How do you verify the fire resistance of a PIR sandwich panel roof?

Identify what each report covers: the panel, the roof assembly or a junction with another building element. Give the supplier the thickness, facings, spans and planned openings. These details allow the supplier to check the actual configuration against the documentation.

Reaction to fire describes a product’s behaviour in specified tests. Some PIR panels have a B-s1,d0 classification. The suffixes refer to smoke and flaming droplets or particles under the classification method. This result does not establish the fire resistance of the roof.

Fire resistance can be expressed as REI followed by a time classification. External fire exposure of a roof covering has its own classification, for example B_ROOF(t1). Determine which combination of properties the building design requires and obtain the corresponding evidence for each.

Check the external fire test method as well. The suffixes t1, t2 and t3 identify different methods. They are not successive levels on a single scale. Match the designation in the documentation to the intended use of the roof.

In REI, R denotes loadbearing capacity, E integrity and I insulation under fire exposure. REI 30 is a classification for 30 minutes under specified conditions and within a defined field of application. A common core name does not extend the result to a different roof build-up.

Check the span, load, supports, fixings and direction of fire exposure. Joint construction and facing thickness may also be specified. Where your design differs from the tested assembly, establish whether it falls within the permitted field of application. Check this even if the proposed core is thicker.

Rooflights, hatches, ducts and other penetrations interrupt the panel field. Check their framing, support and seals against details suitable for the roof’s function. A report for an uninterrupted roof area cannot establish the performance of every subsequent opening.

Inspect the junction with any fire-resisting wall. The parapet or a junction at a fire compartment boundary may govern the detail. Inspect the components beneath the external flashing before the installer conceals them.

Include planned rooftop services before ordering panels. Additional equipment can affect loads and access requirements. Coordinate electrical design, supports and cable routes with the fire assessment of the complete installation.

Check proposed brackets, penetrations and rooflight alterations against the design. They may affect weathertightness and the conditions covered by the classification. Document changes after handover so the roof can be assessed in its actual configuration.

At handover, match delivered panels to the approved specification. Inspect fixings, joints and special details. Keep the classification reports and detail drawings together with photographs taken before flashings concealed the connections.

Give the operator inspection instructions and the limits on alterations. Assess damage and new openings before selecting a repair. The fire resistance assessment belongs to the documented, installed system. The appearance of the profiled sheet alone gives no indication of its rating.