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Dorm’s PEX piping system saves water while delivering it quickly

Feb. 1, 2012
The University heard the call loud and clear and decided to do a $13 million renovation of the dormitory, including a complete interior demolition of the plumbing, HVAC and electrical systems.
LAWRENCE, KAN. — Last year,, an online resource that ranks everything for college students by college students — from parking, transportation and housing to campus life, academics and athletics — gave a very astute observation of the University of Kansas’ Gertrude Sellards Pearson (GSP) Hall: “Great location, but needs renovation.”

The University heard the call loud and clear and decided to do a $13 million renovation of the dormitory, including a complete interior demolition of the plumbing, HVAC and electrical systems.

Built in 1955, the four-story, 109,000-sq.ft. building was initially plumbed with galvanized steel and then re-piped with copper approximately 15 years ago. Before the renovation, the dormitory used steam boilers and an air cooled chiller to generate hot and cold water.

Piping system

When initial bids went out for the new renovation, the plumbing bids came in rather high, so Saladino Mechanical of Kansas City, Mo., decided to rebid the project using PEX. Carl Bachner, foreman at Saladino Mechanical, has been plumbing with PEX since 2003.

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“I was first introduced to PEX back in 2003 when I was installing the plumbing system for an assisted living complex,” said Bachner. “After that, I installed it in my own home.”

Mark Baker, sales representative of Specified Systems Inc., worked with Saladino Mechanical and sent the project through Mike Rivers, associate product manager of plumbing and former design services manager at Uponor. The bid came back on target.

When completed, the dormitory re-piping will use nearly 12,000 feet of ½-in., ¾-in., 1-in., 1¼-in., 1½-in. and 2-in. Uponor AquaPEX for the plumbing system. The piping portion of the project began in the fall of 2011 and is scheduled to be completed this winter.

The system includes piping for 42 bathrooms, a laundry facility and a large kitchen to accommodate the more than 300 students that will be residing in the renovated dormitory. Multi-port tees and elbows will be installed in the bathrooms to supply water to the lavatories and showers.

According to Rivers, the multi-ports make it faster to distribute water to fixtures in a single grouping and also provide advantages for clustered or consecutive uses of hot water, saving on energy and water usage.

“Once hot water arrives at a multi-port, it is readily available to all fixtures connected to that tee or elbow,” said Rivers. “Essentially, that multi-port’s fixture grouping is ‘charged’ with hot water.”

For the flush-valve water closets, PEX along with prefabricated stubouts are being used.

“It is distributed throughout the building and there are valves provided to shut down each restroom bank,” explained Matthew J. Pellman, P.E., senior engineer at Smith and Boucher, the project’s consulting engineer. “The Uponor piping is routed most of the way to each toilet at 1 ¼, but it transitions back to copper pipe behind the wall, before making the connection to the flush valve.”

Besides the piping, Saladino Mechanical is also installing Delta shower valves, Kohler flush valve toilets, under-mount cast iron sinks for the lavatories and standard stainless steel kitchen sinks.

Gas fired water heaters by Aerco will also be installed, and according to Pellman, Aerco is a preference of the University’s housing maintenance department.

The piping system also includes Uponor’s ProPEX engineered polymer (EP) and lead-free brass fittings. The ProPEX connection uses an expansion tool, made by Milwaukee Electric Tool for Uponor, to expand the flexible PEX tubing to insert a fitting. Then, as the PEX shrinks back to its original size, it creates the connection around the fitting.

Hot- and cold-water supply and hot-water return lines in first-floor ceiling of GSP Hall.

“The ProPEX fitting is nice because it doesn't restrict the flow like insert fittings do,” said Bachner.“It keeps the same OD like copper does.”

“The expansion tool is easy to use, it’s compact and easy to get into tight areas with,” said Dan Pederson, one of Saladino Mechanical’s plumbers, installing the piping.

Several runs of pre-insulated AquaPEX tubing are also being used on the project to insulate hot-water lines. Since pre-insulated AquaPEX uses a closed-cell PEX-foam insulation, which can’t be used in a plenum, the plumbing lines in the plenum areas had to be insulated with ½-in. fiberglass insulation.

“When installing PEX in a plenum application, you need to cover it with ½-in. fiberglass insulation if the tubing is installed within 18-in. of the next run of pipe,” Rivers said. “So, the ¾-in. pipe run above the kitchen had to have ½-in. fiberglass insulation installed since the piping was less than 18-in. apart.”


Smith and Boucher also oversaw the design of the HVAC system, which is a water source heat pump system. McElroy’s, Topeka, Kan., is installing the system, consisting of a heat pump in each dorm room; several DOAS rooftop mounted heat pumps to provide fresh air to the dorm room wings and to heat and cool the dining and main lobby areas; and 100% outside air heat pumps to serve the kitchen and server areas. Boilers will be installed on the main loop to provide heat when needed, and a cooling tower will be connected to the main loop by a plate and frame heat exchanger to cool the dormitory when needed.

Available space has been the main challenge for this project, according to Pellman.

“This building was built in 1955 and there is very little space for mechanical systems,” said Pellman. “Through heavy coordination and the strategic use of soffits we have been able to install the systems with a finished look.”

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