Fire Separation Distance Between Roofs

To the closest interior lot line.

Fire separation distance between roofs.

Fire area appears in the building code mostly in chapter 9 where it is used as a threshold for requiring either fire separation or fire sprinkler systems. 5 the firewall will be extended in accordance with the condition when the tangent is drawn from the top of the transformer tank towards to the building from the corner of new firewall although x 15m distance is not provided. Fire separation distance is measured from the face of the building to the property line centerline of a street or alley or to an imaginary line between two buildings. Exterior walls of dwellings garages and accessory buildings must maintain a 5 minimum separation distance from the property line or otherwise be fire protected.

The occupancy group of the building determines whether the exterior wall must be 1 2 or 3 hour construction. The recommendations provide a reasonable level of protection for combustibles within and on the exterior of a building exposed to an external building fire. Where the fire separation distance is five feet or less the construction type is not relevant. For example section 903 2 9 states that one threshold of sprinklering the entire building is when such a building contains a group s 1 fire area of greater than 12 000 square feet.

To the centerline of a street an alley or public way. 4 replacing of roof material with fire proof material and closing of existing windows with fire proof concrete wall. To an imaginary line between two buildings on the lot. External walls including gables required to be fire resisting referred to in 3 7 1 3 or 3 7 1 6 must extend to the underside of a non combustible roof covering or non combustible eaves lining see figure 3 7 1 3 and must.

They are typically 2 thick. 8 thick masonry was a common way to do firewalls in my area. Typical fire separation requirements for townhouses is a 2 hour fire rating. Depending on the fire separation distance degree of opening protection and percentage of openings the distance required between buildings on the same lot can vary anywhere from 0 feet to 60 feet based on ibc table 705 8.

Gypsum board party walls are more common now. If the separation is between 5 feet and 10 feet the requirements ease slightly for all construction types except ia. I think 1 2 thick gypsum board is probably also required at each side on the wall framing adjacent to the 2 shaft liner system.