The$Evolu*on$of$Fire$Life$Safety$ in$building$codes$

Transcription

1 The$Evolu*on$of$Fire$Life$Safety$ in$building$codes$ A!look!at!the!history!of!development!of!our!building!codes! and!safety!opportuni8es!to!facilitate!wood!design! ini8a8ves.! Presented!on!March!4,!2015!by!Keith!Calder,!Sereca!Consul8ng!Inc.! Disclaimer:+This+presenta1on+was+developed+by+a+third+party+and+is+not+funded+by+ WoodWorks+or+the+So=wood+Lumber+Board.!

2 The!Wood!Products!Council!is! a!registered!provider!with!the! American!Ins8tute!of!Architects! Con8nuing!Educa8on!Systems! (AIA/CES),!Provider!#G516.!!! Credit(s)!earned!on!comple8on! of!this!course!will!be!reported!to! AIA!CES!for!AIA!members.! Cer8ficates!of!Comple8on!for! both!aia!members!and!nontaia! members!are!available!upon! request.!!! This!course!is!registered!with! AIA!CES!for!con8nuing! professional!educa8on.!as! such,!it!does!not!include! content!that!may!be!deemed! or!construed!to!be!an! approval!or!endorsement!by! the!aia!of!any!material!of! construc8on!or!any!method!or! manner!ovandling,!using,! distribu8ng,!or!dealing!in!any! material!or!product.! Ques8ons!related!to!specific!materials,! methods,!and!services!will!be!addressed! at!the!conclusion!of!this!presenta8on.!!!

3 Course$Descrip*on$ Over!the!last!80!years,!prescrip8ve!height!and!area! limita8ons!have!remained!rela8vely!unchanged!in!north! American!building!codes!while!technological!advances!and! fire!service!capabili8es!have!improved!considerably.!through! an!examina8on!of!historical!code!development!and! iden8fica8on!of!the!risk!factors!on!which!codes!are!based,! we!can!set!the!stage!for!a!retexamina8on!of!public! percep8on!with!regard!to!combus8ble!construc8on.!this! presenta8on!will!cover!techniques!for!mi8ga8ng!fire!damage! and!reducing!fire!spread!while!describing!how!an! understanding!of!code!intent!can!be!used!to!argue! equivalent!fire!performance!when!wood!solu8ons!lie!outside! typical!codetapproved!applica8ons.!!

4 Learning$Objec*ves$ Evaluate!the!evolu8on!of!fire!life!safety!codes,!including! the!impact!of!historical!fire!events!on!current! requirements.!! Review!the!building!size!limita8ons!in!current!codes!and! the!original!risk!factors!on!which!they!were!based.!t!.!! Explore!techniques!for!mi8ga8ng!fire!damage!and! methods!for!reducing!fire!spread.!! Demonstrate,!with!an!understanding!of!code!intent,!how! equivalent!fire!performance!can!be!achieved!through!the! alternate!means!and!methods!procedure.!

5 Objec*ve$ The!Interna8onal!Building!Code!(IBC)!limits!the!use!of!wood! in!larger!and!taller!buildings!rela8ve!to!other!materials! based!on!its!combus8bility! How!can!the!limita8ons!to!the!use!of!wood!be!addressed?! Development!of!alterna8ve!solu8ons!to!the!IBC! requirements!(equivalents),!or! Changes!to!the!IBC!requirements! How!is!this!achieved?! Iden8fica8on!of!the!risk!basis!of!the!limits! ReTexamina8on!of!the!risk!basis!in!a!current!context! Development!of!means!to!address!the!risk!

6 The$Challenge$

7 Building$Code$Regula*ons$ The!pace!of!innova8on!in!the!built! environment!is!increasing!and! innova8on!results!in!change! The!adaptability!of!a!building!code! to!change!is!a!func8on!of!its! regulatory!structure! The!IBC!is!a!compila8on!of! primarily!specifica8ontbased! regula8ons!supplemented!by!a! few!performancetbased! regula8ons!

8 Specifica*ons$ $Building$Size$Limits$ Building!size!limits!are!expressed!in!specifica8on!format:!

9 Specifica*ons$E$Development$ Incidents!of!significant!scale!or! impact!occur!and!draw!acen8on!to! building!design!issues! Inves8ga8on!and!analysis!follow!to! establish!the!condi8ons!that!led!to! the!incident! Solu8ons!are!developed!to!limit! future!incidents!and!are!based!on! contemporaneous!knowledge,! capability,!materials!and!methods! The!solu8ons!are!wricen!in! specifica8on!format,!becoming! frozen!in!8me! San Francisco Conflagration

10 Specifica*ons$ $Challenges$for$Alterna*ves$ 2012!IBC!!Sec8on!104.11,!Alterna8ve!materials,!design! and!methods!of!construc8on!and!equipment:! An!alterna8ve!material,!design!or!method!of!construc8on! shall!be!approved!where!the!building!official!finds!that!the! proposed!design!is!sa*sfactory$and$complies$with$the$ intent$of$the$provisions$of$this$code,!and!that!the! material,!method!or!work!offered!is,!for!the!purpose! intended,!at$least$the$equivalent$of!that!prescribed!in!this! code!in!quality,!strength,!effec8veness,!fire!resistance,! durability!and!safety!

11 Specifica*ons$ $Challenges$for$Code$Changes$ ICC!Code!Change!Policy:! Reasons:!The!proponent!shall!jus*fy!changing!the!current! Code!provisions,!sta8ng!why!the!code!change!proposal!is! superior$to$the$current$provisions$of$the$code.!code! change!proposals!which!add!or!delete!requirements!shall! be!supported!by!a!logical$explana*on$which$clearly$shows$ why$the$current$code$provisions$are$inadequate$or$overly$ restric*ve,$specifies$the$shortcomings$of$the$current$code$ provisions$and$explains$how$such$code$change$proposals$ will$improve$the$code.!

12 Specifica*ons$E$Challenges$ What!can!be!done?! R.S. Ferguson, NRC, 1959 This!is!the!case!for!the!height!and!area!limits!and!a! proposed!approach!to!a!solu8on!follows!

13 Approach$to$a$Solu*on$ Implicit$Risk:$What!is/was!the!risk!that! ini8ated!the!development!of!the! specifica8on(s)?! Mi*ga*ng$Measures:$What!knowledge,! capability,!materials!and!methods!were! considered!in!mi8ga8ng!the!risk?! Acceptable$Risk:$To!what!level!is/was! the!risk!mi8gated?! Current$Context:$Are!the!specifica8ons! s8ll!relevant?!retexamina8on!of! implicit!risk,!mi8ga8ng!measures!and! acceptable!risk.!

14 Implicit$Risk,$Mi*ga*on$Measures$and$ Acceptable$Risk$

15 Great$Fire$of$Rome$in$64$AD$

16 Summary$ $Early$Times$ Conflagra8ons!in!1087!and!1135!resul8ng!in!destruc8on!of! most!of!the!city!of!london! Majority!of!buildings!at!that!8me!were!constructed!of! wood,!roofed!with!straw.! High!building!density! Implicit$Risk:$ Mi*ga*on:$ Fire!spread!from!building!to!building!resul8ng!in!conflagra8on.! Stone!wall!between!houses:!3!feet!thick!(party!wall/firewall)! Acceptable$Risk:$ Limit!fire!spread!to!individual!buildings!(primarily!houses)!

17 London$ $Great$Fire:$1666$

18 Summary$ $London$1666$to$1774$ Implicit!Risk!Considera8ons! Implicit$Risk:$ Fire!spread!from!building!to!building!resul8ng!in!conflagra8on.! Mi*ga*on:$ Intended$ Result:$ Brick!or!stone!wall!between!houses:!13!inches!thick!and!18!inches! above!the!roof!(party!wall/firewall)! Brick!or!stone!exterior!walls! Limit!fire!spread!to!individual!buildings!(primarily!houses)!

19 London$1850 s$ 60 ft 60 ft 60 ft

20 London$ $Tooley$Street:$June$22,$1861$

21 Summary$ $London:$1774$to$1873$ Implicit!Risk!Considera8ons! Implicit$Risk:$ Mi*ga*on:$ Intended$ Result:$ Single!buildings!(warehouses)!increasing!in!size!resul8ng!in!fire!size! beyond!the!capability!of!the!responding!fire!department.! Increased!poten8al!for!conflagra8on.! Containment!by!limi8ng!height/volume!assuming!fire!service! interven8on! Height!of!60!to!65!l!and!cubic!capacity!of!216,000!cubic!feet.! Limit!fire!spread!to!individual!buildings.!

