Summary
• Fire retardant treatments must meet either Euroclass B or C of EN 13501-1.
• Species specific Classification Reports indicate compliance with the requirements.
• Non-specific reports means testing is based just on generic references.
• Draft standard prEN15912 recognises that durability of the fire retardant is also important.
• Correct application and maintenance are important for superficially applied products.
Timber is our most versatile construction material and its upgrading by fire retardant treatments allows it to be used creatively and safely in a wide range of applications. However, the importance of correctly specifying these fire retardant treatments cannot be overstated: they protect valuable buildings and, ultimately, peoples’ lives. Therefore, there is a need to eliminate any doubt that the product specified is fit for purpose.
Under the Construction, Design and Management Regulations 2007, in the event of a building fire, and any deaths caused, a court of law will want to know how fire protection systems were selected and whether there was adequate liaison between all the parties involved in making sure that the protection was appropriate.
European requirements
Fire retardant treatments must now meet the requirements of either Euroclass B or C of the new European Standard EN 13501-1 to comply with both national Building Regulations and the Constructive Products Directive. But how can you be sure that your fire retardant treated timbers are fully compliant? By using suppliers that have independent, species specific Classification Reports and products with a proven performance record.
Some fire retardant treatments are currently being promoted using non-specific reports. This means that testing has only been undertaken on the basis of generic references and this may not always ensure an effective performance once specific timber species, component designs and end uses are taken into account.
Janet Murrell, technical manager of Warrington Certification Ltd, one of the leading independent fire testing and certification bodies, explained: “In our experience the fire performance of wood and wood-based panels is highly species specific, with different species requiring different chemical retentions to derive the same level of fire protection. Classification Reports supplied by treatment companies or coatings suppliers therefore must be species specific and reports that include generic terms such as ‘softwood’ and ‘plywood’ should be seriously questioned.”
Andrew Hughes, technical director for Arch Timber Protection and chairman of the UK Wood Protection Association (WPA) fire retardant committee, said a first step for any specification of fire retardant treated timbers should be a reference to the WPA checklist which gives general guidance. “However, independent and species specific Classification Reports are a must to give real peace of mind. These should cover four particular requirements: the timber species; the thickness of the timber; whether there will be an air gap behind the timber; and the nature of any backing materials. It is a duty of care for all parties involved in the supply chain of fire retardant treated timbers to demand this proof from their suppliers.
Independent certification
“All Arch Timber Protection fire testing is done through independent certification organisations. We have invested in Classification Reports for a wide range of species and thicknesses, and to match a number of different end uses. These, together with our ISO 9001 accredited treatment facilities, make sure our customers are getting exactly what they expect from our proven Dricon and Non-Com Exterior fire retardant treatments.”
Provision of a Classification Report to confirm compliance is mandatory within new European Standards. In addition, draft standard (prEN15912) now recognises that the durability of the fire retardant protection is also extremely important to ensure the fire performance is maintained over time.
When superficially applied products are selected, their long-term performance depends on correct application rates and/or film thicknesses being achieved. When such products are applied by brush or spray on site, fire performance can only be assured when application is under an independent certification and accreditation scheme for installers. An effective maintenance programme throughout the life of the building has also to be considered to ensure durability of performance. Controlled, industrially applied pressure treatments provide a highly effective and long-term protection on all faces of the timber that will require no maintenance.
In terms of quality assurance and accreditation, fire performance can only be assured when the manufacturing and application of the fire retardant is carried out under an independent certification and accreditation scheme, with third-party audit on a regular basis. ISO 9001, WPA listed and approved status, and BBA (British Board of Agrément) accreditations all give assurance that the product has been applied correctly.
