fire resistance
Technical term used in engineering, construction, and materials science to describe the ability to withstand fire or high temperatures.
This building material has high fire resistance.
A special coating is applied to improve fire resistance.
耐熱性 means 'heat resistance' and is broader, covering resistance to high temperatures in general, not necessarily fire. 耐火性 is specifically about resistance to fire and flames.
Compound of 耐火 (fireproof, from 耐 'withstand' + 火 'fire') and 性 (property, characteristic).