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Fan pressurization

General term applied to any technique involving the production of a steady

static pressure diﬀerential across a building envelope or component. Often

referred to as dc pressurization.

Flame ionization detector

Detector used in conjunction with a gas chromatograph, in which the change in

ionic current caused in a hydrogen–air ﬂame by a tracer or contaminant is

detected. This detector is sensitive to organic compounds.

Flow coeﬃcient

In the power function approach this parameter is used in conjunction with the

ﬂow exponent to quantify ﬂow through an opening.

Flow equation

Equation describing the airﬂow rate through a building (or component) in

response to the pressure diﬀerence across the building (or component).

These equations are usually power law or quadratic law in form.

Flow exponent

In the power function approach, this parameter characterizes the type of ﬂow

through a component (n ¼ 1 represents laminar ﬂow, n ¼ 0:5 represents turbu-

lent ﬂow). For most ﬂow paths, n takes a value between these extremes.

Fortuitous leakage

Uncontrolled air leakage through a building envelope due to the natural action

of wind and temperature, i.e., air inﬁltration.

Gas chromatography

A process by which gases can be separated from one another. Used in this

application to separate tracer gases from each other and from the constituents

of air, thus allowing individual analyses to be performed.

Gasometer

Instruments to measure volumes of any gas.

Grab sampling method

Any tracer gas method where air/tracer samples are obtained from a building

and analysed afterwards in a laboratory .

Guard zone technique

Dual fan pressurization technique used to measure the leakage characteristics

of a building part. One fan is used to pressurize a guarding zone, surrounding

the guarded zone in which the other fan just maintains a zero pressure diﬀeren-

tial between these zones. The measured building part is the only unguarded

part.

Hot wire anemometer

Anemometer in which the temperature of a heated wire exposed to the wind

determines the air velocity.

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Sharp JX-9400 Technical Information Seite 200