N.Y.C. Admin. Code § BC 1406: Section BC 1406: Combustible Materials on the Exterior Side of Exterior Walls

1406.1 General.

Section 1406 shall apply to exterior wall coverings, exterior balconies and similar projections, bay and oriel windows, decks, porches, porticos, entranceways, and storm enclosures constructed of combustible materials. Combustible water-resistive barriers complying with Section 1403.5.1 shall be permitted in exterior wall coverings. Fireblocking shall be installed in accordance with Section 1406.2.3. Existing building retrofits utilizing combustible exterior wall coverings shall also comply with Section 1406.5. Combustible exterior wall coverings shall be subject to the special inspection requirements of Section 1705.16.

1406.2 Combustible exterior wall coverings.

Combustible exterior wall coverings, including architectural trim, shall comply with this section.

Exceptions:

1. Plastics complying with Chapter 26.

2. Metal composite materials (MCM) complying with Section 1407.

3. High-pressure decorative exterior-grade compact laminates (HPL) complying with Section 1409.

1406.2.1 Type I, II, III and IV construction.

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 1406.2.1.1, subject to the following limitations:

1. Combustible exterior wall coverings shall not exceed 10 percent of an exterior wall surface area on any given story. Such combustible exterior wall covering shall not be permitted on exterior walls where the fire separation distance is 5 feet (1524 mm) or less.

2. Combustible exterior wall coverings shall be limited to 40 feet (12 192 mm) in height above grade plane.

3. Combustible exterior wall coverings constructed of fire-retardant-treated wood complying with Section 2303.2 for exterior installation shall not be limited in wall surface area where the fire separation distance is 5 feet (1524 mm) or less and shall be permitted up to 60 feet (18 288 mm) in height above grade plane, regardless of the fire separation distance.

4. Wood veneers shall comply with Section 1405.5.

5. Combustible exterior wall coverings shall not be permitted on buildings of Type IV construction utilizing CLT or SCL complying with Section 602.4.

6. Combustible exterior wall coverings shall not be permitted at exterior balconies in accordance with Section 1406.3.

1406.2.1.1 Ignition resistance.

Where permitted by Section 1406.2.1 of this code, 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 of this code.

1. Wood or wood-based products.

2. Other combustible materials covered with an exterior weather covering other than vinyl sidings included in and complying with the thickness requirements of Table 1405.2 of this code.

3. Aluminum having a minimum thickness of 0.019 inch (0.48 mm).

1406.2.1.1.1 Fire separation 5 feet or less.

Where installed on exterior walls having a fire separation distance of 5 feet (1524 mm) or less, combustible exterior wall coverings shall not exhibit sustained flaming as defined in NFPA 268.

1406.2.1.1.2 Fire separation greater than 5 feet.

For fire separation distances greater than 5 feet (1524 mm), any exterior wall covering 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 exterior wall covering shall be determined from Table 1406.2.1.1.2 of this code based on the maximum tolerable level of incident radiant heat flux that does not cause sustained flaming of the exterior wall covering.

Table 1406.2.1.1.2 Minimum Fire Separation for Combustible Exterior Wall Coverings

Fire Separation Distance (feet)

Tolerable Level Incident Radiant Heat Energy (kW/m

2

)

Fire Separation Distance (feet)

Tolerable Level Incident Radiant Heat Energy (kW/m

2

)

5

12.5

16

5.9

6

11.8

17

5.5

7

11.0

18

5.2

8

10.3

19

4.9

9

9.6

20

4.6

10

8.9

21

4.4

11

8.3

22

4.1

12

7.7

23

3.9

13

7.2

24

3.7

14

6.7

25

3.5

15

6.3

For SI: 1 foot = 304.8 mm, 1 Btu/H

2

× °F = 0.0057 kW/m

2

× K.

1406.2.2 Location.

Combustible exterior wall coverings located along the top of exterior walls shall be completely backed up by the exterior wall and shall not extend over or above the top of the exterior walls.

1406.2.3 Fireblocking.

Exterior wall coverings shall be fireblocked in accordance with Section 718.2.6.

1406.3 Exterior balconies and similar projections.

Exterior wall covering on walls abutting balconies, and cladding on the sides and underside of balconies, shall be constructed of noncombustible materials. Exterior walls abutting balconies shall be noncombustible up to 12 feet (3657.6 mm) above the walking surface or to the underside of the balcony above, whichever is less. On cantilevered balconies, the exterior wall abutting the balcony, plus 3 feet (914.4 mm) on each side, shall be constructed of noncombustible materials. On recessed and semirecessed balconies, the exterior walls abutting the balconies shall be constructed of noncombustible materials.

Exception: Combustible exterior wall coverings shall be allowed on balconies in Type V construction with a fire separation distance greater than or equal to 5 feet (1524 mm).

1406.4 Bay and oriel windows, decks, porches, porticos, entranceways, and storm enclosures.

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.

1406.4.1 Appendages on Type I and II construction.

Appendages on buildings of Type I or II construction shall be constructed of noncombustible materials. However, on buildings not more than three stories or 40 feet (12 192 mm) in height, whichever is less, fire-retardant-treated wood shall be permitted.

1406.4.2 Appendages on Type III, IV and VA construction.

Appendages on buildings of Type III, IV and VA construction may be constructed of combustible materials, provided that all the following conditions are met:

1. Such building does not exceed three stories or 40 feet (12 192 mm) in height, whichever is less.

2. The main use or dominant occupancy of such building is classified in Occupancy Group R-2 or R-3.

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 (914.4 mm) above the highest combustible horizontal surface may be located up to a minimum distance of 36 inches (914.4 mm) from any property line.

4. The appendage is so constructed that its removal or destruction will not reduce the structural stability or fire-resistive integrity of the building.

5. The appendage has a superficial area not exceeding 150 square feet (13.9 m

2

) when viewed from directly above and is included in the area limitations of Table 503* for the entire building.

6. The appendage is not higher than the sills of the second-story windows.

7. 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.

8. 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 or40 feet (12 192 mm) in height, whichever is less, need not comply with Items 2 through 8.

1406.4.3 Appendages on Type VB construction.

Appendages may be constructed of combustible materials on buildings of construction Type VB.

1406.5 Retrofit of existing buildings.

Combustible materials shall not be permitted for use at the outermost surface of the exterior wall covering for exterior envelope retrofits of existing nonsprinklered buildings over 75 feet (22 860 mm), unless the following conditions are satisfied:

1. The outermost surface of the combustible exterior wall covering shall be interrupted by a noncombustible material at least 3 feet (914.4 mm) high between the top of one opening and the bottom of the opening immediately above to form a continuous band across building elevations.

2. On walls without openings, a 3 feet (914.4 mm) high noncombustible band shall interrupt the outermost surface of the combustible exterior wall covering at least every 15 feet (4572 mm) vertically.