The Truth About 60 minute Fire Rated Glass. There is a lot of confusion about what type of fire rated glass to use in 60 minute applications. This article sorts Fact from fiction related to 60 minute fire rated glass applications.
FICTION: 60-minute windows are accepted for use to protect openings as provided by codes.
FACT: There is no such thing as a 60-minute window under building codes, which uniformly limit windows to applications rated 45-minutes or less.
FICTION: 60-minute fire-rated glazing tested and listed for use in windows, sidelights and transoms are permitted by codes when used in accordance with their listings.
FACT: For glazing to be rated for use in 60-minute assemblies, it must be tested to the wall test criteria under ASTM E119 including temperature rise limits.
FICTION: Glazing tested and listed for use in approved 60-minute rated transom and sidelight assemblies are allowed by codes in sizes specified in their listings.
FACT: Fire-rated glazing is permitted in sidelight and transom frames rated 45-minutes or less. For acceptance in 60-minute frames, glazing must meet ASTM E119 criteria, and be tested for use under door test standards.
FICTION: Where 45-minute rated is required, 60-minute rated glazing is better.
FACT: The extra fifteen minutes of fire endurance is not a benefit, says the former NFPA 80 Chairman, because during that time uncontrolled transfer of radiant heat can ignite combustibles on the other side and actually spread fire rather than contain it. CSFM withdrew its listing of FireLite in 60-minute window applications, and now only approves 45-minute window uses to 1296sq. inches, and limits use to 100 sq. inches in 60/90-minute doors.