2603 FOAM PLASTIC INSULATION

Strike Section 2603.5.5 of the International Building Code in its entirety and insert new Section 2603.5.5 in the Building Code in its place to read as follows:

2603.5.5 Vertical and lateral fire propagation. The exterior wall assembly shall be tested in accordance with and comply with the acceptance criteria of NFPA 285.

Exceptions:

1. One-story buildings complying with Section 2603.4.1.4.

2. Wall assemblies where the foam plastic insulation is covered on each face by not less than 1-inch (25 mm) thickness of masonry or concrete and meeting one of the following:

2.1. There is no airspace between the insulation and the concrete or masonry.

2.2. The insulation has a flame spread index of not more than 25 as determined in accordance with ASTM E84 or UL 723 and the maximum airspace between the insulation and the concrete or masonry is not more than 1 inch (25 mm).

2603.5.5.3 Fireblocking. Concealed spaces within exterior wall assemblies shall be fireblocked in such a manner so as to cut off the concealed openings (both vertical and horizontal), and form an effective barrier between floors.

2603.5.5.3.1 Location of fireblocking. Fireblocking shall be installed within concealed spaces of exterior wall assemblies at every floor level or at maximum vertical intervals not exceeding 20 feet. Fireblocking shall be installed at horizontal intervals not exceeding 10 feet in exterior walls of combustible construction and 65 feet in exterior walls of noncombustible construction. Fireblocking required in this section shall extend through any concealed air space and through any foam plastic material in noncombustible construction.

2603.5.5.3.2 Materials. Materials used for fireblocking in exterior wall assemblies shall comply with one or more of the following:

1. Materials demonstrated to remain in place and that prevent the passage of flame and hot gases sufficient to ignite

cotton waste where subjected to ASTM E 119 or UL 263 time-temperature conditions under a minimum positive pressure differential of 0.01 inch (2.49 Pa) of water at the location of the penetration for a time period of 15 minutes.

2. Gypsum board having a minimum thickness of 1/2 inch (12.7 mm) provided all joints have continuous support.

3. Sheet steel not less than 26 ga (0.38 mm) thickness provided all joints have continuous support.

4. Cement-based millboard having a minimum thickness of ¼-inch (6.4 mm).

5. Batts or blankets of mineral wool, mineral fiber or other approved materials installed in such a manner to securely remain in place.

6. Cellulose insulation installed as tested for the specific application.

7. In buildings of noncombustible construction, fire-retardant wood in accordance with Section 603.1.

8. In buildings of combustible construction, materials listed in Section 718.2.1.

SOURCE: Final Rulemaking published at 61 DCR 2782 (March 28, 2014 – Part 2); as amended by Final Rulemaking published at 65 DCR 6838 (June 22, 2018).

The District of Columbia Building Code (2013), referred to as the “Building Code,” consists of the 2012 edition of the International Building Code as amended by the District of Columbia Building Code Supplement (2013)(12 DCMR A). The International Building Code is copyrighted by the International Code Council and therefore is not republished here. However, a copy of the text may be obtained at: http://publicecodes.cyberregs.com/icod/ibc/2012/index.htm?bu=IC-P-2012-000001&bu2=IC-P-2012-000019.