Fire Retardant Roof Covering Class C

Flame through to the underside of a roof deck.

Fire retardant roof covering class c.

A fire resistant rating e g a class a class b or class c fire resistant rating. Certain roof system types can be consid ered class a without testing based on their. 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. Installa tion instructions will include use of an additional material under the aluminum covering in order to receive the class a by assembly rating.

Astm e108 defines fire test methods for roof coverings. A standard fire test is used to determine the fire rating of a roof covering. Tested roof systems are fire classified class a b or c where the most fire resistant roof assemblies are class a and class c is least resistant. Class c roofing provides only light fire protection.

Burning a brand on a roof deck. The class c brand is about the size of an ice cube. Withstand a burning brand measuring 1 5 x 1 5 and weighing 1 4 gram. A and b brands consist of a three layer sandwich construction of 3 4 in.

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. E108 defines the following conditions. An exception to this general rule is an aluminum covering.

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. Class a or i. Building code fire resistance requirements. Roofing with a class c rating is able to.

And class c designates resistance to relatively light fire test exposure. Pressure treated shakes and shingles are the most common roofing materials to fall under the class b rating. Class a designates resistance to relatively severe fire test exposure. 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.

Class b designates resistance to relatively moderate fire test exposure. Building codes establish fire resistance requirements for roofs based on the type of construction e g concrete steel wood for the building. 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. A common misconception about roofs fire ratings is that building codes require class a.

Wood shake plywood or particle board roof are the most common roofing types listed as class c. Because of its low melting point it must be tested. Experience maximum flame spread of 13 feet. Flame spread 26 to 75 other fr surface coatings class c or iii.

Square sticks nailed together with sticks in the middle later running perpendicular to the outside layers. Each requires a spread of flame test and a burning brand test. The flame spread categories are as follows per astm e 84 ul 723. Class a b and c designations.