When a building material is exposed to fire under certain conditions and disintegrates, its behavior against fire also determines its reaction to fire. The fire reaction of the building material is used to identify its fire resistance class. Under the fire conditions specified in the VDE 4102-12 standard, the insulation continuity of the cable is measured in terms of time. This is classified as E-30, E-60, and E-90:

• E-30 → 30 minutes
• E-60 → 60 minutes
• E-90 → 90 minutes