Install Instructions

8
Type B Gas Vent - 3” to 12” Diameter
Installation Instructions
Fire-stopping
• In single-story, slab-floor houses having an attic
space, a
firestop must
be provided
where the vent
passes
through the
ceiling, unless
a support is
used there.
The ceiling
should be cut
away from the
opening frame
to PROVIDE
1-INCH MINIMUM CLEARANCE from the vent
pipe. A firestop consisting of a noncombustible
material, such as 1/4-thick ceramic board or 26-
gauge galvanized sheet met al, should be cut to
fit the pipe and the framed opening. The firestop
should be fastened to the top of the joists and
framing members to eliminate any pockets in
which combustible debris might collet. An RPC
pipe collar may be used on the underside of the
ceiling to finsh off the opening. (See Figure 17.)
• In single-story buildings with an attic space and with the
gas appliance located in a basement or crawl sp ace,
firestops must be provided where the vent passes
through both the floor and the ceiling. This can be
done by cutting away and framing the floor and ceiling
construction and installing firestops of noncombustible
material as shown in Figure 17). All combustible
construction should be cut away sufficiently to PROVIDE
THE MINIMUM CLEARANCE OF 1 INCH FROM THE
VENT PIPE SURFACE.
• In multi-story buildings, a firestop must be provided
at every point where the vent p asses through a
floor or ceiling. These firestops may be provided
as indicated in the paragraph above.
• Four-inch round vent (4RPX) may be used in a 2” x 6”
stud wall. The proper clearance in a 2” x 6” wall is
provided by the spacer on the pipe and by the 4RFS
firestop spacer. All other uses of a 4” pipe require the
normal 1-INCH CLEARANCE TO COMBUSTIBLES.
• Four-inch round vent (4RP) must maintain
1-INCH CLEARANCE T O COMBUSTIBLES.
Terminations using a flashing and a cap
Gas Venting Systems use a termination cap and
may terminate in accordance with Table 3 and
Figure 20.
3" - 8" TOP INSTALLATION
Round tops (for pipe sizes 3"-8") have a spring clip
which engages and locks automatically when the
top is pushed into the upper end of the pipe. (See
Fig. 22-A.) The top will also fit any single wall metal
pipe having full nominal inch dimensions. (Never
use single wall metal pipe where Type B Gas Vent
is required). To attach securely, bend a on e inch
length of the pipe upper end inward about 1/8". The
spring clip will lock under this bent edge. (See Fig-
ure 22-B.) To remove the top from any pipe, pull up
evenly on the opposite sides of the skirt of the top.
Figure 17
Figure 18