22 USA$1872$to$1930 s$ Great!Fire!of!Chicago!!October!10,!1871! Great!Fire!of!Boston!!November!9,!1872! These!fires!called!acen8on!to!the!substandard!condi8ons!of! construc8on!in!ci8es!across!the!united!states! Great Fire of Chicago

23 USA$1873$ $Standard$Building$ New!York!Board!of!Fire!Underwriters!!January!1873:! Standard!Building!height!and!area!limits! Note!that!the!volumetric! limit!based!on!an!area!of! 5,000!l 2!and!height!of!60! feet!is!300,000!l 3.!This! was!the!limit!for!exis8ng! warehouses!in!the!city!of! London!

24 USA$1872$to$1930 s$ $Insurance$Ra*ng$System$ Insurance!ra8ng!system!modifiers:! Feature$ Occupancy:! Type!of!Construc8on:! Accessibility:! Sprinklering:! Area:! Height:! Modifiers$ A!func8on!of!hazard!level!(experien8al)! Fireproof!and!nonTfireproof! Number!of!building!sides!facing!a!street! Gradual!recogni8on!of!benefit!with!increased!reliability! Incremental!increases/decreases!as!a!func8on!of!area! Incremental!increases!to!a!threshold!level!of!7!storeys!then! significant!increases!

25 USA$1890$to$1930 s$ $Model$Building$Code$ Insurance!ra8ng!schedule!translated!into!regula8on! Published!by!the!Na8onal!Board!of!Fire!Underwriters!in!1905! Base!area:!5,000!l 2! Area!modifiers:! Occupancy! Height! Type!of!construc8on! Streets!Facing! Sprinklers!

26 Summary$ $USA$1872$to$1930 s$ Implicit!Risk!Considera8ons! Implicit$Risk:$ Fire!size!beyond!the!capability!of!the!responding!fire!department! Significant!property!loss! Mi*ga*on:$ Intended$ Result:$ Increased!poten8al!for!conflagra8on! Height!of!5!to!6!storeys!(50!to!60!l)!and!base!area!of!5,000!square! feet! Increases!in!height!and!area!based!on!type!of!construc8on,! occupancy,!streets!facing!and!sprinklering! Limit!fire!spread!to!individual!buildings.!

27 USA$1920 s$to$current$ Limits!included!in!the!three!model!codes:! 1927!Uniform!Building!Code!(UBC)! 1946/1947!Southern!Standard!Building!Code!(SSBC)! 1950!Basic!Building!Code!(BBC)! These!limits!were!revised!and!evolved!up!to!1996! 1996!IBC!Occupancy!Commicee! Maximum!height!and!area!of!each!of!the!three!model!codes! was!adopted!for!use!in!the!ibc! Some!modifica8ons!as!a!result!of!differences!in!format!

28 Summary$ $$USA$1930 s$to$current$ Implicit!Risk!Considera8ons! Implicit$Risk:$ Inadequate!evacua8on! Mi*ga*on:$ Full!building!involvement! Fire!size!beyond!the!capability!of!the!responding!fire!department! Collapse!of!high!buildings!! Increased!poten8al!for!conflagra8on! Height!of!6!storeys!(50!to!60!l)!and!area!limits!as!a!func8on!of!occupancy,! type!of!construc8on,!firetresistance,!streets!facing!and!sprinklering.! Increases!in!height!and!area!based!on!type!of!construc8on,!occupancy,! streets!facing!and!sprinklering! Intended$Result:$ Combus8ble!buildings:!Limit!fire!spread!to!building! Noncombus8ble!buildings!(no!ra8ng):!Limit!fire!spread!to!building! Noncombus8ble!buildings:!Limit!fire!spread!to!storey!

29 Considera*ons$ $Current$Context$ Exis8ng!limits!set!long!ago!when!understanding! of!fire!engineering!was!limited! Since!then:! Firefigh8ng!techniques,!equipment,!response! and!overall!capability!has!advanced! significantly! Construc8on!methods!and!materials!have! advanced! Analysis!techniques!have!evolved!significantly! Sprinkler!effec8veness!has!increased!

