Where is the keyhole of the fire door?

On the door leaf. By looking at the fire door, we know that the keyhole of the fire door is on the door leaf. Just insert the key into the keyhole and turn it to the right to open the fire door. Fire doors are fire-proof separation facilities of buildings, which are mainly installed on firewalls, evacuation exits or openings of tube wells, and play an important role in preventing the spread of smoke and fire and reducing fire losses.