Heads up: There are no amended sections in this chapter.
The following words and terms shall, for the purposes of this chapter and as used elsewhere in this code, have the meanings shown herein.
ADHERED MASONRY VENEER. Veneer secured and supported through the adhesion of an approved bonding material applied to an approved backing.
CURTAIN WALL. A curtain wall or panel wall system is a non-load bearing building wall, in skeleton frame construction attached and supported to the structure at every floor or other periodic locations. Assemblies may include glass, metal, precast concrete or masonry elements arranged so as not to exert common action underload and to move independently of each other and the supporting structure.
EXTERIOR INSULATION FINISH SYSTEM (EIFS). Non-load bearing, barrier wall, exterior cladding systems, generally consisting of the following components:
1. Insulation board.
2. Adhesive and/or mechanical fasteners that attach the insulation board to the substrate.
3. Fiberglass reinforcing mesh.
4. Base coat on the face of the insulation board.
5. A textured protective finish coat.
6. Joint and seam treatments.
EXTERIOR WALL. A wall, bearing or nonbearing, that is used as an enclosing wall for a building, other than a fire wall, and that has a slope of 60 degrees (1.05 rad) or greater with the horizontal plane.
EXTERIOR WALL COVERING. A material or assembly of materials applied on the exterior side of exterior walls for the purpose of providing a weather-resisting barrier, insulation or for aesthetics, including but not limited to, veneers, siding, exterior insulation and finish systems, architectural trim and embellishments such as cornices, soffits, facias, gutters and leaders.
EXTERIOR WALL ENVELOPE. A system or assembly of exterior wall components, including exterior wall finish materials, that provides protection of the building structural members, including framing and sheathing materials, and conditioned interior space, from the detrimental effects of the exterior environment.
FIBER CEMENT SIDING. A manufactured, fiber-reinforcing product made with an inorganic hydraulic or calcium silicate binder formed by chemical reaction and reinforced with organic or inorganic nonasbestos fibers, or both. Additives that enhance manufacturing or product performance are permitted. Fiber cement siding products have either smooth or textured faces and are intended for exterior wall and related applications.
METAL COMPOSITE MATERIAL (MCM). A factory-manufactured panel consisting of metal skins bonded to both faces of a plastic core.
METAL COMPOSITE MATERIAL (MCM) SYSTEM. An exterior wall finish system fabricated using MCM in a specific assembly including joints, seams, attachments, substrate, framing and other details as appropriate to a particular design.
Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing, as described in Section 1405.3. The exterior wall envelope and its drainage system shall be designed and constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1404.2 and a means for draining water that enters the assembly to the exterior of the veneer, unless it is determined that penetration of water behind the veneer shall not be detrimental to the building performance. Protection against condensation in the exterior wall assembly shall be provided in accordance with the New York State Energy Conservation Construction Code.
- A weather-resistant exterior wall envelope shall not be required over concrete and masonry walls, designed to resist water penetration and detrimental effects from freeze/thaw cycling and in accordance with Chapters 19 and 21, as applicable.
- Compliance with the requirements for a means of drainage, and the requirements of Sections 1405.2 and 1405.3, shall not be required for an exterior wall envelope that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:
- Exterior wall envelope test assemblies shall include at least one opening, one control joint, and where required one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended end-use configuration.
- Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size.
- Exterior wall envelope assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (psf) (0.297 kN/m2).
- Exterior wall envelope assemblies shall be subjected to a minimum test exposure duration of 2 hours. The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings, or intersections of terminations with dissimilar materials.
Where required by Section 1403.2, an approved continuous water-resistive barrier shall be provided behind the exterior wall covering, or a secondary drainage system shall be provided to divert water out of the wall system to the building exterior. Where asphaltic felt is used, it shall be a minimum of one layer of No. 15 asphalt felt, complying with ASTM D 226 for Type 1 felt, and shall be attached to the sheathing, with flashing as described in Section 1405.3, in such a manner as to provide a continuous water-resistive barrier behind the exterior wall veneer.
Basic hardboard shall conform to the requirements of AHA A135.4.
Exterior walls of masonry construction shall be designed and constructed in accordance with this chapter and Chapter 21. Masonry units, mortar and metal accessories used in anchored and adhered veneer shall meet the physical requirements of Chapter 21. The backing of anchored and adhered veneer shall be of concrete, masonry, steel framing or wood framing.
