Learning Objectives. Copyright Materials NONSTRUCTURAL PROVISIONS FOR MULTI STORY WOOD FRAMED BUILDINGS 2009 WASHINGTON STATE BUILDING CODE (WSBC )

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1 NONSTRUCTURAL PROVISIONS FOR MULTI STORY WOOD FRAMED BUILDINGS 2009 WASHINGTON STATE BUILDING CODE (WSBC ) Prepared dfor Wood dproducts Council WoodWorks Presented by James E. Churchill, P.E. ChurchillEngineering Engineering, Inc. The Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates t of Completion for both AIA members and non-aia members are available upon request. This program 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. Churchill Engineering, Inc. 1 Copyright Materials This presentation is protected by US and International Copyright laws. Reproduction, distribution, ib ti display and use of the presentation ti without written permission of the speaker is prohibited. The Wood Products Council 2011 Learning Objectives At the end of this program, participants will be able to: 1. Participantswill be provided with an overview of non structural provisionsof of the code governing multi story wood frame buildings and be able to more easily navigate through the code. 2. Participants will be provided ddwith an overview of mezzanines and be able to optimize the square footage of a building using mezzanines per the code. 3. Participants will be provided with examples of alternate designs and understand the process for utilizing similar methods on future projects. 4. Participants will be provided with examples of buildings as well as information on how aspects of building height, hihtexterior wall construction, ti opening protection, ti fire walls, fire protections systems, and means of egress effect the building and the participant will be able to optimize the design of the building using these concepts.

2 PRESENTATION OVERVIEW Section 503 General Height and Area Limitations Table GENERAL BUILDING HEIGHTS AND AREAS Automatic Sprinkler Increases Frontage Increase 2. MIXED USE AND OCCUPANCY Accessory, Nonseparated Occupancies & Separated Occupancies 3. SPECIAL PROVISIONS (PODIUM BUILDINGS) Occupancies Permitted 4. TYPE OF CONSTRUCTION (TYPE III, IV & V) Fire retardant treated Wood Exterior Wall Fire resistive Requirements 5. Exterior Wall Openings 6. Fire Walls Diaphragm Continuity Noncombustible Construction 7. Means of Egress Accessible Means of Egress 8. Alternate Designs Examples Churchill Engineering, Inc. 5 Churchill Engineering, Inc. 6 Table 503 WSBC SECTION 504 Height (Number of Stories) Automatic Sprinkler Increase (NFPA 13) Height and area increases permitted together for all occupancies. Exceptions: 1. Buildings, or portions of buildings, classified as a Group I 2 occupancy of Type IIB, III, IV or V construction. 2. Buildings, or portions of buildings, classified as a Group H 1, H 2, H 3or H 5 occupancy. 3. Fire resistance rating substitution in accordance with Table 601, Note d. Seattle Building Code Churchill Engineering, Inc. 7 Churchill Engineering, Inc. 8

3 SECTION 504 Height (Number of Stories) WSBC Section Stair enclosure pressurization increase. SECTION 504 Height (Number of Stories) For Group R1 and R2 occupancies in buildings of Type VA construction equipped throughout with an approved automatic sprinkler system in accordance with Section , the maximum number of stories permitted in Section may be increased by one provided the interior exit stairways and ramps are pressurized in accordance with Section and Section Churchill Engineering, Inc. 9 Churchill Engineering, Inc. 10 SECTION 505 MEZZANINES Considered a portion of the story in which it is contained. Mezzanines shall hllnot contribute to either ih the building area or number of stories. The aggregate area of a mezzanine or mezzanines within a room shall not exceed one third of the floor area of that room or space in which they are located. SECTION 505 MEZZANINES 2009 IBC Handbook Exception: Permitted to be one half of the floor area of the room for Type I or II construction in buildings equipped throughout with an NFPA 13 automatic sprinkler system and emergency voice/alarm communication system. Seattle Building Code Permits aggregate area of mezzanines to be one half of the floor area for all construction types. Churchill Engineering, Inc. 11 Churchill Engineering, Inc. 12

