STRUCTURAL STEEL EDUCATIONAL COUNCIL

TECHNICAL INFORMATION & PRODUCT SERVICE

JANUARY 1992'

STEEL DECK CONSTRUCTIONResum• of Frequently Asked Questions on Formed Steel Floor and Roof Decksc • 0 ` 0 ' 4• ° . · o · . Io . • . • • • <3 • , , . • , 0 4 ' ."J . • , " b o · oc> o · c o l . , .•

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G E N E R A L

What are typical steel specifications for steeldecks?The two most important parts of the steel spectflcatlonare the stress level and the flmsh of the deckASTM A-446 covers zinc coated (galvanized) cold-rolledsteel sheets in slx strength levels which designate mini-mum yield points Those commonly used for steel deckare Grade A (33,000 ps0, Grade B (37,000 ps0, GradeC (40,000 ps0 or Grade E (80,000 psi). The weight of thegalvanized coating is designated by ASTM A-525.The grades of galvamzed coating generally used forsteel deck are G-01 (wipe coat), G-60 (hght commercial)or G-90 (commercial) There are alloyed coatings avail-able if the galvamzed surface is to receive a field coat ofpaintASTM A-611 covers cold-rolled uncoated structuralsteel sheets W•thm th•s speclhcat•on are five strengthlevels which designate minimum yield points Thosecommonly used for steel deck are Grade C (33,000 psi),Grade D (40,000 ps0 or Grade E (80,000 ps0 The cold-rolled steel Is cleaned, washed and given a shop coat ofpnmer paint on both surfaces before fabncahon If,however, concrete as to be poured over it, as for compos-ite floor deck, paint is apphed only to the exposed surfaceaway from the concrete

What are "gauges"?Gauge Js a convenient method to Identify a decimalthickness of steel Roof decks or floor decks range from22 (light) through 16 (heavy) gauge, with lighter orheavier gauges rarely being used As an example, the

*This TIPS Issue/s an update of a pubbcat/on Issued •n January 1986

"nominal" thickness of 20 gauge is 0359" and 16 gaugeis 0598" Steel deck producers can vary from thesenominal thicknesses when developing their safe loadtables based on the AISI allowable minimum decimalthickness of 0 95 times the thickness used in the designof the member

What is the typical design stress for steel decks?The design stress permitted by budding code junsdlc-tJons is 0 6 Fy (Fy = minimum yield strength)

How are vertical load section properties of steeldecks determined?Manufacturers calculate section modulus and moment ofinertia values in accordance with the Spec/f/cat/on for theDesign of Cold Formed Steel Structural Members pub-lished by the Amencan Iron & Steel Institute

What depths of steel decks are available?Decking depths range from 1-1/2" to 7-1/2" However,economic aspects dictate that 1-1/2" and 3" deep decksare normally used. The deep decks are only used whenvery long spans cannot be avoided Corrugated steeldecks are available m depths of 3/8" to 1-5/16" in 28gauge through 20 gauge

ROOF DECK

Framing

What are considerations for steel deck on warpedsurfaces?Steel deck units readdy accept the small out of plane

Figure I

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Metal Cover PlateScrew Or TackWeld To Deck Units

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Square Cut Ends' T - - - -

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warping required to achieve roof drainage. When highlydifferential warped surfaces are required, the lightergauge single sheet units are more adaptable than thedouble plated sections. The designer should investigatethe alignment of supports to be certain of the deck'sability to conform to differential elevations for multiplespans, otherwise the deck should be single span.

What's the proper way to frame a wedge-shapedbay?

It is usually desirable to let the deck ribs run as a tangentof thearc as this entails a minimum of-cutting--and,consequently, reduces waste and cost. When theflanges of the radial beams are wide enough to supportthe deck panels without bevel cutting, the panels areinstalled as a "stair-step" condition. The stair-step gapsare closed (capped) over with a flat plate on the top of thedecking surface to support insulation. See Fig. 1.

Should decking units be continuous over a ridge orvalley?Steel roof deck units have little bending resistance(dependent upon gauge) normal to the ribs, but greatstrength in the direction of the ribs. For changes in pitchparallel to the ribs, the deck units can be stepped downto conform to the change in pitch. When the sheets arerequired to span over a ridge or valley, the ability of theunit to conform is dependent upon its moment of inertia.Gradual changes in pitch can usually be accommo-dated using a man's weight to step it flat to the support.For abrupt changes, however, the sheet should bediscontinued at the ridge or valley and a 20 gauge or 18gauge flat cap sheet bent to the angle of the pitchfastened to the deck sheets. Its purpose is to provide

2 Steel Tips January 1992

diaphragm continuity and support for insulation androofing membranes. The designer should be certain toprovide structural support either at or close to ridge andvalley lines.

