602. CONSTRUCTION CLASSIFICATION

602 CONSTRUCTION CLASSIFICATION Strike Section 602.4 and Table 602.4 in the International Building Code in their entirety and insert new Section 602.4 in the Building Code to read as follows: 602.4 Type IV. Type IV construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of solid wood, laminated wood, heavy timber (HT) or structural composite lumber (SCL) without concealed spaces. The minimum dimensions for permitted materials including solid timber, glued-laminated timber, structural composite lumber (SCL), and cross-laminated timber and details of Type IV construction shall comply with the provisions of this section and Section 2304.11. Exterior walls complying with Section 602.4.1 or 602.4.2 shall be permitted. Interior walls and partitions not less than 1-hour fire-resistance rating or heavy timber complying with Section 2304.11.2.2 shall be permitted. Strike Section 602.4.2 in the International Building Code in their entirety and insert new Section 602.4.2 in the Building Code to read as follows: 602.4.2 Cross-laminated timber in exterior walls. Cross-laminated timber complying with Section 2303.1.4 shall be permitted within exterior wall assemblies not less than 6 inches (152 mm) in thickness with a 2-hour rating or less, provided the exterior surface of the cross-laminated timber is protected by one the following: 1. Fire-retardant-treated wood sheathing complying with Section 2303.2 and not less than 15/32 inch (12 mm) thick; 2. Gypsum board not less than 1/2 inch (12.7 mm) thick; or 3. A noncombustible material. Strike Sections 602.4.3 through 602.4.8 in the International Building Code in their entirety without substitution. Strike Section 602.4.9 in the International Building Code and insert new Section 602.4.9 in its place in the Building Code to read as follows: 602.4.9 Exterior structural members. Where a horizontal separation of 20 feet (6096 mm) or more is provided, wood columns and arches conforming to heavy timber sizes complying with Section 2304.11 shall be permitted to be used externally. SOURCE: Final Rulemaking published at 67 DCR 5690 (May 29, 2020 – Part 2). The District of Columbia Building Code (2017), referred to as the “Building Code,” consists of the 2015 edition of the International Building Code (International Building Code), published by the International Code Council (ICC), as amended by the Building Code Supplement of 2017 (12-A DCMR). The International Building Code is copyrighted by the ICC and therefore is not republished here. However, a copy of the text may be obtained at: https://codes.iccsafe.org/public/document/IBC2015. District of Columbia Municipal Regulations Building Code Supplement of 2017 12-A DCMR § 602