Install Instructions

4
Type B Gas Vent - 3" to 12" Diameter
Installation Instructions
(B) The necessary straight lengths of pipe should be
connected to the elbow, tee, or the draft hood
connector, and all joints should be securely
locked together as indicated above.
(C) Floors, ceilings, and other combustible
construction should be cut away or framed as
necessary to provide a MINIMUM OF 1-INCH
CLEARANCE from the surface of the vent pipe.
Metal straps should be used to maintain the vent
pipe in position to ensure that the 1-INCH
CLEARANCE to combustibles is maintained after
the walls are closed. (See Figure 9.) DO NOT
SCREW INTO THE VENT.
(D) Whenever possible, the vent should be continued
straight out through the roof. If it is necessary to
make offsets in the attic space, the lateral run
should be sloped upward as sharply as possible,
using elbows to minimize resistance. The lateral
run should be supported using metal straps, and
again maintaining the MINIMUM CLEARANCE
OF 1 INCH from combustibles. (See Figure 9.)
(E) Laterals must be supported at 5-foot maximum
intervals. Where vertical vents are spaced by
firestops
between floors,
they need only
be supported at
the bottom.
Figure 9
• If for some reason it is
necessary to uncouple a
joint, this may be easily
done by sliding up the
lock ring and moving the
top section slightly to
loosen the tabs. The
section can then be
lifted off.
Figure 6
Figure 7
Figure 8
(A) Whenever possible, a vertical vent should be
used. This is done by simply using straight
sections of pipe from the draft hood connector out
through the roof. Where this is not possible, a
vent connector using B-vent is used to run
laterally from the draft hood to the base of the
vertical vent. The horizontal length of this vent
connector should not exceed 1½ feet for each
inch of connector diameter. If it is necessary for
B-vent connector to pass through a partition, an
RWT thimble may be used, or the wall framed to
allow 1-INCH CLEARANCE and an RPC collar
used on each side of the partition. When a vent
connector is used, it should have as much
vertical rise as possible BEFORE the horizontal
run. Vent connectors attached directly to side
outlet draft hoods, such
as floor furnaces, shall
be pitched upward at
least ¼ inch per foot.
The lateral run of vent
connectors attached to
top outlet draft hoods
may be either horizontal
or pitched upward.
DO NOT USE
SCREWS IN B-VENT
UNLESS LINING A
MASONRY CHIMNEY.
SCREWS ARE NOT
NECESSARY AND
CAUSE NOISE.
CAUTION
Laterals in common vents are limited to
1½ feet for each inch of vent diameter.
CAUTION
Do not allow the offset pipe to put pressure
on the elbow. Use pipe strap for support.