Should the structural member's supporting flangesurface be flat to the deck surface?It is not necessary for full surface bearing on the support-ing flange provided any wedge-shaped gap is small.Since the majority of steel deck is installed by welding,a gap less than 1/4" can be filled with weld metal toprovide a satisfactory installation. If there are heavyapplied loads or if the deck units are fastened by screws,the usual practice is to use a 14 gauge strip bent to anL-shaped profile and welded to the supporting beam.The slope of the strip after installation should provide abearing surface for the deck unit. The designer iscautioned that decking support members at a hip orridge condition should be reviewed to provide a smoothtransition and continuity at the supporting system for theadjoining decking sheets.

What kind of closures are available to close gapsb e t w e e n supports and deck units?Three types of closures are available: close cell neo-prene rubber, sheet metal and a combination metal andneoprene. Neoprene closures are oversize to fit eitherrib openings (top side) or void (underside) openings.Glue or friction fit ensures tight closing of the opening tostop light, heat and wind penetration. Notched sheetmetal closures are loose fitting and are used to stopsight view (as behind flashing) and as bird or large insect

F i g u r e 2

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Continuous Sheet Metal____ Closure and Fire Stop Support

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/I III I Closure

PerpendicularoT° ] I

Parallel To Deck Condition

stoppers For very large void or nb openings and undersevere pressure condlhons, combination metal/neo-prene rubber closures are recommended

Should I use closures m steel roof deck construc-tion?Use closures whenever an exposed deck overhangs anexterior wall with no soffit cover on the exterior, whensound control •s necessary for interior partitions reach-mg the deck units, and over exterior exposed supportsto prevent bird roosting and to present a more finishedappearance

Are there special considerations for cantileveredroof deck units?Usual engmeenng calculations are sufficient The de-signer should be certain to show a heavy gauge angleor cap channel welded to the outboard end of a cantile-ver to tie adlacent deck sheets together for unity andsupport architectural facsas, dnp flashing, or gutters

Can steel deck panels be used as draft curtains?Yes, steel deck panels are often used to parht•on largeareas for fire safety, building code and insurance ratingreasons They can be installed vertically on the face ofa truss or with a suspended vertical frame An importantdetail to incorporate into the design is the flashing at thetop to inexpensively separate and seal off adjacentareas Corrugated decks 1/2" to 1-5/16' deep are oftenused as draft curtains See Fig 2 (bottom of page 2)

Openings

How large a hole may be cut in steel roof deckwithout supplementary framing?Any hole which does not intersect a vertical web of thedeck may be cut. When holes intersect a deckingvertical web, some general rules will assmt the designerto make a decision, i e

I With 6" or 8" spaced nbs, one web may be cut2 With 12" or greater spaced ribs, avoid any web

removal3 The number of holes within any span of the deck

units should be limited to avoid cutting adjacent ribswithin the span

4 Holes In the high moment areas of the deck unitsmay be more restrictive than those located in theshear area

What kind of reinforcing is suggested for medium-sized opening?It Is preferred to use steel reinforcement angles, tubes,or plates which are applied from the top side It iscustomary to install reinforcement prior to cutting the

hole The reinforcing members should run at rightangles to the direction of the deck and be approximatelythree times the width of opening Designers are cau-honed to place the narrow dimension of the openingnormal to the deck ribs to minimize the structural impactto the deck. In all cases, the ablhty of the deck unitsadjacent to the hole to carry transferred loading shouldbe evaluated.

When are frames for holes required to be part of thestructural frame system?If an opening exceeds the width of the deck sheet or over24 inches (for long span 12" cover width sheets),supplementary framing should be attached to the struc-tural framing by struts or beams to create a framedopening Such openings are usually shown and dimen-sioned on the structural drawings.

