Document G6J5Qyor5yGq8yJkg6qROx8nV

Fire Loss Control FlC 35-3 --Components of heavy timber building showing flooi training and identifvmg components of sennmill-type framing Courtesy Notional Fire Protection Association of the wooden members slows the rate of com bustion Moreover, the char which forms on wooden surfaces serves as an insulator for the wood within Noncombustible construction includes all types of structures in which the structure it self (exclusive of trim, interior finish, and contents) is noncomliustible but not fire re sistant Exposed steel beams and columns, and masonrv, metal, or asbestos panel walls, are the most common forms (Fig 35-4) Because of the tendency of steel to warp, buckle, and collapse under moderate fire exposure, noncombustible construction is relatively vulnerable to fire damage It is, therefore, most suitable for low-hazard occu pancies If quantities of combustibles are present, the structure should be protected with automatic sprinklers Ordinary construction consists of masonry exterior bearing walls, or beanng portions of exterior walls, that aie of noncombustible construction Interioi flaming, floors, and roofs are made of wood oi other combustible material whose "bulk" is less than that re quited foi heav\ timber construction 11 floor and roof construction and their supports have a one-hour fire-resistance rat ing, and all openings through floors (including stairways) are enclosed with partitions having a one-hour fire-resistance rating, then it is known as "protected ordinary construction " 1050