602.4 Type IV.
BC § 602.4
Type IV construction is that type of construction in which the exterior walls are of noncombustible materials or other materials permitted by Section 602.4.1 or 602.4.2, and the interior building elements are of solid wood, glue-laminated timber, heavy timber (HT), structural composite lumber (SCL), or cross-laminated timber (CLT) without concealed spaces. The minimum dimensions for permitted materials including solid timber, glued-laminated timber, SCL, and CLT and details of Type IV construction shall comply with the provisions of Section 2304.11 and this section. 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. Buildings of Type IV construction utilizing SCL or CLT shall be equipped throughout with an automatic sprinkler system where required by Section 903.2.13. In buildings of Type IV construction utilizing SCL or CLT, a fire watch shall be maintained in accordance with Section 901.7.2 of the New York City Fire Code and Section 3303.3 of this code. Exceptions: 1. In Group I-1, R-1, and R-2 occupancies, all exterior walls, fire walls, exit passageways, and shaft enclosures shall be noncombustible.
2.In Group F occupancies subject to Section 270(1) of the New York State Labor Law, all exterior wall assemblies and all structural elements shall meet the requirements for a "fireproof building" as defined in Section 264 of such law.
3.Inside the fire district, exterior load-bearing walls shall be constructed of noncombustible material.
4.Inside the fire district, exterior nonbearing walls may be constructed with fire-retardant-treated wood complying with Section 2303.2 where the building is equipped throughout with an automatic sprinkler system in accordance with Sections 903.3.1.1 through 903.3.1.3, unless otherwise prohibited by Exception 1 or 2 above.
5.Inside the fire district, exterior nonbearing walls are permitted to be constructed with cross-laminated timber (CLT) complying with Section 602.4.2 of this code, unless otherwise prohibited by Exception 1 or 2 above. (Am. L.L. 2023/077, 6/11/2023, eff. 6/11/2023) Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2023/077.
