ADOPTS WITH AMENDMENTS:

International Green Construction Code 2012 (IGCC 2012)

Heads up: There are no amended sections in this chapter.
The provisions contained in this appendix are not mandatory unless specifically referenced in the adopting ordinance.
Buildings in areas of High and Moderate Radon Potential (Zone 1 and 2), as determined by Figure B101.1 and Table B101.1 shall comply with Sections B201.1 through B201.10.

FIGURE B101.1
EPA MAP OF RADON ZONES

a. pCi/L standard for picocuries per liter of radon gas. EPA recommends that all homes that measure 4 pCi/L and greater be mitigated
The United States Environmental Protection Agency and the United States Geological Survey have evaluated the radon potential in the United States and have developed a map of radon zones designed to assist code officials in deciding whether radon-resistant features are applicable in new construction.
The map assigns each of the 3,141 counties in the United States to one of three zones based on radon potential. Each zone designation reflects the average short-term radon measurement result that can be expected to be measured in a building without the implementation of radon control methods. The radon zone designation of highest priority is Zone 1 and Zone 2. Table 804.2 lists the Zone 1 counties illustrated on the map. The counties are listed by state and alphabetically within each zone. More detailed information can be obtained from state-specific booklets (EPA-402-R-93-021 through 070) available through the U.S. EPA National Service Center for Environmental Publications (NSCEP), U.S. EPA Regional Offices or State Radon Offices.

TABLE B101.1
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

ALABAMAALASKAZone 2GilpinNew Haven
Zone 1Zone 2AlamedaGrandNew London
CalhounAnchorage MunicipalityAlpineGunnison
ClayDillingham Census AreaAmadorHuerfanoZone 2
CleburneFairbanks North StarCalaverasJacksonLitchfield
ColbertBoroughContra CostaJeffersonTolland
CoosaKenai PeninsulaEl DoradoKiowaWindham
FranklinBoroughFresnoKit Carson
JacksonMatanuska-SusitnaInyoLa PlataDELAWARE
LauderdaleBoroughKernLarimerZone 2
LawrenceSoutheast FairbanksLos AngelesLas AnimasNew Castle
LimestoneCensus AreaMaderaLincoln
MadisonMariposaLoganFLORIDA
MorganARIZONAMonoMesaZone 2
TalladegaZone 2MontereyMoffatAlachua
ApacheNevadaMontezumaCitrus
Zone 2CochisePlacerMontroseColumbia
AutaugaCoconinoPlumasMorganHillsborough
BarbourGilaRiversideOteroLeon
BibbGrahamSan BenitoOurayMarion
BlountGreenleeSan BernardinoParkMiami-Dade
BullockLa PazSan FranciscoPhillipsPolk
CherokeeMaricopaSan Luis ObispoPitkinUnion
ChiltonMohaveSan MateoProwers
CullmanNavajoSanta ClaraPuebloGEORGIA
DallasPimaSanta CruzRio BlancoZone 1
DeKalbPinalSierraSan MiguelCobb
ElmoreSanta CruzTulareSedgwickDeKalb
EtowahYavapaiTuolumneSummitFulton
FayetteYumaYubaTellerGwinnett
GreeneWashington
HaleARKANSASCOLORADOWeldZone 2
JeffersonZone 2Zone 1YumaBanks
LamarBaxterAdamsBarrow
LeeBentonArapahoeZone 2Bartow
LowndesBooneBacaAlamosaButts
MaconCarrollBentArchuletaCarroll
MarionFultonBoulderConejosCatoosa
MarshallGarlandBroomfieldCostillaCherokee
MontgomeryIndependenceChaffeeEagleClarke
PerryIzardCheyenneHinsdaleClayton
PickensMarionClear CreekLakeCoweta
RandolphMontgomeryCrowleyMineralDawson
RussellRandolphCusterRio GrandeDouglas
ShelbySearcyDeltaRouttElbert
St ClairSharpDenverSaguacheFannin
SumterStoneDoloresSan JuanFayette
TuscaloosaDouglasFloyd
WalkerCALIFORNIAEl PasoCONNECTICUTForsyth
WinstonZone 1ElbertZone 1Franklin
Santa BarbaraFremontFairfieldGilmer
VenturaGarfieldMiddlesexGreene

