Insulation cork has a stable operating temperature of -180°C to +120°C (–292°F to 248°F). It can withstand short bursts up to 140-150°C (284–302°F).

Keep in mind that cork is not fireproof. It is self-extinguishing, meaning that it typically does not sustain combustion without an active flame. It will char and release CO2 smoke under flame. However, at very high temperatures (outside the above range), these properties change, leading to thermal degradation and active flaming.