8
TECHNICAL DATA
PREVENTING DEFORMATION
Conduit and ducts 2” diameter and larger may crimp, flatten, or
deform during the bending process. Bending plugs help to
eliminate this problem. Bending plugs are inserted into the ends
of the conduit before heating. Our adaptors slip over the plugs
and are used for half size conduit and for belled-end pipe. During
the heating cycle, the bending plugs cause the trapped, heated
air, inside the conduit to expand, creating enough pressure inside
the pipe to keep the walls of the conduit supported during the
bending process. This slight amount of pressure is critical in
keeping the walls of the pipe from collapsing or when making a
bend. If a plug pops-out during the bending process, it may be
necessary to reinsert the plug and reheat the pipe to complete a
smooth, kink free bend.
ADDITIONAL BENDING INFORMATION
Very tight radius bends are difficult to achieve with any size PVC
pipe, conduit or duct without the use of special production
techniques. These techniques can include air pressurization of
the piece, insertion of special internal supports, or some other
technique. The following table can be used as a guide that is
applicable to many types of rigid PVC conduit and duct:
NOMIMAL
INTERIOR
DIAMETER
IN INCHES
1/2”
3/4”
1”
1-1/4”
1-1/2”
2”
2-1/2”
3”
3-1/2”
4”
5”
6”
4”
5”
6”
8”
10”
12”
15”
18”
21”
24”
30”
36”
7”
9”
10-1/2”
14”
17-1/2”
21”
26”
31”
36”
41”
52”
62”
27/32”
1-3/64”
1-5/16”
1-21/32”
1-29/32”
2-3/8”
2-7/8”
3-1/2”
4”
4-1/2”
5-9/16”
6-5/8”
2”
2-5/8”
2-3/4”
2-3/4”
3-1/16”
4”
4-3/4”
7-1/2”
8-3/16”
9”
11-1/8”
12-9/16”
11”
14-1/4”
16”
19-1/2”
23-5/8”
29”
35-1/2”
46”
52-3/8”
59-1/2”
74-1/4”
87-1/8”
OUTSIDE
DIAMETER
IN INCHES
MINIMUM
INSIDE
RADIUS
IN INCHES*
LENGTH
OF CURVED
SECTION
IN INCHES
LENGTH OF
STRAIGHT ENDS
IN INCHES**
EACH END
TOTAL STOCK
LENGTH
IN INCHES
*Source: Chapter 9; Table 2 “Radius of Conduit and Tubing Bends” National Electric Code® 2005
Edition. For Conductors without lead sheath - minimum radius of conduit bends.
** Recommended minimum straight section each end.