Who pays for openings?Other than holes shown and dimensioned on the struc-tural drawings, the trade requinng the penetration isresponsible for approval, reinforcement and cutting Ifthe steel deck installer is still on the job, he can do thework on a mutually negohated fee basis

Diaphragms & Connect ions

How strong are steel deck diaphragms?Steel roof decks have a wide range of design values asdiaphragmsto resist honzontal loads Because of Codeapprovals, varying profiles, different fastener types andspacing, individual producers of steel roof decks shouldbe contacted for recommendations

Do lightweight concrete fills have diaphragm val-ues?Yes, the designer may secure the vanous code anddesign values for this type of construction by contactingthe steel deck manufacturer or the producers of hght-weight concrete

When are welding washers used?For corrugated decks hghter than 22 gauge, 14 gaugeweld washers are used when plug welding deck to thesupport

Is it necessary to touch up the welds on steel deckunits?Touch up by the deck erector is limited to top side of theunits only. However, if the deck is covered by concretefill, touch up of welds is not necessary as the concreteoffers adequate protection against corrosion Scorchmarks caused by welding attachments on the undersideof supports or deck un•ts should be touched up and

Steel Tips January 1992 3

painted by the painting subcontractor as part of thiswork Assignment of thru work by proper notation tn theproject speclhcat•ons •s important

How are welds protected?

The top side of the weld is painted w•th a rust inhibitivepaint Weld cleaning and etching Is not required Forgalvamzed surfaces, a zmc-rmh paint may be specified.Flux-type zinc repair compounds cannot be success-fully apphed to metal decks due to rapid dlsslpahon ofheat required for application

Roof ing and Insulat ion

Do steel roof decks always require a built-up roof?

No, and by followmg a few general rules, many deckprofiles may be used exposed (without roofing)

1 Roof slopes at least 1" to 12"2 Fasten with gasketed screws at supports and shtch

the side joints with screws3 Overlap end iomts a minimum of 6"4 Use a full bed of caulking at s•de and end joints5 Install deck units in a posihon to minimize

of side joint, i e, install deck with the side lap on thetop, not on the bottom of the flute

What is the correct thickness of insulation oversteel roof deck?

Aside from thermal requirements, the minimum thick-ness is based on the width of the nb opening related tothe density of the msulabon and Its shear capacity tobndge the openmg In general, a rule of thumb is 1" thickfor 0 to 1" openings, 1-1/2" for 2-1/2" openings Becausethe quahty of the waterproohng membrane •s dependentupon proper support, roofing product manufacturersshould be consulted for their specffmatlons

Can lightweight concrete insulating fills be usedover steel roof deck?

Yes, but some confusion results from "hghtwe•ght" ter-minology It Is necessary to differenhate between light-weight insulating concrete hll which ts approximately 30pcf density and hghtweight structural grade concrete of100 pcf or greater density Either type can be used

What are insulation mechanical fasteners?

Rigid insulabon is usually mechanically fastened tosteel deck by insulation chps There are many varietiesand methods of fastening these chps whmh penetratethe steel deck They are used to wmthstand wind uphftand Factory Mutual regulations These fasteners aresupphed and installed by the roohng contractor

4 Steel T/ps January 1992

What is the purpose of a vapor barrier?

It prevents the absorption of moisture into insulationmaterials When moisture Is absorbed, the thermal Ufactor of the msulabon is adversely affected

What are effective vapor barriers?Steel decks with caulked side seams are somehmesused as a vapor barrier Other types of vapor barriersare asphalt impregnated paper or mcombusbble plasbcfilms above the deck units Mechamcal msulahon chps,if specified, should be consistent with the type of vaporbarrier suggested

Where are vapor barriers used most often?

Usually m cold chmates and on those facilities whoseoccupancy tends to generate moisture and humidity,such as swimming pools or laundnes, etc

Drainage

What is an adequate roof pitch for drainage?

For steel decking roofs, many designers prefer a minm-mum slope of 1/8" per foot when built up roof mem-branes are used For exposed steel roofs, 1" per foot isa usual minimum with 2" per foot preferred

What is an easy way to get roof pitch?

Shortening alternate columns •s a good method on largeroofs to create sump areas, which can be connected tothe storm dram system

What are sump pans?

Standard sump pans are 14 gauge steel, approximately30" square, and of three general types flat, recessed flator recessed sloped Sump pans are flat or recessed flatfor Iow pitch roof surfaces and recessed sloped forsteeper pitch roofs Recessed pans prowde largerdrainage basins than do flat pans See Fig. 3 Sumppans are not used when concrete fill Is placed over thesteel deck m roof construchon

Who supplies the sump pans?

