KA IMO 2021 6 V2.1

36 systemair
Caution
Keep the inner and outer surface of the inspection glass clean. If you notice fouling, thoroughly clean the
glass immediately.
3.4 Filter
Caution
See also section 3.1 General instructions.
Byappropriatelysettingtheairhandlingunitcontrolsystem,makesurethattherelativehumidityinthe
secondlteringstagedoesnotexceed90%andtherelativehumidityintherstlteringstageorinthe
stageupstreamthereofdoesnotexceed80%forthreeconsecutivedays.
Irregularreplacementofltercartridgescausesdusttoenterunitanditscomponents.Asaresult,the
effectiveness of the operation is reduced and damage to the device and system can occur.
• Forsmoothoperation,inspecttheltermediumandreplacethecartridgesingoodtime.Thefrequencyofchanging
theltermediumdependsontheairow,airpollutionandthedegreeofltrationoftheltermedium.
• Replacealltheltersofaparticularlterstageorlterunitatthesametime.Replacementofanindividuallterina
lterstageisonlyallowableintheeventoflterdamage,providedthatnomorethan6monthshavepassedfrom
the previous replacement.
• Thepressuredifferenceinfrontofandbehindtheltermediummustnotbemorethan30Paabovethe
recommendednalvalue.
• Followinginsertionintothelterframe,ltercassettesmustnotbedamaged.
• Whenreplacingthelters,becarefulnottocontaminatethenewlterswithdustfromoldltersorinanyother
manner.
• Storenewlterssuchthattheyareprotectedfromdustandagainstdamage.
• Donotuselterswhoseshelflife,asspeciedbytheltermanufacturer,hasexpired.
• OnlyuseltersthatareincompliancewiththeEN16890-1standard,asdemonstratedbythemanufacturer.
• Handlecontaminatedltersinaccordancewithenvironmentalprotectionregulations.
• Inthecaseofoutdoor-typeairhandlingunits,thelterintherstltering(pre-lter)stagemaybecomeclogged
by snow in extreme weather conditions. Filters may also freeze. In such an event, immediately clean or replace the
lters.
• In order to measure the pressure drop, apply the following instruments: A U tube, inclined tube manometer or an
electronic manometer with acoustic or light signalling. Connect the manometers to the measurement ports upstream
ofanddownstreamofthelter,whichareprovidedontheservicesideonthesectionexternalwall,exceptinthe
case of outdoor-type air handling units, where these ports are provided inside the casing.
• Keep the inner and outer surface of the inspection glass clean. If you notice fouling, thoroughly clean the glass
immediately.
• Insertonlycleanandundamagedlters.
ComparisonofminimumlterclassesbetweenEN779andISO16890andvaluesofrecommendednalpressuredrops:
EN 779 ISO 16890
G4 coarse60%
M5 ePM1060%
M6 ePM2,550%
F7 ePM160%
F8 ePM175%
F9 ePM185%
Filter class
Recommended nal pressure
drop (lower value)
ISO coarse
50 Pa + starting pressure drop
or 3x starting pressure drop
ISO ePM1
100 Pa + starting pressure drop
or 3x starting pressure drop
ISO ePM2,5
ISO ePM10
Filter class
Recommended nal pressure
drop
G1 - G4 150 Pa
M5 - F7 200 Pa
F8 - F9 300 Pa
E10 - H13 500 Pa