practicalpractical ssolutionsolutions © re ng” ng” will reproof- ber or ce- nes 5 general ber spray is less reproofi cations for your cations for your cations for build- ng is “Spray-Applied ng is “Spray-Applied continued on next page for the ratings required re oor area for each construc- oor area ng can be dislodged, such as reproofi cation and use group (Table (Table cation and use group cation for your building that cation for your reproofi What fi re rating do I need? What fi The current politically correct term correct politically The current The Building Code defi The Building The most common spray fi The most common There are medium-density and high- medium-density are There exposed steel there architecturally For What materials are available? What materials be used — there is no need for fancy be used — there it only confuses language and acronyms, people. Fire Resistive Material (SFRM).” In this this In (SFRM).” Material Resistive Fire fi article the term “spray for spray fi for spray parking garages. parking which contain available density products durable far more and are cement, Portland than the low- and water resistant also consider- They are density products. expensive. ably more These intumescent paints available. are to obtain the coats several usually require The high cost of intu- thickness. required mescent paints limits their use to projects it is important to architecturally where expose the structural steel. trucks. The trick is to pick a construc- trucks. tion classifi fi has the lowest building elements. construction classifi ings, with sub categories within each. must pick one of (or the Architect) You the construction classifi particular Structural building project. typically either steel framed buildings are 1 2 construction (Type Type 1 or Type that the structural el- 2 require Type and The Build- ements be non-combustible). ing Code stipulates maximum building height and fl tion classifi in- The code allows 503 of the IBC). limits if the to the height and area creases than or has more building is sprinklered, 25% of the perimeter accessible to fi ing materials are low-density fi low-density ing materials are The fi mentitious sprays. but spray, costly than the cementitious to steel and is eas- as well does not adhere a gyp- have These materials ily dislodged. not suitable for sum based binder and are locations or exposed locations where wet the fi re ng. ghters, re, such as re, re fi reproofi re re protection re re protection of re protection systems protection re re, such as a sprinkler such as re, cations are often vague often vague cations are re protection in school, protection re ng, masonry encasement esign of a building and is often building and is often esign of a reproofi re protection consists of building protection re re protection systems, and that struc- protection re guring out technical stuff when they guring out technical stuff It has been argued that architects do not has been argued that architects It Fire protection systems are classi- systems are protection Fire

ed as passive, active, or manual. Pas- active, ed as passive, protection specifi protection something that enhances the architec- that enhances the something tural d viewed as a necessary fi evil. As a result, and inadequate. training adequate technical often have in fi Of do a better job. tural engineers could learn course structural engineers don’t much about fi but they are often better than architects often better than architects but they are at fi here the facts. So with all of presented are not that the facts — this stuff is really are to understand. hard fi fi sive materials that insulate structural ele- the heat of a fi ments from spray fi system. Manual fi system. Manual those intended to aid fi are systems are systems that are intended systems that are systems are to extinguish a fi or rated ceilings. Active fi or rated ceilings. Active such as standpipes. This articleThis will such as standpipes. fi deal only with passive structural steel using spray fi Copyright re re safety re

ng systems for re protection re- protection re re safe building. safe building. re magazine ng, but the problem ng, but the ng of structural has steel reproofi

reproofi re protection engineers, they protection re re protection engineers have engineers have protection re reproofi STRUCTURE ng thickness gauge

There has been a lot of talk in recent of talk in recent has been a lot There There has also been a lot of debate over been a lot of debate over has also There Some fi The problem is that architects who is that architects The problem re protection rather than prescriptive re- rather than prescriptive protection re years about structuralyears engineers becoming the specifying and in involved more inspecting of fi Fireproofi

