Madison, Wis. — It's much easier to promote yourself as a green contractor when your own building is green. That's what design/build general contractor Marshall Erdman did when it built its new office building here. It not only wanted its office building to be a prime LEED building model, but a place of business for which it could be proud.
Erdman was able to win LEED Gold with the help of water-efficient plumbing systems installed by contractor H&H Industries, along with a siphonic roof drainage system from Jay R. Smith Mfg. Co.
The building is three floors, plus a basement, said Justin Vils, plumbing manager for H&H Industries. There are back-to-back core bathrooms on each floor for public use, plus private tenant bathrooms. The basement, besides housing a parking garage, includes a fitness center and locker room with six showers. Shower valves are by Symmons. Hot water comes from A.O. Smith sealed combustion water heaters. All the water closets are wall-hung Zurn units with dual-flush handles and Zurn waterless urinals. All of the water supply is copper while the DWV is cast iron above ground and PVC below.
Vils' team installed In-Sink-Erator disposers and utility boxes for water for coffee makers and icemakers in break room kitchens on each floor.
LEED requirements meant Vils had to use low-VOC cements, solvents, caulks, and adhesives.
Tom Breu, an engineer with Marshall Erdman had experience with products by Jay R. Smith Mfg. Co. and was aware of the potential siphonic roof drains could provide him in value engineering the project while still incorporating other LEED efforts.
This project was the first siphonic roof drain project in the state of Wisconsin; that meant educating both the state and the city engineers on the product performance and use. The Jay R. Smith representative in Wisconsin, Steve Mellone of Northland Sales, worked with Erdman during this approval process. It was important to them to have the siphonic roof drains approved statewide so that they could be used on future design/build projects. Upon approval by the state, the state simply reviews the hydraulic calculations, plans and specifications to confirm proper technique is used.
During the approval and design process, Erdman worked with Rainwater Management Solutions, a partner with Jay R. Smith on siphonic roof drains. Together they used the Siphoni-Tec Siphonic Roof Drain Design Software to design the siphonic roof drain system for the office building.
Vils likens the siphonic roof drain to an S-trap on a toilet — water accumulates on the roof until it's above the inlet and, once it begins to flow, it's sucked out with the drain pipe being almost completely full. Vils estimates an approximate savings of 30% in both labor and material costs by using a siphonic roof drain system instead of a conventional roof drain system. The amount and the size of the piping decreased, which saved money in material and manpower.
The benefits of using a siphonic roof drainage system are as follows:
Smaller pipe diameters can be used, reducing material costs — 2-in., 3-in., and 4-in. vs. conventional 6-in., 8-in., and 10-in.
Labor costs are lower due to horizontal piping, requiring less manpower.
One main rain leader conductor is used instead of multiple rain leader conductors.
There is reduced sleeving and coring because only one main riser is needed as opposed to four.
Below-slab piping is minimized with one 10-in. connection point as opposed to four smaller connection points.
There is maximum use of space without intrusion of piping. Since the pipe doesn't need to be sloped, it helps avoid elevation conflicts with HVAC components and lighting.
“We expect this type of system to be utilized more and more in the future, and eventually, become an industry standard,” Vils said.