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

HabershamIdahoJerseyHardinHendricks
HallKootenaiJo DaviessJacksonHenry
HaralsonLatahKaneJasperHoward
HarrisLemhiKendallJeffersonHuntington
HartShoshoneKnoxJohnsonJay
HeardValleyLaSalleKankakeeJennings
HenryLeeLakeJohnson
JacksonZone 2LivingstonLawrenceKosciusko
JasperAdaLoganMacoupinLaGrange
LamarBannockMaconMadisonLawrence
LumpkinBear LakeMarshallMarionMadison
MadisonBinghamMasonMcHenryMarion
MeriwetherBonnevilleMcDonoughMonroeMarshall
MonroeCanyonMcLeanMontgomeryMiami
MorganCaribouMenardPerryMonroe
NewtonCassiaMercerPopeMontgomery
OconeeFranklinMorganRandolphNoble
OglethorpeJeffersonMoultrieRichlandOrange
PauldingJeromeOgleSalinePutnam
PickensLincolnPeoriaShelbyRandolph
PikeMadisonPiattSt ClairRush
RabunMinidokaPikeUnionScott
RichmondOneidaPutnamWabashShelby
RockdaleOwyheeRock IslandWashingtonSt Joseph
SpaldingPayetteSangamonWayneSteuben
StephensPowerSchuylerWhiteTippecanoe
TalbotTetonScottWillTipton
TownsTwin FallsStarkWilliamsonUnion
TroupStephensonVermillion
UnionILLINOISTazewellINDIANAWabash
UpsonZone 1VermilionZone 1Warren
WalkerAdamsWarrenAdamsWashington
WaltonBooneWhitesideAllenWayne
WhiteBrownWinnebagoBartholomewWells
WhitfieldBureauWoodfordBentonWhite
CalhounBlackfordWhitley
IDAHOCarrollZone 2Boone
Zone 1CassBondCarrollZone 2
BenewahChampaignChristianCassBrown
BlaineColesClarkClarkClay
BoiseDe KalbClayClintonCrawford
BonnerDe WittClintonDe KalbDaviess
BoundaryDouglasCookDecaturDearborn
ButteEdgarCrawfordDelawareDubois
CamasFordCumberlandElkhartFloyd
ClarkFultonDuPageFayetteFranklin
ClearwaterGreeneEdwardsFountainGibson
CusterGrundyEffinghamFultonGreene
ElmoreHancockFayetteGrantJackson
FremontHendersonFranklinHamiltonJasper
GoodingHenryGallatinHancockJefferson
IroquoisHamiltonHarrisonKnox

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

LakeDes MoinesSacLincolnElk
LaPorteDickinsonScottLoganFranklin
MartinDubuqueShelbyMarionGreenwood
MorganEmmetSiouxMarshallHarper
NewtonFayetteStoryMcPhersonHarvey
OhioFloydTamaMeadeJefferson
OwenFranklinTaylorMitchellLabette
ParkeFremontUnionNemahaLinn
PerryGreeneVan BurenNessLyon
PikeGrundyWapelloNortonMiami
PorterGuthrieWarrenOsborneMontgomery
PoseyHamiltonWashingtonOttawaMorris
PulaskiHancockWaynePawneeMorton
RipleyHardinWebsterPhillipsNeosho
SpencerHarrisonWinnebagoPottawatomieOsage
StarkeHenryWinneshiekPrattReno
SullivanHowardWoodburyRawlinsSedgwick
SwitzerlandHumboldtWorthRepublicSeward
VanderburghIdaWrightRiceShawnee
VigoIowaRileyStafford
WarrickJacksonKANSASRooksStevens
JasperZone 1RushSumner
IOWAJeffersonAtchisonRussellWabaunsee
Zone 1JohnsonBartonSalineWilson
AdairJonesBrownScottWoodson
AdamsKeokukCheyenneSheridan
AllamakeeKossuthClayShermanKENTUCKY
AppanooseLeeCloudSmithZone 1
AudubonLinnDecaturStantonAdair
BentonLouisaDickinsonThomasAllen
Black HawkLucasDouglasTregoBarren
BooneLyonEllisWallaceBourbon
BremerMadisonEllsworthWashingtonBoyle
BuchananMahaskaFinneyWichitaBullitt
Buena VistaMarionFordWyandotteCasey
ButlerMarshallGearyClark
CalhounMillsGoveZone 2Cumberland
CarrollMitchellGrahamAllenFayette
CassMononaGrantAndersonFranklin
CedarMonroeGrayBarberGreen
Cerro GordoMontgomeryGreeleyBourbonHarrison
CherokeeMuscatineHamiltonButlerHart
ChickasawO'BrienHaskellChaseJefferson
ClarkeOsceolaHodgemanChautauquaJessamine
ClayPageJacksonCherokeeLincoln
ClaytonPalo AltoJewellClarkMarion
ClintonPlymouthJohnsonCoffeyMercer
CrawfordPocahontasKearnyComancheMetcalfe
DallasPolkKingmanCowleyMonroe
DavisPottawattamieKiowaCrawfordNelson
DecaturPoweshiekLaneDoniphanPendleton
DelawareRinggoldLeavenworthEdwardsPulaski