Aluminum siding shall conform to the requirements of AAMA 1402.
Plastic panel, apron or spandrel walls as defined in this code shall not be limited in thickness, provided that such plastics and their assemblies conform to the requirements of Chapter 26 and are constructed of approved weather-resistant materials of adequate strength to resist the wind loads for cladding specified in Chapter 16.
Vinyl siding shall conform to the requirements of ASTM D 3679.
Exterior walls shall provide weather protection for the building. The materials of the minimum nominal thickness specified in Table 1405.2 shall be acceptable as approved weather coverings.
|COVERING TYPE||MINIMUM THICKNESS
|Adhered masonry veneer*||0.25|
|Anchored masonry veneer||2.625|
|Aluminum siding||0.0 19|
|Cold-rolled copperd||0.0216 nominal|
|Copper shinglesd||0.0162 nominal|
|Exterior plywood (with sheathing)||0.313|
|Exterior plywood (without sheathing)||See Section 2304.6|
|Fiber cement lap siding||0.25c|
|Fiber cement panel siding||0.25c|
|Glass-fiber reinforced concrete panels||0.375|
|High-yield copperd||0.0162 nominal|
|Lead-coated copperd||0.0216 nominal|
|Lead-coated high-yield copper||0.0162 nominal|
|Particleboard (with sheathing)||See Section 2304.6|
|Particleboard (without sheathing)||See Section 2304.6|
|Precast stone facing||0.625|
|Steel (approved corrosion resistant)||0.0149|
|Stone (cast artificial)||1.5|
|Stucco or exterior portland cement plaster|
|Three-coat work over:|
|Metal plaster base||0.875b|
|Cast-in-place or precast concrete||0.625b|
|Two-coat work over:|
|Cast-in-place or precast concrete||0.375b|
|Terra cotta (anchored)||1|
|Terra cotta (adhered)||0.25|
|Wood siding (without sheathing)a||0.5|
- Wood siding of thicknesses less than 0.5 inch shall be placed over sheathing that conforms to Section 2304.6.
- Exclusive of texture.
- As measured at the bottom of decorative grooves.
- 16 ounces per square foot for cold-rolled copper and lead-coated copper, 12 ounces per square foot for copper shingles, high-yield copper and lead-coated high-yield copper.
Flashing shall be installed in such a manner so as to prevent moisture from entering the wall or to redirect it to the exterior. Flashing shall be installed at the perimeters of exterior door and window assemblies, penetrations and terminations of exterior wall assemblies, exterior wall intersections with roofs, chimneys, porches, decks, balconies and similar projections and at built-in gutters and similar locations where moisture could enter the wall. Flashing with projecting flanges shall be installed on both sides and the ends of copings, under sills and continuously above projecting trim.
Wood veneers on exterior walls of buildings of Type I, II, III and IV construction shall be not less than 1-inch (25 mm) nominal thickness, 0.438-inch (11.1 mm) exterior hardboard siding or 0.375-inch (9.5 mm) exterior-type wood structural panels or particleboard and shall conform to the following:
1. The veneer does not exceed three stories in height, measured from grade, except where fire-retardant-treated wood is used, the height shall not exceed four stories.
2. The veneer is attached to or furred from a noncombustible backing that is fire-resistance rated as required by other provisions of this code.
Stone veneer units not exceeding 10 inches (254 mm) in thickness shall be anchored directly to masonry, concrete or to stud construction by one of the following methods:
1. With concrete or masonry backing, anchor ties shall be not less than 0.1055-inch (2.55 mm) corrosion-resistant wire, or approved equal, formed beyond the base of the backing. The legs of the loops shall be not less than 6 inches (152 mm) in length bent at right angles and laid in the mortar joint, and spaced so that the eyes or loops are 12 inches (305 mm) maximum on center (o.c.) in both directions. There shall be provided not less than a 0.1055-inch (2.55 mm) corrosion-resistant wire tie, or approved equal, threaded through the exposed loops for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length bent so that it will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a right-angle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer.
2. With stud backing, a 2-inch by 2-inch (51 by 51 mm) 0.0625-inch (1.59 mm) corrosion-resistant wire mesh with two layers of waterproofed paper backing in accordance with Section 1403.3 shall be applied directly to wood studs spaced a maximum of 16 inches (406 mm) o.c. On studs, the mesh shall be attached with 2-inch-long (51 mm) corrosion-resistant steel wire furring nails at 4 inches (102 mm) o.c. providing a minimum 1.125-inch (29 mm) penetration into each stud and with 8d common nails at 8 inches (203 mm) o.c. into top and bottom plates or with equivalent wire ties. There shall be not less than a 0.1055-inch (2.68 mm) corrosion-resistant wire, or approved equal, looped through the mesh for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length, so bent that it will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a right-angle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer.
Slab-type veneer units not exceeding 2 inches (51 mm) in thickness shall be anchored directly to masonry, concrete or stud construction. For veneer units of marble, travertine, granite or other stone units of slab form ties of corrosion-resistant dowels in drilled holes located in the middle third of the edge of the units spaced a maximum of 24 inches (610 mm) apart around the periphery of each unit with not less than four ties per veneer unit. Units shall not exceed 20 square feet (1.9 m2) in area. If the dowels are not tight fitting, the holes shall be drilled not more than 0.063 inch (1.6 mm) larger in diameter than the dowel, with the hole countersunk to a diameter and depth equal to twice the diameter of the dowel in order to provide a tight-fitting key of cement mortar at the dowel locations when the mortar in the joint has set. Veneer ties shall be corrosion-resistant metal capable of resisting, in tension or compression, a force equal to two times the weight of the attached veneer. If made of sheet metal, veneer ties shall be not smaller in area than 0.0336 by 1 inch (0.853 by 25 mm) or, if made of wire, not smaller in diameter than 0.1483-inch (3.76 mm) wire.
Anchored terra cotta or ceramic units not less than 1.625 inches (41 mm) thick shall be anchored directly to masonry, concrete or stud construction. Tied terra cotta or ceramic veneer units shall be not less than 1.625 inches (41 mm) thick with projecting dovetail webs on the back surface spaced approximately 8 inches (203 mm) o.c. The facing shall be tied to the backing wall with corrosion-resistant metal anchors of not less than No. 8 gage wire installed at the top of each piece in horizontal bed joints not less than 12 inches (305 mm) nor more than 18 inches (457 mm) o.c.; these anchors shall be secured to 0.25-inch (6.4 mm) corrosion-resistant pencil rods that pass through the vertical aligned loop anchors in the backing wall. The veneer ties shall have sufficient strength to support the full weight of the veneer in tension. The facing shall be set with not less than a 2-inch (51 mm) space from the backing wall and the space shall be filled solidly with portland cement grout and pea gravel. Immediately prior to setting, the backing wall and the facing shall be drenched with clean water and shall be distinctly damp when the grout is poured.
Interior adhered masonry veneers shall have a maximum weight of 20 psf (0.958 kg/m2) and shall be installed in accordance with Section 1405.9. Where the interior adhered masonry veneer is supported by wood construction, the supporting members shall be designed to limit deflection to 1/600 of the span of the supporting members.
Veneers of metal shall be fabricated from approved corrosion-resistant materials or shall be protected front and back with porcelain enamel, or otherwise be treated to render the metal resistant to corrosion. Such veneers shall not be less than 0.0149-inch (0.378 mm) nominal thickness sheet steel mounted on wood or metal furring strips or approved sheathing on the wood construction.
Exterior metal veneer shall be securely attached to the supporting masonry or framing members with corrosion-resistant fastenings, metal ties or by other approved devices or methods. The spacing of the fastenings or ties shall not exceed 24 inches (610 mm) either vertically or horizontally, but where units exceed 4 square feet (0.4 m2) in area there shall be not less than four attachments per unit. The metal attachments shall have a cross-sectional area not less than provided by W 1.7 wire. Such attachments and their supports shall be capable of resisting a horizontal force in accordance with the wind loads specified in Section 1609, but in no case less than 20 psf (0.958 kg/m2).
Metal supports for exterior metal veneer shall be protected by painting, galvanizing or by other equivalent coating or treatment. Wood studs, furring strips or other wood supports for exterior metal veneer shall be approved pressure-treated wood or protected as required in Section 1403.2. Joints and edges exposed to the weather shall be caulked with approved durable waterproofing material or by other approved means to prevent penetration of moisture.
The area of a single section of thin exterior structural glass veneer shall not exceed 10 square feet (0.93 m2) where it is not more than 15 feet (4572 mm) above the level of the sidewalk or grade level directly below, and shall not exceed 6 square feet (0.56 m2) where it is more than 15 feet (4572 mm) above that level. In no event shall thin exterior structural glass veneer be installed more than 35 feet (10 668 mm) above the level of the sidewalk or grade level directly below.
The length or height of any section of thin exterior structural glass veneer shall not exceed 48 inches (1219 mm).
The thickness of thin exterior structural glass veneer shall be not less than 0.344 inch (8.7 mm).
Thin exterior structural glass veneer shall be set only after backing is thoroughly dry and after application of an approved bond coat uniformly over the entire surface of the backing so as to effectively seal the surface. Glass shall be set in place with an approved mastic cement in sufficient quantity so that at least 50 percent of the area of each glass unit is directly bonded to the backing by mastic not less than 0.25 inch (6.4 mm) thick and not more than 0.625 inch (15.9 mm) thick. The bond coat and mastic shall be evaluated for compatibility and shall bond firmly together.
Where glass extends to a sidewalk surface, each section shall rest in an approved metal molding, and be set at least 0.25 inch (6.4 mm) above the highest point of the sidewalk. The space between the molding and the sidewalk shall be thoroughly caulked and made water tight.
Where thin exterior structural glass veneer is installed above the level of the top of a bulkhead facing, or at a level more than 36 inches (914 mm) above the sidewalk level, the mastic cement binding shall be supplemented with approved nonferrous metal shelf angles located in the horizontal joints in every course. Such shelf angles shall be not less than 0.0478-inch (1.21 mm) thick and not less than 2 inches (51 mm) long and shall be spaced at approved intervals, with not less than two angles for each glass unit. Shelf angles shall be secured to the wall or backing with expansion bolts, toggle bolts or by other approved methods.
Unless otherwise specifically approved by the commissioner, abutting edges of thin exterior structural glass veneer shall be ground square. Mitered joints shall not be used except where specifically approved for wide angles. Joints shall be uniformly buttered with an approved jointing compound and horizontal joints shall be held to not less than 0.063 inch (1.6 mm) by an approved nonrigid substance or device. Where thin exterior structural glass veneer abuts nonresilient material at sides or top, expansion joints not less than 0.25 inch (6.4 mm) wide shall be provided.
Thin exterior structural glass veneer installed above the level of the heads of show windows and veneer installed more than 12 feet (3658 mm) above sidewalk level shall, in addition to the mastic cement and shelf angles, be held in place by the use of fastenings at each vertical or horizontal edge, or at the four corners of each glass unit. Fastenings shall be secured to the wall or backing with expansion bolts, toggle bolts or by other methods. Fastenings shall be so designed as to hold the glass veneer in a vertical plane independent of the mastic cement. Shelf angles providing both support and fastenings shall be permitted.
Vinyl siding conforming to the requirements of this section and complying with ASTM D 3679 shall be permitted on exterior walls of buildings of Type V construction located in areas where the basic wind speed specified in Chapter 16 does not exceed 100 miles per hour (161 km/h) and the building height is less than 40 feet (12 192 mm) in Exposure C. Where construction is located in areas where the basic wind speed exceeds 100 miles per hour (161 km/h), or building heights are in excess of 40 feet (12 192 mm), tests or calculations indicating compliance with Chapter 16 shall be submitted. Vinyl siding shall be secured to the building so as to provide weather protection for the exterior walls of the building.
The siding shall be applied over sheathing or materials listed in Section 2304.6. Siding shall be applied to conform with the weather-resistant barrier requirements in Section 1403. Siding and accessories shall be installed in accordance with approved manufacturer's instructions. Unless otherwise specified in the approved manufacturer's instructions, nails used to fasten the siding and accessories shall have a minimum 0.313-inch (7.9 mm) head diameter and 0.125-inch (3.18 mm) shank diameter. The nails shall be corrosion resistant and shall be long enough to penetrate the studs or nailing strip at least 0.75 inch (19 mm). Where the siding is installed horizontally, the fastener spacing shall not exceed 16 inches (406 mm) horizontally and 12 inches (305 mm) vertically. Where the siding is installed vertically, the fastener spacing shall not exceed 12 inches (305 mm) horizontally and 12 inches (305 mm) vertically.
Fiber cement siding complying with Section 1404.10 shall be permitted on exterior walls of Type I, II, III, IV and V construction for wind pressure resistance or wind speed exposures as indicated in the manufacturer's compliance report and approved installation instructions. Where specified, the siding shall be installed over sheathing or materials listed in Section 2304.6 and shall be installed to conform to the weather-resistant barrier requirements in Section 1403. Siding and accessories shall be installed in accordance with approved manufacturer's instructions. Unless otherwise specified in the approved manufacturer's instructions, nails used to fasten the siding to wood studs shall be corrosion-resistant round head smooth shank and shall be long enough to penetrate the studs at least 1 inch (25 mm). For metal framing, all-weather screws shall be used and shall penetrate the metal framing at least three full threads.
Lap siding shall be lapped a minimum of 11/4 inches (32 mm) and shall have the ends sealed with caulking, covered with an H-section joint cover or located over a strip of flashing. Lap siding courses shall be permitted to be installed with the fastener heads exposed or concealed, according to approved manufacturers' instructions.
Weather boarding and wall coverings shall be securely fastened with aluminum, copper, zinc, zinc-coated or other approved corrosion-resistant fasteners in accordance with the nailing schedule in Table 2304.9.1 or the approved manufacturer's installation instructions. Shingles and other weather covering shall be attached with appropriate standard shingle nails to furring strips securely mailed to studs, or with approved mechanically bonding nails, except where sheathing is of wood not less than 1-inch (25 mm) nominal thickness or of wood structural panels as specified in Table 2308.9.3(3).
EIFS cladding conforming to the requirements of this section and tested in accordance with ASTM E 330 shall be permitted on exterior walls of buildings provided that the foam plastic insulation meets the requirements of Chapter 26, the substrate assembly is constructed of approved weather-resistant materials of adequate strength to resist the wind loads for cladding specified in Chapter 16, and the building height is 40 feet (12 192 mm) or less. EIFS may be permitted on the exterior walls of heights in excess of 40 feet (12 192 mm), provided that tests or calculations indicating compliance with Chapter 16 are submitted to the commissioner. EIFS installations on buildings of any height shall comply with the special inspection requirements of Chapter 17.
Where EIFS cladding is within 10 feet (3048 mm) of grade the installation must conform to the requirements of ANSI/EIMA 99 A impact resistance LEVEL 4.
2. Where building expansion joints occur.
3. Where prefabricated panels abut one another.
4. Where the substrate changes.
5. Where significant structural movement occurs, as determined by the design professional.
The inclusion of an EIFS over a listed fire-rated assembly shall not be deemed to reduce the tested or listed rating.
The EIFS insulation shall comply with the requirements of Chapter 26. The assembly of fiberglass reinforcing mesh, base coat and textured protective finish coat shall be tested in accordance with ASTM E 84, and shall have a flame spread rating of 25 or less and a smoke-developed rating of 50 or less. Materials shall be tested in the thickness intended to be used.
Foam insulation shall be listed by an approved testing laboratory and shall be labeled with all of the following information:
1. Inspection agency name.
2. Specific manufacturer's product for which the insulation is listed.
3. Identification of the insulation manufacturer.
The installing contractor shall have a certificate of instruction from the respective EIFS manufacturer's applicator training program.
The system materials shall be fastened to each other and the overall assembly shall be attached to the building frame so as to prevent failure due to elevated temperatures that occur in a building fire, wind loads, wetting or other environmental conditions. Installations over two stories shall be secured with either full bed of adhesive or corrosion-resistant mechanical fasteners.
Combustible exterior wall coverings shall be tested in accordance with NFPA 268.
Exceptions: The following materials are not required to be tested in accordance with NFPA 268. However, such materials shall comply with all other provisions of Section 1406.
For fire separation distances greater than 5 feet (1524 mm), an assembly shall be permitted that has been exposed to a reduced level of incident radiant heat flux in accordance with the NFPA 268 test method without exhibiting sustained flaming. The minimum fire separation distance required for the assembly shall be determined from Table 1406.2.1.2 based on the maximum tolerable level of incident radiant heat flux that does not cause sustained flaming of the assembly.
In buildings of Type I, II, III and IV construction, exterior wall coverings shall be permitted to be constructed of combustible materials in accordance with Section 1406.2.1. Combustible exterior wall coverings shall not exceed 10 percent of an exterior wall surface area on any given story nor exceed 40 feet (12 192 mm) in height above grade plane. Such combustible exterior wall coverings shall not be permitted on exterior walls where the fire separation distance is 5 feet (1524 mm) or less. Exterior wall coverings that exceed 40 feet (12 192 mm) in height above grade plane shall be constructed of approved noncombustible materials and shall be secured to the wall with metal or other approved noncombustible brackets.
Where the combustible exterior wall covering is furred from the wall and forms a solid surface, the distance between the back of the covering and the wall shall not exceed 1.625 inches (41 mm) and the space thereby created shall be fireblocked in accordance with Section 717 so that there will be no open space exceeding 100 square feet (9.3 m2). Where wood furring strips are used, they shall be of approved wood of natural decay resistance or preservative-treated wood.
- Fireblocking of cornices is not required in single-family dwellings.
- Fireblocking shall not be required where installed on noncombustible framing and the face of the exterior wall finish exposed to the concealed space is covered by one of the following materials:
Exterior balconies and similar projections shall be permitted to be constructed of combustible materials provided that the exterior balcony or similar projection affords the fire-resistance rating required by Table 601 for floor construction.
Bay and oriel windows, decks, porches, porticos, entranceways, and storm enclosures shall conform to the type of construction required for the building to which they are attached, including required fire-rating, unless otherwise modified by the requirements of this Section. For the purposes of this Section, such structures shall be referred to as, "appendages".
Exception: Plastic complying with Chapter 26.
Appendages on buildings of Type III, IV, and VA construction may be constructed of combustible materials, provided that all the following conditions are met:
- Such building does not exceed 3 stories or 40 feet (12 192 mm) in height, whichever is less.
- The main use or dominant occupancy of such building is classified in Occupancy Group R-2 or R-3.
- The appendage has an exterior separation on all exposed sides of at least 15 feet (4572 mm), measured from the outermost surface of the appendage, except that appendages with exposed sides protected by minimum 1-hour fire-rated construction extending at least 36 inches (914 mm) above the highest combustible horizontal surface may be located up to a minimum distance of 36 inches (914 mm) from any property line.
- The appendage is so constructed that its removal or destruction will not reduce the structural stability or fire resistive integrity of the building.
- The appendage has a superficial area not exceeding 150 square feet (13.9 m2) when viewed from directly above and is included in the area limitations of Table 503 for the entire building.
- The appendage is not higher than the sills of the second story windows.
- The vertical surface area of the combustible portions of the appendage does not exceed 10 percent of the total wall area (windows excluded) of the building.
- For enclosed appendages, the roof of the appendage has a class A roof covering, and the soffit or ceiling covering the combustible roof framing shall have a minimum 1-hour fire-resistance rating.
Exception: Appendages constructed of fire-retardant-treated wood, on buildings not exceeding 3 stories or 40 feet (12 192 mm) in height, whichever is less, need not comply with Items 2 through 8.
Appendages may be constructed of combustible materials on buildings of construction Type VB.
MCM shall be separated from the interior of a building by an approved thermal barrier consisting of 0.5-inch (12.7 mm) gypsum wallboard or equivalent thermal barrier material that will limit the average temperature rise of the unexposed surface to not more than 250°F (121°C) after 15 minutes of fire exposure in accordance with the standard time-temperature curve of ASTM E119. The thermal barrier shall be installed in such a manner that it will remain in place for not less than 15 minutes based on a test conducted in accordance with UL 1715.
- The thermal barrier is not required where the MCM system is specifically approved based on tests conducted in accordance with UL 1040 or UL 1715. Such testing shall be performed with the MCM in the maximum thickness intended for use. The MCM system shall include seams, joints and other typical details used in the installation and shall be tested in the manner intended for use.
- The thermal barrier is not required where the MCM is used as elements of balconies and similar appendages, architectural trim or embellishments.
MCM shall have a self-ignition temperature of 650°F (343°C) or greater when tested in accordance with ASTM D 1929.
Sections of MCM shall not exceed 300 square feet (27.9 m2) in area and shall be separated by a minimum of 4 feet (1219 mm) vertically.