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Powdertech Wood Finish achieves an excellent fire rating

Richard Besant, Director, Powdertech Corby describes how building products are tested for fire rating.

Fire safety protection begins by using materials that comply with specified tests for fire resistance from the outset. Materials used in construction must conform to strict standards laid down for an acceptable ‘reaction to fire’. Building Regulations now state that for relevant buildings with a storey at least 18m above ground level, external walls and thus facade materials are required to achieve a reaction to fire classification of A2-s1, d0.

Put to the test

Powdertech Corby has put one of its most popular powder coatings, PWF, (Wood Finish) through the stringent tests required for A2,s1-d0 conformance, at Warringtonfire Testing and Certification.

The test procedure was a two-stage process. Firstly, the polyester powder and other components making up PWF were subjected to calorific heat release tests, meaning that they were burnt individually to measure the amount of heat produced. All the components passed as they did not exceed the maximum threshold, giving Powdertech the confidence to undertake the Single Burning Item (SBI) test as defined by standard EN 13823.

The single burning item test determines the reaction to fire behaviour of building products when exposed to the thermal attack by a single burning item (a sand-box burner supplied with propane). The specimen is mounted on a trolley, positioned in a frame beneath an exhaust system and the reaction of the specimen to the burner is monitored both instrumentally and visually. Heat and smoke release rates are measured, and physical characteristics are assessed by observation.

Suitability confirmed

Powdertech coated three pairs of aluminium panels in different PWF shades. Each pair formed an internal corner against which the SBI test was carried out. All three passed, and the worst-performing of the three shades was selected to make up three more sets of panels. These three sets were individually put through the SBI test again. The final report values for PWF take the average of these three results. The fire growth rate of PWF is 100% below the maximum allowed, and the total heat release is 95% below the maximum allowed. Smoke growth rate and total smoke production are both 65% below the maximum allowed. There are no flaming droplets at all – the product does not melt.

Powdertech Wood Finish offers warmth, texture and superior performance finishes for metallic substrates to rival the use of wood. With an A2 rating, it is judged to have only a very limited combustibility. The customer can have the look of timber and the performance of aluminium at an affordable price. No maintenance is required, beyond the occasional wash with clean water. Painting and varnishing are not necessary; rotting and mildew do not occur. PWF carries 25-year guarantees for colour, gloss and adhesion.

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