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

RobertsonLetcherYorkJacksonDouglas
RussellLewisZone 2KalamazooFaribault Count
ScottLivingstonKnoxLenaweeFillmore
TaylorLoganSagadahocSt JosephFreeborn
WarrenLyonWaldoWashtenawGoodhue
WoodfordMadisonWashingtonGrant
MagoffinZone 2Hennepin
Zone 2MartinMARYLANDAlconaHouston
AndersonMasonZone 1AlgerHubbard
BathMcCrearyBaltimoreAlpenaJackson
BellMcLeanCalvertAntrimKanabec
BooneMeadeCarrollBaragaKandiyohi
BoydMenifeeFrederickBarryKittson
BrackenMontgomeryHarfordCharlevoixLac qui Parle
BreathittMorganHowardClintonLe Sueur
BreckinridgeMuhlenbergMontgomeryDickinsonLincoln
ButlerNicholasWashingtonEatonLyon
CaldwellOhioEmmetMahnomen
CampbellOldhamZone 2GeneseeMarshall
CarrollOwenAlleganyGogebicMartin
CarterOwsleyAnne ArundelHoughtonMcLeod
ChristianPerryBaltimore CityInghamMeeker
ClayPikeCecilIoniaMower
ClintonPowellCharlesIronMurray
CrittendenRockcastleGarrettKentNicollet
DaviessRowanPrince George'sKeweenawNobles
EdmonsonShelbySomersetLapeerNorman
ElliottSimpsonLeelanauOlmsted
EstillSpencerMASSACHUSETTSLivingstonOtter Tail
FlemingToddZone 1MarquettePennington
FloydTriggEssexMenomineePipestone
GallatinTrimbleMiddlesexMonroePolk
GarrardUnionWorcesterMontcalmPope
GrantWashingtonMontmorencyRamsey
GraysonWayneZone 2OaklandRed Lake
GreenupWebsterBarnstableOtsegoRedwood
HancockWhitleyBerkshirePresque IsleRenville
HardinWolfeBristolSanilacRice
HarlanDukesShiawasseeRock
HendersonMAINEFranklinRoseau
HenryZone 1HampdenMINNESOTAScott
HopkinsAndroscogginHampshireZone 1Sherburne
JacksonAroostookNantucketBeckerSibley
JohnsonCumberlandNorfolkBig StoneStearns
KentonFranklinPlymouthBlue EarthSteele
KnottHancockBrownStevens
KnoxKennebecMICHIGANCarverSwift
LarueLincolnZone 1ChippewaTodd
LaurelOxfordBranchClayTraverse
LawrencePenobscotCalhounCottonwoodWabasha
LeePiscataquisCassDakotaWadena
LeslieSomersetHillsdaleDodgeWaseca

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

WashingtonNodawayMaconBeaverheadMusselshell
WatonwanPlatteMadisonBig HornPetroleum
WilkinMariesBlaineSweet Grass
WinonaZone 2MarionBroadwaterTreasure
WrightAdairMcDonaldCarbonWheatland
Yellow MedicineAudrainMercerCarterYellowstone
BarryMillerCascade
Zone 2BartonMoniteauChouteauNEBRASKA
AitkinBatesMonroeCusterZone 1
AnokaBentonMontgomeryDanielsAdams
BeltramiBollingerMorganDawsonBoone
BentonBooneNewtonDeer LodgeBoyd
CarltonCaldwellOregonFallonBurt
CassCallawayOsageFergusButler
ChisagoCamdenOzarkFlatheadCass
ClearwaterCape GirardeauPerryGallatinCedar
CookCarrollPettisGarfieldClay
Crow WingCarterPhelpsGlacierColfax
IsantiCedarPikeGraniteCuming
ItascaCharitonPolkHillDakota
KoochichingChristianPulaskiJeffersonDixon
LakeClarkPutnamJudith BasinDodge
Lake of the WoodsColeRallsLakeDouglas
Mille LacsCooperRandolphLewis and ClarkFillmore
MorrisonCrawfordRayLibertyFranklin
PineDadeReynoldsLincolnFrontier
St LouisDallasRipleyMadisonFurnas
DaviessSalineMcConeGage
MISSISSIPPIDeKalbSchuylerMeagherGosper
Zone 2DentScotlandMineralGreeley
AlcornDouglasShannonMissoulaHamilton
ChickasawFranklinShelbyParkHarlan
ClayGasconadeSt CharlesPhillipsHayes
LeeGentrySt ClairPonderaHitchcock
LowndesGreeneSt FrancoisPowder RiverJefferson
NoxubeeGrundySt Louis cityPowellJohnson
PontotocHarrisonSt LouisPrairieKearney
RankinHenrySte GenevieveRavalliKnox
UnionHickoryStoneRichlandLancaster
WashingtonHowardSullivanRooseveltMadison
HowellTaneyRosebudNance
MISSOURIJasperTexasSandersNemaha
Zone 1JeffersonVernonSheridanNuckolls
AndrewJohnsonWarrenSilver BowOtoe
AtchisonKnoxWashingtonStillwaterPawnee
BuchananLacledeWayneTetonPhelps
CassLafayetteWebsterToolePierce
ClayLawrenceWorthValleyPlatte
ClintonLewisWrightWibauxPolk
HoltLincolnRed Willow
IronLinnMONTANAZone 2Richardson
JacksonLivingstonZone 1Golden ValleySaline

