Green Plumbing & Mechanical Design
Space City Savings
by Paul V. Dudkowski
September 1, 2011
Through a series of renovations over a multi-year period, 1 Houston Center earned a LEED EB: O & M Gold rating. Photo courtesy of Crescent Real Estate.
1 Houston Center was typical of late 1970s design.
Water and energy took a backseat to durability, reliability and
flexibility.
Located in the heart of Houston’s central business district, the 48-story, 1.3
million-sq.-ft. high-rise was designed as the world headquarters of the Texas
Eastern Pipeline Co.
But it wasn’t until the mid-1990s that conservation of energy and natural
resources was highly regarded. At the time, though, the business climate was
not ready to invest down that road. Instead, the building stuck to its policy
of extending the life of existing equipment, which consumed water to the tune
of 35 million gallons per year.
In 1998, Crescent Real Estate
purchased the building and its engineers decided to begin an aggressive plan
toward reducing water consumption — one that eventually led the building to earn
the U.S. Green Building Council’s Leadership in Energy and Environmental Design
Gold distinction in the Existing Buildings: Operations and Maintenance
category.
Starting Simple
In 2002, bathrooms started to be equipped with hands-free faucets. Three
years later, TOTO sensor faucets and Total Concepts AutoFlush mechanisms,
attached to the Sloan flushometers, made their way into restrooms and further
advanced the green process, as did the installation of low-flow (0.2-gpm) aerators
on faucets. The cost was $5,000 to
convert each of the 48 floors with all work done in-house.
That first step saw water usage reduced 20% or 27.8 gallons per occupied square
foot. Engineers were pleased, but looked for more to
change.
“We needed a road map,” Dale Roane,
the building’s assistant chief engineer, says. “If we don’t know where we are,
we’ll never know where we are going.”
In 2007, submeters and landscape irrigation were installed. The following year,
Crescent became intrigued by the U.S. Green Building Council’s LEED
initiative.
“Once we understood the requirements for water conservation credits we were
given the green light to move further for additional savings,” Roane states.
So began the biggest in-house retrofit done in the history of 1 Houston Center. In two
years, engineers replaced every commode and many of the urinals with low-flow
models. The original 4.5-gpf toilets and 2.0-gpf urinals were replaced with
Kohler 1.6-gpf commodes and Kohler 1.0-gpf urinals.
The replacement began slowly because the original mounting bolts were not long
enough to hold the heavier wall units. Engineers found a modified “off the
shelf” carrier nut that was narrower, deeper and more acceptable for the new shortened
bolt.
With that problem solved, the transformation kicked into a higher gear. After
two years with overtime weekends, the building had cut down from 27.29 gallons
per occupied square foot to almost 24 gallons per occupied square foot.
More Work To Do
Two projects remained to complete the water conservation program. First,
was a complete redesign of the landscape to native and adaptive vegetation.
Doing this met another LEED EB: O&M credit. Engineers, along with landscape
contractor Silversand Services, opted to remove the conventional pop-up spray
heads, which measured at 14 gpm and installed Techline micro-drip irrigation. A
Weathermatic SmartLine controller and an onsite SmartLine weather station also
helped contribute to a 20-psig decrease in water pressure and a 72% reduction
in water flow.
The final project improved the performance of the cooling tower cycles. 1 Houston Center operated between
3 1/2 and 5 cycles of concentration, but with a switch to an acid-based system,
engineers wanted the system to run at 8 cycles. With water treatment partner
ChemCal providing guidelines, Roane designed the new water treatment facility.
Almost one year later, they reached their goal of 8 cycles.
After seven years, the overall water usage dropped from 34.56 gallons per
occupied square foot to 21.99 gallons per occupied square foot — a reduction of
36%.
“Blue is the new green,” Roane says. “We’re ready for anything.”
Paul V. Dudkowski
Paul V. Dudkowski was a U.S. Navy
engineer from 1974-1978. In 1979, he entered commercial real estate as an
operating engineer in Houston.
Dudkowski is currently the senior chief engineer for Crescent Real Estate at 1 Houston Center.
Links
Did you enjoy this article? Click here to subscribe to the magazine.
In the AEC Store
2009 Hydronics Know How II CD
Virtual encyclopedia on modern hydronic systems.
CONNECT WITH PM ENGINEER: