The use of fire-retardant plywood in construction
Fire-retardant plywood takes a special place in the construction code of the USA. First of all, the material is used for roof decking in multiple-dwelling structures. It is adjacent to the firewall, that extends from the foundation up to the roof, dividing building sections. The rules of modern construction require the use of fire rated plywood on both sides of the firewall as a part of roof sheathing. The remaining roof decking is not necessary shall be fireproof, that is why other materials of more competitive price are used for the rest of the structure, e.g. OSB. In some cases, to improve the fire safety of a building, two layers of flame retardant plywood for roof sheathing are used next to the firewall.
How does fire-retardant plywood work? The high temperature of open flame activates special acids in the plywood, that prevent the spread of the flame over its surface and reduces combustion. So, instead of bursting into flames, fire rated plywood will char slowly.
There are three categories of fire rated plywood according to the American classification: Interior Type A, Interior Type B and Exterior. FR plywood Type A is not usually used for roof sheathing due to being exposed to outside elements. FR plywood Type B is not advisable for this application as well. Not only the treatment process but also labelling shall conform to the conditions specified by Building code authorities, such as American Wood Preservers Association (AWPA).
In the past few years, the issue of the combination of flame retardant plywood with plastics and other modern materials has drawn a lot of attention. Composite materials combine the best properties of its components. A lot of opportunities for combining fire-retardant plywood with other materials are being thoroughly studied, new products are developed and introduced to the market. Plyterra Group follows the trends and offers fire-retardant plywood panels overlaid with fireproof high-pressure laminate (HPL). It is a perfect solution for interior design, comprising beauty, functionality and safety.