Sump pans are supphed and welded to the deck units bythe roof deck subcontractor The hole for the drain is cutin the plate by the plumbing contractor who also installsthe roof drain and connechons to the drainage system

What is the proper treatment of parapet conditions?

The designer can show either standard cant strips(minimum 20 gauge steel) or tapered steel cants whichvary the daagonal dimension to create a swale leading toa sump area For very wide tapered cant conditions, asloping shelf angle is used at the parapet and steeldecking of varying lengths is used to create a swale

Figure 3

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Flat Sump Plate\ i I I /

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Recessed Sump Pan -- P•tched

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Tapered Cant

spanning from the shelf angle to the metal deckingalready in place It is good pracbce to place scuppersthrough the parapet to reheve abnormal water heightsSee Fig 4

F L O O R DECK

General

What are the general types of floor deck panels?Steel floor deck panels fall into two general categonescellular and non-cellular Cellular panels are producedby spot welding a nbbed panel to a flat panel to createa void whtch ns usable as a raceway for in-floor power,hghtmg, electrJcal and communJcatJon dJstrJbutJon Non-cellular panels are simply fluted (ribbed) panels

Is concrete always used over floor deck?Concrete is usually used over steel floor deck In thiscapacJty, Jt fumJshes a smooth surface covering the

ribbed deck and the accessones It acts as part or all ofthe steel panel hreproohng and can be destgned to workcompositely to increase structural capacity without anincrease tn steel wetght There are structural uses offloor panels such as servtce catwalks, package convey-ors, shelving or temporary floormg where concrete ns notordinanly used

Is concrete over the steel deck units required to bestructural grade?

Only tf compostte achon between the deck umts and theconcrete hll is required to provtde the design require-ments

Some temperature control mesh is required and theusual value Js 00083 times the area of concrete abovethe steel deck.

What causes concrete surface cracking?Concrete slabs that are poured on imperwous surfacessuch as steel deck or Vtsqueen can cause the topsurface to dry relatively quickly whde the lower portion ofthe slab remaJns wet The water bleeds to the top

Steel T/ps January 1992 5

surface and evaporates, causing cracks to open abovethe top surface of the rebars or mesh, whmh thenpropagate to the surface. Troweling closes the cracksonly at the surface and they tend to reopen m a matterof days.

How can surface cracking be prevented?

A good way to reduce slab cracking Is to have a light fogwater spray applied to the slab during the finishingoperations. The concrete will have a sheen while it iswet. When this sheen starts to disappear, the fog sprayshould be applied to maintain the sheen Care should betaken not to get excess water on the slab Venting of thedeck may help to reduce cracking in the concrete.

How should the concrete be cured?

There are several ways of curing the concrete Productsthat are sprayed on have e•ther a wax or a resin base.E•ther one may impair the application of a sealant orhardener later It is recommended that the surface becovered with craft paper, Visqueen or polyethylene

Are additives to the concrete fill recommended?

No Corrosive salts should not be allowed as they canreact adversely with the steel deck units, especially withgalvanized decking

Framing

Is it necessary to put in additional support atcolumns or other areas of deck interruptions?Steel deck support angles are used If the nbs of thedeck units are left unsupported at the columns. SeeFig. 5. The project specifications should call for thesupport angles to be supplied by the structural steelsuppher. They can be installed by the metal deckerector. Voads mn the metal deck units may need to beclosed w•th sheet metal or other closures to preventconcrete leakage.

Are cover plates or splice plates on structural steelmembers a problem?Any projection above the steel support sunace canimpose a hardship on the steel deck erector. If the topflange of the steel beam supporting the deck is notlevel, Jt may be difficult to achieve adequate bearing forthe steel deck units.

Are concrete closures necessary?

The designer should show a concrete closure wher-ever there is a concrete leak possible as at changes ofdlrecbon and ends of decking runs, at columns, duct orshaft openings, building perimeters, etc The closuredoes not have to match the profile of the deck. Whenshown on the drawing, a concrete slab edge form isprovided to retain the concrete slab at its approximateheight above the deck. Since concrete edge forms arenot intended to be screeds, they are not adjustable to

Figure 5

Deck {Direction "A" -

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NoteOmit Angles InDeck DIr "A" WhenM1 · 6" or in DeckDir "S" When M2 · 6"

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Floor Support and Edge of Column

Q •s Less than 6"

6 Steel T/ps January 1992

elevahon to meet the varying needs of the budding.The typical concrete edge form •s a galvamzed sheetmetal angle, with a thickness to meet required needs

Openings

What is the proper treatment for holes ortions through a steel floor deck?

