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8/19/2019 Air & Ventilation, Environmental
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VentilationDr. Rahul Netragaonkar
Associate Professor
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Air of occupied room
Occupied room air Vitiated air
Human activity
Chemical changes CO ! O
At rest ".# cu ft CO $hr$per person
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Air of occupied room
Physical changes %
&emperature ' (ody e)pels heat
Humidity ' *kin ! lung perspiration #""gm vapour$man$day
Air movement ' Overcro+ding ,O-struction
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Air of occupied room
Physical changes %
(ody odour ' Perspiration/ -ad oral hygiene/dirty cloths
(acterial pollution '
0)haled air % microorganismsDuring conversation/ coughing/ snee1ingtalking/ spitting etc.
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Air of occupied room
Causes %
Discomfort /efficiency of +ork /
Headache /dro+siness /ina-ility to concentrate
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Indices of thermal comfort
2. A3R &04P0RA&5R06. A3R &04P0RA&5R0 AND
H543D3&76.8. COO93N: PO;0R 6 Air temperature/
humidity and air movement +ereconsidered together and e)pressed asata &hermometer tomeasure the cooling po+er.
= A dry >ata reading of ? and a-ove/and a +et >ata reading of " anda-ove/ +ere regarded as indices ofthermal comfort.
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2. 0@@0C&3V0 &04P0RA&5R06 temperature/ humidity andmovement of the internal air on the sensation of +armth orcold felt -y the human -ody..
. CORR0C&0D 0@@0C&3V0 &04P0RA&5R06 3mprovementover the 0ffective &emperature 3nde).
= 3nstead of the dry -ul- temperature/ the reading of the:lo-e &hermometer is used to allo+ for radiant heat.
= Air temperature/ velocity/ humidity and mean radiant heat.2. 4cARD90 * 4AB3454 A99O;A(90 *;0A& RA&0 6 .
litres of s+eat e)creted in four hours as the ma)imumallo+a-le s+eat rate compati-le +ith physiological normal
reaction of acclimati1ed/ healthy young men for repeatede)posures to heat.= 4cArdle has put P *R value of 8 as upper limit of comfort
1one
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Comfort zones
= Comforta-le thermal conditions are those under +hich aperson can maintain normal -alance -et+een productionand loss of heat/ at normal -ody temperature and +ithouts+eating.
C orrected effective temperature deg C 2. Pleasant and cool%%%%%%%%%%%%%%%%%%%%%%%%%%%%
. Comforta-le and cool%%%%%%%%%%%%%%%%%%%%%%%%%%8. Comforta-le%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
. Hot and uncomforta-le%%%%%%%%%%%%%%%%%%%%%%%%%
. 0)tremely hot%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
?. 3ntolera-ly hot%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Predicted four-hour sweat rate(P4SR)
2.Comfort 1one%%%%%%%%2%8 litres
.Gust tolera-le%%%%%%%%%8% . 8.3ntolera-le%%%%%%%%%%%%% .
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Ventilation
Definition 6%
Replacement of vitiated air !control of incoming air +ith regard
to it s temperature/ humidity !purity.
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Ventilation
*tandards of ventilation6% Cu-ic space% 4in. 8""%8""" cu. ft $hr$per
Air change% 9iving room% %8 $hr
;ork rooms ! Assem-lies ' %? $hr
@loor space% "%2"" sI. ft.$per
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Ventilation
&ypes of ventilation6%
&he +ind%
Natural
4echanicalNatural
Perflation Aspiration
Cross Ventilation
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Ventilation
0)haust ventilation ' 3n halls/ auditoriums/3ndustries etc.
4echanical
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Ventilation
Plenum ventilation ,Propultion '4echanical
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Ventilation
(alanced ventilation ,Com-ination
0)haust F Plenum
4echanical
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Ventilation
Air conditioning '
*imultaneous control of factorsPhysical ! Chemical
&emperature/ humidity/ movement/
distri-ution/ dust/ -acteria/ odour ! to)ic gase
Affect human health
4echanical
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Ventilation
Place '
3ndustries / hospitals /
operation theatre
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Process '
vapoursaturation
distri-ution
@ilter
heatingat desired temperature
removal of e)cess moisture
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Air conditioning
Difference in Outside temp ! inside temp J "KC
Desira-le ' 2" ' 2 KCTransition room – or !cclimati"ation3f temperature difference is large -et+een outside
atmosphere and air conditioned room/
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