Wood Roof Fire Rating

The brands consist of an ignited wood lattice placed directly on top of the test specimen.

Wood roof fire rating.

Both are burn through tests and the ultimate roof systems rating is the lowest of the three tests. Many of these advances have changed and improved wood construction s acceptance by building codes and insurance rating agencies. Fire protection rating is calculated from the flame side of the assembly and of course some assemblies have multiple flame sides. The class a brand weighs 2 000 grams class b 500 grams and class c 9 1 4 grams.

If wood shakes and shingles are impregnated with fire retardant chemicals they meet the requirements for a class b fire rating and can meet a class a rating if additional materials are included in the roof assemblies. Fire rated systems form w305 is designed to bring you up to date on what are considered today among the most cost effective fire rated construction systems you can design or build wood and wood structural panels systems. 722 6 2 1 fire resistance rating of wood frame assemblies. Class a class b class c or unrated.

A standard fire test is used to determine the fire rating of a roof covering. The reluctance to rely on approved test results is unwarranted as explained in section 17a and section 17b of sbca s metal plate connected wood truss handbook. The total fire rating is determined by adding each component to reach a minimum total of 60 minutes. For additional information on fire resistance rated assemblies see sbca research report 1509 01.

The fire resistance rating of a wood frame assembly is equal to the sum of the time assigned to the membrane on the fire exposed side the time assigned to the framing members and the time assigned for additional contribution by other protective measures such as insulation. If the roof deck is combustible such as wood plywood or osb two additional tests must be conducted. A class a roof is ideal for fire protection and may be required by your building codes depending on your place of residence.