Heat-fused connections in a Visual Arts Building hallway.

University Selects PP-R Pipe for Retrofit of Chilled-Water System

July 15, 2013
Polypropylene-random Aquatherm Blue Pipe (known as Aquatherm Climatherm at the time) was chosen for a new four-pipe fan-coil system.

Built in 1975, the Visual Arts Building had been the hub of cultural and intellectual life at Colorado State University (CSU) in Fort Collins, Colo., for years. Within its industrial, art-strewn walls, however, was a dated mechanical system in need of updating.

The Visual Arts Building was largely uncooled. A 30-year-old R-11 chiller supplied four rooftop units. CSU sought to replace the chilled-water distribution system with a new four-pipe fan-coil system. The system would feed 83 Johnson Controls FN units that would condition approximately 90,000 sq ft of office, classroom, and studio space.

Heat-fused connections in a Visual Arts Building hallway.

Earlier in 2010, eight CSU maintenance-staff plumbers and assistants received on-site training before repiping the university’s roughly 3,600-sq-ft mission-critical data center with German-manufactured Aquatherm Blue Pipe (known as Aquatherm Climatherm at the time). For its underfloor piping system, the data center required an installation process that was flameless and fumeless and would not release particulates into the air. Aquatherm polypropylene-random (PP-R) pipe is connected via heat-fusion welding.

“You do have to be creative with the welding machines sometimes, like taking it off of the stand and things like that, which shows that there is some craft to working with fusion welding and especially with butt fusion,” CSU Remodels and Construction Services Plumbing Supervisor Chuck Fox said.

Butt fusion is the welding process used for Aquatherm pipe over 4 in. in diameter. As with smaller welds, it turns pipe and fitting into a single material, creating long-lasting, monolithic connections that eliminate leak paths. While there is a learning curve, Fox said the training is effective, and the process is quickly and easily mastered.

Based on the success of the data-center project, CSU decided to use Aquatherm PP-R pipe to connect the fan coils.


A dependable system that could be installed without an open flame was essential.

“Almost every square inch of the building wall and even ceiling space is covered with art of various media, from pencil drawings and paintings to sculptures and other three-dimensional presentations, all of it fragile and much of it flammable,” Gene Ellis, mechanical engineer for CSU Campus Facilities Management, said. “So we were happy to have avoided sparks, flames, and fumes, as that would have complicated the process.

“The product’s installation characteristics allowed us to install long runs of large pipe without welding or soldering in hallways, classrooms, or offices,” Ellis continued.

In February 2011, installation of nearly 3,500 ft of Aquatherm Blue Pipe in 6-in. to 1¼-in. sizes began. The six in-house installers used the training and experience from their first Aquatherm installation to save time and money.

“We probably cut our time by one-quarter on this job,” Fox said.

The installers noted the benefits of using the Aquatherm welding machine.

“With the fabrication machine, you can reduce the labor down to half of the time on the smaller stuff, and you can fabricate 20 to 30 ft and hang it and push it on,” Fox said.

The Aquatherm fabrication machine was developed for stationary welding of pipe and fittings with an external diameter of ½ in. to 4 in. and is equipped with a hand crank to facilitate precise pre-assembly of complicated parts.

As was the case with the data center, the team needed to keep the building operational throughout installation. That meant working from 10 p.m. until 6 a.m. Aquatherm Blue Pipe was used for all piping larger than 1 in., with 6-in. mains and 2-in. to 3-in. branches serving each wing.

Aquatherm brass FIP fittings were used to connect the piping to the fan-coil units.

“We used 1-in. copper off of the fan-coil units because it was quicker with transitions, control valves and strainers, etc.,” Fox said. “The Aquatherm flanges and gaskets are great. We have never had a problem with them.”

The installers had to X-ray many of the walls and core-drill the holes.

“We drilled the holes larger than the diameter of the pipe and inserted a sleeve and then put in QUIKRETE Hydraulic Water-Stop Cement, in addition to fire-caulking some spots to meet the fire code,” Fox explained.

Bubble Testing

When the system was completed, the installers performed bubble tests on all of the connections.

“We had zero leaks on the Aquatherm piping or fittings,” Fox said.


Ellis said CSU saved an estimated 20 percent on labor using PP-R as opposed to copper or steel.

“Also, we were able to work about 25-percent more quickly and efficiently with the Aquatherm product due to our experience with the data center,” Fox said. “I love the product. It does not leak, if you put it together right; it just will not leak.”

Added Ellis: “The system in the Visual Arts Building turned out great. We now have cooling to our entire building and a very grateful customer. This is a win-win for CSU for both cost and customer satisfaction.”

SIDEBAR: Aquatherm Goes Back to School

The data-center and Visual Arts Building installations went so well that CSU implemented Aquatherm pipe systems while renovating historic Washington Elementary School, which opened its doors as CSU’s Early Childhood Center in January 2013. By using PP-R as opposed to copper, CSU cut labor time by one-quarter or more and saved roughly $8,000 in material costs, according to Ellis.

The installation went smoothly, with no leaks or other issues.

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