The power of PEX

BY MIKE CHILES,

contributing writer

Throughout history pipes have been made of many different materials. We should expect to see continuing innovation in the plumbing and heating industry as new materials, such as PEX, gain market acceptance.

The earliest pipes in recorded history were made of cross-linked polymers. Today, many of the most advanced pipes, such as PEX, are also made of cross-linked polymers. History’s early pipes were made of cross-linked cellulose and lignin, molecules made of carbon and hydrogen, as are PEX and pe pipes today. These first pipes, also known as hollow logs, conveyed water, and until the twentieth century, low pressure gas. 

Beginning some 20 centuries ago, sheets of lead were pounded over round forms and seam soldered to form pipes. The use of lead was so common that plumbers received their name the Latin word plumbum; meaning lead. Later in the 18th century pipes began to be made of cast iron, then steel; and in the early twentieth century, copper.

Today we see a growing variety of pipes in the plumbing and heating marketplace. Around the world monowall pipes are now being made of cross-linked polyethylene (PEX), high density polyethylene (hdpe), raised temperature resistant polyethylene (pe-rt), polypropylene, polybutylene (pb), pvc and cpvc and other more exotic polymers.

Composite pipes are made of multiple layers of materials, bonded together for strength and chemical resistance. They’re made of various combinations of PEX, epdm, pe and polypropylene, with reinforcing centers of aluminum, aramid fiber, stainless steel and even copper.

Why has the market rapidly shifted toward these newer forms of pipe? And, what does the future hold for plumbing and heating professionals?

As contractors begin to re-examine their piping options, everyone wants to select materials that will be safe, serviceable and a credit to the industry.

And somewhat surprisingly, the pipes of the future will be from the same materials as our original log pipes. These basic materials used in PEX, epdm, pe and pb are carbon and hydrogen-derived from natural gas. Unlike photosynthetic cross-linking, manmade cross-linking takes common materials and binds the molecules together to make tough, flexible and long lasting PEX pipes.

Many processes are used to activate cross-linking of these molecules, but all PEX cross-linking processes depend upon the use of various chemicals combined with heat, pressure or electron beams. Regardless of the method used, cross-linking effectively unites the molecules to achieve a tougher, more damage-resistant product.

To maintain these benefits, however, the cross-linked molecules must still be protected against chemical attack from sunshine, oxygen, heat and especially chlorine. To achieve this protection, each manufacturer adds protective chemicals.

PEX pipes offer an attractive combination of benefits to contractors and end users.

Lower labor and material costs lead the list of benefits, but there are other important reasons to switch to PEX pipe, such as longevity and resistance to corrosion.

As our nation’s water quality continues to deteriorate, and as many areas add more aggressive water treatment products to the drinking water, metal, and especially copper pipes, are increasingly more susceptible to chemical attack. Chemical issues include a steady drop in many system’s pH (acidity), increased seepage of road salt into aquifers, the use of chloramines to replace free chlorine and the generally higher rate of chlorine usage to compensate for the possibility of terrorist attacks. Many parts of Florida, Arizona, California and other states with water quality issues have seen large scale replacement of copper pipes with PEX and other plastic pipes.

In Germany, PEX pipes have surpassed copper piping in recent years, and this trend continues across Europe.

In North America, copper retains a market edge, but is quickly losing ground to PEX, especially in residential construction. Copper still dominates over PEX, especially in larger diameters used for commercial construction.

Two factors have limited PEX pipes growth into the commercial marketplace, and these two factors will have to be addressed for PEX to gain widespread commercial acceptance.

The first limiting factor is chlorine resistance. Unlike most residential construction, commercial projects will almost always have many lines running domestic hot water on a 24/7 basis. All PEX pipes listed for plumbing in the United States today are rated to the astm 2023 standard, but many believe this standard does not provide sufficient basis for assuming a minimum 40 year life where the pipe is used in continuous domestic hot water recirculation.

For continuous duty at 140F, where the water may be acidic, and/or heavily chlorinated, NSF and UL have developed competing standards for PEX. Confusingly, both of these performance standards are known as Cl-R, meaning that they are rated for continuous duty in domestic hot water service with a life expectancy in excess of 50 years. By contrast, Cl-Td means that a pipe is rated for only a 25% duty cycle of exposure to domestic hot water, appropriate for most residential duty.

