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.

403.2.3.4 Other wall assemblies.

Any other wall assembly that provides impact resistance equivalent to that required by Sections 403.2.3.1 and 403.2.3.2 for Hard Body Impact Classification Level 3, as measured by the test method described in ASTM C 1629 / C 1629M, shall be permitted.

403.2.4 Sprayed fire-resistant materials (SFRM).

The bond strength of the SFRM installed throughout the building shall be in accordance with Table 403.2.4.

Table 403.2.4
Minimum Bond Strength

 

Height of Building a	SFRM Minimum Bond Strength
Up to 420 feet	430 psf
Greater than 420 feet	1,000 psf

 

For SI: 1 foot = 304.8 mm, 1 pound per square foot (psf) = 0.0479 kW/m 2 .

a.   Above the lowest level of fire department vehicle access.

403.3 Automatic sprinkler system.

Buildings and structures shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 and a secondary water supply where required by Section 403.3.3.

403.3.1 Number of sprinkler risers and system design.

Each sprinkler system zone in buildings that are more than 300 feet (91 440 mm) in building height shall be supplied by no fewer than two risers. Each riser shall supply sprinklers on alternate floors. If more than two risers are provided for a zone, sprinklers on adjacent floors shall not be supplied from the same riser.