Large holes (over 24" wide) should be en-cased by structural frames connected to themare framing members Smaller holes arecreated by block-outs an the concrete (such asstyrofoam or wood forms) Either angles orrebar are used as headers in the slab, with thearea of the reinforcing equal to or greater thanthe area of the steel to be cut out. The headerbars should be installed on the d•agonal at thecorner of the opening After the concrete hascured, the block-out can be removed and thesteel deck an the area of the hole removed witha cutting torch

Diaphragms and Connect ions

penetra-

Figure 6

Are there any precautions advised when using steeldecks in either roof or floor over open web steeljoists?Yes, at end laps of the deck for roof deck, the lap shouldbe over one angle See Fig. 6 If the deck is butted onroof decks, there should be a continuous plate added totransfer the shear from one angle to the other See Rg7 For decks w•th structural concrete, the plate is notnecessary if the concrete does not have a joint over theJoist

/- • typical support weld

//

I Open web steel joist

Suggested Detail at Deck Lapon Open Web Steel Joist

How effective are steel floor panels as ahorizontal diaphragm?Combined wath concrete the assemblies offergreat ngidity and strength without greatly add-ing to the diaphragm wetght. Values aredependent upon deck profile, weld patternsand spans In concept, the steel deck can actas the shear transfer device between the con-crete fill and the perimeter (shear collector)framing member Shearconnectorsordowelscan also be used for shear transfer

How are steel floor units attached?By welding through the deck umts (arc-spotweld) to the steel supports Side laps arebutton punched, welded or screwed to meet eitherstructural requirements or the specification of Under-writers Laboratories

How are diaphragm values of steel floor or roofdecks determined?Values are based on full-scale tests and on formulasdeveloped in the Se/stoic Design for Buildings (TnService Manual, Army TM 5-809-10) Each quahfieddeck manufacturer has on file with ICBO or vartouscities an Evaluation Report for approved welding pat-terns and decking profiles

Figure 7• typical support weld

I•Add mm 1/8' P. con t

Detail at Deck Butt Joint

See Fig. 8 (top of next page), which dlustrates a potentialproblem when an open web joist IS poslboned close toa wall The joist has camber and unlessthe ledger angleis placed with the same camber, it is difficult to bend thedeck down to the ledger angle The solution is to eitherpoSlbOn the joist far enough from the wall to allow thedeck to bend, or to camber the ledger angle the same asthe joist

Electrification

In in-floor wiring systems using cellular panels,how are the systems carried normal to the deckrun?Through the use of cross ducts above the top of the

Steel T/ps January 1992 7

Figure 8

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Joist too close to wall to •allow deck to bend

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Detail to Avoid

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cellular unats Cross ducts are of two types, header ductand trench header. See Fig. 9

Figure 9

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Header Duct

potenhal common problem areas are resolved prior tobid time

Is header duct still used?Originally the only method to dlstnbute wire, it stdl hashmated use For example, header duct does not dasturbeither the d•aphragm action of the assembly or thevertical load capacity of the composite deck In addition,it is often used as a jack header to carry dlstnbution tocells interrupted by columns, openings and changes mdeck layout direction

Composite Construction

What consideration should I give trench headers?Since trench headers interrupt vertical composite de-signed loading, the deck un•ts must carry the total deadand live loads non-compositely Moment analysas at themost critical area of the trench dact will determine thestructural requirements of the deck units Trench head-ers should occur in areas of Iow diaphragm values orthedeck reinforced to carry the diaphragm without con-crete It is desirable to locate the trench duct outside ofthe effective beam flange area in composite beamconstrucbon. If this is not possible, design the beams asslab one side or non-composately Also rewewthe effectof the trench headers crossing the girder d that memberis designed on a composite basis, as wide trenchheaders can ehmmate both studs and concrete Closecoordinahon is required between the structural designerand the electrical designer so that rewew and solution of

8 Steel T/ps January 1992

Can steel deck units be used with composite beamconstruction?Yes, stud welding is a relahvely simple process whichprowdes high quahty welded connecbons The headedshear connectors may be apphed to the beam flangedirectly through the steel decking sheets Arc spot weldsmay be eliminated where they coincide wrth shear studplacement