The second limiting factor is market acceptance of the necessary fittings and hardware. Many large diameter fitting systems are being introduced, but some time will be required before they are generally accepted by professional specifiers.

For 1-1/4" and smaller sizes, there is a wide variety of fittings and accessories for all applications, both new construction and remodeling. Transitional fittings are available for plumbing PEX to copper, iron, pe, pb and all other types of piping. The use of manifolded “home run” systems is growing in popularity, especially with homeowners who enjoy the convenience of being able to shut off individual fixtures for easy service. Home run systems also enable the use of smaller lines, which means that individual fixtures enjoy faster hot water delivery.

The National Association of Home Builders (NAHB) and other professional associations have accepted the use of PEX in homes, and have published booklets outlining the cost savings of PEX versus copper. Depending on the size of the home, savings can run from hundreds to thousands of dollars. Most importantly, PEX pipe offers price stability to contractors, especially compared to copper.

A very helpful publication, design guide, Residential PEX Water Supply Plumbing Systems, is available from NAHB at http://www.toolbase.org/Design-Construction-Guides/Plumbing/PEX-design-guide.

Mike Chiles is president of Watts Radiant.

PEX tubing is here. Are you ready for it?

By CHIP O’NEIL,

contributing Writer

Industry trends can be an uncontrollable influence to your business. But, if you build on your current success and incorporate these often positive influences within your company, you will be positioned for continued success. One such positive trend is the rapid conversion from copper tubing to cross-linked polyethylene (PEX) tubing systems.

There are several reasons for this transition to PEX tubing. First of all, last year saw a significant fluctuation in material costs associated with copper tubing. To be more competitive, plumbing contractors and/or builders were looking to reduce their overall costs and PEX tubing offered that solution. Secondly, contractors found certain homeowner benefits that went with installing PEX for single-family homes and low-density, multi-family housing. PEX offers an increase in water efficiency, as well as provides a quieter system. Another reason for the transition to PEX is the installation benefits. Depending on the pipe support system a contractor uses, the minimizing or even the elimination of flames, chemicals, and soldering will help reduce the overall installation costs for a project.

For the last several years, PEX has mainly been used in single-family homes and low-rise, multi-family construction. But, as PEX continues to grow and spread in usage throughout the country, contractors and builders are seeing the value in using it in projects such as high-rise condos and hotels. With this growth across the country, I am hearing a lot of contractors asking the same question, “How do I support PEX?” My response to them is always the same. You can’t support PEX the same way you have always supported copper or cpvc tubing. Here are some tips on how to support PEX for some of your applications that will ultimately reduce your installed costs.

If you currently use a block of wood or a “makeshift method” to support your copper or other tubing, you will need to rethink how you support PEX. Because of the benefits of minimizing concealed joints and reducing in-wall fittings associated with PEX, solutions must be used that provide rigidity and maintain the integrity of the tubing. For example, multiple blocks of wood would be needed for all of your mid-span support requirements in order to keep the tubing from coming into contact with various noise-transferring building components, such as sheet rock. Also, you must ensure the correct “bend radius” of the tubing at fixture stub out locations without damaging the tube or compromising the water flow. Look toward solutions that might cost more than finding a scrap of wood, but reduces your actual installed costs for the project.

Contractors who are using more of an “engineered solution” with brackets to support tubing will find it easy to transition to PEX. Although a common way to stub out for fixtures is still with copper bullet, I’m also seeing an increase in the number of stub outs done in PEX. Like brackets made for copper tubing, specific brackets are made especially for PEX that exactly position the tubing at the desired stub out location. For many contractors and builders, stubbing out in PEX is now a shop standard. Ironically, several of these contractors said they would never stub out with anything but copper. They were also the same group that said they would never use PEX tubing to begin with.

Another support application for PEX tubing is the installation within an elevated concrete slab. You can reduce your overall installation cost by using products that provide 90-degree “pop-up” solutions instead of the makeshift method of using electrical conduit 90s, strap rebar, high wire and zip ties. One example of this improved method is the Juhl Condo project in Las Vegas. Interstate Plumbing and Air Conditioning installed this type of product that sent PEX tubing through the slab. Sam Riccihiazzi, who oversees the commercial construction, and Mike Calix, foreman, mentioned that the system they use provides flexibility for securing not only single-run tubing, but also interlocking the pop-up chairs to create a manifold installation. The end result is a professional installation while reducing his overall installation costs.

