ASTM C635/C635M:17 pdf free download – Standard Specification for Manufacture, Performance, and Testing of Metal Suspension Systems for Acoustical Tile and Lay-in Panel Ceilings.
4.1.1 The structural classilIcation of ceiling suspension systems shall be based on the load-carrying capacity of the main runners of the structural network. Load-carrying capacity as used herein is based on the more stringent requirement of esthetic acceptance rather than the less confining prevention of structural failure. The criterion is the arbitrary hut widely established limit of deflection to ½60 of the span between supports.
4.1.2 The load-carrying capacity shall be the maximum uniformly distributed load (pounds force per linear foot IN/mi) that a simply supported main runner section having a span length of 4 ft. 0 in. 11200 mmi is capable of supporting without the mid-span deflection exceeding 0.133 in. 13.33 rnml or
of the 4 ft. 0 in. 11200 mmj span length. as tested in accordance
with Test Methods E309O/E3(0M.
4.1.3 The structural classification or grade of ceiling suspension systems shall be determined by the capability of main runners or nailing bars to support a uniformly distributed load. These classifications shall be:
4.1.3.1 Lighr-1)urv Svstem.s, used where ceiling loads other than acoustical tile or lay-in panels are not anticipated. such as residential and light commercial structures.
4.1.3.2 Inir,nediute-Durv Sv.siems. used where ceiling loads other than acoustical tile or lay-in panels (light fIxtures, air dithisers. etc.) are anticipated. such as ordinary commercial structures.
4.1.3.3 Heab-v-flutv Svsiem.. used where the quantities and weights of ceiling fixtures (lights, air diffusers, etc.) are greater than those for an ordinary commercial structure.
4.1.4 For the purpose of determining the structural classification of iiiain runner members as covered in 4.1.2. their simple-span. minimum load-carrying capabilities, when tested in accordance with the test method described in Test Methods E30)0/E30’N)M. shall be listed as shown in Table I and Table
4.2 Cross runners shall be capable of carrying the load specified by the manufacturer without exceeding the maximum allowable deflection equal to ¼to of its span.
4.3 The design and definition of the suspension system shall be the responsibility of the manufacturer. Included is selection of appropriate materials, metal thicknesses, dimensions of necessary component section configLlrations. design of special hanger and assembly devices, and provision for whatever accessory items are needed to ensure satisfactory ceiling performance within the scope of this specilication.
4.3.1 Sysem manufacturers may provide supplementary data describing load deflection capabilities of main runners in each classification for spans other than 4 ft 11200 mml.
4.4 Where specialized loading conditions that ait outside the scope of this specification exist, the manufacturer should be consulted for his recommendations: and, he iiiav furnish engineering data as required. Specification or design of superstructure anchors or fasteners are nd the responsibility of the ceiling sysleni manufacturer unless specified by the ceiling system manufacturer as part of the suspension system.