30 Current$Context$

31 Approach$to$a$Solu*on$ Implicit$Risk:$What!is/was!the!risk!that! ini8ated!the!development!of!the! specifica8on(s)?! Mi*ga*ng$Measures:$What!knowledge,! capability,!materials!and!methods!were! considered!in!mi8ga8ng!the!risk?! Acceptable$Risk:$To!what!level!is/was! the!risk!mi8gated?! Current$Context:$Are!the!specifica8ons! s8ll!relevant?!retexamina8on!of! implicit!risk,!mi8ga8ng!measures!and! acceptable!risk.!

32 Current$Context$ AAA! Will changes to the Building Code to allow greater use of wood result in an increase in fire risk beyond that currently permitted in the 2012 IBC?

33 Current$Context:$Sta*s*cal$Analysis$ Growth!and!spread!of!fire!can!be! characterized!as!a!func8on!of!fire! type! Compartment! Concealed!space! Exterior! Current!fire!loss!sta8s8cs!collected! in!a!manner!that!does!not!correlate! with!building!code!principles! Data!collected!within!a! fire!type! framework!to!gauge!effec8veness!of! Codes! Published:!Interflam!2013,!London!

34 Completed$Context:$Sta*s*cal$Analysis$ Used!inThouse!fire!inves8ga8on!data! to!examine!framework! Data!collected!from!89,!3T4!story,! mul8tfamily!(apartment)!residen8al! fire!losses!over!a!10!year!period! Buildings!details! Built!between!1912!and!2008! Combus8ble!woodTframe! construc8on! 3!to!4!storeys!in!building!height! Mostly!unsprinklered!buildings!

35 Compartment$Fires$ Common!Causes! Smoking! Electrical!Equipment! Appliances! Incendiary! Fuel!Load! Combus8ble!contents! Combus8ble!interior!finish! Spread!Mechanisms! Exterior!spread!primarily!via!balconies! Inadequate!or!failure!of!enclosure!fire!separa8on!

36 Example$Compartment$Fire$ Three!storey!residen8al!apartment! structure! Fire!ini8ated!in!centre!of!living! room!as!a!result!of!smoking! materials! Fire!damage!contained!to!single! residen8al!unit!

37 Sta*s*cal$Summary$ $Compartment$Fires$ 16! 48!Fires! 14! 12! 90% Fire contained to (fire-rated) compartment of origin 10% Fire spread beyond (fire-rated) compartment of origin Number$of$Fires$ 10! 8! 6! 4! 2! Characteristics: 5 Fires Spread primarily via exterior balcony/windows or suite door 0! Increasing$Damage$

38 Current$Context:$Compartment$Fire$Spread$ 10%!spread!beyond!fire!rated!compartment!of!origin:! Spread$Mechanism$ Fire!in!compartment!with! open!door!to!corridor! Fire!in!compartment! impac8ng!window!to!exterior! Fire!in!compartment! impac8ng!window/door!to! balcony! Poten*al$Consequence$ a) Localized!burn!damage!to!public!corridor! a) Spread!up!cladding/balconies! b) Spread!into!arc!space! c) Spread!through!roof!structure,!drop!down!to!other! balconies! a) Balcony!fire!growth! b) Spread!up!cladding/other!balconies! c) Spread!into!arc!space! d) Spread!through!roof!structure,!drop!down!to!other! balconies!

39 Concealed$Space$Fires$ Common!Causes! Electrical! Worker s!torch! Fuel!Load! Combus8ble!construc8on! Combus8ble!insula8on! Combus8ble!cables! Spread!Mechanisms! Inadequate!fire!stopping! Service!penetra8ons!

40 Example$Concealed$Space$Fire$1$ Three!storey!residen8al!apartment!structure!separated!into! three!buildings!by!2!firewalls! Fire!ini8ated!in!concealed!wall!space!of!first!storey!as!a! result!of!worker!ac8vi8es! Fire!damage!to!two!building!components!and!water/smoke! damage!to!all!three!building!components! Structure!eventually!demolished!as!a!result!of!extent!of! damage!

