Mid- Rise Wood Frame Fire and Life Safety Requirements. Presented by: Ethan Mar0n, P.E. February 24 & 25, 2016

Transcription

1 Mid- Rise Wood Frame Fire and Life Safety Requirements Presented by: Ethan Mar0n, P.E. February 24 & 25, 2016

2 Outline Mid- Rise Construc0on Types & Life Safety Review Exterior Walls Interior Walls Fire Walls Fire Barriers Fire Par00ons ShaN Walls Corridors

3 Type III Construc>on Exterior walls are of noncombus0ble materials and interior building elements are of any material. Fire Retardant Treated (FRT) wood is permised in exterior walls of 2hr fire ra0ng or less. Non combus0ble Exterior walls Fire Retardant Treated allowed Exterior walls if fire ra0ng is 2hr or less Heavy Timber HT used in place of 1hr ra0ng or less Untreated Lumber All interior elements

4 Type V Construc>on Type V are generally combus0ble such as wood although V permits any material permised by code All structural elements can be combus0ble construc0on: Exterior walls Floor Roof Interior walls

5 Fire Resistance Ra>ngs Key Differences in Fire Ratings for Construction Types IIIA IIIB VA Exterior (bearing) wall framing FRT FRT non-frt Exterior bearing wall fire rating 2 hr 2 hr 1 hr Interior bearing wall fire rating 1 hr 0 hr 1 hr Interior non-bearing wall fire rating 0 hr 0 hr 0 hr Floor assembly fire rating 1 hr 0 hr 1 hr Fire wall rating 3 hr 3 hr 2 hr IBC Tables 601 & Note: FRT = Fire Retardant Treated

6 Fire Performance Combus>bility Fire Resistance Flame Spread Classificaiton

7 Fire- Resistance Rated Wall Assemblies Fire- Resistance Ra>ng: The period of 0me a building element, component or assembly maintains the ability to confine a fire, con0nues to perform a given structural func0on, or both, as determined by the tests, or the methods based on tests, prescribed in Sec0on 703. Tested under a standardized test fire exposure for a given dura0on to: 1. Prevent the passage of flame and temperature rise from one side to the other 2. Con0nue to provide ver0cal structural support when exposed to fire and elevated temperatures Fire Confinement Structural Performance

8 Fire- Resistance Rated Wall Assemblies There are five basic types of fire- resistance rated wall assemblies: Light Frame Bearing Walls (IBC ) Exterior Walls (IBC 705) Fire Wall or Party Wall (IBC 706) Fire Barrier (IBC 707) Fire Par00on (IBC 708)

9 Light Frame Bearing Walls (IBC ) King studs, jack studs, and boundary elements may have fire- resistance ra0ng provided by membrane in load bearing wall Typ. Bearing Wall Opening Framing

10 Outline Mid- Rise Construc0on Types & Life Safety Review Exterior Walls Interior Walls Fire Walls Fire Barriers Fire Par00ons ShaN Walls Corridors

11 Exterior Wall Fire Resistance

12 Exterior Wall Bearing vs. Non Bearing Non loading- bearing exterior walls may have lower fire resistance ra0ng requirements than bearing walls in certain situa0ons. IBC Chapter 2 defines load bearing walls as:

13 Exterior Walls - FSD Basic assump0on is that fires begin at the interior and rated wall assemblies are not required from the exterior unless close to another structure. Interior Fire Protec0on on Inside of Building Exterior

14 Exterior Walls (IBC 705) Fire Resistance Ra>ngs: Exterior walls shall be fire- resistance rated in accordance with Tables 601 and 602 and this sec0on. The required fire- resistance ra0ng of exterior walls with a fire separa0on distance of greater than 10 feet (3048 mm) shall be rated for exposure to fire from the inside. The required fire- resistance ra0ng of exterior walls with a fire separa0on distance of less than or equal to 10 feet (3048 mm) shall be rated for exposure to fire from both sides. Lot Line X < 10 Exterior Interior Table 601 & 602

15 Exterior Wall Fire Ra>ngs Using the provisions of sec>on and Tables 601 and 602 could result in requiring a 1 hour or 2 hour ra>ng on the inside face of exterior walls, while no ra>ng is required on the exterior face of exterior walls. How do we specify such an asymmetric assembly? This is where prescrip>ve code methodology begins to break down: procedural data does not align with requirements. Most building jurisdic>ons understand that this is a deficiency of the system and will recognize one tested assembly for the outside and a second for the inside.

16 Type III Exterior Walls FRT Type III and IV Construc>on - IBC Sec>on 602.3: Fire- retardant- treated wood framing complying with Sec0on shall be permised within exterior wall assemblies of a 2- hour ra0ng or less What does this FRTW requirement include? Wall Framing (Studs & Plates) Yes Wall Sheathing Yes Floor sheathing? Rim Joist? Floor Joists? Everything in the plane of the wall? Or only wall framing?

17 Exterior Walls Structural Stability Structural Stability: The wall shall extend to the height required by Sec0on and shall have sufficient structural stability such that it will remain in place for the dura0on of 0me indicated by the required fire- resistance ra0ng. Where exterior walls have a minimum fire separa0on distance of not less than 30 feet (9144 mm), interior structural elements which brace the exterior wall but which are not located within the plane of the exterior wall shall have the minimum fire- resistance ra0ng required in Table 601 for that structural element. Structural elements which brace the exterior wall but are located outside of the exterior wall or within the plane of the exterior wall shall have the minimum fire- resistance ra0ng required in Tables 601 and 602 for the exterior wall.

18 Exterior Walls Ver>cal Offsets There is no requirement for an exterior wall to extend to the founda>on in a stepped building. Posts, beams or walls, that support a rated exterior wall must be fire resistance rated not less than the ra0ng of the supported wall (IBC ) Exterior wall No less than Same ra>ng as wall above Exterior wall

19 Exterior Walls Addi>on of WSP Can include WSP in assemblies which were tested without them: ESR 2586 AWC s DCA4 Gypsum Associa0on Manual GA Fire Resistance Design Manual item 23 in Sec0on 1 of the General Explanatory Notes: "When not specified as a component of a fire- resistance rated wall or par66on system, wood structural panels shall be permi;ed to be added to one or both sides. ESR 2586:

20 Exterior Walls Using FRT Studs Wood stud walls may contain fire- retardant- treated studs as well as untreated wood studs. The use of fire- retardant- treated plywood (wood structural panels) may be used in Designs that contain use of untreated plywood when all other specified a;ributes are equivalent to the wood structural panel used in the Design.

21 Intersec>on of Assemblies - Ra>ngs Key Differences in Fire Ratings for Construction Types IIIA IIIB VA Exterior (bearing) wall framing FRT FRT non-frt Exterior bearing wall fire rating 2 hr 2 hr 1 hr Floor assembly fire rating 1 hr 0 hr 1 hr Fire wall rating 3 hr 3 hr 2 hr IBC Tables 601 & Note: FRT = Fire Retardant Treated

22 Intersec>on of Tested Assemblies 2 Hour Wall

23 Intersec>on of Tested Assemblies 1 Hour Floor

24 Intersec>on of Tested Assemblies Many op>ons are available for fire resistance tested floor assemblies and wall assemblies No tested intersec>on details exist We must understand the intent of the code, provide a ra>onale that meets the code s intent, and u>lize available informa>on and tes>ng results 2 Hour Wall 1 Hour Floor 2 Hour Wall

25 Outline Mid- Rise Construc0on Types & Life Safety Review Exterior Walls Interior Walls Fire Walls Fire Barriers Fire Par00ons ShaN Walls Corridors

26 Interior Fire- Rated Walls: Differences Fire walls Openings are protected Con0nuous from founda0on to/through roof Structural stability per Fire Barrier Con0nuous from floor through concealed space Fire Par00on: Openings are protected May terminate at a fire rated floor/celiling/ roof assembly

27 Fire Walls Ra>ngs & Materials IBC Fire walls shall be of any approved non- combus0ble materials. Excep>on: Buildings of Type V construc0on

28 Fire Walls Structural Stability Structural Stability: Fire walls shall have sufficient structural stability under fire condi0ons to allow collapse of construc0on on either side without collapse of the wall for the dura0on of 0me indicated by the required fire- resistance ra0ng or shall be constructed as double fire walls in accordance with NFPA 221.

29 Fire Walls Ra>ngs & Materials Opportunity for Wood Framed Fire Walls: Permieed in type V Construc>on Fire Walls in type V Construc>on of A, B, E, R and several other occupancies may be 2 hour Fire Walls in type III and IV construc>on are required to be constructed of non- combus>ble materials Opportunity for wood frame bearing walls on each side of fire wall to meet structural stability requirements

30 Fire Barriers IBC 707 Commonly used in: ShaN enclosures Interior exit stairway Exit stairway enclosures Exit passageways Incidental uses Separated occupancies Fire Areas Fire Barrier Example 2012 IBC Code & Commentary

31 Fire Barriers IBC 707 Fire Barriers: May be constructed with any materials permised by the construc0on type Fire Resistance Ra0ngs: ShaN Enclosures: IBC Hr when connec0ng 4 stories or more, 1 hr if less Separated Occupancies: IBC Table Fire Areas: IBC Table

32 Fire Barriers IBC : Con0nuity: Fire barriers shall extend from the top of the founda0on or floor/ceiling assembly below to the underside of the floor or roof sheathing, slab or deck above and shall be securely asached thereto. Such fire barriers shall be con0nuous through concealed space, such as the space above a suspended ceiling Suppor0ng Construc0on: The suppor0ng construc0on for a fire barrier shall be protected to afford the required fire- resistance ra0ng of the fire barrier supported. Hollow ver0cal spaces within a fire barrier shall be fireblocked in accordance with Sec0on at every floor level. Other requirements for openings, penetra0ons, joints

33 Fire Barriers IBC 707 Common Detailing Method: Fire Barrier & membrane extend to underside of floor deck above

34 Fire Par>>ons IBC 708 Commonly used to separate: Dwelling or sleeping units in same bldg. Tenant spaces in malls Corridor walls Minimum 1 hr ra0ng except: Some corridors Separate dwelling units in VB and IIB Fire Par00on Example 2012 IBC Code & Commentary

35 Fire Par>>ons IBC 708 Fire Par>>ons: May be constructed with any materials permised by the construc0on type Fire Resistance Ra0ngs: Fire par00ons shall have a fire- resistance ra6ng of not less than 1 hour. Excep>ons: 1. Corridor walls permised to have a 1 / 2 hour fire- resistance ra0ng by Table Dwelling unit and sleeping unit separa0ons in buildings of Type IIB, IIIB and VB construc0on shall have fire- resistance ra0ngs of not less than 1 / 2 hour in buildings equipped throughout with an automa0c sprinkler system in accordance with Sec0on

36 Fire Par>>ons IBC Con>nuity. Fire par00ons shall extend from the top of the founda0on or floor/ceiling assembly below to the underside of the floor or roof sheathing, slab or deck above or to the fire- resistance- rated floor/ceiling or roof/ceiling assembly above, and shall be securely asached thereto. In combus0ble construc0on where the fire par66ons are not required to be con0nuous to the sheathing, deck or slab, the space between the ceiling and the sheathing, deck or slab above shall be fireblocked or dranstopped in accordance with Sec0on and at the par00on line. The suppor0ng construc0on shall be supported to afford the required fire- resistance ra0ng of the wall supported, except for...walls separa0ng dwelling units, walls separa0ng sleeping units, and corridor walls, in buildings of Type IIB, IIIB and VB construc0on.

37 Fire Par>>ons IBC 707 Common Detailing Method: Fire Par00on & membrane stop at underside of rated floor/ceiling with fireblocking/dranstopping if required

38 Outline Mid- Rise Construc0on Types & Life Safety Review Exterior Walls Interior Walls Fire Walls Fire Barriers Fire Par00ons ShaN Walls Corridors

39 Shag Walls Types of Shags: Elevator Stair Mechanical Some points of shag wall construc>on apply to any type of shag. Some are unique to each type of shag. Requirements in the code do not differen>ate between these different types of shags.