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

SarpyEsmeraldaTaosPutnamGaston
SaundersHumboldtZone 2RensselaerGraham
SewardNyeCatronSchoharieHaywood
StantonStoreyChavesSchuylerIredell
ThayerWashoeCibolaSenecaJackson
ThurstonCurrySteubenLincoln
WashingtonNEW HAMPSHIREDe BacaSullivanMacon
WayneZone 1Dona AnaTiogaMadison
WebsterCarrollEddyTompkinsMcDowell
YorkGrantUlsterPolk
Zone 2GuadalupeWashingtonRutherford
Zone 2BelknapHardingWyomingStokes
AntelopeCheshireHidalgoYatesSurry
BannerCoosLeaSwain
Box ButteGraftonLincolnZone 2Vance
BuffaloHillsboroughLos AlamosClintonWake
ChaseMerrimackLunaJeffersonWarren
CheyenneRockinghamMcKinleyLewisWilkes
CusterStraffordOteroMonroeYadkin
DawesSullivanQuayMontgomeryYancey
DawsonRooseveltNiagara
DeuelNEW JERSEYSan JuanOneidaNORTH DAKOTA
DundyZone 1SandovalOrleansZone 1
HallHunterdonSierraOswegoAdams
HowardMercerSocorroSaratogaBarnes
KeithMonmouthTorranceSchenectadyBenson
Keya PahaMorrisUnionSt LawrenceBillings
KimballSomersetValenciaWayneBottineau
MerrickSussexBowman
MorrillWarrenNEW YORKNORTH CAROLINABurke
PerkinsZone 1Zone 1Burleigh
Scotts BluffZone 2AlbanyAlleghanyCass
SheridanBergenAlleganyBuncombeCavalier
ShermanBurlingtonBroomeCherokeeDickey
SiouxCamdenCattaraugusHendersonDivide
ValleyCumberlandCayugaMitchellDunn
EssexChautauquaRockinghamEddy
NEVADAGloucesterChemungTransylvaniaEmmons
Zone 1HudsonChenangoWataugaFoster
Carson CityMiddlesexColumbiaGolden Valley
DouglasPassaicCortlandZone 2Grand Forks
EurekaSalemDelawareAlexanderGrant
LanderUnionDutchessAsheGriggs
LincolnErieAveryHettinger
LyonNEW MEXICOGeneseeBurkeKidder
MineralZone 1GreeneCaldwellLaMoure
PershingBernalilloLivingstonCaswellLogan
White PineColfaxMadisonCatawbaMcHenry
MoraOnondagaClayMcIntosh
Zone 2Rio ArribaOntarioClevelandMcKenzie
ChurchillSan MiguelOrangeForsythMcLean
ElkoSanta FeOtsegoFranklinMercer

