Burnham K2WTC - Design Requirements Unique to Horizontal Twin Pipe Venting Systems

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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
Figures 7.6 – 7.10. In addition to the requirements in Section VII - A, observe the following design requirements:
1. Permitted Terminals for Horizontal Venting:
Terminal Option A: Fittings (Acceptable for Vent Options 1-4) – Vent terminates in a plain end (coupling for PVC, bell
endforPolyPro,PolyueandplainendpipeforInnoFlue).IntaketerminatesinaPVC90sweepelbowpointingdown.
Outer edge of both terminals must be within 10” of the wall surface (Figures 7.6, 7.9). The section of DuraVent PolyPro,
CentrothermInnoFlueorSelkirkPolyueexposedtotheoutdoorsmustbeUVresistant.
Use of rodent screens (not supplied) is generally recommended for both terminations. These can be fabricated from 2 x 2
(1/2” mesh) stainless steel screen. Rodent screens and are installed as shown in Figure 7.28. Rodent screens (“bird guards”)
forPolyPro,InnoFlueandPolyueareasfollows:
Size/Vent System Rodent Screen (“Bird Guard”)
3” PolyPro DuraVent # 3PPS-BG
3”Polyue  Selkirk#3PV-HVST
3” InnoFlue Centrotherm # IASPP03
Ifnecessarytoachieverequiredclearanceabovegrade,CPVCorCPVC/PVCventsystemsmaybeterminatedusingttings
on snorkels as shown in Figure 7.12. When this is done, the equivalent length of all pipe on the exterior of the building,
exceptfortheterminalttingsthemselves,mustbecountedwhencalculatingtheequivalentlength.Themaximumvertical
runofthesnorkelis7feet.Braceboththeventandinletpipingifrequired.PolyPro,InnoFlueandPolyuemaynotbe
snorkeled.
TerminalOptionB:IpexLowProleTerminal(AcceptableforVentOption1) – This terminal is shown in Figure 7.7. If the
terminal is oriented vertically (alternate orientation shown in Fig 7.7) the exhaust opening must be on the top as shown. See
Section VII - E of this manual and the Ipex instructions provided with the terminal, for installation details.
TerminalOptionC:DiversiTech“LowProle”Terminal(AcceptableforVentOption1) – This terminal is shown in Figure
7.7. If the terminal is oriented vertically (alternate orientation shown in Fig 7.7) the exhaust opening must be on the top as
shown. See Section VII - E of this manual and the DiversiTech instructions provided with the terminal, for installation details.
Terminal Option D: Ipex FGV Concentric Terminal (Acceptable for Vent Option 1) - 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
196006 3 x 20” PVC
196106 3 x 32” PVC
196116 3 x 44” PVC
197107 3 x 32” CPVC
197117 3 x 44” CPVC
See Section VII - E of this manual and the Ipex instructions provided with the terminal, for installation details.
Terminal Option E: DiversiTech Concentric Terminal (Acceptable for Vent Option 1) - This terminal is shown in Figure 7.8
and may be used with CPVC/PVC vent systems. See Section VII - E of this manual and the DiversiTech instructions provided
with the terminal, for installation details.
Terminal Option F: DuraVent PolyPro Concentric Terminal (Acceptable for Vent Option 2) - This terminal is shown in
Figure 7.10 and may be used with DuraVent 3” PolyPro vent systems. See Section VII - F of this manual and the DuraVent
instructions provided with the terminal, for installation details.
VII. Venting B. Design Requirements Unique to Horizontal Twin Pipe Venting Systems (continued)