the inverters’ location on the roofs],” according to Christie. By disconnecting Graham Hall’s
electricity, firefighters can cut power close to the
panels rather than risking live wattage somewhere in the building.
“One of the nice things about the age of the
building is that it actually used to have an incinerator,” said Christie, “which meant that it had a
chimney going the length of the building.” Graham Hall’s chimney offered a protected place to
run conduits from the roof to the first-floor electrical room. “It wasn’t very fun for the man doing it,
to climb seven stories down a chimney,” Christie
said, but the team devised a safe way to do it.
The system was installed last summer. Mov-
ing materials to the seven-story rooftop required
a crane and avoidance of power lines surround-
ing the building. Installers also worked in tan-
dem with the roofing team, who roofed over the
old surface and then, after the solar crew had
installed the mounting feet, installed a white
membrane. Drilling down to bare concrete to
sink anchors meant special equipment and extra
days in the mid-90s heat. To reduce the number
of roof penetrations on Graham Hall, GridPoint
used an extra-deep rail that spread the bolted
penetrations to 8 feet ( 2. 4 meters) apart.
A view from the middle of the Graham hall roof,
looking north. To avoid the weight of ballast
on the seven-story building, GridPoint bolted
down the system. The panels were installed at a
10-degree angle to minimize wind loading.
reducing THA’s commitment to $280,000.
Throughout the installation, Graham Hall’s
residents followed closely, discussing details
with the crew. At a recent THA meeting, they
inquired about whether it was performing as
expected. According to THA Grants Director
Carrie Kline, “They’re still asking questions
about it.” ST
Copyright © 2011 by the American Solar Energy Society Inc. All rights reserved.
July 12-14, 2011 / San Francisco
Moscone Center, West Hall, Level 1
booth number: 7253