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

MortonHuronMorganAdamsCrawford
MountrailJeffersonNobleAlleghenyElk
NelsonKnoxOttawaArmstrongErie
OliverLickingPauldingBeaverFayette
PembinaLoganPortageBedfordForest
PierceMadisonPutnamBerksGreene
RamseyMarionSanduskyBlairJefferson
RansomMercerSciotoBradfordLawrence
RenvilleMiamiTrumbullBucksMcKean
RichlandMontgomeryVintonButlerMercer
RoletteMorrowWashingtonCameronPike
SargentMuskingumWilliamsCarbonPotter
SheridanPerryWoodCentreSomerset
SiouxPickawayChesterWarren
SlopePikeOKLAHOMAClarionWashington
StarkPrebleZone 2ClearfieldWayne
SteeleRichlandAdairClinton
StutsmanRossBeaverColumbiaRHODE ISLAND
TownerSenecaCherokeeCumberlandZone 1
TraillShelbyCimarronDauphinKent
WalshStarkDelawareDelawareWashington
WardSummitEllisFranklin
WellsTuscarawasMayesFultonZone 2
WilliamsUnionSequoyahHuntingdonNewport
Van WertTexasIndianaProvidence
OHIOWarrenJuniata
Zone 1WayneOREGONLackawannaSOUTH CAROLINA
AdamsWyandotZone 2LancasterZone 1
AllenBakerLebanonGreenville
AshlandZone 2ClatsopLehigh
AuglaizeAshtabulaColumbiaLuzerneZone 2
BelmontAthensCrookLycomingAbbeville
ButlerBrownGilliamMifflinAnderson
CarrollClermontGrantMonroeCherokee
ChampaignCuyahogaHarneyMontgomeryLaurens
ClarkDefianceHood RiverMontourOconee
ClintonErieJeffersonNorthamptonPickens
ColumbianaFultonKlamathNorthumberlandSpartanburg
CoshoctonGalliaLakePerryYork
CrawfordGeaugaMalheurSchuylkill
DarkeHenryMorrowSnyderSOUTH DAKOTA
DelawareHighlandMultnomahSullivanZone 1
FairfieldHockingShermanSusquehannaAurora
FayetteJacksonUmatillaTiogaBeadle
FranklinLakeUnionUnionBon Homme
GreeneLawrenceWascoVenangoBrookings
GuernseyLorainWashingtonWestmorelandBrown
HamiltonLucasWheelerWyomingBrule
HancockMahoningYamhillYorkBuffalo
HardinMedinaCampbell
HarrisonMeigsPENNSYLVANIAZone 2Charles Mix
HolmesMonroeZone 1CambriaClark

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

ClayMelletteCarterHutchinsonWayne
CodingtonPenningtonCheathamJeff DavisWeber
CorsonShannonChesterLamb
DavisonToddClayLipscombVERMONT
DayTrippCockeLlanoZone 2
DeuelZiebachCoffeeLubbockAddison
DouglasDecaturLynnBennington
EdmundsTENNESSEEDeKalbMasonCaledonia
FaulkZone 1DicksonMooreEssex
GrantAndersonFentressOchiltreeFranklin
HamlinBedfordHamiltonOldhamLamoille
HandBlountHardinParmerOrange
HansonBradleyHendersonPotterOrleans
HughesClaiborneHoustonPresidioRutland
HutchinsonDavidsonJohnsonRandallWashington
HydeGilesMarionReevesWindham
JerauldGraingerMcNairyRobertsWindsor
KingsburyGreeneMontgomerySherman
LakeHamblenOvertonSwisherVIRGINIA
LincolnHancockPickettTerrellZone 1
LymanHawkinsPolkAlleghany
MarshallHickmanPutnamUTAHAmelia
McCookHumphreysRobertsonZone 1Appomattox
McPhersonJacksonSevierCarbonAugusta
MinerJeffersonStewartDuchesneBath
MinnehahaKnoxSumnerGrandBland
MoodyLawrenceUnicoiPiuteBotetourt
PerkinsLewisVan BurenSanpeteBrunswick
PotterLincolnWarrenSevierBuckingham
RobertsLoudonWhiteUintahCampbell
SanbornMaconChesterfield
SpinkMadisonTEXASZone 2Clarke
StanleyMarshallZone 2BeaverCraig
SullyMcMinnArmstrongBox ElderCumberland
TurnerMeigsBaileyCacheDinwiddie
UnionMonroeBrewsterDaggettFairfax
WalworthMooreCarsonDavisFluvanna
YanktonPerryCastroEmeryFrederick
RoaneCrosbyGarfieldGiles
Zone 2RutherfordCulbersonIronGoochland
BennettSmithDallamJuabHenry
ButteSullivanDeaf SmithKaneHighland
CusterTrousdaleDonleyMillardLee
DeweyUnionFloydMorganLouisa
Fall RiverWashingtonGarzaRichMontgomery
GregoryWayneGraySalt LakeNottoway
HaakonWilliamsonHaleSan JuanOrange
HardingWilsonHansfordSummitPage
JacksonHartleyTooelePatrick
JonesZone 2HemphillUtahPittsylvania
LawrenceBentonHockleyWasatchPowhatan
MeadeCannonHudspethWashingtonPulaski

