According to different fire resistance, steel fire doors can be divided into three grades: A, B and C. The fire resistance limit of Class B fire door is 60 minutes. The fire door is not only strong in fire resistance, but also considered in the design to prevent smoke diffusion.

Mga pultahan sa sunog sa ZHTdoors, 31 ka tuig nga kasinatian sa produksiyon sa mga pultahan sa sunog ug Windows. Ang nag-unang UL fire doors, EN fire doors, BS EN fire doors, etc.,.We have certification.ZHTdoors support OEM and free design.Our advantages:good quality, factory price, good service.Welcome to consult us.