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When routing plumbing, consideration should be tak-
en to ensure it will be properly guided so that it
moves as intended. Common practice is to strap
plumbing lines with a galvanized plumbing strap an-
chored by 1 or 2 fasteners. These types of mounting
allow for movement perpendicular to the direction of
the strap. If plumbing is strapped parallel to the di-
rection of movement without a means of accommo-
dating it in the line, thermal effects can tear out the
strapping and cause costly damages. Refer to local
plumbing codes for proper mounting practices of
PVC.
There are multiple methods of accommodating both
bank and plumbing movement. Figure 7 below ex-
plains some ways of accommodating both bank and
plumbing movement. More details are available in
Appendix C for reference.
The use of a plumbing offset is a largely common
means of enabling axial growth and shrinkage in long-
er runs of plumbing. By offsetting the plumbing with
90° fittings and strapping it in accordance with Fig-
ure 18 and Table 5 in Appendix C, proper movement
can be allowed to take place without cracking fittings,
tearing out mounting points, and restricting the
movement of a solar system.
Note that this is not the only means of properly ac-
commodating for plumbing and bank movement. In-
dustry standard methods are also acceptable. For
more details on proper plumbing mounting and move-
ment, consult a certified pluming specialist and local
plumbing codes.
Figure 7 | Row Plumbing Movement
A bank of 5 collectors from the Fixed Collector can move up to 2.5” from normal temperature fluctuations (1.2” in a single direction). Two
Plumbing Expansion Hoses are advised to accommodate this movement when the plumbing is strapped as shown. Refer to Table 6 in
Appendix C for recommended Plumbing Expansion Hose lengths. In this case, the movement in the bank corresponds to 1.2” which can also be
transposed to an equivalent of 40ft PVC pipe (Table 5). Additionally, there is a 10ft line of PVC. Adding the two provides 50ft of equivalent
length, requiring a 16” expansion hose (sourced from Table 6). Since the plumbing can be mounted as Fixed or Guide supports, an offset may
also be useful to absorb some or all of the movement in the above figure. Refer to Appendix C for more variations of Row Plumbing Movement.
Note: It’s also acceptable to use another industry standard method to accommodate for thermal movement. Variations of
these recommendations can be used as long as sufficient movement for a standard temperature range of 80°F is allowed.
PHASE I — Site Preparations & Planning Cont’d
Fix-Mounted Collector
Bank Moves up to 5X
(±1/4”) = 2.5”
Collector 0
Collector 1
Collector 2
Collector 3
Collector 4
Collector 5
Flexible
Expansion
Joint
(advised)
Fixed
Support
Fix-Mounted Collector
Collector 0
Collector 1
Collector 2
Collector 3
Collector 4
Collector 5
~4ft
~4ft
~10ft
~16in
Hose
Guide
Support
Figure 6 | 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 movement. 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. See Appendix C
for alternate methods of accommodating for plumbing movement.
Regular PVC Pipe
(2X) Straight
Line Plumbing
Fixed
Support
Guide
Supports
Fixed
Support
(~4ft)
Length of Pipe
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