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Term Definition
Face Brick

Brick made or selected to produce an attractive exterior wall.

Faceted Glass Window

A window made by bonding 1 inch (25.4 mm) thick glass pieces with an epoxy resin matrix or reinforced concrete.

Factor of Safety

Ratio of the ultimate unit stress to the working or allowable stress.

Fahrenheit Temperature

The temperature scale on which. at standard atmospheric pressure. the boiling point of water is 212 degrees Fahrenheit, the freezing point is 32 degrees Fahrenheit, and absolute zero is 2459.69 degrees Fahrenheit.

Fan Coil Unit

The fan and heat exchanger for cooling and heating that are assembled in a common cabinet.


Board fastened to the ends of the rafters or joists forming part of a cornice.

Fast Track

Method that telescopes or overlaps traditional design-construction process. Overlapping phases as opposed to sequential phases is keynote of the concept.


Condition of material under stress that has lost, to some degree, its power of resistance as a result of repeated application of stress, particularly if stress reversals occur as with positive and negative cyclical loading.

Fatigue Limit

The number of cycles of loading of a specified type that a specified material can withstand before failure.

Fatigue Strength

A measure of the ability of a material or structural member to carry a load without failure when the loading is applied a specified number of times.

Fatigue Test

A test to determine the behavior of a material under fluctuating stresses.


A sheet material made using a fiber mat that has been saturated and topped with asphalt.


An area that allows light to pass into a building, commonly referring to glazed windows. Also, the arrangement of windows in an exterior wall.


Iron-based metallic materials.

Fiber Saturation Point

The moisture content of wood at which the cell walls are saturated but there is no water in the cell cavities.


A panel made from vegetable fibers and binding agents.


An inert material added to a plastic resin to alter the strength and working properties and to lower the cost.

Finish Coat

The third or final coat of gypsum plaster.

Finish Floor

The flooring that is left exposed to view.

Finish Floor Level

The completed floor surface on which building occupants walk.

Finish Grade

The elevation of the ground surface after completion of all work.

Finish Lime

A hydrated lime used in finish coats of plaster and in ornamental plasters.

Finish Plaster

The topcoat of plaster on a wall or ceiling.

Fire Endurance

Measure of elapsed time during which an assembly continues to exhibit fire resistance under specified conditions of test and performance. As applied to elements of buildings, it shall be measured by the methods and to the criteria defined in ASTM. Methods E119, Fire Tests of Building Construction and Materials; ASTM Methods E152, Fire Tests of Door Assemblies; ASTM Methods E814, Fire Test of Through-Penetration Fire Stops; or ASTM Methods E163, Fire Tests of Window Assemblies.

Fire Resistance

Relative term, used with a numerical rating or modifying adjective to indicate the extent to which a material or structure resists the effect of fire.

Fire Resistant Gypsum

A gypsum product that has increased fire-resistance properties due to the addition of fire-resistant materials in the gypsum core.

Fire Stop

Obstruction in a cavity designed to resist the passage of flame, sometimes referred to as "fire blocking."

Fire Taping

The taping of gypsum board joints without subsequent finishing coats. A treatment method used in attic, plenum or mechanical areas where aesthetics are not important.

Fire Wall

Fire-resistant partition extending to or through the roof of a building to slow the spread of fire. See Area Separation Wall.

Fire-Rated Partition

A partition assembly that has been tested and given a rating indicating the length of time it will resist a fire in hours.


Refers to properties or designs to resist effects of any fire to which a material or structure may be expected to be subjected.


Denotes substantially lower degree of fire resistance than fire-resistive. Often used to describe materials that are combustible but have been treated to slow ignition or spread of fire under conditions for which they were designed.


A brick made from special clays that will withstand high temperatures.


Deep mined clays that withstand heat.


Use of this term in reference to buildings is discouraged because few, if any, building materials can withstand extreme heat for an extended time without some effect. The term "fire-resistive" or "resistant" is more descriptive.