For Dummies P.E. DeStefano, Jim By Fire Protection of Structural Steel... Structural of Protection Fire 2005 magazine • November STRUCTURE 17 structural steel. The collapse of the World World of the The collapse structural steel. has focused public Center towers Trade the inadequacies in attention on some of the way fi the adequacy of Building Code require- the adequacy of Building ments for fi been treated in the past. been treated proposed mandating performanceproposed based fi Although performance based quirements. a lot more would make requirements for fi work complicat- in more result will probably ed and less understood code provisions. the fi This is not likely to improve not taken much systems have protection is not protection in them. Fire interest are typically charged with specifying fi are of buildings. is not the codes, it is improper application improper is not the codes, it is of the code provisions. and enforcement fi When the prescriptive quirements are correctly implemented, correctly are quirements in a verythey result fi Once you know your construction class- ifi cation, Table 601 of the IBC defi nes the fi re ratings required for each building ele- ment, fl oor construction, roof construc- tion, columns, etc.. This part is real easy. There are no fi re ratings tabulated for brace elements that resist only wind or seismic lateral loads. This is based on the assumption that it is unlikely that a hurricane or earthquake will strike while the building is on fi re. The code does require that beams which brace a column must have the same rating as the column that they are bracing. Similarly, beams that support a wall around a stair must have the same rating as the wall. Is it an assembly or just a beam? Flutes of metal deck have not been completely fi lled over beam © Fire ratings are listed as restrained assem-Copyright blies, unrestrained assemblies and unre- umn will typically require thicker fi reproofi ng “restrained” has a different meaning from that strained beams. If you are attempting to than adjacent beams that frame into a girder. commonly used by structural engineers. achieve a fi re rated fl oor or roof, you are deal- A building fi re is often limited to a small ing with an assembly. If you are fi re rating It is restrained or unrestrained? area of a building and only heats up the a beam that braces a column or supports a There is considerable confusion and misin- structural steel immediately above the fi re. If rated wall, you are dealing with an unre- formation about what constitutes a restrained there is surrounding fl oor or roof construc- strained beam. Since an unrestrained beam assembly. Restrained assemblies require less tion that is capable of restraining the thermal requires a thicker application of fi reproof- fi reproofi ng thickness than unrestrained as- expansion of the structural steel in the vicin- ing than a restrained fl oor assembly with the semblies with the same fi re rating. ity of the fi re, the assembly will perform bet- same fi re rating, beams that frame into a col- In the context of fi re rated assemblies, the term ter and is considered to be restrained. There is a table contained within the ASTM E119 standard (Table X3.1) that gives guidance in evaluating if an assembly is restrained or unrestrained. If steel beams are welded, riveted, or bolted to other steel beams, the assembly is considered restrained. If steel beams or joists are supported on bearing walls, then single spans and end STRUCTUREbays are considered unrestrained. It is clear that structural steel construction is almost always restrained. magazineIt is not uncommon for a product sales- man to encourage architects and engineers to treat all assemblies as unrestrained. This allows them to sell considerably more fi re- proofi ng material for a project. Some local www.structuremag.org For Advertiser Information, visit Information, Advertiser For

