Fire Protection in Wood Buildings

CONTINUING EDUCATION

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CONTIN Identify and select tested fire-rated wood-frame assemblies to use or, non-listed assemblies, calculate the fire endurance of load bearing and non-load bearing wood assemblies using the (CAM). Method Additive Component Discuss the fundamentals of passive and active protection. fire Determine allowable wood use in buildings in accordance with the 2009 IBC. Describe provisions in the IBC for increasing the height and area of wood buildings beyond the base tabular amounts. Analyze fire protection in wood buildings in terms of compliance with the 2009 International Building Code

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W Sponsored by reThink Wood, the | American reThink Wood, Council by Sponsored Wood and WoodWorks U.S. Fire Protection in Wood Buildings Buildings in Wood Protection Fire design wood of Expanding possibilities the not typically with found structural other versatile effective, is cost Wood materials. and has a light renewable It’s and adaptable. record also has a proven It carbon footprint. in its use not only evidenced by safety, for construction but home of90 percent all U.S. non- most innovative ofin some today’s architecture. residential the same perform all buildings to to require ofWood level safety of regardless materials. buildings can be meet designed rigorous to is why which performance, for standards the the use of in a wide wood range of building types—including taller and structures that are designers realize. than some area more have buildings with in wood a focusprotection and is with the 2009 IBC, compliance on Design Wood Conforming the Code based on Wood American Series the by developed Code and the International (AWC) Council safety a fire incorporates Building Council. Based on the Code Conforming Design Wood Series by the American Council Wood and International Code Council Architect: David Baker Architects. Structural engineer: Structural Design Engineers. Photo: Bruce Damonte. Damonte. Bruce Photo: Engineers. Design Structural engineer: Structural Architects. Baker David Architect: FIRE PROTECTION IN WOOD BUILDINGS

For example, regulation of the size of structures wood (FRTW) exterior walls, while CODE HISTORY is based on specific hazards associated with combustible or noncombustible materials The IBC was introduced in 2000, the occupancy as well as the characteristics of may be used for interior elements. consolidating three regional model construction materials used. u Type IV, often called Heavy Timber (HT) building codes into one uniform code IBC Table 503 provides basic per-story construction, has exterior walls made of that has since been adopted by most maximum floor areas reflecting the accepted noncombustible materials or FRTW and jurisdictions. This consolidation increased level of hazard for buildings and occupants interior building elements made of solid or the possibilities for wood construction related to height and size of the structure. laminated timber without concealed spaces. by recognizing fire protection systems However, these tabular values can be increased u Type V construction allows the use of both and techniques that had a demonstrated through the presence of passive and active fire noncombustible and combustible materials history of fire safety in one of the legacy protection systems. in structural elements and exterior and codes. Subsequent versions of the IBC have expanded the opportunities for interior walls. wood use even further through the STRUCTURAL FRAME Types I, II, III and V construction are application of additional state-of-the-art Although the combustibility of building further subdivided into two categories (IA fire protection features. materials is important in determining levels of and IB, IIA and IIB, IIIA and IIIB, and VA and The IBC is intended to protect public safety, the expected response that a building will VB) with the difference being the degree of health, safety and general welfare have in a fire condition is vital to determining fire resistance required for various building as related to the construction and equivalent risk, which is fundamental to the elements and assemblies. For example, in occupancy of buildings and structures. To IBC. The code classifies structures by type of Type VA construction, all interior and exterior this end, it requires all building systems construction in an effort to account for the load-bearing walls, floors, roofs and structural to perform to the same level of safety expected response that building elements will members are required to have a minimum regardless of the building material used. have in a fire. The IBC defines five main types 1-hour fire-resistance rating. In Type VB of construction: Types I, II, III, IV and V. For construction, no fire-resistance rating is Occupancy classification or use of a each, it specifies the materials permitted and required. building plays a key role in the organization minimum fire-resistance ratings associated with and prescription of appropriate fire protection the various structural members. ESTABLISHING FIRE RESISTANCE measures. Throughout the IBC, occupancy Table 601 of the IBC shows the required fire group classifications are fundamental u Types I and II construction must only have resistance of building elements (structural in determining the necessary features of noncombustible building elements, except as frame, walls, floors and roofs) for each construction and occupant safety, including permitted in Section 603. construction type. Ratings are given in hours. limitations to building geometry, means of u Type III construction must have The exception is Type IV, where the wood egress, fire protection and interior finishes. noncombustible or fire-retardant-treated structural elements are assumed to have inherent fire resistance due to their required Architect: JSSH Architects, Inc. Structural engineer: Blanchard Engineering. Photo: JSSH Architects, Inc. minimum dimensions (no fire resistance rating is necessary except for exterior walls). Required Applewood Point of Langton Lake, a fire resistance is based on the expected intensity senior housing project in Minnesota, counts among its features stairwells of a fire that originates within the building designed with double sheet-rocked as a result of its fire load and the level of risk wood-frame walls and 2-hour fire associated with the size of the building and its ratings to serve as areas of refuge. occupancy. Fire resistance describes the rate at which a building material or assembly degrades due to a fire. Resistance is based on how rapidly the strength of the member or assembly is affected by the fire and whether the member or assembly can maintain its design strength while preventing the passage of heat or flames. Fire resistance of wood members and assemblies may be established by any one of five means listed in IBC Section 703.3. The most common methods—tested assemblies and calculated fire resistance—are discussed in the following pages.