(continued)

TABLE B101.1—continued
EPA RADON ZONE 1 and 2 COUNTIES BY STATEa

RoanokePend OreilleBarbourMarathonOneida
RockbridgeSkamaniaBraxtonMenomineeOutagamie
RockinghamSpokaneCabellPepinOzaukee
RussellStevensCalhounPiercePolk
ScottClayPortagePrice
ShenandoahZone 2DoddridgeRichlandRacine
SmythAdamsFayetteRockRusk
SpotsylvaniaAsotinGilmerShawanoSauk
StaffordBentonHarrisonSt CroixSawyer
TazewellColumbiaJacksonVernonSheboygan
WarrenDouglasLewisWalworthTaylor
WashingtonFranklinLincolnWashingtonTrempealeau
WytheGarfieldMarionWaukeshaVilas
GrantMasonWaupacaWashburn
Zone 2KittitasNicholasWoodWaushara
AlbemarleKlickitatPleasantsWinnebago
AmherstLincolnPutnamZone 2
ArlingtonWalla WallaRaleighAdamsWYOMING
BedfordWhitmanRandolphAshlandZone 1
BuchananYakimaRitchieBarronAlbany
CarrollRoaneBayfieldBig Horn
CharlotteWEST VIRGINIATaylorBrownCampbell
CulpeperZone 1TuckerBurnettCarbon
DickensonBerkeleyTylerCalumetConverse
FauquierBrookeUpshurChippewaCrook
FloydGrantWayneClarkFremont
FranklinGreenbrierWebsterColumbiaGoshen
GraysonHampshireWirtDouglasHot Springs
GreeneHancockWoodDunnJohnson
HalifaxHardyEau ClaireLaramie
LoudounJeffersonWISCONSINFlorenceLincoln
LunenburgMarshallZone 1ForestNatrona
MadisonMercerBuffaloIronNiobrara
MecklenburgMineralCrawfordJacksonPark
NelsonMonongaliaDaneJuneauSheridan
Prince EdwardMonroeDodgeKenoshaSublette
Prince WilliamMorganDoorKewauneeSweetwater
RappahannockOhioFond du LacLa CrosseTeton
WisePendletonGrantLincolnUinta
PocahontasGreenManitowocWashakie
WASHINGTONPrestonGreen LakeMarinette
Zone 1SummersIowaMarquetteZone 2
ClarkWetzelJeffersonMilwaukeePlatte
FerryLafayetteMonroeWeston
OkanoganZone 2LangladeOconto
DRAIN TILE LOOP. A continuous length of drain tile or perforated pipe extending around all or part of the internal or external perimeter of a basement or crawl space footing.
RADON GAS. A naturally occurring, chemically inert, radioactive gas found in soil that is not detectable by human senses.
SOIL-GAS-RETARDER. A continuous membrane of 6-mil (0.15 mm) polyethylene or other equivalent material used to retard the flow of soil gases into a building.
SUBMEMBRANE DEPRESSURIZATION SYSTEM. A system designed to achieve lower-submembrane air pressure relative to crawl space air pressure by use of a vent drawing air from beneath the soil-gas-retarder membrane.
SUBSLAB DEPRESSURIZATION SYSTEM (Active). A system designed to achieve lower subslab air pressure relative to indoor air pressure by use of a fan-powered vent drawing air from beneath the slab.
SUBSLAB DEPRESSURIZATION SYSTEM (Passive). A system designed to achieve lower subslab air pressure relative to indoor air pressure by use of a vent pipe routed through the conditioned space of a building and connecting the subslab area with outdoor air, thereby relying on the convective flow of air upward in the vent to draw air from beneath the slab.
A layer of gas-permeable material shall be placed under all concrete slabs and other floor systems that directly contact the ground and that are within the walls of the occupied spaces of the building, as a prerequisite for passive and active subslab depressurization systems. The gas-permeable layer shall consist of one of the following:
  1. A uniform layer of clean aggregate, not less than 4 inches (102 mm) in thickness. The aggregate shall consist of material that will pass through a 2-inch (51 mm) sieve and be retained by a 1/2-inch (12.7mm) sieve. Size 5, 56 or 6 aggregate shall be used and shall meet the specifications of ASTM C 33. Where compaction is required or practiced, a geotextile fabric or reinforced vapor retarder shall be used beneath the aggregate to prevent fines and soil from being introduced into the aggregate.
  2. A uniform layer of sand (native or fill), not less than 4 inches (102 mm) in thickness, overlain by a layer or strips of geotextile drainage matting designed to allow the lateral flow of soil gases.
  3. Geotextile drainage matting, or other materials, systems or floor designs with demonstrated capability to permit depressurization across the entire subfloor area.
A radon suction pit without aggregate shall be installed in the center of each 100,000 square feet (9390 m2) of floor area that is in contact with the earth and that has no subslab barriers. The suction pit void area shall be not less than 4 square feet (0.371 m2) and the pit shall be not less than 8 inches (203 mm) in depth. The resulting suction pit void to aggregate interface shall be 7 square feet (0.65 m2), or 30 times the cross sectional area of a 6-inch (157.4 mm) radon vent pipe. Alternatively, a concrete drainage distribution box or similar structure meeting the 30:1 ratio shall be employed. The suction pit shall be covered with 3/4-inch-thick (19.05 mm) pressure-treated plywood or an equivalent material prior to pouring the slab. The section of slab covering the suction pit shall be reinforced.
