9
B. Design Requirements Unique to Horizontal Twin Pipe Venting Systems
Table 7.5 summarizes all horizontal twin pipe vent options. Illustrations of horizontal twin pipe vent systems are shown in
Figures7.6–7.10.InadditiontotherequirementsinPartVII-A,observethefollowingdesignrequirements:
1. Permitted Terminals for Horizontal Venting:
TerminalOptionA:Fittings(AcceptableforVentOptions1-8)–Ventterminatesinaplainend(couplingforPVC,bell
endforPolypro,PolyueandplainendpipeforInnoFlue).IntaketerminatesinaPVC90sweepelbowpointingdown.
Outeredgeofbothterminalsmustbewithin10”ofthewallsurface(Figures7.6,7.9).ThesectionofDuraVentPolypro,
CentrothermInnoFlueorSelkirkPolyueexposedtotheoutdoorsmustbeUVresistant.
Useofrodentscreensisgenerallyrecommendedforbothterminations.Thesecanbefabricatedfrom2”x2”(1/2”mesh)
stainlesssteelscreenandareinstalledasshowninFigure7.28.Rodentscreens(“birdguards”)forPolyPro,InnoFlueand
Polyueareasfollows:
Size/VentSystem RodentScreen(“BirdGuard”)
2” Polypro DuraVent # 2PPS-BG
3” Polypro DuraVent # 3PPS-BG
2”Polyue Selkirk#2PF-HVST
3”Polyue Selkirk#3PV-HVST
2” InnoFlue Centrotherm # IASPP02
3” InnoFlue Centrotherm # IASPP03
Ifnecessarytoachieverequiredclearanceabovegrade,CPVCorCPVC/PVCventsystemsmaybeterminatedusingttings
on snorkels as shown in Figure 7.12. When this is done, the equivalent length of all pipe on the exterior of the building,
exceptfortheterminalttingsthemselves,mustbecountedwhencalculatingtheequivalentlength.Themaximumvertical
runofthesnorkelis7feet.Braceboththeventandinletpipingifrequired.Polypro,InnoFlueandPolyuemaynotbe
snorkeled.
TerminalOptionB:IpexLowProleTerminal(AcceptableforVentOptions1,2) – This terminal is shown in Figure 7.7. If
theterminalisorientedvertically(alternateorientationshowninFig7.7)theexhaustopeningmustbeonthetopasshown.
See Part VII-E of this manual and the Ipex instructions provided with the terminal, for installation details.
TerminalOptionC:Diversitech“LowProle”Terminal(AcceptableforVentOptions1,2) – This terminal is shown in Figure
7.7.Iftheterminalisorientedvertically(alternateorientationshowninFig7.7)theexhaustopeningmustbeonthetopas
shown. See Part VII-E of this manual and the Diversitech instructions provided with the terminal, for installation details.
TerminalOptionD:IpexFGVConcentricTerminal(AcceptableforVentOptions1,2) - This terminal is shown in Figure 7.8
and may be used with CPVC/PVC vent systems. This terminal is available in various lengths and in both PVC and CPVC.
Terminals acceptable for use with these vent options are as follows:
Ipex PN FGV Concentric Terminal Description
196005 2x16”PVC
196105 2x28”PVC
196125 2x40”PVC
196006 3x20”PVC
196106 3x32”PVC
196116 3x44”PVC
197107 3 x 32” CPVC
197117 3x44”CPVC
See Part VII-E of this manual and the Ipex instructions provided with the terminal, for installation details.
TerminalOptionE:DiversitechConcentricTerminal(AcceptableforVentOptions1,2) - This terminal is shown in Figure 7.8
and may be used with CPVC/PVC vent systems. See Part VII-E of this manual and the Diversitech instructions provided with
the terminal, for installation details.
TerminalOptionF:DuraVentPolyProConcentricTerminal(AcceptableforVentOptions3,4) - This terminal is shown in
Figure 7.10 and may be used with DuraVent 2” or 3” PolyPro vent systems. See Part VII-F of this manual and the DuraVent
instructions provided with the terminal, for installation details.