5
PROVIDINGADEQUATE
VENTILATION
Thefollowingareexcerptsfrom
NationalFuelGasCode.NFPA54/
ANSIZ223.1,Section5.3. Airfor
Combustionand Ventilation.All
spaces inhomesfallintooneof
thethree following ventilation
classifications:
1. UnusuallyTightConstruction
2.Unconfined Space
3. Confined Space
Theinformation on pages 5through
6willhelpyouclassifyyour space
andprovide adequateventilation.
ConfinedandUnconfined
Space
TheNational FuelGasCodeANSI
Z223.1 defines aconfined spaceas
aspacewhose volumeisless than
50 cubicfeet per1,000Btuper hour
(4.8m3perkw)of theaggregatein-
putratingofall appliancesin-
stalledinthatspaceand anuncon-
finedspaceasaspace whose
volumeisnotless than50 cubic
feetper1,000Btuperhour(4.8m3
perkw) oftheaggregateinput rat-
ing ofall appliances installedin
thatspace.Roomscommunicating
directlywiththespaceinwhichthe
appliances areinstalled*,through
openings notfurnishedwithdoors,
areconsideredapart of the uncon-
finedspace.
Thisheatershall notbeinstalled
inaconfinedspaceorunusually
tight construction unlessprovisions
areprovidedforadequatecombus-
tionandventilationair.
*Adjoiningroomsarecommunicat-
ingonlyif therearedoorless pas-
sagewaysorventilationgrillsbe-
tween them.
UnusuallyTightConstruction
Theairthat leaks around doorsand
windowsmayprovideenoughfresh
airforcombustionand ventilation.
However, inbuildingsofunusually
tightconstruction, youmustprovide
additionalfreshair.
Unusuallytightconstructionis
defined as constructionwhere:
a.Wallsand ceilingsexposed to
theoutsideatmospherehave a
continuouswatervaporretarder
witharating of oneperm(6×10-11 kg
per pa-sec-m2)or lesswithopenings
gasketedorsealedand
b.Weatherstripping has been
added onopenablewindowsand
doorsand
c.Caulking orsealantsareapplied
toareas suchas jointsaround
windowanddoorframes,between
soleplates and floors,between
wall-ceilingjoints,betweenwall
panels,atpenetrationsforplumbing,
electrical,and gas lines,and at
otheropenings. If yourhomemeets
all ofthe threecriteriaabove,you
must provide additional fresh air.
SeeVentilationAirFromOutdoors,
page 6.
If your homedoesnot meetall of
thethree criteriaabove,seeDeter-
miningFresh-AirFlowforHeater
Location,page5.
DETERMININGFRESH-AIRFLOWFORHEATERLOCATION
Determining if you haveaConfined orUnconfined Space*
Usethisworksheet todetermine if youhave aconfinedorunconfinedspace.
Space: Includesthe roominwhichyouwillinstallheaterplus anyadjoiningroomswithdoorlesspassageways
or ventilation grillsbetweentherooms.
1. Determinethe volumeofthespace(length×width×height).
Length×Width×Height= cu.ft. (volumeofspace)
Example: Spacesize20ft. (length)×16ft.( width)×8ft. (ceiling height)=2560cu. ft. (volumeof space)
If additionalventilationtoadjoiningroomissupplied withgrillsoropenings,addthevolumeoftheserooms
tothe totalvolumeofthespace.
2.Dividethespacevolumeby50 cubicfeettodeterminethemaximumBtu/Hrthespacecansupport.
(volumeof space) 50 cu. ft.=(MaximumBtu/Hr thespacecansupport)
Example: 2560 cu. ft. (volumeof space) 50 cu.ft.=51.2or 51.200(maximumBtu/Hr thespacecansupport)
AIRFORCOMBUSTION
ANDVENTILATION
WARNING:Thisheatershall
notbeinstalledinaconfined
spaceorunusuallytightcon-
structionunlessprovisions are
providedforadequatecombus-
tionandventilationair.Readthe
followinginstructionstoinsure
properfreshairforthisand
otherfuel-burningappliancesin
yourhome.
