Specifications

13
2) MaximumVentandAirIntakeLengths-Themaximumlengthoftheventairintakepipingdependsuponthevent
optionselectedandtheboilersize.SeeTable7.1or7.9forthemaximumventlength.Inhorizontalventsystems,the
lengthsshowninTable7.1areinadditiontotherststandardelbowontopoftheboiler.Forverticalventsystems,
themaximumverticalventlengthsshowninTable7.9areinadditiontotwoelbows.Ifmoreelbowsaredesired,the
maximumallowableventlengthmustbereducedbytheamountshowninTable7.8 foreachadditionalelbowused.
Terminationttingsarenevercounted,althoughthelengthoftheconcentricterminalsection,includedwiththeboiler,is
counted.
Example:
A60/100mmconcentricventsystemisplannedforahorizontallyventedFCM120whichhasthefollowingcomponents:
80/125x60/100mmReducingElbow(suppliedwiththeboiler)
5ftStraightPipe.
90elbow
1½ftStraightPipe
45Elbow
UncutTerminalSection(suppliedwiththeboiler)
 TheVentOption#1columninTable7.1describesahorizontaldirectventsystemusing60/100mmconcentricventpipe.
Fromthiscolumn,weseethataFCM120mayhaveaventlengthofupto18ft.The90degreereducingelbowisnot
considered.Thelengthoftheterminalsection(notincludingtheplasticterminalitself)isapproximately221/2”(1.9
ft)installed.FromTable7.8,weseethattheequivalentlengthofthe60/100mmelbowis4.5ftandthattheequivalent
lengthofthe45degreeelbowis4ft.Thetotalequivalentlengthoftheplannedventingsystemistherefore:
 5ft(Straight)+4.5ft(90Elbow)+1.5ft(Straight)+4ft(45Elbow)+1.9ft(UncutTerminalSection)=16.9ft.
 SinceTable7.1showsamaximumallowableventlengthof18ft,theplannedventsystemlengthisacceptable.
3)MinimumVentandAirIntakeLengths-Observetheminimumventlengthsshownintables7.1and7.9.
4)PermittedTerminalsforHorizontalVenting:
• Vent Option 1-Theconcentric60/100mmconcentricventterminalissuppliedwiththeboileraspartofthestandard
ventsystem.
• Vent Option 2-TheexhaustterminalisU.S.Boilerpart8110701.Theairintakettingisa90degreeelbowwitha
rodentscreensuppliedbytheinstaller.Thiselbowismadeoutofthesamematerialastherestoftheairinletsystem
(eithergalvanizedorPVC)andisinstalledasshowninFigure7.3
• Vent Option 3 -Twoterminalsarepermitted:
a. 80/125mmConcentricVentTerminal(U.S.Boilerpart101494-01).
b. 80/125mmSnorkelTerminal(U.S.Boilerpart101544-01).Thisterminalallowstheventsystemtoexitthe
buildingclosetogradeandgouptheexteriorwallfarenoughtoprovideadequateclearancebetweentheterminal
itselfandthesnowline(seeFigure7.7).
5)HorizontalVentandAirIntakeTerminalLocation-Observethefollowinglimitationsontheventterminallocation(also
seeFigures7.6a,7.6b,7.6cand7.7).Whenlocatingaconcentricterminal,observethelimitationsoutlinedbelowfor
“ventterminals”.
• Ventterminalsmustbeatleast1footfromanydoor,window,orgravityinletintothebuilding.
• Fortwinpipeterminals,maintainthecorrectclearanceandorientationbetweentheventandairintaketerminals.
Theventandairintaketerminalsmustbeatthesameheightandtheircenterlinesmustbebetween12and36inches
apart.Bothterminalsmustbelocatedonthesamewall.
• Thebottomofallterminalsmustbeatleast12”abovethenormalsnowline.Innocaseshouldtheybelessthan12”
abovegradelevel.
• Thebottomoftheventterminalmustbeatleast7feetaboveapublicwalkway.
• Donotinstalltheventterminaldirectlyoverwindowsordoors.
• Thebottomoftheventterminalmustbeatleast3feetaboveanyforcedairinletlocatedwithin10feet.
• Aclearanceofatleast4feethorizontallymustbemaintainedbetweentheventterminalandgasmeters,electric
meters,regulators,andreliefequipment.Donotinstallventterminaloverthisequipment.
• Donotlocatetheventterminalunderdecksorsimilarstructures.
• Topofventterminalmustbeatleast5feetbeloweves,softs,oroverhangs.Maximumdepthofoverhangis3ft.