action to reduce exposure. Below 300 Bq/m³, you should still document your assessment and decide when to review or repeat testing.

What are the legal consequences if our school ignores high radon levels?

If a school fails to act on known high radon levels, it may be in breach of the Health and Safety at Work etc. Act 1974, the Management Regulations and, where 300 Bq/m³ is exceeded, IRR17. HSE and local authorities can issue improvement or prohibition notices and, in serious cases, pursue prosecutions and fines for failing to protect staff and pupils.

Key official sources and citations

HSE – Radon in the workplace: workplace action level and re‑measurement guidance: https://www.hse.gov.uk/radiation/ionising/radon.htm
HSE – Notification of work with ionising radiation (including radon above 300 Bq/m³): https://www.hse.gov.uk/radiation/ionising/notification.htm
UKradon – Responsibilities to employees and radon hazard information: https://www.ukradon.org/information/hands
UKradon – Radon in schools awareness and measurement campaign (PDF): "Radon in schools – Raising awareness of a natural radioactive gas in your buildings"
BRE / UKradon – Radon sump and fan design and maintenance guidance (Good Repair Guides and BRE radon remedial measures)