EXAMPLE OF TESTED 1-HOUR FLOOR/CEILING ASSEMBLY

3/4” plywood parallel chord truss

steel furring channel

5/8” proprietary type X wallboard Courtesy: The American Wood Council

2 FIRE PROTECTION IN WOOD BUILDINGS

Architect: Togawa Smith Martin, Inc. Structural engineer: Englekirk Structural Engineers, Inc. Photo: Michelle Kam-Biron.

Americana at Brand in CONTINUING EDU Glendale, California, is a Type III building. It includes five stories of wood-frame construction over a concrete podium and one level of subterranean parking. C ATION

TESTEDASSEMBLIES the NDS method as well as design examples. Code recognition of 1- and 2-hour wood-frame Although IBC Section 721.6.3 also contains walls, floors, ceilings and roofs are predicated an acceptable calculation method, it is limited on successful fire and hose stream testing to 1-hour fire resistance. This provision has conducted in accordance with ASTM E119, been deleted in the 2015 edition of the IBC, Standard Test Methods for Fire Tests of Building since the NDS Chapter 16 method has broader Construction Materials or UL 263, Standard for application and provides a more reliable Fire Tests of Building Construction and Materials. calculation procedure. Depending on the application, building elements may need to be fire-rated from one DESIGN TOOLS FOR ASSEMBLIES Photo: FPInnovations side or both sides. For specific exterior wall Many sources are available for identification applications where there is adequate fire distance and selection of tested fire-rated assemblies. CHAR separation from adjacent structures or the Generally, publications from recognized testing Wood products such as the large beams property line, the IBC allows wood-frame walls laboratories are the source for listings. Fire-rated used in heavy timber construction and to be tested for exposure to fire from the inside wood-frame assemblies can be found in listings cross laminated timber (CLT) may perform only. Rating for both interior and exterior fire contained in such publications as: better in a fire situation than noncombus- exposure is only required when the wall has u Underwriters Laboratories (UL) Fire tible materials. Because these products a fire separation distance of less than 10 feet. Resistance Directory are thick and solid, they char on the out- For floors, ceilings and roofs, resistance to fire u Intertek Testing Services’ Directory of side at a slow and predictable rate while exposure is measured from below. Listed Products retaining strength, slowing combustion For a detail of a 2-hour exterior wall u Gypsum Association’s Fire Resistance and allowing time to evacuate the build- assembly, see page 8. Design Manual ing. The char protects the wood from Fire-rated assemblies may also be selected further degradation, helping to maintain the building’s structural integrity and CALCULATED FIRE RESISTANCE from one of the prescriptive assemblies provided reducing its fuel contribution to the fire, The fire resistance of exposed wood members in IBC Section 720 based on ASTM E 119 or UL which in turn lessens the fire’s heat and may be calculated using the provisions of 263 test results, or by calculating an assembly’s flame propagation. Section 602.4 of the Chapter 16 of the National Design Specification® capacity using IBC Section 721. The AWC 2009 IBC has prescriptive provisions for (NDS®) for Wood Construction (see IBC publication AWC Design for Code Acceptance wood members which meet the definition Section 721.1). AWC’s Technical Report No. (DCA) 3 – Fire-Rated Wood Floor and Wall of heavy timber. 10 (TR10), Calculating the Fire Resistance of Assemblies is also helpful in determining the Exposed Wood Members, contains full details of fire rating of wood-frame wall and floor/ceiling/