40 Detailing: Shag Walls vs. Exterior Walls IBC 713.2: Shag Walls shall be constructed as Fire Barriers Key Differences between Exterior Walls and Shag Walls (Fire Barriers) Con>nuity Suppor>ng Construc>on Fire Resistance Ra>ngs Construc>on Materials

41 Detailing: Shag Walls vs. Exterior Walls Shag Wall Requirements: 707.5: Fire Barrier Con>nuity: Must extend from top of the founda0on or floor/ceiling assembly below to the underside of the floor or roof sheathing Through concealed spaces : Suppor>ng Construc>on: The suppor0ng construc0on for a fire barrier shall be protected to afford the required fire- resistance ra0ng of the fire barrier supported.

42 Detailing: Shag Walls vs. Exterior Walls Shag Wall Requirements: Fire- Resistance Ra>ng: 2 hours (4 stories or more) 1 hour (less than 4 stories) Number of connected stories includes basement but not mezzanine Fire ra0ng shall not be less than floor assembly penetrated, but need not exceed 2 hours 707.2: Construc>on Materials: Any permised by construc0on type FRTW not required for shan walls in types III, IV, V

43 Detailing: Shag Walls vs. Exterior Walls How do we achieve these requirements? Con>nuity: The general requirements in were not wrisen with plasorm construc0on in mind... they were asemp0ng to preclude large open concealed spaces to provide a con0nuous barrier between one por0on of the building and another Many jurisdic0ons have recognized that con0nuity of the fire barrier s fire protec0on can be maintained even if the wall framing does not extend to the underside of the decking above

44 Detailing: Shag Walls vs. Exterior Walls Suppor>ng Construc>on: Must have same fire resistance ra0ng as fire barrier being supported

45 Detailing: Shag Walls vs. Exterior Walls Suppor>ng Construc>on: In plasorm and semi- balloon frame construc0on, if we have a 2 hour shan wall and a 1 hour floor, how do we achieve this? If we are able to demonstrate the wall s 2 hour con0nuity, should not need to consider the floor suppor0ng construc0on? 1 Hour Floor 2 Hour Wall

46 Outline Mid- Rise Construc0on Types & Life Safety Review Exterior Walls Interior Walls Fire Walls Fire Barriers Fire Par00ons ShaN Walls Corridors

47 Corridors Fire Resistance Ra>ngs Check requirements of IBC Tables 601 and for Corridor Wall and Floor/Ceiling Fire- Resistance Ra0ngs

48 Corridors Fire Resistance Ra>ngs

49 Corridor Walls IBC : Corridor walls required to be fire- resistance rated shall comply with Sec0on 708 for fire par00ons Fire- resistance ra>ng. Fire par00ons shall have a fire- resistance ra0ng of not less than 1 hour. Excep0on: Corridor walls permised to have a 1 / 2 hour fire- resistance ra0ng by Table (applies to R occupancies with sprinkler systems)

50 Corridor Walls Con>nuity. Fire par00ons shall extend from the top of the founda0on or floor/ceiling assembly below to the underside of the floor or roof sheathing, slab or deck above or to the fire- resistance- rated floor/ceiling or roof/ceiling assembly above, and shall be securely asached thereto. Excep>ons: 2. Where the room- side fire- resistance- rated membrane of the corridor is carried through to the underside of the floor or roof sheathing, deck or slab of a fire- resistance- rated floor or roof above, the ceiling of the corridor shall be permised to be protected by the use of ceiling materials as required for a 1- hour fire- resistance- rated floor or roof system. 3. Where the corridor ceiling is constructed as required for the corridor walls, the walls shall be permised to terminate at the upper membrane of such ceiling assembly.

51 Corridor Walls Excep>on 2

52 Corridor Walls Excep>on 3

53 Ques>ons? Ethan Mar>n, P.E. Pacific Northwest Regional Director WoodWorks

54 Copyright Materials This presenta0on is protected by US and Interna0onal Copyright laws. Reproduc0on, distribu0on, display and use of the presenta0on without wrisen permission of the speaker is prohibited. The Wood Products Council 2016