Are all steel floor panels composite construction?Since the introduction of composite type floor construc-tion 25 to 30 years ago, nearly all floor assembhes nowtake advantage of the economies gamed by reduction ofweight of the steel, be •t the frame or the deck panel Incomposite construcbon, steel floor panels hrst act tosupport wet concrete and temporary construchon loads,and upon curing of the slab act as the pos•hve steelreinforcement of the concrete slab by bonding to the

concrete Embossed ridges (in a variety of patternsdependent upon the producer) assist the bonding func-tion Steel studs complete the composite action byassisting the floor slab and steel beam to act as a singlecomposite unit

Can I use composite steel floor decks in everyapplication?Basically the answer Is yes, but some cautEons arenecessary Since a composite steel floor slab is essen-tially a one-way reinforced slab, it ts designed for officebuilding type installations When subjected to movingloads such as fork lift trucks In Industrial applications orheavy concentrated loads, special considerations suchas posd•ve or negative moment reinforcement are oftenrequired. It is recommended that a deck manufacturerbe consulted for special applications

How are section properties of a composite floordeck developed?Producers of composite floor decking material publishdata based upon full-scale tests Designers shouldreview individual manufacturers' building code approv-als

What are the design specifications for compositebeam/steel deck construction?AISC recognizes this form of construction with designcriteria given in the AISC Manual of Steel Construct/on,9th Edition, using e•ther ASD or LRFD In addition, theInternational Conference of Building Officials (ICBO)issues Evaluahon Reports listing approved use anddesign load values for individual stud manufacturers

Is there a maximum thickness of metal decking forthrough-deck stud welding?

The maximum deck thickness is 16 gauge with lightcommercial (6 oz) galvamzed coating For doubleplated decks, I e, cellular panels, 18/18 is the maxi-mum

What are the usual size studs permitted for through-deck welding?The usual size is either 5/8" diameter or the widely used3/4" diameter. Studs larger than 3/4" are not presentlyapproved under AISC specifications Standard studsizes are stocked and should be specified wheneverpractical. Lead times are excessive for special lengthsand alloys on headed products

Does the design specify extra stud length to ac-count for burnoff?Studs from 1/4" through 1/2" diameter lose 1/8" in lengthduring the welding process, 5/8" through 7/8" diameterslose 3/16" However, when welding 3/4" inch shearconnectors through metal deck, 3/8" to 1/2" is burnedoff. Most manufacturers offer (stock) studs that accom-modate commonly specified after-weld lengths

When studs are used in through-deck welding, whatare the requirements for the top flange of the sup-porting steel beam?The top flange of the beam should be free of deleteriousmatenal which includes paint, rust and debris However,small amounts of mill scale and rust can be toleratedprovided the metal deck fits tightly to the steel beamsurface. Mimimum flange width of 4-1/2" is suggestedfor a single row of studs. For two rows of studs, theminimum flange width suggested is 5-1/2" Flange thick-ness should always be at least 1/3 of the stud diameterto ensure complete development of fastener strength

Who installs shear connectors in through-deck ap-plications?The shear connector studs act as a structural weldbetween the metal deck and the steel beam and areinstalled by the metal deck installer. The shear connec-tors cannot be placed in the shop because of field safetyregulations.

How is the soundness of arc spot welds (puddlewelds) determined?By assessing the ability of the welder to make an arc-spot weld as specified in AWS D1 3 Specification forWelding Sheet Steel /n Structures and by visual inspec-tion.

How are shear studs inspected in the field?Inspection, testing and operator qualification are out-lined in the Structural Welding Code, ANSI/AWS D1 1and the budding code governing the project.

CODE REQUIREMENTS

General

What agencies approve steel floor deck?Local, regional and state code authorities issue evalua-tion reports including seismic shear allowable and ver-tical load limits for each manufacturer's product. Inaddition, national codes and review bodies such asUnderwriters Laboratories (UL) conduct electrical andfire tested assemblies evaluations

What label service does Underwriters Laboratoriesoffer?UL authorizes the use of labels on products for fireresistance and for use as electrical raceways. They alsomaintain a follow-up service

Are steel floor units fire safe?Yes, steel floor decks are part of fire-resistant assem-blies Contact the deck manufacturer and review theFire ResJstance Directory handbook of UnderwritersLaboratories, Inc., for one of many assembhes bestsuited to your needs

Steel T/ps January 1992 9

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