3 FIRE PROTECTION IN WOOD BUILDINGS roof assemblies, and is available for free at which fire-resistance ratings of wood assemblies www.awc.org/codes/dcaindex.html. can be established using this calculation method. To permit use of “non-listed” assemblies, IBC AWC’s publication DCA 4 – Component Additive Section 721.6 also recognizes a methodology for Method (CAM) for Calculating and Demonstrating calculating the fire endurance of load bearing Assembly Fire Endurance provides a history of the and non-load bearing wood assemblies (floor, method and an in-depth explanation of its use wall, ceiling and roof assemblies) through a and application. calculation methodology called Component Additive Method (CAM). CAM was developed EXTERIOR WOOD-FRAME WALLS in the early 1960s by the Fire Test Board of Wood stud framing is permitted for all load the National Research Council of Canada and bearing and non-load bearing exterior walls validated through full-scale wood-framed in Type V construction. In Type III and IV assembly fire tests. buildings, exterior walls may be FRTW in CAM calculates fire endurance to equal compliance with IBC Section 2303.2 when the sum of: the exterior wall assembly is required to have u the contribution of the fire exposed a 2-hour rating or less. The required rating of membrane, exterior walls in Type III and IV buildings is u the time to failure of the framing members, predicated on fire separation distances contained and, if applicable, in Table 602, so care must be taken when using u additional protection due to the use of cavity this alternative to the general requirement for insulation or reinforcement of the membrane. noncombustible material. Section 721.6 contains the procedures by INTERIOR WOOD-FRAME Photo: FPInnovations WALLS AND PARTITIONS In Types I and II construction, interior partitions dividing single tenant offices or retail and not creating corridors serving 30 or more occupants are permitted to be FRTW, 1-hour fire-resistance- SEPARATIONS AND OPENINGS rated construction, or wood panels or similar light Exterior openings are generally required to construction up to 6 feet in height. In Types III be protected with a rated opening protective and V construction, interior building elements assembly when the exterior wall is within may be wood. In Type IV construction, however, relatively close proximity (< 30 feet) to the wood-stud-framed partitions must be 1-hour property line. IBC Tables 601 and 602 determine fire-resistance-rated construction or solid wood when the exterior walls are required to be rated formed by at least two layers of 1-inch matched and Table 705.8 defines the allowable percentages boards or 4-inch-thick laminated construction. of protected and unprotected openings in those walls. ROOFS AND ROOFTOP STRUCTURES Unlimited amounts of unprotected openings In Type I and II construction, FRTW framing are permitted by Table 705.8 provided the exterior in roofs is permitted when certain conditions walls are 30 feet or more from the property line, are met. FRTW framing can be used in roof or 10 feet or more in a Type IIB or VB building. CROSS elements in Type II construction of any height No unprotected openings are permitted in the LAMINATED TIMBER and in Type I construction of any height exterior wall within 5 feet of the property line for provided the vertical distance between the roof nonsprinklered buildings and no openings are A successful ASTM E119 fire endurance and floor below is at least 20 feet. Heavy timber permitted if the wall is closer than 3 feet from the test of a cross laminated timber (CLT) wall is allowed in any construction where a 1-hour or property line. was key to the decision to recognize CLT less fire-resistance rating is required. Bay and oriel windows must conform to the in the 2015 edition of the IBC. The wall, a type of construction required for the building; 5-ply CLT specimen approximately 7 inch- es thick, was covered on each side with however, FRTW is permitted for Type I, II, III EXAMPLE OF 1-HOUR RATED WALL – and IV buildings not more than three stories a single layer of 5/8-inch Type X gypsum COMPONENT ADDITIVE METHOD (CAM) wallboard. The wall was loaded to the above grade plane. Untreated wood may be 2’ X 4” Wood Stud maximum attainable by the test equip- used in Type V buildings (IBC Section 1406.4). ment, although it remained significantly Interior wood doors are required to be below the full design strength of the CLT. protected when the wall assembly they are in It was then exposed to a standard fire that 5/8” Type X Gypsum Board requires a fire-resistance rating, such as exit reached over 1,800 degrees Fahrenheit enclosures or exit access corridor walls. The in the first 90 minutes of exposure. While 2” X 4” Wood Stud 20 min. minimum required fire protection rating of only seeking a 2-hour rating as required 5/8” Type X Gypsum Board 40 min. the fire door is given in IBC Table 715.4 and by building code provisions, the test specimen lasted 3 hours 6 minutes. Total 60 min. ranges from 20 minutes to 3 hours based on the Courtesy: The American Wood Council required fire-resistance rating of the wall assembly.

