Page 20 - igem-g-4 edition 2

IGEM/G/4 Edition 2
filter outlet valve (FOV)
Valve fitted downstream of, and adjacent to, a filter to shut off the supply of gas.

fixed factor conversion
Means of converting metered gas consumptions from actual conditions to reference conditions
by means of a multiplying factor which takes account of temperature and/or pressure
(including compressibility) and which is based upon the assumed constant metering
temperature and/or pressure (including compressibility), as appropriate.

flame detector
That part of a flame safeguard which is responsive to flame properties and signals the
presence of flame.

flame failure
Loss of flame from the normally-detected position by any cause other than the action of
de-energising the safety shut-off system.

flame safeguard
Control responsive to flame properties detecting the presence of flame and, in the event of
ignition failure or subsequent loss of flame, causing safety shut-down and/or lockout.

flame simulation
Condition in which a flame detector signals the presence of flame (whether or not it exists).

flammability limits
lower flammability limit (LFL): Concentration of flammable gas or vapour in air, below
which the gas atmosphere is not flammable.

upper flammability limit (UFL): Concentration of flammable gas or vapour in air, above
which the gas atmosphere is not flammable.

Note: Although a mixture which has a concentration above UFL is not a flammable gas atmosphere, it can readily
become so and, in certain cases for hazardous area classification purposes, it is considered as a flammable
gas atmosphere.

flooding holes, relating to a watersealed gasholder
Holes in a cup plate which allow the cup to fill and empty with water without overflowing or
gas release and enable the changes in water levels as a gasholder cups and uncups to take
place more easily.

flow computer
Device that utilises a high frequency signal and calculates a standard cumulative flow of gas
based on this signal, pre-programmed parameters and other gas properties determined by
suitable transducers.

flow straightener
Series of plates or tubes used to remove turbulence in the combustion air or gas flow which is
caused by air or gas passing through an obstruction such as a bend.

flue
Passage for conveying combustion products to outside air within a chimney.

flue break
Opening into a secondary flue in the same room as, and in addition to, the opening at a
draught diverter.

flue lining
Wall of a chimney, consisting of components the surface of which is in contact with the
products of combustion.

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