Radon vent piping shall be not less than 6 inches (157.4 mm) in diameter and constructed of PVC or equivalent gas-tight pipe.
A section of vent pipe not less than of 5 feet (1.52 m) in length shall be placed in the aggregate and shall enter the suction pit horizontally. One end of the vent pipe shall be placed so as to terminate midway in the suction pit. The vent pipe shall be supported at the boundary of the aggregate-void space so as to maintain its position. The horizontal pipe run shall provide positive condensation drainage to the suction pit with a pitch of not less than 1/8 inch per foot (13 mm per meter).
A 90-degree (1.57 rad) elbow shall be installed on the end of the vent pipe in the aggregate. A section of vent pipe shall be connected to the elbow and shall pass vertically through and above the slab to a height of not less than 2 feet (610 mm), and shall be covered with a temporary cap. A pipe sleeve or coupling extending through the full depth of the slab shall be used to protect the vent pipe where it passes through the slab, and the slab penetration shall be sealed in accordance with Section B201.5.
A minimum 6-mil (0.15 mm) [or 3-mil (0.075 mm) cross-laminated] polyethylene or equivalent flexible sheeting material that conforms to ASTM E 1643 shall be placed on top of the gas-permeable layer prior to casting the slab or placing the floor assembly to serve as a soil-gas-retarder by bridging any cracks that develop in the slab or floor assembly and to prevent concrete from entering the void spaces in the aggregate base material. The sheeting shall cover the entire floor area with separate sections of sheeting lapped at least 12 inches (305 mm). The sheeting shall fit closely around any pipe, wire or other penetrations of the material. All punctures or tears in the material shall be sealed or covered with additional sheeting having an overlap of not less than 12 inches (305 mm) on all sides.
Potential radon entry routes shall be sealed or closed in accordance with Sections B201.5.1 through B201.5.10.
Piping and other penetrations through concrete slabs or other floor assemblies shall be filled or sealed with a polyurethane caulk or equivalent sealant that complies with ASTM C 920 Class 25 or greater and is applied in accordance with the manufacturer's recommendations. Prior to sealing, backer rods shall be used to fill gaps greater than 1/2 inch (12.7 mm).
Slab joints, control saw joints, isolation joints, construction joints, pour joints, floor and wall intersection joints, and any other joints in concrete slabs or between slabs and foundation walls shall be sealed with a caulk or sealant. Gaps and joints shall be cleared of loose material and filled with a polyurethane caulk or other elastomeric sealant that complies with ASTM C 920 Class 25 or greater and is applied in accordance with the manufacturer's recommendations. Prior to sealing, backer rods shall be used to fill gaps that are greater than 1/2 inch (12.7 mm) in depth.
Where floor, condensate and other drains discharge to the soil and not a sewer, such drains shall be provided with a water-seal trap or shall be water trapped or routed through nonperforated pipe to a point above grade.
Sump pits open to soil or serving as the termination point for subslab or exterior drain tile loops shall be covered with a gasketed or otherwise sealed lid. Sumps used as a floor drain shall have a lid equipped with a trapped inlet.
Hollow block masonry foundation walls shall be constructed with either a continuous course of solid masonry, one course of masonry grouted solid, or a solid concrete beam at or above finished ground surface to prevent passage of air from the interior of the wall into the living space. Where a brick veneer or other masonry ledge is installed, the course immediately below that ledge shall be sealed. Joints, cracks and other openings around all penetrations of both exterior and interior surfaces of masonry block or wood foundation walls below the ground surface shall be filled with a polyurethane caulk or other equivalent sealant that complies with ASTM C 920 Class 25 or greater and is applied in accordance with the manufacturer's recommendations. Penetrations of concrete walls shall be filled.
The exterior surfaces of portions of concrete and masonry block walls below the ground surface shall be dampproofed.
Air-handling units in crawl spaces shall be sealed to prevent air from being drawn into the unit.