41 Main$Floor$ Firewall

42 Example$Concealed$Space$Fire$1$ Service Penetrations Through a Firewall Fire Damage at Roof Level

43 Example$Concealed$Space$Fire$2$ Fire!ini8ated!in!concealed!wall!space!of!first!storey!as!a! result!of!worker!ac8vi8es! Fire!spread!to!roof!level!through!concealed!wall!assembly! with!inadequate!firestopping! Fire!spread!from!one!end!of!structure!to!other!through!roof! mansard! Structure!demolished!as!part!of!fire!figh8ng!ac8vi8es!

44 Example$Concealed$Space$Fire$2$

45 Example$Concealed$Space$Fire$2$ ¾-inch T&G Shiplap Floor assembly void space 2x7 inch joists Top Plate Wall void space 2x4 inch framed drop ceiling Floor assembly void space Unit 4 washroom 5/8-inch Gypsum Board 5/8-inch Donna-Conna 2x4 inch stud 2 inch insulation located between joists 5/8-inch Gypsum Board 2x4 inch stud 2 inch insulation located between joists

46 Example$Concealed$Space$Fire$2$ Interior of Mansard Mansard Roof

47 Example$Concealed$Space$Fire$2$

48 Example$Concealed$Space$Fire$2$

49 Sta*s*cal$Summary$ $Concealed$Space$Fires$ Number$of$Fires$ 9! 8! 7! 6! 5! 4! 16!Fires! 44% Fire contained to (fire-stopped) concealed space of origin Fire spread out of (fire-stopped) concealed space of origin 56% 3! 2! 1! Characteristics: 9 Fires Spread primarily via lack of fire stops/blocks 0! Increasing$Damage$

50 Completed$Building$Fire$Risk:$Eviden*ary$Risk$ Concealed$Space$Fires:$Fire$Spread$ 56%!spread!to!adjacent!concealed!spaces!or!compartments! :! Spread$Mechanism$ Poten*al$Consequence$ Fire!in!space!with!nonexistent! or!inadequate!fire!stopping/ blocking! Fire!in!space!with!nonexistent! or!inadequate!fire!stopping/ blocking! a) Spread!to!adjacent!fire!compartment! b) Spread!to!adjacent!concealed!space! a) Spread!from!storeyTtoTstorey! b) Spread!into!arc!space! c) Spread!through!roof!structure,!drop!down!to!other! balconies!

51 Exterior$Fires$ Common!Causes! Smoking!!peat!moss! Worker s!torch! Fuel!Load! Combus8ble!construc8on! Combus8ble!cladding! Spread!Mechanisms! Underside!of!balcony! Roof!soffit!

52 Example$Exterior$Fire$1$ Four!level!residen8al!apartment!structure!separated!into! three!buildings!by!2!firewalls! Fire!ini8ated!on!balcony,!spread!on!exterior!of!structure!to! concealed!roof!space! Roof!of!all!three!building!components!heavily!fire!damaged! Water!and!smoke!damage!to!remainder!of!the!structure! Structure!reconstructed!

53 Example$Exterior$Fire$1$

54 Example$Exterior$Fire$1$ Roof Level Damage

55 Example$Exterior$Fire$1$ ¼ inch Space at Top of Fire Block

56 Example$Exterior$Fire$2$ Four!level!residen8al!apartment!structure! Fire!ini8ated!inside!and!was!transferred!to!the!balcony!by! the!tenant! Fire!spread!along!cladding!to!roof!space.! Roof!heavily!fire!damaged! Water!and!smoke!damage!to!remainder!of!the!structure!

57 Example$Exterior$Fire$2$

58 Example$Exterior$Fire$2$

59 Example$Exterior$Fire$3$ Four!level!residen8al!apartment!structure! Sprinklered!in!accordance!with!NFPA!13R! Fire!ini8ated!on!balcony,!spread!through!aluminum!clad! soffit!to!unsprinklered!concealed!roof!space! Roof!heavily!fire!damaged! Water!and!smoke!damage!to!remainder!of!the!structure!

