RADON MITIGATION TOPIC 5
(2026/2027) UPDATE|EXAM
QUESTIONS WITH MULTIPLE
CHOICES |VERIFIED & REVISED
ANSWERS (NEW)!!!
Ifmamsingle-storym1000-square-footmhousemwithm8-
footmceilingsmhasmanmairmexchangemratemofm0.5mairmchangempermhour,mwhichmofmthemfollowingmismit
smnaturalmventilationmrate?
Selectmone:
A.m6.7mcfm
B.m40mcfm
C.m67mcfm
D.m4000mcfmm-mCORRECTmANSWERmC.m67mcfm
Calculatemvolumemofmhouse:AreamxmHeightm=mVolumem(1000msqmftmxm8mftm=m8000mcubicmfeet)
VolumemxmACHm=mRatemofmExchangem(8000mxm0.5m=m4000mcubicmfeetmpermhour)
Butmwait,mthatmismnotmanmanswer!mNotemthatmthemanswersmareminmunitsmofmcubicmfeetpermminute.m
So,msimplymdividemyourmanswermbym60m(4000m/m60m=m66.6m--
mroundedmupmtom67)=m67mcubicmfeetmpermminute.
Amhomeownermhasmpurchasedmandminstalledmanmairmcleanermwhichmremovesmparticlesmfrommthem
housemair.mFollow-upmcharcoal-
detectormmeasurementsmhavemshownmessentiallymnomradonmreduction.mWhatmshouldmthemdiagno
stician/mitigatormtellmthemhomeownermifmcalledminmformconsultation?
Selectmone:
, A.mAssumingmthatmweathermconditionsmandmradonmentrymforcesmweremsimilarmduringmbothmthempr
e-mandmpost-operationmmeasurements,mthemairmcleanermismprobablymdefective.
B.mIfmthemairmcleanermwasmoperatedmaccordingmtommanufacturer'smspecifications,meithermthempre-
mormpost-operationmmeasurementmismlikelymtombeminmerror.
C.mAirmcleanersmaremcompletelymineffective,mevenmwhenmtreatingmonlymisolatedmareas.
D.mSincemthemairmcleanermremovesmonlymradonmdecaymprogeny,mnomreductionminmcharcoal-
detectormmeasurementsmwouldmbemexpected.m-
mCORRECTmANSWERmD.mSincemthemairmcleanermremovesmonlymradonmdecaymprogeny,mnomreductio
nminmcharcoal-detectormmeasurementsmwouldmbemexpected.
Amslab-on-grademhousemhasm2000msquaremfeetmofmslabmlivingmarea,mandmstandardm8-
footmceilings.mThemestimatedmairmexchangemrate,mcalculatedmfrommblowermdoormtesting,mism0.5mair
mchangempermhour.mItmismdesiredmtomreducemthemradonmfromm8mtom2mpCi/Lmusingmanmair-to-
airmheatmexchanger.mAssumemthatmthemexchangermworksmsimplymbymdilutionmofmthemindoormradon
m(i.e.,mnotmbymhousempressurizationmeffects).mWhatmapproximatemexchangermcapacitymwillmbemreq
uired?
Selectmone:
A.m133mcfm
B.m266mcfm
C.m425mcfm
D.m532mcfmm-mCORRECTmANSWERmC.m425mcfm
Ambalancedmheatmrecoverymventilationmsystemmhasmbeenminstalledminmambasementmspace.mAnmimp
ortantmreasonmthatmthismsystemmbemproperlymmaintainedmandmbalancedmismthat:
Selectmone:
A.mAnmunbalancedmsystemmmightmexhaustmmoremairmfrommthembasementmthanmentersmthembasem
ent,mthusmpotentiallymdrawingmmoremradonmintomthemhouse.
B.mDirtymfiltersmusuallymincreasemthemnumbermofmradonmdecaymprogenyminmair.
(2026/2027) UPDATE|EXAM
QUESTIONS WITH MULTIPLE
CHOICES |VERIFIED & REVISED
ANSWERS (NEW)!!!
Ifmamsingle-storym1000-square-footmhousemwithm8-
footmceilingsmhasmanmairmexchangemratemofm0.5mairmchangempermhour,mwhichmofmthemfollowingmismit
smnaturalmventilationmrate?
Selectmone:
A.m6.7mcfm
B.m40mcfm
C.m67mcfm
D.m4000mcfmm-mCORRECTmANSWERmC.m67mcfm
Calculatemvolumemofmhouse:AreamxmHeightm=mVolumem(1000msqmftmxm8mftm=m8000mcubicmfeet)
VolumemxmACHm=mRatemofmExchangem(8000mxm0.5m=m4000mcubicmfeetmpermhour)
Butmwait,mthatmismnotmanmanswer!mNotemthatmthemanswersmareminmunitsmofmcubicmfeetpermminute.m
So,msimplymdividemyourmanswermbym60m(4000m/m60m=m66.6m--
mroundedmupmtom67)=m67mcubicmfeetmpermminute.
Amhomeownermhasmpurchasedmandminstalledmanmairmcleanermwhichmremovesmparticlesmfrommthem
housemair.mFollow-upmcharcoal-
detectormmeasurementsmhavemshownmessentiallymnomradonmreduction.mWhatmshouldmthemdiagno
stician/mitigatormtellmthemhomeownermifmcalledminmformconsultation?
Selectmone:
, A.mAssumingmthatmweathermconditionsmandmradonmentrymforcesmweremsimilarmduringmbothmthempr
e-mandmpost-operationmmeasurements,mthemairmcleanermismprobablymdefective.
B.mIfmthemairmcleanermwasmoperatedmaccordingmtommanufacturer'smspecifications,meithermthempre-
mormpost-operationmmeasurementmismlikelymtombeminmerror.
C.mAirmcleanersmaremcompletelymineffective,mevenmwhenmtreatingmonlymisolatedmareas.
D.mSincemthemairmcleanermremovesmonlymradonmdecaymprogeny,mnomreductionminmcharcoal-
detectormmeasurementsmwouldmbemexpected.m-
mCORRECTmANSWERmD.mSincemthemairmcleanermremovesmonlymradonmdecaymprogeny,mnomreductio
nminmcharcoal-detectormmeasurementsmwouldmbemexpected.
Amslab-on-grademhousemhasm2000msquaremfeetmofmslabmlivingmarea,mandmstandardm8-
footmceilings.mThemestimatedmairmexchangemrate,mcalculatedmfrommblowermdoormtesting,mism0.5mair
mchangempermhour.mItmismdesiredmtomreducemthemradonmfromm8mtom2mpCi/Lmusingmanmair-to-
airmheatmexchanger.mAssumemthatmthemexchangermworksmsimplymbymdilutionmofmthemindoormradon
m(i.e.,mnotmbymhousempressurizationmeffects).mWhatmapproximatemexchangermcapacitymwillmbemreq
uired?
Selectmone:
A.m133mcfm
B.m266mcfm
C.m425mcfm
D.m532mcfmm-mCORRECTmANSWERmC.m425mcfm
Ambalancedmheatmrecoverymventilationmsystemmhasmbeenminstalledminmambasementmspace.mAnmimp
ortantmreasonmthatmthismsystemmbemproperlymmaintainedmandmbalancedmismthat:
Selectmone:
A.mAnmunbalancedmsystemmmightmexhaustmmoremairmfrommthembasementmthanmentersmthembasem
ent,mthusmpotentiallymdrawingmmoremradonmintomthemhouse.
B.mDirtymfiltersmusuallymincreasemthemnumbermofmradonmdecaymprogenyminmair.
