§ 260. Incombustible, fireproof and fire-resisting or fire-resistive material. 1. "Incombustible material" means material which will not burn or support combustion as determined and specified in the rules of the board.

2. "Fireproof material" means material capable of resisting the effect of fire to a sufficient extent to insure the safety of the occupants of the building. The board shall determine and specify in its rules what materials are fireproof materials.

3. "Fire-resisting material" or "fire-resistive material" means material conforming to the requirements of the board which shall determine and specify in its rules what materials, not being fireproof materials, are fire-resisting or fire-resistive materials.