4 SECTION 506 Area Modifications df Increased due to frontage (I f ) and automatic sprinkler system protection (I s ) Width limits W/30 = 1.0 SECTION Frontage Increase Maximum increase is.75 of Table 503 area Open space on same lot or dedicated for public use Churchill Engineering, Inc. 13 Churchill Engineering, Inc. 14 BLDG B SECTION 506 Frontage Increase Example P = 674 LF (Including Fire Wall) F = 325 LF (BLDG Perimeter fronting on Public Way) W = 30 I f = (F/P 0.25) W/30 I f = (325/674.25) 30/30 I f =.23 SECTION Automatic Sprinkler System Area Increase Requires NFPA percent increase for multistory buildings 300 percent increase for single story buildings Height and area increases permitted together for all occupancies Exceptions: 1. Buildings, or portions of buildings, classified as a Group I 2 occupancy of Type IIB, III, IV or V construction. 2. Buildings, or portions of buildings, classified as a Group H 1, H 2, H 3 or H 5 occupancy. 3. Fire resistance rating substitution in accordance with Table 601. Churchill Engineering, Inc. 15 Churchill Engineering, Inc. 16

5 SECTION Building Area Determination For two stories multiply A a by 2 For three or more stories multiply A a by 3 Example: Four story Group R 2 occupancy of Type VA construction, protected throughout by an NFPA 13 sprinkler system, no frontage increase. Allowable building area per story : A a = 12,000 SF + (2 X 12,000 SF) = 36,000 SF Allowable building area for building: A T = A a X 3 = 36,000 SF X 3 = 108, SF SECTION 508 Mixed Use and Occupancy Accessory occupancies (Section 508.2) Nonseparated occupancies (Section 508.3) Separated occupancies (Section 508.4) Where a building contains more than one occupancy group, the building or portion thereof shall comply with Sections (Accessory occupancies), (Nonseparated occupancies), (Separated occupancies) or a combination of these sections. Churchill Engineering, Inc. 17 Churchill Engineering, Inc. 18 SECTION 508 Mixed Use and Occupancy Accessory occupancies (Section 508.2) Subsidiary to main occupancy or portion thereof Shall not occupy more than 10% of story Shall not exceed Table 503 without height and area increases Allowableareaandheight area and based onmainoccupancy occupancy No separation required SECTION 508 Accessory Uses 50831(2) (2) Churchill Engineering, Inc. 19 Churchill Engineering, Inc. 20

6 SECTION 508 Incidental Uses Areas SECTION 508 Mixed Use and Occupancy Nonseparated occupancies (Section 508.3) Individually classified in accordance with Code requirements apply to each portion based on occupancy Most restrictive provisions of Chapter 9 Allowable area & height based on most restrictive occupancy No separation is required between occupancies Churchill Engineering, Inc. 21 Churchill Engineering, Inc. 22 SECTION Nonseparated Occupancies Example SECTION Separated Occupancies B B, S 1 A 3 Churchill Engineering, Inc. 23 Churchill Engineering, Inc. 24

7 WSBC SECTION 509 Special Provisions (Podium Buildings) Horizontal building separation allowance (section 509.2) Basement and/or first story, Type IA 3 hour horizontal assembly Building above limited to : Group A; each with an occupant load of <300 Group B, M, R, or S uses Building below is permitted to be any of the following: Group S 2 used for parking and storage of private motor vehicles Multiple Group A, each with occupant load of <300 Group B or M Group R Maximum height based on building above 2009 SEATTLE BUILDING CODE SECTION Special lprovisions i (Podium Buildings) Horizontal building separation allowance Buildings separated by 3 hour horizontal assembly Building below is no more than two stories above grade plane Buildings permitted to be any of the following: Group S 2 used for parking and storage of private motor vehicles Multiple Group A, each with occupant load of <300 Group B, M or R uses Maximum height based on building above Entire structure shall not exceed seven stories Pressurized stairways required where building below 3 hour horizontal assembly is twostories Churchill Engineering, Inc. 25 Churchill Engineering, Inc. 26 WSBC SECTION Special lprovisions i 2009 IBC Commentary SECTION Group R 1 & R 2 Buildings of Type IIIA Construction Increased to six stories Increased to 75 feet First floor assembly above the basement has 3 hour rating Floor area of each flooris subdivided by 2 hour fire walls into areas of not more than 3,000 square feet Churchill Engineering, Inc. 27 Churchill Engineering, Inc. 28

8 SECTION Group R 1 & R 2 Buildings of Type IIIA Construction CHAPTER 6 Types of Construction Churchill Engineering, Inc. 29 Churchill Engineering, Inc. 30 CHAPTER 6 Types of Construction TYPEIII AND IV CONSTRUCTION Typically, exterior walls are of noncombustible construction. However, fire retardant treated wood framing is permitted within exterior wall assemblies with a 2 hour rating or less (Sections and 602.4). CHAPTER 6 Exterior Wall Fire Resistive Requirements Churchill Engineering, Inc. 31 Churchill Engineering, Inc. 32

