6
105705
VENTED TYPE DECORATIVE APPLIANCE
VGL850 Series
®
VENTING
INSTALLATION
A B-type venting system must be connected
to the appliance for venting to the outside of
the building.
The following section is provided as a guide
to a standard B-type vent installation.
Standing codes requirements concerning B-
type vent installations may vary within your
state, province or local codes jurisdiction.
Therefore, it is recommended that you check
with your local building codes for specific
requirements or in absence of local codes,
follow Section 7.0 of the current National
Fuel Gas Code NFPA No. 54/ANS Z223.1
and in Canada with CAN/CGA B149 for
Category I systems using double wall B-1
vent pipe.
This gas appliance must be vented to the
outdoors only and may not be terminated
into an attic space or into a chimney flue
servicing a solid-fuel burning appliance.
This appliance may be vented through a
manufactured chimney system or a masonry
chimney using a B-vent adapter or a chim-
ney liner system if all are listed, inspected
and approved by local codes and/or building
authorities.
The examples shown in Figure 9 are typical
of most B-vent installations and codes prac-
tices.
Example 1:
Shows the minimum allowable
system height and lateral offset for a 60
°
degree or greater inclination. Code specifies
that offsets at 60
°
degrees or greater are
considered horizontal and must follow the
75% percent rule for lateral to total vertical
system height. Codes also allows only one
offset in the total system when at 60
°
de-
grees or greater. The total vertical height in
this example represents the minimum height
of 8 feet and therefore the allowable lateral
is 6 feet when the 75% percent rule applies.
If the lateral length must exceed 75% then
the system must be sized in accordance with
the Category I venting tables.
Maintain
Listed
Clearance
12' Min.
12' Min.
45
°
45
°
6'
8'
12' Min.
60
°
45
°
Position
Firestop
Position
Firestop
Position
Firestop
Listed
Vent Cap
Listed
Vent Cap
Listed
Vent Cap
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Maintain
Listed
Clearance
Support Each
Lateral At
Least Every
Six (6) Feet
Maintain
Listed
Clearance
10'
EXAMPLE 3
EXAMPLE 2
EXAMPLE 1
Example 2:
Shows a multiple offset each
at 45
°
degrees of inclination. Multiple off-
sets are permitted if they do not exceed 60
°
degrees of inclination. The total lengths of
the two offsets are not required to meet the
75% percent allowable rule.
Example 3:
Shows a single offset at 45
°
degrees of inclination and therefore the
lateral length at 10 feet of offset does not
have to meet the 75% percent rule.
In each case the offsets must be supported
and firestops must be positioned wherever
the vent must pass through a sub-floor,
ceiling joist or an attic overhang. The vent
pipe must terminate vertically into a listed
type vent cap and extend a sufficient height
through an approved roof flashing, roof
jack or a roof thimble. At all points the listed
clearances must be maintained.
Figure 9 - Typical B-Vent Configuration