4 FIRE PROTECTION IN WOOD BUILDINGS

Architect: LARGE Architecture. Structural engineer: Western Wood Structures, Inc. Photo: Western Wood Structures, Inc. methods by which construction can be evaluated to determine fire performance requirements, CONTINUING EDU including fire walls. In addition, NFPA 221: Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls specifies requirements for the design and construction of high challenge fire walls, fire walls and fire barrier walls including protection of openings and penetrations.

EXTERIOR WALL FINISH C Wood veneer is permitted on Type I, II, III or ATION IV buildings up to 40 feet above grade—60 feet if FRTW is used, provided the veneer is 1-inch nominal thickness, 7/16-inch exterior hardboard siding or 3/8-inch exterior-type wood structural panels or particleboard. Open or spaced veneers without concealed spaces are not permitted to project more than 24 inches from the building wall (IBC Section 1405.5).

INTERIOR FINISH Wood and wood-based products are widely used in interior wall, ceiling and floor surfaces The LeMay Auto Museum in in all types of buildings. Appearance, acoustical Tacoma, Washington, includes a qualities and interior design versatility have Type IV heavy timber roof. made wood surfaces highly desired. In general, wood materials may be used as interior finish Architect: EHDD. Structural engineer: Tipping Mar Structural. Photo: Jeremy Bittermann. within almost all occupancies. IBC Table 803.9 places minimum finish performance classifications on finish materials based on their location within the building. They are expressed in terms of flame spread index numbers. These values are determined in a standard fire test which evaluates the surface burning characteristics of a material. Different maximum flame spread indices are permitted depending on building occupancy, location of the material in the building, and the presence of sprinklers—Class A (flame spread index 0-25); Class B (26-75); or Class C (76-200). The standard fire test used to evaluate flame spread characteristics of wood building