Exception: Units with gasketed seams or units that are otherwise sealed by the manufacturer to prevent leakage.

Ductwork for supply or return air shall not be located in crawl spaces or beneath a slab in areas with high or moderate radon potential. Where ductwork passes through or beneath a slab, it shall be of seamless material or sealed water tight. Joints in such ductwork shall be sealed water tight.
Openings around all penetrations through floors above crawl spaces shall be caulked or otherwise filled to prevent air leakage.
Access doors and other openings or penetrations between basements and adjoining crawl spaces shall be closed, gasketed or otherwise filled to prevent air leakage.
In buildings with crawl space foundations, the following components of a passive submembrane depressurization system shall be installed during construction.
Exception: Buildings in which an approved mechanical crawl space ventilation system or other equivalent system is installed.
Crawl spaces shall be provided with vents to the exterior of the building.
The soil in crawl spaces shall be covered with a continuous layer of minimum 6-mil (0.15 mm) polyethylene soil-gas-retarder that conforms to ASTM E 1643. The ground cover shall be lapped a minimum of 12 inches (305 mm) at joints and shall extend to all foundation walls enclosing the crawl space area.
A plumbing tee or other approved connection shall be inserted horizontally beneath the sheeting and connected to a 3- or 4-inch-diameter (76 mm or 102 mm) fitting with a vertical vent pipe installed through the sheeting. The vent pipe shall be extended up through the building floors, terminate at least 12 inches (305 mm) above the roof in a location at least 10 feet (3048 mm) away from any window or other opening into the conditioned spaces of the building that is less than 2 feet (610 mm) below the exhaust point, and 10 feet (3048 mm) from any window or other opening in adjoining or adjacent buildings.
In basement or slab-on-grade buildings, the following components of a passive subslab depressurization system shall be installed during construction.
A minimum 3-inch-diameter (76 mm) ABS, PVC or equivalent gas-tight pipe shall be embedded vertically into the subslab aggregate or other permeable material before the slab is cast. A "T" fitting or equivalent method shall be used to ensure that the pipe opening remains within the subslab permeable material. Alternatively, the 3-inch (76 mm) pipe shall be inserted directly into an interior perimeter drain tile loop or through a sealed sump cover where the sump is exposed to the subslab aggregate or connected to it through a drainage system.
The pipe shall be extended up through the building floors, terminate at least 12 inches (305 mm) above the surface of the roof in a location at least 10 feet (3048 mm) away from any window or other opening into the conditioned spaces of the building that is less than 2 feet (610 mm) below the exhaust point, and 10 feet (3048 mm) from any window or other opening in adjoining or adjacent buildings.
In buildings where interior footings or other barriers separate the subslab aggregate or other gas-permeable material, each area shall be fitted with an individual vent pipe. Vent pipes shall connect to a single vent that terminates above the roof or each individual vent pipe shall terminate separately above the roof.
All components of the radon vent pipe system shall be installed to provide positive drainage to a suction pit beneath the slab, or to the ground beneath the slab or soil-gas-retarder. The slope of vent piping shall be not less than 1/8 unit vertical in 12 units horizontal.
Radon vent pipes shall be accessible for future fan installation through an attic or other area outside the habitable space.
Exception: The radon vent pipe need not be accessible in an attic space where an approved roof-top electrical supply is provided for future use.
All exposed and visible interior radon vent pipes shall be identified with at least one marking on each floor and in accessible attics. The marking shall read: "Radon Reduction System."
Combination basement/crawl space or slab-on-grade/crawl space foundations shall have separate radon vent pipes installed in each type of foundation area. Each radon vent pipe shall terminate above the roof or shall be connected to a single vent that terminates above the roof.
To provide for future installation of an active submembrane or subslab depressurization system, an electrical circuit terminated in an approved box shall be installed during construction in the attic or other anticipated location of vent pipe fans. An electrical supply shall also be accessible in anticipated locations of system failure alarms.
ASTM
C 33-08Standard Specification for
Concrete Aggregate
B201.1
C 920-11Standard Specification for
Elastomeric Joint Sealants
B201.5.1
B201.5.2
B201.5.5
E 1643Standard Practice for Selection,
Design, Installation, and
Installation, and Inspection of
Water Vapor Retarder Used in
Contact with Earth or Granular
Fill Under Concrete Slabs
B201.6.2
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