20
• Determine each appliance remaining connected to common
venting system properly vents when tested as outlined
above. Then return doors, windows, exhaust fans and any
other gas-burning appliance to their previous condition of
use.
• Any improper operation of common venting system
should be corrected so installation conforms with National
Fuel Code, ANSI Z223.1/NFPA 54 and/or Natural Gas
and Propane Installation Code, CAN/CSA B149.1. When
re-sizing any portion of common venting system, common
venting system should be re-sized to approach minimum
size as determined using appropriate tables in Chapter 13
of the National Fuel Gas Code, ANSI Z223.1/NFPA 54 and/
or Natural Gas and Propane Installation Code, CAN/CSA
B149.1.
6 - COMBUSTION AIR AND VENT PIPING
6.3 Definitions
1.
Coaxial piping
– exhaust and air intake pipe have a
common axis.
2.
Twin Pipe –
Figure Exhaust and intake air are separate
pipes, can be terminated using single wall terminals from
the vent manufacturer or field built configuration using
elbows or tees.
PN 240011662 Rev. H [04/30/2019]