At the David & Lucile Packard Foundation materials is ASTM E-84, Standard Test Method company headquarters, wood was an for Surface Burning Characteristics of Building important part of the strategy to achieve Materials. Nonsprinklered buildings typically LEED Platinum certification. require lower flame-spread materials than sprinklered buildings. FIRE WALLS By definition: “A fire wall is a fire-resistance- Tested wood products typically have a flame Ideally, fire growth and fire spread will be rated wall having protected openings, which spread index of less than 200, making them contained to the building of origin and any restricts the spread of fire and extends acceptable under the IBC for a wide range of adjacent buildings will be protected against continuously from the foundation to or through interior finish uses. Most wood species qualify fire exposure. A fire wall, as defined in the IBC, the roof, with sufficient structural stability under as Class C, while some, such as cedar, western is commonly used to divide a structure into fire conditions to allow collapse of construction hemlock, Idaho white pine, redwood and spruce, separate buildings or to separate a new addition on either side without collapse of the wall.” A can qualify as Class B. Flame spread indices for a from the existing portion of a structure. Each fire wall is not required to be cantilevered and range of proprietary wood-based interior finish portion of a building separated by one fire remain in place if construction on both sides of materials are available from manufacturers. wall or more is considered a separate structure. it collapses. Fire walls must extend to the outer Commercially available fire-retardant treatments Generally, fire walls must be of approved edge of horizontal projecting elements, such as for wood and panel products can reduce flame noncombustible materials, but may be wood- balconies and roof overhangs. spread performance to an index of 25 or less, frame in Type V construction. Chapter 7 identifies acceptable techniques and meeting Class A requirements.

