Do you need filling materials inside the frame of steel fireproof doors?

The door leaf of a steel fireproof door should be filled with fireproof and thermal insulation materials, otherwise relying solely on the steel material of the door leaf cannot meet the requirements of fire insulation and fire integrity. So, does the steel fireproof door frame need to be filled with materials?

In completed projects, some of the fireproof door frames are filled with materials, while others are not filled with materials.

According to 5.2.1.1 of the current national standard "Fire Doors GB12955-2008", if the door leaf of a fire door is filled with materials, it should be filled with fire insulation materials that do not affect the human body. However, it was not specified whether filling materials were needed inside the door frame.

According to 5.3.8 of the national standard "Code for Construction and Acceptance of Fireproof Rolling Blinds, Fireproof Doors, and Fireproof Windows GB50877-2014", the steel fireproof door frame should be filled with cement mortar.

Filling the door frame with cement mortar (or concrete) can increase the stiffness and strength of the door frame. In case of fire, it can ensure that the door frame does not deform at high temperatures, thereby ensuring the overall stability and integrity of the fireproof door. Therefore, the frame of steel fireproof doors should be filled with cement mortar (or concrete) as required.