Fireproofi ng should be applied to bare unpainted steel

18 STRUCTURE magazine • November 2005 hesion of the fi reproofi ng. If for some reason the steel has been painted, things get more complicated. Unless you can substantiate that the fi reproofi ng will have adequate ad- hesion to the paint, you must take addition- al steps such as applying a bonding agent to the steel or securing metal lath to the beam prior to fi reproofi ng. Many fi re rated assemblies require the under- side of the metal deck to be spray fi reproofed along with the beams. Often galvanized metal deck will have a light fi lm of oil on its surface that needs to be removed by solvent cleaning. Fireproofi ng manufacturer’s specifi cations will often say that the cleaning of the metal deck will be by others. Your spec should indicate who is responsible for the solvent cleaning, since it is not likely that the Ironworkers will Copyright be doing it. © What Special Inspections are required? Spray fi reproofi ng is subject to Special Application of fi reproofi ng Inspections under chapter 17 of the IBC. Testing is required of the fi reproofi ng thick- building codes such as the California code What thickness should the ness, bond/adhesion and density. The code actually stipulate that all assemblies must be fi reproofi ng be? requires that one thickness test be performed treated as unrestrained. for every 1,000 square feet of rated fl oor or The UL test will indicate the fi reproofi ng thickness that is required for a given fi re rat- Which UL design should I use? ing. This thickness is valid only for the beam The Underwriters Laboratory (UL) pub- size that was used in the test. For instance, UL lishes a directory that lists the fi re rated assem- test D739 was based on a W8x28 steel beam. blies, beams, columns and walls that they have Unless your project has been designed with all tested. UL is not the only testing laboratory of the beams being W8x28s, you will need to that performs fi re tests, but they are the most adjust the fi reproofi ng thickness for each beam prolifi c. There are other laboratories such as size used. FactorySTRUCTURE Mutual that also list fi re test results. There is a simple formula that is used to Fire tests are defi ned in ASTM E119. A calculate the required fi reproofi ng thickness full size mock-up is placed in a test furnace based on the ratio of beam weight to heated and subjected to a fi re with a prescribed time- perimeter. This is referred to as W/D, where magazine For Advertiser Information, visit temperature curve. The time period to failure W is the weight per foot in pounds and D is recorded for the test. Since actual building is the heated perimeter in inches (not beam fi re conditions are different from an E119 depth). You don’t actually have to do this test, an assembly with a 2 hour rating will calculation yourself, instead you should not necessarily survive a real fi re for 2 hours. require the fi reproofi ng contractor to submit The E119 test is a good method of rating the W/D calculations for approval along with a relative fi re resistance of different building schedule of fi reproofi ng thickness for each www.structuremag.org elements, but it is not a good predictor of an beam and column size on the project. element’s actual duration in a real fi re. Just to keep everybody confused, some ref- Each listing in the UL directory describes in erences will base the thickness calculations on great detail all of the signifi cant components the ratio of cross sectional area to heated pe- of the test specimen, such as beam size, type rimeter. This is referred to as A/P, where A is and thickness of fi reproofi ng, type, size and the area in inches squared and P is the heat- gage of metal deck, thickness of concrete slab ed perimeter in inches (note that they have and type of concrete aggregate. Your building changed from D to P). construction must match all of the components of the test specimen for the UL test that you What about surface preparation? reference. This requires some tedious reading Spray fi reproofi ng is intended to be ap- through the UL directory to fi nd a test that is plied over bare, unpainted steel. A light similar to the construction of your project. coating of rust will actually improve the ad-

STRUCTURE magazine • November 2005 19 0 STRUCTURE magazine•November 2005 20 For Advertiser Information, visit www.structuremag.orgSTRUCTURE

magazine Fireproofi ngmixer andpump

Copyright common inspectiontasksare asfollows: plication requires inspection.Some ofthe a testingagency. messyandisbestleftto adhesion testingisvery inexpensive. Conversely, bond/ performing testing agency. and d engineering technicianwithsometraining, pattern. This addsuptoalotoftesting. thickness measurements takenonaprescribed One thickness testconsistsofaveraging several 10,000square feetwascustomary.for every rated beamsandcolumns.Previously, onetest roof assembly, andfor25%oftheindividually thickness ofthefi fees generatedforinspectingandtestingthe vices foryour project, there are considerable tions. If you provide Special Inspection ser- tional work. At themost,itisacoupleofhoursaddi- longtodo.cation, itreally doesnottakevery ing andhave developed your standard specifi once you have learnedhow tospecifyfi won’tget abiggerfeefor doingso. Of course, you probablying inyour scopeofservices ing. ifyou includesprayfi This istrue, assume responsibility forspecifyingfi engineer additional feestohave thestructural engineers isthatarchitects are unwillingtopay tion if you will be performing inspections. tion ifyou willbeperforming invested inpreparingthe effort thespecifi Jim DeStefano, P.E. iswithDeStefano Associates www.structuremag.org thefi toprevent moldfrom growing in 3. Ensuring there isadequateventilation work area. heatingofthe methodsandtemporary 2. Reviewing coldweather protection above beams. deckhave been completelyfi 1. Making sure thefl In additiontotesting,thefi by an Thickness testingcanbeperformed The real payoff comeswithSpecial Inspec- A commoncomplaintamongststructural structural engineerslocatedinFairfi Visit STRUCTUREmagazine Visit oes notneedtobedelegateda reproofi How doIgetpaidto specify fi reproofi ng? ng. Thickness gagesare relatively on-line reproofi utes ofthemetal ng. It iswell worth reproofi lled

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