Fire Retardant Roof Covering Class C

A common misconception about roofs fire ratings is that building codes require class a.

Fire retardant roof covering class c.

Square sticks nailed together with sticks in the middle later running perpendicular to the outside layers. 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. A standard fire test is used to determine the fire rating of a roof covering. The flame spread categories are as follows per astm e 84 ul 723.

The class c brand is about the size of an ice cube. Building codes establish fire resistance requirements for roofs based on the type of construction e g concrete steel wood for the building. A fire resistant rating e g a class a class b or class c fire resistant rating. These tests may be conducted at ul inc fm global or any other certified testing laboratory.

Flame spread 25 or less frtw some fr surface coatings class b or ii. Class a or i. Each requires a spread of flame test and a burning brand test. Astm e108 defines fire test methods for roof coverings.

Pressure treated shakes and shingles are the most common roofing materials to fall under the class b rating. Flame through to the underside of a roof deck. Building code fire resistance requirements. The maximum flame spread is 6 feet for a class a rated roof 8 feet for class b and 13 feet for class c.

Installa tion instructions will include use of an additional material under the aluminum covering in order to receive the class a by assembly rating. Wood shake plywood or particle board roof are the most common roofing types listed as class c. Class c fire retardant treatment a product that is effective against light fire exposures. Over non combustible roof decks such as steel poured gypsum or concrete only the spread of flame on the top surface of the roof system is evaluated.

Flame spread 76 to 200 untreated lumber and plywood frtw must have a flame spread of 25 or less in the 10 minute astm e 84 ul 723 test. Withstand a burning brand measuring 1 5 x 1 5 and weighing 1 4 gram. Class c roofing provides only light fire protection. Class a designates resistance to relatively severe fire test exposure.

Burning a brand on a roof deck. Certain roof system types can be consid ered class a without testing based on their. Class a b and c designations. E108 defines the following conditions.

A and b brands consist of a three layer sandwich construction of 3 4 in. And class c designates resistance to relatively light fire test exposure. Roofing with a class c rating is able to. Class c fire resistant roofing material obviously since wildfires and the fire season has become increasingly worse it is important to note the roofing materials that are the lowest rated.

Experience maximum flame spread of 13 feet. An exception to this general rule is an aluminum covering. Under such exposures roof coverings of this class are not readily flammable afford a measurable degree of fire protection to the roof deck do not slip from position and pose no flying brand hazard. Class b designates resistance to relatively moderate fire test exposure.