9 CHAPTER 7 Exterior Wall Projections Section CHAPTER 7 Exterior Wall Projections Section Projections shall not extend beyond the distance determined by the following three methods, whichever results in the lesser projection: 1. A point 1/3 distance from wall to lot line where protected openings or a combination of protected and unprotected openings are required in the exterior wall. 2. A point one half the distance from the exterior face of the wall to the lot line where all openings in the exterior wall are permitted to be unprotected or the building is equipped throughout with an NFPA 13 automatic sprinkler system. 3. More than 12 inches into areas where openings are prohibited. Seattle Building Code Permits whichever is the least restrictive Churchill Engineering, Inc. 33 Churchill Engineering, Inc. 34 CHAPTER 7 Section Exterior Wall Openings SECTION EXTERIOR WALL OPENINGS Churchill Engineering, Inc. 35 Churchill Engineering, Inc. 36

10 WSBC SECTION EXTERIOR WALL OPENINGS In determining the maximum area of openings permitted in the east facing exterior wall of the first story, should ldthe fire separation distance be measured from the imaginary line to grid line A or to grid line B? SECTION EXTERIOR WALL OPENINGS WSBC? SBC Allowableexterior exterior wall openings at Grid Line A is based on fire separation distance from Grid Line B Churchill Engineering, Inc. 37 Churchill Engineering, Inc. 38 SECTION SBC INTERPRETATION EXTERIOR WALL OPENINGS SECTION 706 FIRE WALLS Each portion of building separated by fire walls considered as a separate building All provisions of the code? Area, height and type of construction What about means of egress and other provisions of the code? Churchill Engineering, Inc. 39 Churchill Engineering, Inc. 40

11 SECTION 706 FIRE WALLS 2009 IBC Q & A NON STRUCTURAL PROVISIONS (see pages 82 & 83). The intent of Chapter 7 is to provide construction requirements for building elementswhenthose those elements are required elsewhere in the code. A design needs to take into account the presence of a fire wall and evaluate compliance for all aspects of the code for each distinct building in the structure. However, the total structure should also be evaluated for these systems, and, where it provides an equivalent level of safety and protection, the local building official can approve the provision of systems for the total structure and not for each building independently. SECTION 706 FIRE WALLS Fire walls shall have sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall for the duration of time indicated by the required fire resistanceresistance rating. Churchill Engineering, Inc. 41 Churchill Engineering, Inc. 42 SECTION 706 FIRE WALLS SECTION 706 FIRE WALLS Churchill Engineering, Inc. 43 Churchill Engineering, Inc. 44

12 SECTION 706 FIREWALLS continued SECTION 1005 EGRESS WIDTH The total width of means of egress in inches shall not be less than the total occupant load served by the means of egress multiplied by 0.3 inches per occupant for stairways and by 0.2 inches per occupant for other egress components. EXCEPTIONS: 1. Means of egress complying with Section For other than H and I 2 occupancies, 0.2 inches per occupant for stairways and 0.15inches per occupant for other egress components in buildings that are provided with sprinkler protection and an emergency voice/alarm communication system (Note 2009 SBC does not require emergency voice/alarm communication system). Multiple means of egress shall be sized such that the loss of any one means of egress shall not reduce the available capacity to less than 50 percent of the required capacity. Churchill Engineering, Inc. 45 Churchill Engineering, Inc. 46 SECTION 1007 ACCESSIBLE MEANS OF EGRESS SECTION 1007 ACCESSIBLE MEANS OF EGRESS continued Provide two accessible means of egress Continuous to public way Stairway enclosures; exterior stairways; elevators; horizontal exits; areas of refuge Elevators in five or more story buildings required unless using horizontal exit Exterior area for assisted rescue Exit stairway Enlarged floor level landing or accessed from area of refuge or horizontal exit Areas of refuge not required in buildings equipped with NFPA 13 &13R automatic sprinkler systems Elevators Standby power Accessed from area of refuge or horizontal exit Two way communication required at elevator landing even if the elevator is not considered an as an accessible means of egress (Section ) Churchill Engineering, Inc. 47 Churchill Engineering, Inc. 48

13 The 2009 WSBC allows the building official the authority to approve alternate building methods, "provided the building official finds that the proposed design is satisfactory and complies with 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, effectiveness, fire resistance, durability and safety. Churchill Engineering, Inc. 49 Churchill Engineering, Inc. 50 MIXED USE PODIUM BUILDING Project includesfive stories of residential apartments (Type IIIA Construction) located over a ground floor (Type IA Construction) containing a common area, lobby, office, laundry room and computer area serving the residential units above, a church sanctuary, multi purpose room and parking area; and two levels of subterranean parking. Churchill Engineering, Inc. 51 Churchill Engineering, Inc. 52

