In most applications the boards are not exposed to any fire risk or are protected by non-combustible materials e.g. cavity wall insulation, plasterboard linings etc and combustibility is not an issue. PUR and PIR foams are thermoset plastics and which do not melt leading to flaming droplets - this is possible with thermoformed materials such as polystyrene and polyethylene.

Products are available which meet Class 1 surface spread of flame performance when tested to BS 476, Part 7.

In the new Euroclass system where products are classified from Class A (non-combustible) through to Class F (No Performance Determined), PUR and PIR insulation products are able to meet up to and including Class B.

In critical applications such as cavity wall and warm pitched roof insulation the boards are covered by BBA certification which specifically states that the boards will not prejudice the fire performance or contribute towards the development of a fire.

We have a specific PIR board, Powerdeck, that carries FM Approval, Class 1, in approved flat roof details. This equates to a fire performance comparable to that of mineral fibre products.