Value Engineering with PEX-a Plumbing Systems

By Jayson Drake

We live in challenging economic times for the commercial construction industry, where good projects are tough to win and being profitable can be even tougher. In this competitive environment, landing attractive jobs requires a fresh look at your value engineering options.

One of the most effective solutions for managing project costs is the use of PEX-a pipe for your commercial, domestic-water plumbing systems. PEX-a, or crosslinked polyethylene, has been used in the construction industry for decades and has now displaced most of the copper and CPVC plumbing being installed in the residential market. The benefits provided by PEX-a in new residential construction produce even greater value in commercial domestic water applications.

Plumbing pipe options

Copper and CPVC are traditional products that have been used in the plumbing industry for years. But just as the inherent characteristics of those products allowed them to replace old-fashioned galvanized steel and cast iron, flexible PEX-a has significant advantages over copper and CPVC that are fast making it the preferred choice over these rigid pipe systems.

Produced in sizes 3/8-inch to 3 inches in straight “sticks” and coils up to 1,000 feet long, PEX-a plumbing pipe is conveniently available in white, red and blue colors. Using the “Engel” manufacturing method, which results in a very high degree of molecular crosslinking, provides PEX-a with exceptional durability and flexibility. That flexibility, combined with the availability of PEX-a in long coils, eliminates many of the fittings and connections required in rigid copper and CPVC plumbing systems. Eliminating fittings means less material, less installation labor and fewer potential leak points, all of which results in more efficient installs and lower costs.

PEX-a’s flexibility and durability also provide added protection against the damage and leaks caused by freezing and stress cracking. Since PEX-a naturally expands up to three times its original size without cracking or splitting, frozen water and impacts won’t create the expensive leaks that can occur in rigid copper and CPVC plumbing systems.

If you’re using copper for your plumbing jobs, you know how much your pipe costs continue to increase and how quickly those increases can fluctuate. Unlike copper, PEX-a pricing is relatively consistent and affordable. This means that you can quote and win a plumbing job with the confidence that your pipe price is going to remain stable. And you’ll no longer have to worry about jobsite theft of expensive copper.

Fittings

In addition to using fewer fittings than rigid pipe systems, PEX-a plumbing systems allow the use of efficient and affordable fittings made from durable engineered polymers. These “EP” fittings are molded into a wide variety of multiport configurations with varying numbers of inlets and outlets in assorted diameters. These “multiport tees” eliminate additional connections and the labor needed to make them, resulting in even more efficient installations and lower costs.

Connection methods

The natural ability of PEX-a to expand and contract permits the use of an “ASTM F1960 cold-expansion connection,” one of the simplest, strongest and most reliable connections in the industry. Making a PEX-a F1960 connection requires just four easy steps:

1. Cutting the pipe with a plastic tubing cutter.
2. Placing a PEX-a expansion ring on the end of the pipe.
3. Expanding the pipe and the ring with a Milwaukee® ProPEX® expansion tool.
4. Inserting the larger-diameter fitting.

The pipe and ring will then immediately and naturally begin contracting back to their original shape, compressing tightly against the primary and secondary fitting barbs with up to 7,800 pounds of radial force. It’s just that easy: no deburring, no torches, no flux, no solder, no cements and no curing or cooling time.

The resulting permanent connection holds tight in tests up to 1,000 pounds of pull force. In addition, since the pipe is expanded before the fitting is inserted, it’s impossible to dry-fit the connection, eliminating the possibility of incomplete fittings and the resulting blow-off leaks.

Case study: Coborn’s Grocery

Let’s see how these various advantages of PEX-a over rigid piping systems played out on an actual commercial project, the construction of a grocery store in Minnesota.

When Rice Building Systems of Sauk Rapids, Minn., set out to construct a new concept store for St. Cloud, Minn.-based Coborn’s Inc., the company had strict orders to capitalize on innovative materials and efficient design, while maintaining the 90-year-old Midwest grocery chain’s high standards for quality and customer service.

When plumbing bids went out, pricing for the copper systems that were typical for other Coborn’s stores came back way too high. So Rice sent out rebids, opening the doors to alternative plumbing materials, including PEX-a and CPVC.

“The owners wanted value engineering,” says Chris Rice, president of Rice Building Systems. “We knew any bid that came back had to incorporate suitable cost savings in addition to intelligent design and efficient installation methods to effectively meet our budget and tight construction schedule.”

Scott and Ben Kiffmeyer, owners of Kiffmeyer Plumbing Inc. in Sauk Rapids, 19-year veterans in the plumbing industry, had used PEX-a pipe in several previous installs. They offered a unique idea that would provide the value engineering that Coborn’s was seeking, while also conforming to the stringent construction schedule.

“Rice came back asking for ideas, and we went to them with the concept of running PEX-a underground,” said Scott Kiffmeyer. “That’s how we got the job.”

The underground PEX-a concept came from a presentation Kiffmeyer Plumbing received from Dean Corrigan of FourMation Sales and Casey Swanson, commercial sales representative from Uponor, a PEX-a manufacturer located in Apple Valley, Minn. Uponor also offers design and technical support for plumbing, fire sprinkler and radiant floor heating and cooling systems.

“They needed to get the plumbing system in quickly, so this was a great approach to speed up their construction schedule,” says Swanson. “It was also much more cost-effective than doing copper overhead.”

The plumbing system, which used ½ inch through two-inch Uponor AquaPEX® pipe for the 36,330-square-foot store, ran the PEX-a pipe underground instead of overhead, like a typical copper plumbing system application. The underground PEX-a system also incorporated Uponor’s EP fittings, which are approved for direct burial in soil.

The underground installation started in mid-August; the store opened just 14 weeks later, in mid-November. Both Rice and Kiffmeyer estimate installing PEX-a underground saved at least a week, compared with installing an overhead copper pipe system. “PEX-a provided great time and labor savings,” says Scott. “That, in turn, offered great cost savings for the owner.”

A subsequent in-depth analysis of the installed cost of the plumbing system revealed dramatic savings. When compared to the copper systems installed in previous Coborn’s projects, the Uponor PEX-a system reduced labor costs by 37 percent and material costs — including pipe, fittings, insulation and various accessories — by 54 percent, for a combined savings of 46 percent. See chart on page 60.

As the Coburn’s case study clearly demonstrates, by delivering significant material savings, faster installs and reduced liability, PEX-a is changing how commercial jobs are being plumbed. With its established and quantifiable benefits over copper and CPVC, PEX-a is rapidly becoming the preferred value engineering solution in commercial construction.

Jayson Drake is the senior product manager of plumbing and fire safety at Uponor, a manufacturer of PEX-a tubing and a supplier of radiant heating and cooling, plumbing and fire sprinkler systems. He can be reached at jayson.drake@uponor.com.