Section 26 – Fire and Flammability:
Category A: Fire-Proof
Equipment installed in fire zone which must function during the first five minutes of fire and which must keep its safety functions for at least fifteen minutes.
Category B: Fire Resistance
Equipment installed in fire zone, which must function or not cause a hazardous condition during the five first minutes of fire without structural degradation
Category C: Flammability
Non-metallic equipment, component parts, sub-assemblies installed in pressurized or non-pressurized zones and non-fire zones with largest dimension greater than 50 mm.