Fail Safe Control

A device which opens circuit when sensing element fails to operate.

Family Room

An informal living room, usually the center of family activities.

Fan

Any device that creates air currents.

Fan Coil

An indoor component of a heat pump system, used in place of a furnace, to provide additional heating on cold days when the heat pump does not provide adequate heating.

Fan Coil Units And Air Handling Units

These may be manufactured for the direct expansion market or for the hydraulic market. They generally consist of a filter, fan and a cooling and/or heating coil. The difference between a fan coil unit and an air-handling unit has become increasingly blurred. A fan coil unit generally is a small unit quite often located in the conditioned environment, they may also be located above a false ceiling and connected to a very small amount of ductwork. Air handling units are generally always intended to be connected to distribution ductwork, and the fan is sized to facilitate this. Large fan coil units have fans capable of providing up to 150 Pascal's static pressure (~0.6 inches water gauge).

Fan Window

See circlehead window.

Fanlight

A half-circle window over a door or window, with radiating bars. Also called circle top transom.

FAQ

An acronym for Frequently Asked Questions.

Farad

A unit of electrical capacity of a condenser which, when charged with one coulomb of electricity, gives difference of potential of one volt.

Faraday Experiment

Silver chloride absorbs ammonia when cool and releases ammonia when heated. This is basis on which some absorption refrigerators operate.

Fascia (Or Facia)

A horizontal board that is nailed vertically to the ends of roof rafters sometimes supports gutters.

FBT

Flexible black tubing

Feathering

The tapering of one surface into another.

Feathering Strips

Tapered wood filler strips placed along the butts of old wood shingles to create a level surface when reroofing over existing wood shingle roofs. Also called horsefeathers.

Felt

Fibrous material saturated with asphalt and used as an underlayment or sheathing paper.

Fenestration

The placement of window openings in a building wall, one of the important elements in controlling the exterior appearance of a building. Also, a window, door, or skylight and its associated interior or exterior elements, such as shades or blinds.

Fiberboard

A prefabricated building material made of wood or other plant fibers compressed and bonded into a sheet.

Fiberglass

Finespun filaments of glass that are made into yarn and used in batts as insulation added to gypsum concrete products to increase tensile strength. A composite material made by embedding glass fibers in a polymer matrix. May be used as a diffusing material in sheet form, or as a standard sash and frame element.  Also used as furnace filter material in some disposable furnace filters.

Fiberglass Mat

An asphalt roofing base material manufactured from glass fibers.

Field Pole

The part of stator of motor which concentrates magnetic field of field winding.

Field Tile

Porous tile placed around a building's foundation to drain off excess water and prevent seepage into the foundation.

File Card

A tool used to clean metal files.

Filter

A device for straining impurities from the air any porous material such as filter paper, charcoal, etc,  A device for removing pollutants from the air.  Any device that removes

impurities through a straining process or the removing of small particles from a fluid.

Fire Doors And Walls

Doors and walls constructed of fire resistive materials designed to prevent the spread of fire .

Fire Retarding Material

Material that tends to inhibit combustion.

Firebrick

A brick made of fireclay that is capable of resisting high temperatures and used to line heating chambers at fireplaces.

Fireplace Insert

Woodburning stove designed to be installed in a fireplace. Its purpose is to make the fireplace more efficient.

Fireproofing

The use of incombustible materials to protect the structural components of a building so that a complete burnout of its contents will not impair its structural integrity.

Fixed Light

A pane of glass installed directly into non-operating framing members also, the opening or space for a pane of glass in a non-operating frame.

Fixed Panel

An inoperable panel of a sliding glass door or slider window.

Fixed Window

A window that does not open e.g., fixed bay window, fixed bow window, picture window.  A window with no operating sashes.

Fixture

Any non-portable device which is more or less permanently built in or attached securely to the walls, floors, and/or ceiling. The permanent parts of a heating system such as furnaces, air conditioners, etc.

Flame Test For Leaks

A tool which is principally a torch and when an air-refrigerant mixture is fed to flame, this flame will change color in presence of heated copper.

Flange

Projecting rim or collar, such as on a skylight, that aids attachment or increases stiffness.