5 FIRE PROTECTION IN WOOD BUILDINGS

for more than 25% of the building perimeter, Nonsprinklered Buildings Minimum Interior Finish Classification by Occupancya may increase the allowable floor area using IBC Minimum Interior Finish Classification Location Equation 5-2 (see below). Ab B C Exit enclosures and A, B, E, I, M If = [ F / P - 0.25 ]W / 30 F, S, R-2 R-3 exit passagewaysc R-1, R-4, Where: Ad, I-2, I-3, B, E, M, S, I-1, R-1, Corridors F, R-3 If = Area increase due to frontage I-4 R-2, R-4 F = Building perimeter that fronts on a public way or A-3, A-4, A-5, open space having 20 feet open minimum width (feet) Enclosed spaces I, A-1, A-2, B, E, F, M, S, and rooms R-4 R-1, R-2, R-3 P = Perimeter of entire building (feet) W = Width of public way or open space (feet) in a This simplified table is not comprehensive; more exceptions c Exit enclosures and exit passageways are permitted to use accordance with Section 506.2.1 can be found in IBC Table 803.9 footnotes. Class C wainscoting or paneling in the grade lobby for not A weighted average may be used when W varies along b Buildings less than three stories above grade plane permit more than 1,000 square feet of applied surface when applied the perimeter. W is the open space width plus the width to a noncombustible base. the reduction of the exit enclosure and exit passageway of the public way. classifications to Class B. d Lobby areas in corridors may use Class B interior finishes for Group A occupancies. It should be noted that frontage widths (W) greater than 30 feet will only receive credit for a value of 30 feet. The maximum increase that Sprinklered Buildings Minimum Interior Finish Classification by Occupancya,b can be obtained for frontage would occur when Minimum Interior Finish Classification 100% of the perimeter has frontage of 30 feet Location A Bc C or more and would result in a 75% floor area Exit enclosures and A, B, E, M, R-1, R-4, increase. The figure below illustrates the frontage I-3 F, R-2, R-3, S exit passagewaysd I-1, I-2, I-4 increase concept for a three-story office building Corridors I-3 A, I-2, I-4 B, E, F, M, R, S, I-1 of Type IIIA construction. Enclosed spaces A, B, E, F, M, R, S, I-2, I-4 and rooms I-1, I-3 ACTIVE FIRE PROTECTION Active fire protection is characterized by a This simplified table is not comprehensive; more exceptions the reduction of the exit enclosure and exit passageway can be found in IBC Table 803.9 footnotes. classifications to Class C. detection and response. Detection of a fire b Automatic sprinkler system meeting the requirements of NFPA d Exit enclosures and exit passageways are permitted to use Class through smoke or heat sensors initiates a chain of 13 or NFPA 13R as appropriate C wainscoting or paneling in the grade lobby for not more events that reduces threats from the fire. Once a than 1,000 square feet of applied surface when applied to a c Buildings less than three stories above grade plane permit noncombustible base. detection system is activated, other programmed actions ensue, including: sounding of alarms, closure of smoke and fire dampers, closure of Flame Spread Performance of Wood Products automated fire doors through de-energizing Class Example Flame Spread Smoke Development of magnetic door stops, and opening of fire AFire-retardant-treated wood 0-25 0-450 sprinklers or other fire suppression system. B Redwood, cedar 26-75 0-450 Once detected, the fire can be controlled or extinguished manually through the use of Most other wood species; softwood plywood; C 76-200 0-450 hardwood plywood; particleboard extinguishers and fire hoses or automatically by fire sprinklers, fire fighting foam systems, hypoxic Courtesy of the American Wood Council air systems or other devices. Traditional wood floor coverings are 5-1 (see below) establishes modifications to the IBC Chapter 9, Fire Protection Systems, exempt from floor finish requirements. Wood maximum allowable tabular floor areas based prescribes minimum requirements for active fire interior trim, such as baseboards, chair rails on the provision of building frontage open space protection systems to perform one or more of and handrails, are required to meet a Class C and the provision of fire sprinklers. the following functions: detect a fire, alert the classification and cannot exceed 10% of the wall occupants or fire department of a fire emergency, or ceiling area to which it is attached. Aa = {At + [ At x If ] + [ At x Is ]} control smoke, and control or extinguish the Where: fire. Fire protective systems must be installed, OPEN PERIMETER FIRE PROTECTION Aa = Allowable building area per story (square feet) operated and repaired in accordance with the In general, there are two passive measures that At = Tabular building area per story in accordance International Fire Code (IFC). with Table 503 (square feet) decrease a building’s fire hazard: isolating the If = Area increase factor due to frontage as calculated building from other structures and constructing in accordance with Section 506.2 AUTOMATED SPRINKLER SYSTEMS I = Area increase factor due to sprinkler protection the building with fire-resistive materials. IBC s Automatic sprinkler systems must be equipped as calculated in accordance with Section 506.3 Chapter 5 provides for increases to the base with approved audible alarms that are monitored tabular heights and areas of Table 503 for the for integrity by an approved supervising station. addition of open perimeter spacing and the use ALLOWABLE INCREASES FOR The alarm must be installed on the exterior of fire-resistive assemblies. FRONTAGE PROTECTION of the building in a location approved by the Isolating a building from adjacent structures Buildings located next to a public way or open building official. This alarm is not intended to decreases the fire hazard of a building as well space adjoining a public way, with the exterior be an evacuation alarm. However, when a fire as that of adjacent structures. IBC Equation wall a minimum of 20 feet from the public way alarm system is installed, the sprinkler system

6 FIRE PROTECTION IN WOOD BUILDINGS must be interconnected with the building fire ALLOWABLE INCREASES FOR above the level of exit discharge (typically the alarm system so that, when the sprinkler system AUTOMATIC SPRINKLER SYSTEM first story), or has an occupant load exceeding CONTINUING EDU activates, it sounds the evacuation alarms PROTECTION 100, the A-2 building must be sprinklered required for the fire alarm system. When a building is equipped throughout with in accordance with IBC Section 903.2.1.2. Where the code requires that a building or an NFPA 13 compliant automatic sprinkler Increases for both open frontage and sprinklers portion thereof be equipped throughout with system, the allowable floor area is permitted could then be taken. an automatic sprinkler system, the sprinklers to be increased by 300% for a one-story must be in accordance with NFPA 13, Standard building and 200% for a multi-story building. PRECAUTIONS DURING for the Installation of Sprinkler Systems. In addition to the area increase, IBC Section CONSTRUCTION

