4.3.4 Preserving the integrity of the roof mem-
brane is the most important roofing consider-
ation. Ensure that all roof penetrations required
to plumb and mount the solar collector are
properly flashed and sealed in accordance with
standard roofing practices and in compliance
with all local codes and ordinances.
4.3.5 If the region is subject to hurricane con-
ditions, additional steps may be required to
secure the collector and mounting hardware to
the structural members. In certain areas of the
country, local building codes may require col-
lector wind load testing or prescribe specific
mounting procedures. Consult your local build-
ing department regarding any special consider-
ations in your area.
4.4 Collector Loop Plumbing
The collector loop must be plumbed using cop-
per or stainless steel piping and copper, brass,
bronze or stainless steel fittings. Lead-free
solder shall be used. Use of galvanized steel,
CPVC, PVC, PEX or any other type of plastic
pipe is prohibited. The collectors can produce
temperatures that will melt plastic piping.
The collector loop pipe sizing must be ade-
quately sized to handle the design flow rates
for the collector(s). SunEarth recommends ½”
nominal diameter pipe sizes for single collec-
tor systems and ¾” nominal diameter pipe for
two collector systems. It may be necessary to
increase the pipe size for longer pipe runs or
reduce the pipe size for shorter runs or higher
efficiency pumps. The pipe must be large
enough that the velocity of the HTF does not
exceed 4 ft/s. Hot HTF flowing at over 4 ft/s
in a pipe will erode the pipe and reduce system
life. When more than one collector is used in
the system, the collectors should be plumbed in
a reverse return piping arrangement in order to
maintain equal flow through all collectors in the
array. Where reverse return piping is not pos-
sible flow balancing valves must be installed to
ensure that the difference in flow rates between
collectors is no more than +/- 10%.
Piping in new solar installations can be covered
with dirt, grease, solder flux or other impurities
that over time affect the quality of the propylene
P.9
20% OF COLLECTOR
LENGTH
T
COLLECTOR
ROOF RAFTER
ROOF DECKING
BARREL TILE
COLLECTOR
C-SSN
SOLAR STRUT
BARREL TILE
ROOF DECKING
ROOF RAFTER
STANDOFF
BASE FLASHING
LAG BOLTS
FLEXIBLE TILE FLASHING
STRUT ON STANDOFF FOR
CURVED TILE ROOF
fig. 7