Fire Resistance Design Primer for Mass Timber Construction

Transcription

1 Fire Resistance Design Primer for Mass Timber Construction (AWC presentation DES602-2) Paul Coats, PE, CBO Southeast Region Manager American Wood Council

2 The American Wood Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES), Provider # Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. Participants may download the presentation here: es This course is registered with AIA CES for continuing professional education. 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 construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 2

3 COURSE DESCRIPTION This presentation examines how fire resistance ratings in the 2015 International Building Code (IBC) apply to mass timber and heavy timber construction. Topics include how the IBC incorporates fire testing and calculation methods to quantify fire resistance as well as how various materials, including wood, behave when exposed to high temperatures in fires. Discussion will include code compliant calculation methods for fire resistance ratings of wood frame assemblies and for wood members exposed to fire per the 2015 National Design Specification (NDS ) for Wood Construction Chapter 16. Mass timber fire resistance ratings when fully exposed or provided with some degree of noncombustible protection is addressed based on current and proposed future code provisions. Also included is information on fire testing, practical considerations for navigating 2015 IBC Chapter 7 on fire and smoke protection features, and an introduction to cross laminated timber (CLT). 3

4 LEARNING OBJECTIVES Upon completion, participants will be better able to: Visualize how mass timber and heavy timber building elements behave when subjected to fire. 1 3 Learn how fire resistance ratings of wood assemblies and mass timber are calculated. 2 4 Understand basic methods to achieve fire resistance ratings in the 2015 IBC. Utilize an introduction to CLT as incorporated in the 2015 IBC along with future code change concepts to form a basis of understanding about taller and larger timber structures. 44

5 ABOUT AWC Codes and Standards Green Building Manufacturing Environmental Regulation Advocacy and Public Policy E n t e r P r e s e n t a t i o n T i t l e H e r e 5

6 CO DE ASSISTANCE AWC FIELD STAFF Dennis Richardson West Jim Smith Midwest Matt Hunter Northeast Dave Tyree South Central Paul Coats Southeast Sam Francis National Director

7 Free to Qualified Officials Free Standard Pubs Discounts Code Official Connections WoodPost Newsletter WoodWorks Software 7

8 Education Resources In-Person Seminars Monthly Webinars Recorded Presentations CEUs Available 8

9 Education Resources Education Tab 9

10 Professional Directory Pubs Discounts IMPACT Newsletter Design Professional Membership WoodPost Newsletter Wood Design Focus Wood Design & Building 10

11 Outline fire resistance design for mass timber 1. IBC principles--heavy timber and mass timber 2. Fire resistance rating methods and details 3. Mass timber fire testing 11

12 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Image courtesy of Fast + Epp 12

13 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Cross-laminated timber 13

14 CANADIAN PR O JECTS E n t e r P r e s e n t a t i o n T i t l e H e r e 14

15 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER mass timber conventional frame 15

16 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER mass timber traditional heavy timber 16

17 TYPE IV HEAVY TIMBER 17

18 TYPE IV HEAVY TIMBER SUPPORTING: HEAVY TIMBER CONSTRUCTION ELEMENT Width, inch Floor Column; loads Framed sawn or only; glued-laminated timber arches, which combined spring from the floor line; floor and Framed timber trusses roof loads Roof loads only MINIMUM NOMINAL SOLID SAWN SIZE Depth, inch MINIMUM GLUED- LAMINATED NET SIZE Width, inch Depth, inch MINIMUM STRUCTURAL COMPOSITE LUMBER NET SIZE Width, inch Depth, inch ¾ 8 ¼ 7 7 ½ Wood beams and girders ½ 5 ¼ 9 ½ ¼ 5 ¼ 7 ½ Lower half of: Wood-frame or gluedlaminated arches, which spring from the floor line or from grade; Column; Upper half of: Wood-frame or gluedlaminated arches, which spring from the floor line or from grade; Framed or glued-laminated arches that spring from the top of walls or wall abutments; Framed timber trusses and other roof framing ¼ 5 ½ 4 a /8 3 ½ 5 ½ Source: 2018 IBC Table

19 TYPE IV HEAVY TIMBER Exterior walls: Noncombustible materials, FRTW, or protected CLT 19

20 TYPE IV HEAVY TIMBER 20

21 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Heavy timber fire resistance = minimum prescriptive dimensions 21

22 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Heavy timber fire resistance = minimum prescriptive dimensions 22

23 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Heavy timber fire resistance = minimum prescriptive dimensions Mass timber fire resistance = minimum dimensions for a calculated fire resistance; or 23

24 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Heavy timber fire resistance = minimum prescriptive dimensions Mass timber fire resistance = minimum dimensions for a calculated fire resistance; or noncombustible protection for the wood; or 24

25 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Heavy timber fire resistance = minimum prescriptive dimensions Mass timber fire resistance = minimum dimensions for a calculated fire resistance; or noncombustible protection for the wood; or BOTH 25

26 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Waugh Thistleton Architects (Stradthaus Murry Grove) 26

27 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Noncombustible (703.5) Fire resistant (703.2 and 703.3) 27

28 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Noncombustible = Section 703.5: ASTM E136 tested (elementary materials) plus thick material with flamespread 50 per ASTM E84 or UL 723 (composite materials) 28

29 I BC PRINCIPLES FOR HEAVY TIMBER AND MASS TIMBER Fire resistant = Section 703.2: ASTM E119 or UL 263 tested; or Section 703.3: Other methods for establishing fire resistance (based on the fire exposure and acceptance criteria of ASTM E119 or UL 263) 29