However, where allowed in buildings of Group 504.2 permits the tabular building heights to be IBC Chapter 33 provides minimum safety C R occupancy, up to and including four stories increased by 20 feet and the number of stories precautions for fire during construction and ATION in height, the automatic sprinkler system shall above grade plane to be increased by one story, the protection of adjacent public and private be in accordance with NFPA 13R, Standard for except in Group I-2 occupancies which are properties. The section includes provisions for the Installation of Sprinkler Systems in Low-Rise not allowed the increase of a story when using fire extinguishers, standpipes, means of egress, Residential Occupancies. sprinklers. and sprinkler system commissioning. The IFC IBC Chapter 9 regulates the installation of For Group R buildings, a similar height also contains detailed requirements for fire automatic sprinklers in a building based on increase (but no area increase) is given for the precautions during construction. certain factors, such as occupancy group, height, use of NFPA 13R compliant systems, up to 60 size of the building/fire area, and occupant load. feet and four stories. Fire Extinguishers All water supply control valves and water- The figure above can also be used to During construction, one portable fire flow switches are required to be electrically illustrate the combined effect of frontage and extinguisher shall be placed at each stairway supervised in accordance with Section 903.4. automatic sprinkler systems on the allowable on all floor levels with combustible materials, Central stations, remote supervising stations or area calculation. in each storage or construction shed and where proprietary supervising stations are approved special hazards exist, such as the storage and A = A + (A x I ) + (A x I ) services recognized in NFPA 72. a t t f t s use of flammable and combustible liquids.

Note: The construction of one- and two- Aa = 28,500 + (28,500 x 0.75) + (28,500 x 2) = family dwellings is generally governed by the 106,875 ft2 per floor Maintaining Means of Egress provisions of the International Residential Required means of egress must be maintained A = 320,625 ft2 (> 33,750 actual) Code (IRC), which allows the installation of t at all times during construction, demolition, an automatic sprinkler system in accordance This assumes full open frontage (as the example remodeling or alterations and additions to with NFPA 13D, Standard for the Installation shows) and sprinklers. buildings. During construction, when of Sprinkler Systems in One- and Two-Family Including automatic sprinklers in the a building height reaches 50 feet or four s Dwellings and Manufactured Homes. If the building will permit the largest allowable area tories, a minimum of one temporary lighted one- or two-family dwelling does not comply and greatest number of stories. As this example stairway shall be provided unless a permanent with the building geometry limitations of the demonstrates, the code permits a much larger stairway is available for use at all times per IRC, then the building must comply with the wood building than is proposed. IBC Section 3310. requirements of the IBC and an NFPA 13D system can still be used, but the installation CHAPTER 9 AREA LIMITS FOR Standpipes of the 13D system will not provide for any NONSPRINKLERED BUILDINGS In buildings required to have standpipes, increases to the allowable height or area. Many occupancies have area thresholds not less than one standpipe shall be available Automatic 13D systems in one- and two-family beyond which sprinklers are required per IBC during construction for fire department use. dwellings do not require electrical supervision, Section 903. The same thresholds apply to all The standpipe shall be installed before the through exception. construction types. When increases are taken construction is 40 feet above fire department Sprinklers offer a substantial increase to life for open frontage in nonsprinklered buildings, access. The standpipe is placed adjacent to safety, which is well documented and merits the the allowable area per floor can exceed usable stairs and has fire department hose consideration of designers for that reason alone. allowable fire areas and a sprinkler system may connections. The standpipe is extended during But their advantages can also be economic. be required. If sprinklers are provided, however, construction to within one floor of the highest The code offers considerable trade-offs for allowable area increases for both sprinklers and point of construction having flooring per IBC providing sprinklers, including: open frontage may be taken. Alternatively, fire Section 3311. During demolition a standpipe u Increases to allowable heights and areas areas may be kept below sprinkler thresholds shall be maintained in operable condition. The u Reductions in corridor ratings and corridor by compartmentalizing floor areas with fire- standpipe may be demolished floor by floor as opening protection resistance-rated construction in accordance demolition proceeds, but not more than one u Flexibility in means of egress (travel distance with the definition for fire area and the floor below the floor being demolished. to exits, number and separation of exits, requirements of Chapter 7. common path of travel) The requirement for sprinklers can also Sprinkler System Commissioning u Reductions in dwelling unit separations be triggered by specific use, height above The sprinkler system must be tested and u Relief from emergency escape openings grade, or occupant load. For instance, although approved before the certificate of occupancy is u Relief from certain fire and smoke damper unsprinklered Group A-2 occupancies awarded per IBC Section 3312 and the building requirements (restaurants) may exceed one story above is occupied, except as provided in Section 111.3, u Interior finish flexibility grade in Type III construction, if the A-2 is temporary occupancy.

