Exterior walls for Steel Building

exterior walls of many forms are used in steel building construction. Walls must be structurally sound, have adequate fire-resistance and insulating properties, offer protection against condensation of water vapor, be durable and easily maintained, and be pleasing in appearance.

Bearing walls must be strong enough to support, in addition to their own weight, any loads from floors and the roof which frame into them. According to the Uniform Building Code, bearing walls of plain masonry must be not less than 12 in thick, except that walls of one-story business buildings and residential buildings not over three stories high may be 8 in thick. Each successive 35-ft height of wall below the topmost 35 ft must be increased 4 in. in thickness. The minimum thickness of unreinforced, grouted. Brick masonry walls may be 2 in less than that required for plain masonry walls. 

Similar, but less severe, limitations are prescribed for reinforced-concrete bearing walls. Panel walls (also called curtain walls) in skeleton frame construction are usually specified in terms of their fire  -  resistance rating. 
 

ddddddFor example, the BOCA National Building Code requires that the fire-resistance rating of panel walls be not less than 4 h for both fireproof and semi fireproof construction.Except for reinforced-concrete walls, this requirement necessitates masonry walls ranging in thickness from 8 to 12 in.

Corrugated cement-asbestos board and corrugated-metal siding are used extensively for walls of industrial buildings. Wall sections consisting of two steel sheets with a layer of insulation between have also been widely accepted. Very attractive architectural effects are produced with fluted metal wall panels, which may be aluminum, stainless steel, galvanized copper-bearing steel, or porcelain-enameled iron or steel. 

Structural glass blocks, which are hollow, colorless, and translucent, are appropriate for exterior walls when ventilating sash are not required or when clear glass is not needed for visibility. Since their coefficient of heat transfer is less than one-half that of single-thickness common glass, heating costs are reduced and air conditioning improved. Glass blocks should not be subjected to vertical loads other than their own weight.