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BRADFORD WHITE CORP.
Page 8
WARNING
Vent pipe diameter must be as required by the
National fuel Gas Code Z223.1 or the Canadian
Installation Codes for Gas Appliances CSA-B149.1.
Undersize pipe can result in inadequate venting
and oversize pipe can result in vent condensation.
In either case the result can be release of
combustion products to the indoors. This can cause
serious injury or death by carbon monoxide
poisoning or asphyxiation.
AVERTISSEMENT
Le diamètre des tuyaux de ventilation doit répondre
aux exigences du National Fuel Gas Code Z223.1
ou du code canadien des installations des appareils
à gaz CSA B149.1. Des tuyaux trop petits rispquent
d’entraîner une ventilation inadéquate et des tuyaux
trop gros risquent de provoquer une condensation
dans les tuyaux. Dans un cas comme dans l’autre,
des produits de combustion risquent de s’échapper
dans le bâtiment et causer des blessures graves ou
l’asphyxie par le monoxyde de carbone.
Do not weld or fasten the vent pipe to the boiler
draft diverter. The weight of the stack must not rest on
the boiler.
The draft diverter and boiler top must be
easily removable for normal boiler service and
inspection.
Avoid horizontal runs of the vent pipe, and 90°
elbows, reductions and restrictions. Horizontal runs
should have at least a 1/4" rise per foot (20mm per
meter) in the direction of flow. A vent connector shall
be supported for the design and weight of the material
employed to maintain clearances and prevent physical
damage and separation of joints.
Avoid terminating boiler vents near air
conditioning or air supply fans. The fans can pick up
exhaust flue products from the boiler and return them
inside the building, creating a possible health hazard.
Do not located the vent terminal where flue products
could strike against building materials and cause
degradation.
Always use double-wall or insulated vent pipe
when used as a chimney (Type B or equivalent). In
cold weather, uninsulated outside vents can chill the
rising flue products, blocking the natural draft action
of the venting system. This can create a health hazard
by spilling flue products into the boiler room. Use
engineered venting tables acceptable to the authority
having jurisdiction to size the venting pipe or liner.
Avoid oversize vent piping or extremely long
runs of the pipe which may cause excessive cooling
and condensation.
Before connecting a vent connector to a
chimney, the chimney passageway shall be examined
to ascertain that it is clear and free of obstructions.
When inspection reveals that an existing chimney is
not safe for the intended application, it shall be rebuilt
to conform to nationally recognized standards (see
National Building Code or ANSI/NFPA 211), lined or
relined with a suitable liner, or replaced with a vent or
chimney suitable for the equipment to be attached.
3.4 Common Venting Systems
3.4.1 Venting Multiple Appliances
When common venting BJVS or BJVT natural
draft boilers with other appliances through one shared
duct called a “common vent”, special care must be
taken by the installer to ensure safe operation. In the
event that the common vent is blocked, it is possible,
especially for fan-assisted devices, to vent backwards
through non-operating appliances sharing the vent,
allowing combustion products to infiltrate occupied
spaces. If the appliances are allowed to operate in
this condition, serious injury or death may occur.
BJVS/BJVT Vent Pipe Diameter
Size inch cm
50 4 10
75 5 13
100 5 13
125 6 15
160 6 15
225 7 18
Table 3. Exhaust Vent Connection Size.
3.3 Vent Pipe Sizing and General
Installation
All vent installations and boiler stacking must be
designed and installed in accordance with all local,
state or provincial codes and with:
1. Chapter 7, “Venting of Equipment” of the
national Fuel Gas Code, ANSI 223.1 latest
edition, or the applicable provisions of the local
building codes.
2. In Canada, CSA-B149.1.
The draft diverter outlet is to be connected to an
unobstructed vent pipe of the same or larger diameter,
terminating outside the building. The vent pipe must
have a listed vent cap and extend at least two feet
above any object with a ten foot radius. All
connections should be made with rustproof sheet
metal screws.
IMPORTANT NOTE: Do not use sheet metal screws
at the snap lock joints of Type B gas vents.