CPD 04 2026: Enhancing Fire Safety Knowledge for Roofs and Rooftop Solar

The rapid growth of rooftop solar across the UK has brought with it a fire safety challenge that the industry is still learning to manage. Government-commissioned research published in early 2026 reveals that photovoltaic panels can dramatically alter fire behaviour on rooftops, accelerating flame spread by up to 38 times under certain conditions. A new CPD module, 'Fire Safety for Roofs and Rooftop Solar', aims to equip fire safety professionals with the knowledge to address these risks.

Why rooftop solar changes the fire equation

Solar panels are not inherently dangerous, but their interaction with roofing materials creates fire dynamics that conventional building regulations were not designed to address. Research commissioned by the Building Safety Regulator and conducted at the HSE science and research centre found that PV arrays trap heat between the panel and the roof surface, creating a channel effect that intensifies fire behaviour.

The key findings are stark:

• Heat fluxes beneath PV arrays can reach up to 50 kW/m², far exceeding the 12.5 kW/m² assumed in standard test methods such as BS EN 13501-5

• Flame spread can accelerate by a factor of 38 when the gap between panel and roof falls below critical thresholds

• Plastic-backed panels (Class C) allow significant vertical fire spread up the full length of the array, while glass-backed panels (Class A) contained fire to the first panel

• Building-integrated photovoltaic (BIPV) systems are significantly harder to extinguish because fire becomes trapped in sealed cavities behind waterproof layers

According to insurer QBE, fires involving solar panels saw a 60% increase over the past two years, with UK fire services now tackling a solar panel fire every two days.

The gap height problem

The single most important variable in rooftop solar fire safety is the gap between the underside of the panel and the roof surface. When this gap is too small, heat builds up and re-radiates onto the roof covering, dramatically accelerating fire spread. When the gap is large enough, convective cooling reduces the risk.

The government research identified specific gap heights as critical thresholds, though the exact values depend on panel type, roof pitch, and material classification. Current testing standards, including those referenced in Approved Document B and CEN/TS 1187 Test 4, do not fully capture the unique fire dynamics introduced by PV arrays because they assess roof coverings in isolation, without the panel overhead.

This is one reason the current ADB consultation proposes new fire safety provisions specifically for rooftop PV installations, including enhanced fire performance requirements for products beneath PV arrays and limitations on panel placement near roof openings.

Material classification matters

Not all solar panels behave the same way in a fire. The pitched-roof experiments demonstrated a clear hierarchy:

• Glass-backed panels (Class A): fire did not extend past the first PV panel, with limited flame extension from the ignition area

• Plastic-backed panels (Class C): significant vertical fire spread up the array, reaching the top of the test rig

• Concrete roof tiles provided better fire containment than plastic alternatives

• Plastic roof tiles produced unexpectedly rapid flame spread despite high BS EN 13501-5 classification

Mounting rail positioning also proved significant: aluminium support rails appeared to slow fire spread by forcing flames downward and acting as fire breaks along the edge material.

Fire brigade access and DC isolation

Rooftop solar creates specific operational challenges for firefighters. DC cabling can remain live during a fire even after the mains supply is isolated, and electrical faults may occur near the roof surface. Arcing DC current is difficult to extinguish and can re-ignite roofing materials.

Insurer guidance recommends maintaining clear access routes across the roof and around PV arrays to allow inspection, maintenance, and safe firefighter access. The number and complexity of cable penetrations through the roof build-up can also create pathways for fire to enter and spread within the roof construction.

Clean Energy Associates has conducted over 600 safety audits of rooftop PV installations, revealing that 97% of systems presented safety issues linked to ignition hazards.

What the CPD course covers

The CPD 04 2026 module addresses these issues directly. Sponsored by ROCKWOOL and published through Building magazine, the course covers:

• The regulatory context and functional fire performance requirements for roofs under Approved Document B

• How PV panel materials and installation configurations affect fire behaviour

• The influence of specification decisions on fire risk, including gap heights, panel types, and roof covering classifications

• Fire safety implications when flat roofs are used as amenity spaces with PV installations

• Case studies and practical scenarios drawn from recent UK incidents and experimental data

Who should attend

This course is directly relevant to fire risk assessors, fire engineers, building control officers, facilities managers, and any responsible person involved in the planning, installation, or maintenance of rooftop solar systems. With the ADB consultation proposing specific new provisions for PV installations (targeted for implementation in September 2029), professionals who complete this training will be ahead of the regulatory curve.

Practical takeaways

• Understand how PV panels alter fire dynamics on different roof types and why current test standards may not capture the full risk

• Learn the critical role of gap height, panel material classification (Class A vs Class C), and mounting rail design in fire containment

• Recognise the operational challenges PV systems create for fire services, including DC isolation and restricted roof access

• Apply the latest research findings to fire risk assessments for buildings with existing or planned solar installations

• Prepare for the new ADB provisions on rooftop PV that are expected to come into force in 2029

Sources: GOV.UK — Thermal exposure to roofs from fires involving PV panels, GOV.UK — Fire spread over pitched roofs with solar panels, Building magazine CPD 04 2026, PV Magazine