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Flammability

The insulating properties of timber can provide built-in fire resistance. Large timber members burn slowly, and form char on the surface.

Even though wood does burn, the contribution from the timber building materials to the fire load is usually small compared with the contribution of the building contents which constitute the main source of fuel.

There is no New Zealand standard for fire retardant treated timber approved for use in New Zealand, although some proprietary products are available as coatings to timber surfaces to reduce flame spread.

Some compounds will be effective fire retardants, e.g. borates, but a high concentration is required.

LOSP treated timber must be substantially free of solvent prior to dispatch from the treatment facility to minimise risks to those handling the treated timber.

The Best Practice Guidelines for the Safe Use of Timber Preservatives and Antisapstain Chemicals recommends a minimum of four days in fillet stack, or an equivalent procedure, to allow solvent flash-off before the timber leaves the treatment plant site. 

LOSP treated timber should be stored protected from the weather and always in a well-ventilated area.