Glossary

F

FD30

A door assembly rated at 30 minutes fire resistance when tested in accordance with BS 476-22.

FD30S

A door assembly rated at 30 minutes fire resistance when tested in accordance with BS 476-22, with additional smoke resistance when tested in accordance with BS 476-31.1.

Face-fixed

Door furniture or seals mounted directly on the surface of the door leaf.

Finger guard

A device covering the gap between a door leaf and its frame on the hinged edge, extending and contracting with the movement of the door. Its purpose is to provide protection from the risk of fingers being accidentally caught in the gap if the door should suddenly close.

Fire resistance

The ability of a door assembly to withstand exposure to fire when tested in accordance with a recognised standard.

Fire seal

A seal designed to enhance the performance of a fire door assembly, generally by virtue of an intumescent core in the seal profile.

Flush bolt

A flush bolt is a security device to be used on pairs of doors to secure the inactive leaf. It is activated lever, that drops the bolt into a keep in the floor.

Free area

Is the area within an aperture unobstructed by the components of an air transfer grille product when in the normal or open position through which air is free to flow. Its size can be given in square metres, square centimetres, square millimetres, square feet or square inches.

Frequency

The character of a sound wave referring to the number of vibrations or cycles per second and measured in Hertz.