7 FIRE PROTECTION IN WOOD BUILDINGS

Additional Requirements EXAMPLE OF 2-HOUR EXTERIOR WALL Additional requirements in the IFC include: u Temporary heating equipment must be listed and labeled; installation and maintenance of For more examples, the equipment must be in accordance with the a library of free listing (IFC 3303). architectural and engineering details u Smoking is prohibited except in approved areas is available at with posted signage (IFC 3304). woodworks.org. u A fire watch must be maintained with qualified personnel if required by the fire code official (IFC 3304). u Welding operations must follow the provisions of IFC Chapter 35. Electrical wiring must follow the provisions of NFPA 70 (IFC 3304). u The owner must designate a fire prevention superintendent responsible for the fire prevention program during construction.

Photo: VanDorpe Chou Associates

Image courtesy Togawa Smith Martin, Inc FIRE SAFETY DURING CONSTRUCTION Requirements for the program are listed in IFC SUMMARY Section 3308. Wood construction offers advantages in terms Although less than 2% of building fires u An accessible emergency phone is provided of cost, design versatility and sustainability— occur during construction, this phase in an approved location at the construction while meeting code requirements for safety in presents unique risk scenarios that make site. The construction site street address and fire buildings that range from schools and offices any building more vulnerable regardless of department emergency phone number must be to mid-rise/multifamily, civic, institutional, material. The IBC provides extensive safety posted by the phone (IFC 3309). industrial and retail. It has a history of proven precautions for this phase, but the fires that u Fire-fighting vehicle access must be provided performance and is making history with new do occur are often caused when required elements—such as fire doors, smoke alarms within 100 feet of temporary or permanent fire mass timber products that offer exceptional and sprinklers—have not been put in place. department connections (IFC 3310). strength and continue to expand the possibili- For this reason, construction site fire safety u An approved water supply for fire protection ties wood design. For more detailed informa- includes some unique challenges that are must be available when combustible material is tion on the subjects covered in this CEU, a new best addressed through education and at the construction site (IFC 3312). version of the American Wood Council’s Code increased planning. u Requirements for safeguards during roofing Conforming Wood Design based on the 2009 IBC operations are listed in IFC Section 3317. is available as a free download at www.awc.org.

The reThink Wood initiative is a coalition of interests representing North America’s wood products industry and related stakeholders. The coalition shares a passion for wood and the forests it comes from. Innovative new technologies and building systems have enabled longer wood spans, taller walls, and higher buildings, and continue to expand the possibilities for wood use in construction. www.rethinkwood.com

American Wood Council is the leading developer of engineering data, technology, and standards on structural wood products in the U.S. These tools are used widely by design professionals, building officials, and manufacturers of traditional and engineered wood products to ensure the safe and efficient design and use of wood structural components. www.awc.org

WoodWorks is an initiative of the Wood Products Council established to provide free one-on-one project support, education, and resources related to the design of non-residential and multifamily wood buildings. If you have a project that requires technical expertise in wood design, contact [email protected]. www.woodworks.org