®
32
Direction of
Plumbing
Movement
L/4
L/2
L
L/4
Guide
Supports
Only
Figure 18 | PVC Plumbing Offset
Right:
A common industry standard for a plumbing offset
(see
Table 5
below for offset distance L).
This offset can be oriented vertically (as shown) or hori-
zontally to accommodate thermal movement in the direc-
tion of the plumbing. Notice the loose plumbing mounting
points which restrict movement except in the axial direc-
tion. Refer also to
Figures 19, 20, 21 and 22 A, B and
C
along with associated tables for further use of offsets.
Plumbing Movement
APPENDIX C
—
Reference Tables & Figures
Figure 19 | Row Plumbing Movement
A straight line of plumbing can move up 1” for a length of 25ft. Plumbing Expansion Joints are advised to accommodate this mo
vement. An industry standard method, such as
an
offset
should be used so that the line can move as needed. Refer to
Table 5
for Regular PVC Joint Offset lengths and
offset
type for a length of pipe.
Regular PVC Pipe
(2X) Straight
Line Plumbing
Fixed
Support
Guide
Supports
Fixed
Support
(~4ft)
Length of Pipe
To accommodate for long plumbing runs, refer to the table or incorporate an industry standard plumbing offset. If space doesn
’t
permit, it may be advisable to use an alternate
Offset
method (as in
Figures 20 or 21
) for a single long run of plumbing.
Table 5 | Thermal Expansion of PVC Piping
Expansion Dimensions Chart for PVC Offsets T=80°F
Most Installations Most Installations, with Bank Movement
Uncommon Installations
Length of Pipe (ft)
10
20
30
40
50
60
70
80
90
100
Thermal Exp (in)
0.6
0.8
1.2
1.5
1.8
2.1
2.4
2.7
3.0
3.3
L/4 (in)
7
10
12
14
16
17
19
20
21
22
L/2 (in)
14
20
24
28
32
34
38
40
42
44
Single Offset Dist (in)
28
40
48
56
64
68
76
80
84
88
Exposed PVC (in)
8.7
14.7
18.7
22.7
26.7
28.7
32.7
34.7
36.7
38.7
