UL fire doors are different from other fire doors. The obvious feature of American standard fire doors is that American standard fire doors need to pass the fire water strike test. The five accessories of the fire door must also have a UL label.

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.