Frequently Asked Questions

Fire retardantant-treated wood basics

Pressure treatment is a process that forces fire retardants into the wood. Wood is placed inside a closed cylinder, the cylinder is filled with fire retardants and then vacuum and pressure are applied to force the fire retardants into the wood. The fire retardants helps resist the spread of flames on the wood.

Wood is a plentiful and economical building material which comes from a renewable and sustainable resource. However, wood is subject to burning. To ensure public safety, structural soundness and long service life, building codes require that wood used in some structureal applications must include protection from fire.

This is especially important in multifamily and multistory structures where fire retardant wood is used between common walls and other areas to prevent fire from spreading and allow time for evacuation of the building. In short, fire retardant-treated wood provides users a long-lasting product that has an enhanced safety factor to protect occupants and allow them time to safely evacuate in the event of a fire.

Unlike spray on coatings, dips and intumescent coverings, fire retardant-treated wood can last the lifetime of the building. According to a survey results compiled by FPinnovations, “buildings are often torn down within 50 years, regardless of material, because of changing needs and increasing land values as opposed to performance issues.” Many fire retardant manufacturers warranty their products for up to 50 years.

Western wood treated to AWPA standards or have an ICC_ESR report will have an end label or ink stamp that references the standards and bears the quality mark of an ALSC accredited agency. Building codes required the stamp contain specific elements, such as brand of treatment, species, flame or smoke developed index number and identification of the third party inspection agency. For more information, see the Quality Marks section.

The requirements for handling fire retardant-treated wood are the same for untreated wood. When handling fire retardant wood, wear gloves and long sleeve shirt to protect your hands and arms from splinters. When sawing treated wood, wear a dust mask and eye protection to protect against breathing in the dust or getting it in an eye.

First, it is important to remember that fire retardant-treated wood, like preservative-treated wood, is not a hazardous product and has not been listed as a hazardous waste.

It is completely proper and legal to send fire retardant-treated wood to a landfill. However, due to the growing shortage of landfill space, many industrial users select recycling of wood as their disposal option. There is a growing movement to “manage” the disposal of wood. In many cases, the fire retardant-treated wood can be reused in its original use or used in secondary applications.

In cases where the wood cannot be reused, it can be disposed of in landfills.

Most fire retardant-treated wood products are no more corrosive to fasteners and connectors that untreated wood products. Fire retardant manufacturers suggest following these same fastner requirements as those used for preservative-treated: hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Fasteners other than nails, timber rivets, wood screws and lag screws shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B 695, Class 55 minimum.