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 retardant roof covering class c.
Class b designates resistance to relatively moderate fire test exposure.
Installa tion instructions will include use of an additional material under the aluminum covering in order to receive the class a by assembly rating.
A fire resistant rating e g a class a class b or class c fire resistant rating.
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.
Experience maximum flame spread of 13 feet.
Class c fire retardant treatment a product that is effective against light fire exposures.
Wood shake plywood or particle board roof are the most common roofing types listed as class c.
Roofing with a class c rating is able to.
A common misconception about roofs fire ratings is that building codes require class a.
The class c brand is about the size of an ice cube.
Burning a brand on a roof deck.
E108 defines the following conditions.
A standard fire test is used to determine the fire rating of a roof covering.
And class c designates resistance to relatively light fire test exposure.
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 c roofing provides only light fire protection.
Pressure treated shakes and shingles are the most common roofing materials to fall under the class b rating.
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.
Because of its low melting point it must be tested.
Each requires a spread of flame test and a burning brand test.
The maximum flame spread is 6 feet for a class a rated roof 8 feet for class b and 13 feet for class c.
The flame spread categories are as follows per astm e 84 ul 723.
Class a or i.
Class a b and c designations.
Building code fire resistance requirements.
Astm e108 defines fire test methods for roof coverings.
Flame spread 26 to 75 other fr surface coatings class c or iii.
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.
Flame spread 25 or less frtw some fr surface coatings class b or ii.
Withstand a burning brand measuring 1 5 x 1 5 and weighing 1 4 gram.
Class a designates resistance to relatively severe fire test exposure.
Flame through to the underside of a roof deck.
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.
Certain roof system types can be consid ered class a without testing based on their.
Square sticks nailed together with sticks in the middle later running perpendicular to the outside layers.
