www.desatech.com
108796-01M
9
INSTALLING TRANSITION PIPE AND
STARTER COLLAR
The transition pipe and starter collar shown in
Figure 9 are supplied with the fireplace, unat
-
tached and ready for installation. Remove the
starter collar and set aside. Slide the transition
pipe over the vent collar and attach with a
minimum of three screws. Replace the starter
collar over the transition pipe and attach using
four screws located on the leg stands (five
used on the model M4E). To install B-vent
piping, slide the first piece of B-vent over the
transition pipe and attach with either a mini-
mum of two screws or other means approved
by the vent manufacturer.
Figure 9 - Installing Transition Pipe and
Starter Collar
B-Vent Piping
Transition Pipe
Starter Collar
Vent Collar
PreInstallatIon
PreParatIon
Continued
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 ANSI Z223.1/NFPA 54
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 10, page 10
are typical of most B-vent installations and
codes practices.
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° degrees
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.
Example 2:
Shows a multiple offset each at
45° degrees of inclination. Multiple offsets are
permitted if they do not exceed 45° 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° de-
grees 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, ceil
-
ing 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.
Vent terminations must be located in ac-
cordance with height and proximity rules of
NFPA No. 54 or CAN/CGA B149. These rules
apply to vents at 1 in. diameter or less and
require a minimum height in accordance with
the roof pitch and a minimum of 8 ft. distance
from a vertical wall or obstruction (see Figure
11, page 10).