30 FIRE RESISTANCE RATING METHODS Methods for establishing fire resistance (703): 1. Tested fire assembly (ASTM E119 or UL 263) 2. Fire-resistance designs documented in approved sources 3. Prescriptive assemblies using fire-resistance rated designs in Section Calculation of fire-resistance per Section Engineering analysis based on a comparison of building element, component or assembly designs that have been tested 6. Alternative protection methods per Section Fire-resistance designs certified by an approved agency 30

31 FIRE RESISTANCE RATING METHODS Methods for establishing fire resistance (703): 1. Tested fire assembly (ASTM E119 or UL 263) 2. Fire-resistance designs documented in approved sources 3. Prescriptive assemblies using fire-resistance rated designs in Section Calculation of fire-resistance per Section Engineering analysis based on a comparison of building element, component or assembly designs that have been tested 6. Alternative protection methods per Section Fire-resistance designs certified by an approved agency 31

32 CALCULATED FIRE RESISTANCE Wood at high temperature: - low thermal conductivity - dimensionally stable - inner portion remains cool - does not lose strength 32

33 CALCULATED FIRE RESISTANCE IBC Chapter 16 TR-10 33

34 CALCULATED FIRE RESISTANCE 34

35 CALCULATED FIRE RESISTANCE 35

36 CALCULATED FIRE RESISTANCE 36

37 CALCULATED FIRE RESISTANCE Glued-lam: tension lam provisions 37

38 CALCULATED FIRE RESISTANCE CLT: modified char depth model 38

39 CALCULATED FIRE RESISTANCE 39

40 CALCULATED FIRE RESISTANCE Determination of effective CLT residual crosssection Assume 1.5 each ply = 7.5 Determine thickness for 1-hour rating a char = 1.8 (NDS Table B) d = = 5.7 Could conservatively assume 3-ply panel for design

41 CALCULATED FIRE RESISTANCE Heavy timber fire resistance = minimum prescriptive dimensions Mass timber fire resistance = minimum dimensions for a calculated fire resistance; or noncombustible protection for the wood; or BOTH 41

42 CALCULATED FIRE RESISTANCE FRR of Element = FRR of Wood + FRR of Added Gypsum 42

43 CALCULATED FIRE RESISTANCE PERCENTAGE OF MATERIAL STRENGTH 2012 IBC Code & Commentary 43

44 CALCULATED FIRE RESISTANCE 44

45 CALCULATED FIRE RESISTANCE - CONNECTIONS Source: US CLT Handbook 45

46 CALCULATED FIRE RESISTANCE - CONNECTIONS Source: US CLT Handbook E n t e r P r e s e n t a t i o n T i t l e H e r e 46 46

47 CALCULATED FIRE RESISTANCE - CONNECTIONS A B C Source: US CLT Handbook E n t e r P r e s e n t a t i o n T i t l e H e r e 47 47

48 CALCULATED FIRE RESISTANCE - CONNECTIONS Source: US CLT Handbook E n t e r P r e s e n t a t i o n T i t l e H e r e 48 48

49 CALCULATED FIRE RESISTANCE - CONNECTIONS 49

50 MASS TIMBER FIRE TESTING CLT Test Report WP

51 MASS TIMBER FIRE TESTING Residential Fire Load Demonstration

52 MASS TIMBER FIRE TESTING Residential Fire Load Demonstration

53 MASS TIMBER FIRE TESTING Residential Fire Load Demonstration

54 MASS TIMBER FIRE TESTING 54

55 MASS TIMBER FIRE TESTING 55

56 MASS TIMBER FIRE TESTING Residential Fire Load Demonstration

57 MASS TIMBER FIRE TESTING Residential Fire Load Demonstration

58 MASS TIMBER FIRE TESTING 58

59 MASS TIMBER FIRE TESTING Type IV: Type IV-C: Type IV-B: Type IV-A: -minimum heavy timber dimensions; -minimum heavy timber dimensions -minimum heavy timber dimensions -minimum heavy timber dimensions -no concealed spaces -MINIMUM fire resistance ratings -INCREASED fire resistance ratings -MAXIMUM fire resistance ratings -protected concealed spaces -protected concealed spaces -protected concealed spaces? -PROTECTION required (gypsum covering, multiple layers, most surfaces) -COMPLETE PROTECTION required (gypsum covering, multiple layers, for all surfaces) 12 STORIES? 20 STORIES? E n t e r P r e s e n t a t i o n T i t l e H e r e 59 Fire-Resistance Design Primer for Mass Timber Construction

60 MASS TIMBER FIRE TESTING ATF Fire Research Laboratory

61 MASS TIMBER FIRE TESTING ATF Fire Research Laboratory

62 MASS TIMBER FIRE TESTING ATF Fire Research Laboratory

63 MASS TIMBER FIRE TESTING ATF Fire Research Laboratory

64 MASS TIMBER FIRE TESTING ATF Fire Research Laboratory

65 MASS TIMBER FIRE TESTING ATF Fire Research Laboratory

66 Construction Fire Safety Coalition: constructionfiresafety.org 66

67 My contact info: This concludes the American Institute of Architects Continuing Education Systems Course T h i s p r e s e n t a t i o n i s p r o t e c t e d b y U S a n d I n t e r n a t i o n a l C o p y r i g h t l a w s. R e p r o d u c t i o n, d i s t r i b u t i o n, d i s p l a y a n d u s e o f t h e p r e s e n t a t i o n w i t h o u t w r i t t e n p e r m i s s i o n o f A m e r i c a n W o o d C o u n c i l ( A W C ) i s p r o h i b i t e d. A m e r i c a n W o o d C o u n c i l