The fire resistance time of Class B fire door shall not be less than 1.0 hours, and the hardware fittings used on the fire door must also be fire-resistant hardware fittings. Usually, the fire door of this grade is generally used for the entrance door of family decoration.

Deriyên agir ZHTdoors, 31 sal ezmûna hilberînê di deriyê agir û pencereyan de. Deriyên agir ên sereke yên UL, deriyên agir EN, deriyên agir BS EN, hwd.. Em xwedî sertîfîkayê ne.