What does FRL _/120/120 mean?

FRL stands for Fire Resistance Level. The three numbers represent Structural Adequacy / Integrity / Insulation, expressed in minutes:

• _ (dash) — Structural adequacy is not applicable (the downlight is not a load-bearing element).
• 120 — The system maintains integrity (prevents passage of flames and hot gases) for 120 minutes.
• 120 — The system maintains insulation (limits temperature rise on the unexposed face) for 120 minutes.

This means the downlight, when installed as part of a compliant tested ceiling assembly, is designed to prevent fire and heat from breaching the ceiling for up to 2 hours.