Generally applied to radial- and axial-flow blowers that increase the density of the air passing through them by a maximum value of 5%. Various types are in use, e.g. centrifugal, axial flow and propeller fans.

A water or refrigerant coil through which air is circulated for conditioning.

A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields.

Some electrical linemen wear Faraday suits, which allow them to work on live, high-voltage power lines without risk of electrocution.

Fast breeder reactor (FBR) which use fast (i.e.: unmoderated) neutrons to breed fissile plutonium and possibly higher transuranics from fertile uranium-238.

A fast neutron is a free neutron with a kinetic energy level close to 1 MeV (100 TJ/kg), hence a speed of 14,000 km/s, or higher

A fast-neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons (carrying energies above 0.5 MeV or greater, on average), as opposed to thermal neutrons used in thermal-neutron reactors.

A measure of length, equal to 6 linear feet, used for depths of water and lengths of anchor chain.

It refers to the failure of materials exposed to repeated actions of stress fluctuation. It is responsible for a large proportion of cracks occurring in welded ship structural details.

Fatigue is the initiation and propagation of cracks in a material due to cyclic loading.

A crack that results from the continued application of a cyclic load.

The ability of a metal component or structure to perform without suffering any consequences of fatigue loadings.

The period during which a structural member may operate without suffering reductions in strength due to the action of repetitive loads.

The maximum number of cycles in load application to a structure that can be applied before the appearance of any effects of fatigue (cracks).

The strength against crack initiation under dynamic loads during operation.

Fatigue testing is a specialised form of mechanical testing that is performed by applying cyclic loading to a coupon or structure.

Fault zone hydrogeology is the study of how brittlely deformed rocks alter fluid flows in different lithological settings, such as clastic, igneous and carbonate rocks.

Feathering the blades of a propeller means to increase their angle of pitch by turning the blades to be parallel to the airflow.

A boiler feed water supply valve which is non-return but can be also regulated.

A heat exchanger which increases the temperature of boiler feed water, usually by using some form of waste, or exhaust steam that is condensed.