403.2 Construction.

The construction of high-rise buildings shall comply with the provisions of Sections 403.2.1 through 403.2.4.

403.2.1 Types of construction.

The following modifications to the minimum fire-resistance rating of the building elements in Table 601 shall be as follows:

   1.   High rise buildings 420 feet (128 m) or greater in building height shall be constructed of Type IA construction.

   2.   For high rise buildings not greater than 420 feet (128 m) in building height, and constructed to meet the fire-resistance rating requirements of Type IB or IIA construction, the required fire-resistance rating of columns supporting floors shall be constructed to meet Type IA construction.

403.2.2 Seismic considerations.

For seismic considerations, see Chapter 16.

403.2.3 Structural integrity of interior exit stairways and elevator hoistway enclosures.

For all high-rise buildings, exit enclosures for interior exit stairways and elevator hoistway enclosures shall comply with Sections 403.2.3.1 through 403.2.3.4.

   Exception: Where fire-resistance rating is not required by this code for the enclosure or portions thereof.

403.2.3.1 Wall assembly.

The wall assemblies making up the enclosures for interior exit stairways and elevator hoistway enclosures shall meet or exceed Soft Body Impact Classification Level 2 as measured by the test method described in ASTM C 1629 / C 1629M.

403.2.3.2 Wall assembly materials.

The face of the wall assemblies making up the enclosures for interior exit stairways and elevator hoistway enclosures that are not exposed to the interior of the enclosures for interior exit stairways or elevator hoistway enclosure shall be constructed in accordance with one of the following methods:

   1.   The wall assembly shall incorporate no fewer than two layers of impact-resistant construction board each of which meets or exceeds Hard Body Impact Classification Level 2 as measured by the test method described in ASTM C 1629 / C 1629M.

   2.   The wall assembly shall incorporate no fewer than one layer of impact-resistant construction material that meets or exceeds Hard Body Impact Classification Level 3 as measured by the test method described in ASTM C 1629 / C 1629M.

   3.   The wall assembly incorporates multiple layers of any material, tested in tandem, that meets or exceeds Hard Body Impact Classification Level 3 as measured by the test method described in ASTM C 1629 / C 1629M.

403.2.3.3 Concrete and masonry walls.

Concrete or masonry walls shall be deemed to satisfy the requirements of Sections 403.2.3.1 and 403.2.3.2.