14 Churchill Engineering, Inc. 53 Churchill Engineering, Inc. 54 Churchill Engineering, Inc. 55 Churchill Engineering, Inc. 56

15 Alternate Design Approach Use of standard wood framing within exterior walls versus fire retardanttreated wood. Utilize the special provisions of Section with a Group A use having an occupant load of 300 or more located within the Type IA portion of the building. Allow 3 hour fire walls located between Building A and Building B and between Building A and Building C to extend from the first floor level to the roof level where the building code would require these fire walls to extend from the foundation level. Allow a vertical off set within the 3 hour horizontal assembly at the second floor level. Churchill Engineering, Inc. 57 Churchill Engineering, Inc. 58 Churchill Engineering, Inc. 59 Churchill Engineering, Inc. 60

16 Churchill Engineering, Inc. 61 Churchill Engineering, Inc. 62 Following design elements will be provided: Enhanced automatic sprinkler system design within the Type IIIA residential buildings. Provide an additional layer of Type X gypsum board on each side of the corridor and unit separation walls. Provide an increase in the fire resistance rated assemblies between the church sanctuary and mezzanine level and the remaining portions of the project to 4 hours. Increase the horizontal assembly between the Type IA building and the Type IIIA buildings above from 3 hours to 4 hours. Provide a minimum of three exits from the church sanctuary where only two exits are required by code. Churchill Engineering, Inc. 63 Churchill Engineering, Inc. 64

17 MIXED USE TWO STORY BUILDING Project includes tenant improvements within the first floor of an existing two story building for a new restaurant. The proposed restaurant use is considered as a change of occupancy from the occupancy classification designated on the original approved plans which were designed in accordance with the 2001 California Building Code (1997 UBC). Additionally, i the existing i type of construction for the building must be changed to accommodate the new use. Churchill Engineering, Inc. 65 Churchill Engineering, Inc. 66 Building ud A approved as a shell structure under the 1997 UBC Building A is connected to an adjacent two story building (Building B) to the east via an open breezeway structure Both buildings, including the breezeway structure, were considered as a single building of Type V 1 hour, with automatic sprinklers used as a substitute for 1 hour construction Protected by NFPA 13, including breezeway Churchill Engineering, Inc. 67 Churchill Engineering, Inc. 68

18 A 2 Fire aea area > 5,000 sq. ft. and doccupant load > 100 occupants, therefore, 2006 IBC precludes the use of an approved automatic sprinkler system in lieu of 1 hour fire resistance rated construction Buildings A and B reclassified as Type VB structures and the existing breezeway structure considered as a pedestrian walkway Buildings A and B considered as separate structures Churchill Engineering, Inc. 69 Churchill Engineering, Inc. 70 Churchill Engineering, Inc. 71 Churchill Engineering, Inc. 72

19 Churchill Engineering, Inc. 73 Churchill Engineering, Inc. 74 Alternate Design Approach Change Type of Construction to VB and consider Buildings A & B as separate buildings. Allow pedestrian walkway to exceed the maximum width permittedby the building code. The proposed alternate design utilizes an automatic sprinklersystemsystem within the pedestrian walkway in lieu of restricting the total width to 30 feet. Churchill Engineering, Inc. 75 Churchill Engineering, Inc. 76

20 Alternate design approach to allow the buildings to utilize the special provisions of Section with two stories of Type IA construction located below EXAMPLE #3 the Group R 2 occupancy buildings where the building code limits the building below the horizontal assembly to no more than one story above grade plane. Churchill Engineering, Inc. 77 Churchill Engineering, Inc. 78 EXAMPLE #3 EXAMPLE #3 The proposed alternate design will limit the residential buildings located above the two story Type IA buildings to four (4) stories for Type IIIA construction and three (3) stories for Type VA construction. Therefore, the overall number of stories and building height for the buildings will not exceed those permitted by Section Churchill Engineering, Inc. 79 Churchill Engineering, Inc. 80

21 EXAMPLE #3 EXAMPLE #3 Churchill Engineering, Inc. 81 Churchill Engineering, Inc. 82 EXAMPLE #3 EXAMPLE #3 Churchill Engineering, Inc. 83 Churchill Engineering, Inc. 84

22 Questions? This concludes The American Institute of Architects Continuing Education Systems Course James E. Churchill, P.E. (CA) President Churchill Engineering, Inc th Avenue, Suite C San Diego CA Telephone com Wood Products Council