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Chapter 4
Air Control in ABuilding
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Chapteroutline
To feelcomfort
Fresh air:At the correcttemperature,
Right amount of moisture,Free from odours and
pollutant
Ventilation ;Process changing the air from
outside to the air in theroom/internal space of a
uilding
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Airsupplies
VENTILATION
!uppl" o#"gen forhuman reath
Control air humidit" and
air $elocit"
Remo$e :
a% caron dio#ide from human reathing
% odours
c% microorganism
d% cessi$e heat energ"
e% 'ater $apor
f% particles such us smo(e and dust
g% $olatile organic compound from sources
such as cleaning
h% comustion products from heating andcoo(ing
i% o)one gas from photocopier and laser
printer
*% methane gas and deca" products from
ground condition
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Ventilationre+uirement
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or(edample4%-
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.umidit"
Rate at'hichuildingmaterial
dr".0121T
3
2urailit"of
uildingmaterials
.eatalance
n
humanod"Comfort
of humanod"
Can causecondensatio
n inuilding
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.umidit"
Saturation
!aturated air is the air that contain the ma#imumamount of 'ater $apour possile at that
temperature%
Saturated Vapour Pressure (SVP)
Vapour pressure increase at the amount of 'ater$apour increase and at the saturation, the $apourpressure reach a stead" $alue called the saturate$apour pressure
!VP is the $apour pressure of 'ater $apour in anair that contain the ma#imum amount of $apourpossile at that temperature
Water vapor- can e de5ned as a sustance in the gases
state 'hich might e li+ue5ed " compression%6 For e#ample, it formed naturall" in the spaceao$e li+uid 'ater 'hich is left open to the air%
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!aturated
air atdi7erenttemperature
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!peci5cation ofhumidit"
!ome of the properties of watervapour:
Moisture content (nit ! "#$%# or dr& air)
Vapour pressure (nit ! Pasca')
Vapour pressure is the partial pressure e#erted "
the molecules of a $apour% The unit is Pascal ew point (nit ! o or "
2e' point is the temperature in 'hich a 5#edsample of air ecomes saturated%
*e'ative +u,idit& (nit !)
The relati$e humidit" of a sample of air comparesthe actual amount the moisture in the air 'ith thema#imum amount of moisture the air can containat that temperature%
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or(edample4%9
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.igrometer
."grometr" or Ps"chometr" is themeasurement of humidit"
.air and paper h"grometer
2e' point h"grometer
et and dr" ul h"grometer
&lectric h"grometer
http://'''%lael%pl/en/re(
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Ps"chometric chart
Ps"chometric chart is a set of graph'hich are comined and sho'ed therelationship et'een the di7erent$ariales used to specif" humidit"
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Ps"chometric chart
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Ps"chometric chart
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or(edample4%
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Condensation in auilding
Condensation in a uilding occurs 'hene$er 'arm
moist air meets surface that are or elo' the de'point of that air
-% !urface condensation
a%occurs on the surface of 'alls, 'indo's, ceilingand =oor%
%1t occurs as a 5lm of moisture or as a eads of'ater
9% 1nterstitial condensationoccurs 'ithin the construction of a uilding as
sho'n in 5g% 4%>
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Causes ofCondensation
ONENSATIO
N
0oisturesources
se of
uilding
Ventilatio
n
Temperature
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Remedies
forCondensation
*EMEIESONENSATIO
N
Ventilation
1nsulation
.eating
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T+an% &ou
for &ourattention
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