A material used to protect various members from damage due to fire.

Flame Spread

Index of the capacity of a material to spread fire under test conditions, as defined by ASTM Standard E84. Materials are rated by comparison with the flame-spread index of red oak flooring assigned a value of 100 and inorganic reinforced cement board assigned a value of 0.

Flame Spread Rate

The rate at which flames will spread across the surface of a material.

Flame Spread Rating

A numerical designation given to a material to indicate its comparative ability to restrict flaming combustion over its surface.


The ability of a material to resist burning.


Capability of a combustible material to ignite easily, burn intensely or have rapid rate of flame spread.

Flanking Paths

Paths by which sound travels around an element intended to impede it, usually some structural component that is continuous between rooms and rigid enough to transmit the sound. For example, a partition separating two rooms can be "flanked" by the floor, ceiling or walls surrounding the partition if they run uninterrupted from one room to the other. Ducts, conduits, openings, structural elements, rigid ties, etc., can be sound flanking paths. The acoustic effect of sound flanking paths is dependent on many factors.

Flash Point

The temperature at which a flammable material will suddenly break into a flame.

Flash Set

Very rapid setting of the cement in concrete.


Strips of metal or waterproof material used to make joints waterproof, as in the joining of curtain wall panels.


A flat hand tool used to smooth the surface of freshly placed concrete after it has been leveled with a darby.

Float Process

A glass manufacturing process in which the molten glass ribbon flows through a furnace supported on a bed of molten metal.

Flocked Construction

Carpet formed by electrostatically spraying short strands onto an adhesive-coated backing material.

Flood Coat

A heavy coating of asphalt poured and spread over a surface.

Flood Plain

The land surrounding a flowing stream over which water spreads when a flood occurs.

Floor Area Ratio (FAR)

The ratio of the floor area of a building to the area of the lot.

Flow Line

The path down which water flows.


The emission of visible light from a substance as a result of the absorption of radiation of short wavelengths.


A mineral added to molten iron to cause impurities to separate into a layer of molten slag on top of the iron.

Flying Formwork

Large sections of formwork for pouring concrete slabs that are lifted from story to story by a crane in an assembled condition.


The unit of illumination equal to 1 lumen per square foot.


Lower extremity of a foundation or loadbearing member that transmits load to load-bearing substrate.


The lowest, widest part of the foundation that distributes the load over a broad area of the soil.


A unit for measuring brightness or luminance. It is equal to 1 lumen per square foot when brightness is measured from the surface.


Amount of applied energy to cause motion, deformation or displacement and stress in a body.


Temporary construction used to contain and give shape and support to concrete as it cures.


Component that transfers weight of building and occupants to the earth.

Framed Connections

Connections joining structural steel members with a metal, such as an angle, that is secured to the web of the beam.

Framing Plan

A drawing showing the location of structural members.

Freezing Cycle Day

A day when the temperature of the air rises above or falls below 32 degrees Fahrenheit or 0 degrees Celcius.

Freezing Point

The temperature at which a given substance will solidify (freeze).

Frequency (Sound)

Number of complete vibrations or cycles or periodic motion per unit of time.

Front Yard

In zoning, the minimum legal distance between the front property line and a structure.


The length of a lot line along a street or other public way.

Frost Line

The maximum depth in the earth to which the soil can be expected to freeze during a severe winter.

Frost Line

The deepest penetration of frost below grade.

Frost Point

The temperature at which frost forms on exposed, chilled surfaces.

Fuel Contributed

A rating of the amount of combustible material in a coating.


Member or means of supporting a finished surfacing material away from the structural wall or framing. Used to level uneven or damaged surfaces or to provide space between substrates. Also an element for mechanical or adhesive attachment of paneling.


An overcurrent protection device that opens an electric circuit when the fusible element is broken by heat due to overcurrent passing through it.

Fusion-Bonded Construction

Carpet formed by bonding pile yearn between two sheets of backing material and cutting the pile yarn in the center, forming two pieces of carpet.

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