Chasing and Recesses Chasing and recesses can affect the fire resistance periods for a wall. Refer to AS3700 or Think Brick Australia, Design Manual 5, Fire Resistant Levels for Clay Brick Walls for further details on when chasing and recesses must be considered. Fire Resistance and Sound Rating Brick Technical Manual 44 4.2 Sound Rating 4.2.1 Acoustic Properties Sound Transmission Measurements The NCC requires that building elements have certain levels of insulation from airborne noise and impact sound. The weighted sound reduction index (Rw) describes the acoustic performance of a construction system. It is a single number quantity for the airborne sound insulation rating of building elements. As the acoustic performance of a material or construction improves, the higher the Rw value will be. Rw ratings are determined by laboratory tests of a specimen of the construction system. The specimen is fixed within a frame to form the wall between two test chambers. A high noise level is generated in one room and the difference in sound level between the source room and the receiver room represents the transmission loss through the test specimen. The measurements are conducted over a range of sound frequencies. The Rw rating is then determined by comparing the results with reference curves.

8.21.3 Diaphragm Action of Decks In addition to their normal function as roof panels under gravity loading, steel roof deck assemblies can be used as shear diaphragms under lateral loads, such as wind and seismic forces. When steel roof deck is used for these purposes, special attention should be paid to connections between panels and attachments of panels to building frames. For design purposes, see SDI Diaphragm Design Manual. 8.21.4 Details and Accessories of Steel Roof Deck In addition to the use of nesting or upstanding seams, most roof-deck sections are designed so that ends can be lapped shingle fashion. Special ridge, valley, eave, and cant strips are provided by roof-deck manufacturers (Fig. 8.16). Roof decks are commonly arc welded to structural steel supports with puddle welds at least 1/4 in in diameter or with elongated welds of equal perimeter. Electrodes should be selected for amperage adjusted to fuse all layers of steel roof decking to supporting members without creating blowholes around the welds.Welding washers are recommended for thicknesses less than 0.028 in. Fillet welds at least 1 in long should be used to connect lapped edges of roof

c Framing at adjoining edge panels should have a nominal width of 3 in or more and nails should be staggered. d If studs are spaced at most 16 in c to c or if panels are applied with the long dimension across the studs, shears may be increased to the values shown for 15/32-in-thick sheathing with the same nail spacing. e Framing at adjoining panels should have a nominal width of 3 in or more and nails with a penetration into the framing exceeding 15/8-in and 3-in spacing c to c should be staggered. For 3/8-in-thick siding or APA Rated Siding when used as exterior siding applied directly to the framing, stud spacing of 16 in c to c is recommended. gValues apply to all-veneer plywood APA Rated Siding panels only. For APA Rated Siding on framing spaced 16 in c to c, the plywood may be 11/32 in thick, 3/8 in thick, or thicker. Thickness at the point of nailing on panel edges governs shear values. Panel grade Minimum nominal panel thickness, in Minimum nail penetration in framing,