
Wallmaterials, such as drywall, should be set ush with
theroughfront faceofthe Vent-Freereplace.Thiswill allow
forplacementofrequirednon-combustiblesurroundmaterialin
suchawaythat thesurroundmaterial canlayatagainst the
nishedwallsurfaceandalsoalignwiththeleadingedgeofthe
rebrickinterioroftheVent-Freereplace(seeFigure 15).
Trim Facings: Partsof the combustible mantle assembly located along
thesidesofthe reboxopening,whichproject morethanone
andone-halfinches(1-1/2”)fromthefaceofthereplace,shall
bekeptatleasteightinches(8”)fromthereboxopening.
Adjoining Room Walls:Interiorwall surfaces of adjoining room walls must be at a
minimumhorizontalmeasureoftwenty fourinches(24”)away
fromthenishedopeningoftheVent-Freereplace.
D1W
1-1/2”
8”MIN.NON-COMBUSTIBLEMATERIAL
FRAMING
Figure 14
Model W D1
MM39VF 43” 73-1/2”
MM44VF 48” 77”
MM49VF 53” 80-1/2”
1-1/2”
8”MIN
20”
MIN
8”MIN.NON-COMBUSTIBLEMATERIAL
FRAMING
Figure 15
Air for Combustion and Ventilation
Energyefcienthomesrequire homestobeairtight butatthe
sametime provide sufcient fresh air to breathe. Fresh air
entersthe home through air conditioning duct vents, around
doorsandwindowsbutalsomust provideenoughfreshairfor
propercombustiononallfuel-burningappliancesinthehome.
Exhaust fans, replaces, clothes dryers, and fuel-burning
appliancesdrawairfromthehousetooperate.Youmustprovide
adequatefreshairfortheseappliances.Thiswillinsureproper
ventingofventedfuel-burningappliances.
Non-combustible
FlexHose
Figure 16 Exterior
Providing Adequate VentilationInaccordancewiththeNationalFuelGasCodeNFPA54/ANSI
Z223.1,Section 5.3, Air for Combustion and Ventilation, all
spacesinhomesfallinto oneofthethreefollowing ventilation
classications:
1.UnusuallyTightConstruction
2.UnconnedSpace
3.ConnedSpace
Thefollowinginformationwillhelpyouclassifyyourspaceand
provideadequateventilation.
Unusually Tight Construction
Theairthatleaksaround doorsandwindowsmay provide
enough fresh air for combustion and ventilation. However,
in homes of unusually tight construction, you must provide
additionalfreshair. Unusually tight construction is dened as
constructionwhere:
a.Wallsandceilingsexposedtotheoutside atmospherehave
acontinuouswatervaporretarderwitharatingofoneperm*
orlesswithopeningsgasketedorsealedand...
b.Weatherstrippinghasbeenaddedonopenablewindowsand
doorsand...
c.Caulking or sealants are applied to areas such as joints
aroundwindowand doorframes,between soleplates and
oors,between wall-ceiling joints, between wall panels, at
penetrations for plumbing, electrical, and gas lines, and
otheropenings.
*Apermis aunitof permeanceorwater vaportransmission,
theUSperm-inchisdenedasthepassageof1grainofvapor
through1squarefootof1inchthickmaterialin1hourundera
pressuredifferenceof1inchofmercury.
Ifyourhomemeetsallthethreecriteriaabove,youmustprovide
additionalfreshair.