60 Example$Exterior$Fire$3$

61 Example$Exterior$Fire$3$

62 Example$Exterior$Fire$3$

63 Sta*s*cal$Summary$ $Exterior$Fires$ 25! 25!Fires! Number$of$Fires$ 20! 15! 10! 8% Fire spread limited to single storey 92% Fire spread beyond single storey to entire wall/roof 5! Characteristics: 23 Fires Spread primarily via cladding/soffit, into roof space 0! Increasing$Damage$

64 Completed$Building$Fire$Risk:$Eviden*ary$Risk$ Exterior$Fires:$Fire$Spread$ 92%!spread!beyond!fire!rated!compartment!of!origin:! Spread$Mechanism$ Exterior!fire!impinging!on! cladding! Poten*al$Consequence$ a) Spread!up!cladding/balconies! b) Spread!into!arc!space! c) Spread!through!roof!structure,!drop!down!to!other! balconies! Balcony!fire! a) Balcony!fire!growth!(limited!detec8on)! b) Spread!up!cladding/other!balconies! c) Spread!into!arc!space! d) Spread!through!roof!structure,!drop!down!to!other! balconies!

65 Overall$Sta*s*cal$Summary$ Course!of!Construc8on! 25! 20! Compartment! Concealed! Exterior! Number$of$Fires$ 15! 10! 57% 43% 5! 0! Increasing$Damage$

66 Current$Context:$Summary$ FireTrated!compartments:! Unsprinklered:!perform!as!intended!by!the!Codes,!limi8ng!the! growth!and!spread!of!fire!to!the!compartment!of!origin!regardless! of!building!size!or!height.! Sprinklered:!rarely!result!in!fire!spread!beyond!compartment.! Compartmenta*on$is$effec*ve!$Na8onal!Research!Council!Canada:! Canada!T!Standing!Commicee!on!Fire!Protec8on!1990 s:!

67 Current$Context:$Summary$ Concealed!Spaces:! Fire!spread!predominantly!as!a!result!of!lack!of!fire!stopping/ blocking! Lack!of!fire!stopping/blocking!observed!in!older!preT1980 s! buildings! Use!of!fire$stopping/blocking$has!improved!significantly!since!the! 1980 s!and!is$effec*ve!$ Exterior!Fires:! Fire!spread!predominantly!as!a!result!of!balcony!fire!development,! combus8ble!exterior!cladding!and!spread!into!arc!spaces! Significantly!reduced!by!sprinklering!balconies!and!arc!spaces! Sprinklering$is$effec*ve!$

68 Current$Context:$Summary$ Fire!compartmenta8on! Fire!stopping/blocking! Sprinklering!

69 Future$Considera*ons$

70 Future$Considera*ons$E$Capability$ ReTexamine!fire!service!capability!rela8ve!to!building!size! Equitable Fire Los engine building Angeles, design fire, February New Jacques York, 05, 1912 Besson,

71 Future$Considera*ons$E$Materials$ Consider!materialTindependent!fire!performance! Original!assump8on:!Material!contribu8on!to!fire! considered!significant!t!conflagra8ons! What!is!the!actual!risk!associated!with!material! contribu8on?! Limited!research! Forensic!experience!suggests!material!contribu8on!to!fire! not!significant! More!research!required!

72 Future$Considera*ons$ $Analyses$Techniques$ Analysis!techniques!have!advanced!significantly! in!the!last!several!decades!and!! Becer!able!to!analyze!and!predict:! Material!behavior!to!fire! Fire!growth!and!spread! Occupant!response!and!movement! Risk!analysis!

73 Future$Considera*ons$ $Methods$ Original!limits!were!established!at!a!8me!when!building! compartmenta8on!was!minimal:! Open!stairs,!! Unprotected!elevators/shals! Risk!of!fire!spread!to!involve!en8re!building!was!greater! than!it!is!today!(sta8s8cs)! Fire$compartmenta*on$has$increased$significantly$over$ *me$ Consider!the!fire!compartment!as!the!unit!of!control!

74 Future$Considera*ons$ $Methods$Con*nued$ Limit!fire!compartment!areas!rather! than!building!height!and!area:! NFPA!5000,!Appendix!D,!Enhanced! Fire!Compartments! New!Zealand!approach!

75 Summary$ Current!codes!are!not!en8rely!based!on!current!technology!or! relevant!fire!data! Life!safety!and!property!can!be!preserved!in!woodTbased! structures!through!reasonable!design!measures!to!address!the! risk!of!fire!spread! Codes!need!to!change!to!keep!pace!with!innova8on!and! embrace!current!technology! Implementa8on!of!material!independent!fire!performance! Compartmenta8on!as!unit!of!control!rather!than!a!building!

76 Ques8ons?$ Keith!Calder! Sereca!Consul8ng!Inc.!