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Building Design and Construction Handbook - Merritt - Ventech!

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8.48 SECTION EIGHT<br />

TABLE 8.14 Fire Resistance Ratings for Steel Floor <strong>and</strong> Roof Assemblies*<br />

Roof construction Insulation<br />

Min. 1 1 ⁄2-in-deep<br />

steel deck on steel<br />

joists or steel<br />

beams<br />

Min. 1 1 ⁄2-in-deep<br />

steel deck on steel<br />

joists or steel<br />

beams<br />

Min. 1 3 ⁄4-in-thick<br />

listed mineral<br />

fiberboard<br />

Min. 1 1 ⁄16-in-thick<br />

listed mineral<br />

fiberboard<br />

Floor construction Concrete<br />

1 1 ⁄2-, 2-, or 3-in-deep<br />

steel floor units on<br />

steel beams<br />

1 1 ⁄2-, 2, or 3-in-deep<br />

steel floor units on<br />

steel beams<br />

2 1 ⁄2-in-thick normalweight<br />

or<br />

lightweight<br />

concrete<br />

2 1 ⁄2-in-thick normalweight<br />

or<br />

lightweight<br />

concrete<br />

Underside<br />

protection Authority<br />

2-h rating†<br />

Min. 1 3 ⁄4-in-thick,<br />

direct-applied,<br />

sprayed<br />

vermiculite plaster,<br />

UL listed<br />

Min. 1 9 ⁄16-in-thick,<br />

direct-applied,<br />

sprayed fiber<br />

protection, UL<br />

listed<br />

UL design P711†<br />

UL design P818†<br />

Underside<br />

protection Authority<br />

2-h rating‡<br />

Min. 3 ⁄8-in-thick,<br />

direct-applied,<br />

sprayed<br />

vermiculite plaster,<br />

UL listed<br />

Min. 3 ⁄8-in-thick,<br />

direct-applied,<br />

sprayed fiber<br />

protection, UL<br />

listed<br />

UL design D739‡<br />

UL design D858†<br />

* Based on ‘‘Fire Resistance Directory,’’ 1990, Underwriters Laboratories, Inc., 333 Pfingsten Rd., Northbrook,<br />

IL 60062.<br />

†1 1 ⁄2-h <strong>and</strong> 1-h ratings are also available.<br />

‡ 1-h, 2 1 ⁄2-h, 3-h, <strong>and</strong> 4-h ratings are also available.<br />

consists of closely spaced cellular raceways. These are connected to a main trench<br />

header duct with removable cover plate for lay-in wiring. Set on a repetitive module,<br />

the cellular raceways are assigned to electrical power, telephone, <strong>and</strong> data wiring.<br />

At prescribed intervals, as close as 2 ft longitudinally <strong>and</strong> 2 ft transversely over the<br />

floor, preset inserts may be provided for access to the wiring <strong>and</strong> activation workstations.<br />

When an insert is activated at a workstation, connections for electrical<br />

power, telephone, <strong>and</strong> data are provided at one outlet. Insert fittings may be flush<br />

with the top floor surface or project above it.<br />

This system provides the required fire-resistive barrier between stories of a building.<br />

The cellular metal floor units also serve the structural purposes of acting as<br />

working platforms <strong>and</strong> concrete forms during construction <strong>and</strong> as tensile reinforcement<br />

for the concrete floor slab after the building is occupied.<br />

Cellular steel floor raceways have many desirable features including moderately<br />

low cost, good flexibility, which contributes to lower life-cycle cost, <strong>and</strong> minimal

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