Proposal to Exempt 20-Minute Fire Windows from Hose Stream Test Fails

Committee action in support of code change proposal FS135, submitted by William O'Keeffe with SAFTI FIRST, which would exempt 20-minute fire windows from the hose stream test requirement, was disapproved yesterday during the International Building Code Fire Safety hearings in Minneapolis.

According to code documents, the proposal "is a clarification and addition to the code to specifically address the rating requirements for interior windows. The more correct terminology for section 715.5.7.3 should be 'area' limits, rather than 'size' limits. The new proposed section 715.5.7.2 addresses 20-minute windows tested to NFPA 257 now specified in Table 715.5 for ½-hour fire partitions. Since a ½-hour fire resistance rated fire partition assembly is tested to ASTM E 119 without the hose stream test, and fire doors tested for 20-minutes as required in Table 715.4 are not subject to the hose stream test, for consistency in the code, the fire window component of a ½-hour fire partition should be likewise exempt from the hose stream test under NFPA 257."

Based on the fact that ASTM E 119 does not require the hose stream test for partitions qualifying for a 30-minute fire rating and Section 715.4.3 allows 20-minute rated fire doors to be tested without the hose stream test, the committee agreed that the hose stream test should not be required for a 20-minute rated fire protection window.

Thom Zaremba, representing Pilkington Fire Protection Glass NA Inc., spoke against the motion. According to Zaremba's public comments in the code documents, "Other than adding symmetry to the code, there is no technical justification for the committee's support of this proposal. It is true that 1/2-hour fire-resistance rated fire partitions forming the subject of this proposal are tested to ASTM E 119 without the hose stream test. It is also true that 20-minute fire doors may be tested without the hose stream test. However, symmetry does not always assure an adequate level of fire safety and it is not true that exemptions from hose-stream testing for wall materials and doors should be extended to fire windows."

Zaremba explained that exempting wall materials from the hose stream test recognizes that the types of materials used in fire-resistance rated walls are not likely to degrade sufficiently by the end of a 1/2 hour test to warrant hose stream testing; exempting 20-minute doors from the hose stream test recognizes that it is unlikely that fuel loads will be stacked in front of doors, blocking access through doorways. However, the glass used in fire windows cannot be compared to the types of materials used in fire-resistance rated walls.

"Tempered glass is not the same as the materials that are going to be found in the products we're talking about," Zaremba said during the hearing. "There is simply no structural glazing strength to a tempered product that has been exposed to a fire for 20 minutes."

According to Zaremba, "as soon as tempered glass experiences a significant temperature delta it disintegrates. For that reason, even when subjected to a fire test for only a few minutes, tempered glass can fail catastrophically when subjected to the hose stream test. If adopted, FS135 would make the testing of fire windows more symmetrical to wall materials and doors in 1/2-hour fire partitions. However, glass is not the same as the opaque materials used in walls and the fire loads experienced by fire windows can be far greater than those experienced by doors."

Code consultant Bill Koffel agreed.

"This code has never allowed fire-protection glass of any kind without a hose stream test," said Koffel. "We have not allowed any other glass product to be tested without a hose stream."