| Criterion
6.5.5 Building Penetrations
Criterion
text:
Penetrations
of the building through which piping or wiring is passed shall
not reduce or impair the function of the enclosure. Penetrations
through walls or other surfaces shall not allow intrusion by insects
and/or vermin. Required roof penetrations shall be made in accordance
with applicable codes and also by practices recommended by the
National Roofing Contractors Association.
Comments:
Installers must follow the instructions provided in the
SRCC approved manufacturer's installation manual. In addition,
installers need to be familiar with appropriate construction,
roofing and solar industry practices.
There
are numerous methods used for penetrating, flashing and proper
sealing of building penetrations. The following are examples of
proper as well as improper methods.
Listed
below in Figure 1 is a standard pipe penetration and flashing
method using a solar industry developed copper flashing unit.
Note that the flashing has been completely sealed. The copper
flashing is installed below the shingle. This is a well sealed,
clean and aesthetic installation.
Figure
1
Another
type of pipe flashing mechanism is shown in Figure 2. Note that
the insulation ends have been butted to the flashing and collector.
Figure 2
Figures
3 and 4 are further examples of proper flashing methods. Note
in Figure 4 that the flashing is once again concealed under
the roof shingles.
Figure 3
The
pipe penetration in Figure 4has been well sealed. Sealing material,
preferably polyurethane or other acceptable roof sealing material,
was applied under the copper flashing. This method also includes
a cap which is soldered to the penetrating piping. This allows
the piping and cap to move ever so slightly with the expansion
and contraction of the piping. This prevents any water penetration
through the pipe joints. (See the bottom right photograph in
Figure 1 above for a close up view of the flashing and cap.)
The piping is then covered with insulation.
Figure 4
In
some cases, especially in multi-story residences with basements
that house the water heater, collector loop piping is routed
externally. In these situations, penetrations are often made
in the side of the house adjacent to the basement. (This prevents
having to route piping several stories through rooms within
the house.) In these cases, special care must once again be
taken to properly seal the wall penetration from insect and
vermin intrusion. (As well as rain and snow.) Figure 5 shows
a wall penetration. The penetrations will then be sealed with
appropriate sealing material. Expanding spray insulation is
ideal for these situations.
Figure 5
The
following photographs indicate penetration and sealing methods
that should not be followed.
Figure
6 shows a flashing method that will surely, in time, allow water
penetration. The flashing has been sealed using the gunk method
by which the installer applies as much sealant material and
hopes for the best. In this case, the installer used standard
roof sealing compound that will eventually harden and form cracks.
This will allow water to pool and eventually seep along the
piping into the structure. Also note the uninsulated piping
gap as well as the loose piping run. Hard copper should have
been used to place the piping run closer to the roof for piping
run stability.
Figure 6
Figure
7 shows that the installer used a standard flashing boot and
then modified it to allow pipe and sensor wire penetration.
A section of PVC piping was inserted through the flashing to
accommodate the piping and wire. Standard pipe insulation was
butted to the PVC piping. Sealant was used to seal any gaps.
A close investigation indicated that there were indeed very
small gaps at the top of the PVC piping which would eventually
allow water penetration. (From both rain and melting snow.)
Eventually, the insulation will shrink and cause even more penetration
points. Installers should use industry accepted flashing and
not customize with what is on hand.
Figure 7
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