FRL
FRL (Fire Resistance Level) is the code measure of how long an element resists fire. Three numbers: structural adequacy/integrity/insulation in minutes.
Ask Chalkline about this →FRL (Fire Resistance Level) is the code-standard way of rating how long a structural element, wall, floor, or door can resist a standard fire test. It is expressed as three numbers separated by slashes, for example 30/30/30 or 60/60/60. Each number is in minutes and represents a different criterion: structural adequacy (the element keeps supporting its load), integrity (no cracks or gaps that let flames through), and insulation (the unexposed face stays cool enough that it won’t ignite adjacent material).
FRL appears most often on wall and floor separations in the NCC. In bushfire construction under AS 3959-2018, a BAL-FZ wall must achieve a minimum FRL of 30/30/30 (clause 9.4 of the standard), because direct flame contact is assumed at that rating.
A dash in any of the three positions (e.g. -/60/60) means that criterion is not required for that element.
Also known as: Fire Resistance Level.
Category: Compliance & approvals.
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Last updated: 2026-05-07. Verified: 2026-05-07. Quarterly review for currency.