Fire retardant (FR) treatments for any construction material are designed to do a very important job. Should a fire arise in a building, the protected materials will slow down combustion and limit the spread of flame and generation of smoke.

Any death caused in a building fire is a tragedy for those linked to the victims. And, in addition, because of legislation such as the Construction (Design and Management) Regulations 2007, the ramifications can have severe consequences for any company or designer associated with the design and build of the project.

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.

So how can you be sure that your fire retardant protected timbers are fully compliant?

Failure to perform when required carries serious consequences. So it is important to carry out some simple due diligence to make sure that you can demonstrate that you have made the correct decision.

It is important that you ensure that any FR treatments from your suppliers have independent, species specific Classification Reports. Fire retardant treatments must now meet the requirements of either Euroclass B or C of the European Standard EN 13501-1 to comply with both national Building Standards and the Construction Products Regulation.

The fire performance of wood and woodbased 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 therefore must be species specific and reports that include generic terms such as ‘softwood’ and ‘plywood’ should be seriously questioned.

A first step for any specification of fire retardant treated timbers should be a reference to the UK Wood Protection Association (www.wood-protection.org) checklist, which gives general guidance and listings of Approved FR products and quality treatment companies.

Then ensure these companies use independent and species specific Classification Reports, relevant to the timbers you are using and where and how they will be used.

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 both specifiers and building control officers to demand this proof from the treatment supplier.

Other key factors to consider in the specification of fire retardant treated timbers are product performance and assurance; quality of application; durability and maintenance; and availability and cost.

Performance and assurance
Industrially applied FR systems may claim to offer both Euroclass B or C rating to EN 13501-1. However, to support a Classification Report from an independent notified testing body, previous simple fire test reports are no longer sufficient. The description of the product or treatment given in the Classification Report has to be comparable to the exact specification of the timber components to be used in the project.

Quality of application
If fire retardant treatments are required for new timbers going into a building then by far the most effective are those that are applied in factory-controlled conditions where independently audited control systems are in place, in accordance with ISO 9001, the international standard for quality management systems.

Durability and maintenance
When specifying you need to be assured that the fire retardant performance of the treated timbers will last in either an interior or exterior end use.

Well researched and specified FR timbers will provide a permanent fire protection within the structure that will not require further FR maintenance and are designed to meet the life of the building, providing effective, competitive lifetime value.

Availability and cost
The performance of FR-treated timber can be a matter of life and death. It is therefore paramount that professional contractors resist low cost, low performance, on-site options and build realistic production schedules into any specification to allow for adequate factory processing, which can take up to four to six weeks.

In terms of costs, controlled, factory-applied treatments may be initially higher than on-site applied options. However, if the whole life cost of the building and the timbers is considered in terms of regular maintenance and recoating required for some products, then the ‘one-off’ factory-applied treatments provide real value for money.

Many leading merchants are now offering ready available stocks of popular species and profiles of pressure-treated fire retardant timber claddings and panel products, which may provide a short deadline option. However, be certain the specification of these off-the-shelf products meets your needs.

In summary, if you require a quality fire retardant protection for either interior or exterior timber applications that you can have real confidence in, then proven, factory applied treatments provide the answer. They are controlled and end use specific treatments with a ‘one-off’ and permanent protection, which requires no further maintenance.

Further information
Lonza Wood Protection offers a choice of proven pressure impregnated fire retardant treatments for solid timbers and panel products. Both DRICON (interior and weather protected exterior applications) and NONCOM Exterior treatments for exterior cladding applications are supplied through its ISO 9001 and ISO 14001 accredited treatment facilities at Castleford, West Yorkshire and the company is also listed in the UK Wood Protection Association (WPA) quality scheme.