715.5.1 Testing under positive
pressure. NFPA 257 shall evaluate fire-protection-rated
glazing under positive pressure. Within the first 10 minutes
of a test, the pressure in the furnace shall be adjusted
so at least two-thirds of the test specimen is above the
neutral pressure plane, and the neutral pressure plane shall
be maintained at that height for the balance of the test.
715.5.2 Nonsymmetrical
glazing systems. Nonsymmetrical fire-protection-rated
glazing systems in fire partitions, fire barriers or in
exterior walls with a fire separation distance of 5 feet
(1524 mm) or less pursuant to Section
704 shall be tested with both faces exposed to the furnace,
and the assigned fire protection rating shall be the shortest
duration obtained from the two tests conducted in compliance
with NFPA257.
715.5.3 Wired glass. Steel
window frame assemblies of 0.125-inch (3.2 mm) minimum solid
section or of not less than nominal 0.048-inch-thick (1.2
mm) formed sheet steel members fabricated by pressing, mitering,
riveting, interlocking or welding and having provision
for glazing with 1/4-inch (6.4 mm)
wired glass where securely installed in the building construction
and glazed with 1/4-inch (6.4 mm)
labeled wired glass shall be deemed to meet the requirements
for a %-hour fire window assembly. Wired glass panels shall
conform to the size limitations set forth in Table
715.5.3.
715.5.4 Non wired glass.
Glazing other than wired glass in fire window assemblies
shall be fire-protection-rated glazing installed in accordance
with and complying with the size limitations set forth in
NFPA 80.
715.5.5 Installation.
Fire-protection-rated glazing shall be in the fixed position
or be automatic-closing and shall be installed in approved
frames.
715.5.6 Window mullions.
Metal mullions that exceed a nominal height of 12 feet (3658
mm) shall be protected with materials to afford the same
fire-resistance rating as required for the wall construction
in which the protective is located.
715.5.7 Interior fire window
assemblies. Fire-protection-rated glazing used in fire
window assemblies located in fire partitions and fire barriers
shall be limited to use in assemblies with a maximum fire-resistance
rating of 1 hour in accordance with this section.