As PEX becomes more of a standard in high-rise condos and hotels, plumbing contractors and builders will need to re-evaluate, and even re-establish, what their shop standard should be when supporting PEX tubing. PEX is here. Are you ready to support it?

Chip O’Neil is director of business development for Hubbard Enterprises/HOLDRITE, located in Vista, Calif. He can be reached at 800/321-0316 or coneil@holdrite.com. Hubbard Enterprises/HOLDRITE is a leading U.S. manufacturer of pipe support systems, seismic water heater supports and acoustical plumbing products. For more information, visit them at www.holdrite.com.

PEX piping will save you time, money

BY ASA FOSS,

contributing writer

Faster and easier installation. Lower material costs. Higher water quality. Fewer callbacks. More satisfied clients. These benefits have persuaded many plumbers and builders to switch to PEX for water distribution piping.

Cross-linked polyethylene piping (PEX) is a flexible plastic (polymer) pipe, not to be confused with earlier plastic piping products made from polybutylene that often failed under normal use. PEX has 30 years of proven success in the United States and Europe -- a major consideration for Jimmie Cunningham, president of Cunningham Plumbing in Tulsa, Oklahoma. Cunningham has been in the plumbing business for over 35 years; three years ago, he made the switch to PEX.

Why did you start working with PEX?

JC: As copper prices started inching up, we switched to PEX to save on material costs. We started mostly with large diameter pipes in our commercial jobs, and PEX gradually made its way over to our residential projects. Now we use PEX exclusively.

I gave PEX a shot because it has been proven in the field. Rehau has been producing PEX for over 30 years. If this was something brand new, I would be skeptical about changing, no matter what the cost and time savings, because of the bad experiences a lot of plumbers had with polybutylene. But since PEX does have a long track record, we went for it. And we’ve been pleased.

Have you seen other advantages?

JC: Even if PEX cost the same as copper, we’d still use PEX because we don’t see the buildup we’ve seen in metallic systems. If you were to change out a water heater, sometimes there is so much calcium buildup on the inside of the copper or galvanized pipe that you can’t fit a #2 pencil through. With PEX, there is no buildup. If you take a sample of galvanized copper and PEX after they’ve been in use for a while, and you put each sample in a glass of water and ask your customer which one they would rather drink out of, they would choose PEX every time.

We also get fewer callbacks because even after putting in the required protection plates, we’ve had carpenters pierce the plate and get into the copper. A nail will stay in a copper line for up to two years before it rusts out. When it inevitably leaks, it’ll be a big deal because it’s behind a finished wall. When PEX gets hit with a nail, it will leak immediately, so you can fix it at the sheet rock stage. The homeowners haven’t moved in, and the paint isn’t even on the wall. So it’s no big hassle when PEX gets pierced, and there are no repercussions two years later.

Callbacks also are reduced because you don’t get any clogs from loosened flux and solder. We’ve gotten calls when the flux and solder has stopped up the showerheads after the homeowners have been in the home for a year because they never used the guestroom shower, for example. Fixing problems like these is a waste of our time. We don’t have to deal with them anymore now that we’re using PEX.

What about leaks? Are there advantages here contractors should consider?

JC: There are no sweat leaks with PEX. Although most of the old timers have the experience to avoid sweat leaks on copper piping, lots of the new guys may not have their torch set right, they may not have the right tip on the torch, they may be using old solder or old flux or sand too much. The point is that there are a lot of things that can go wrong with copper piping, so you inevitably get sweat leaks once in a while.

What’s your experience with installation speed?

JC: On remodels, using PEX is very fast, especially in crawlspace jobs. PEX is faster because it comes in coils, not in sticks. When you’re stringing out a copper pipe, you have to make a joint every 20 feet. With PEX, you can do a full 60-foot run at once. You can drill a hole in the bottom of the cabinet and go to the hot water tank -- or whatever the source -- in one run. You can also do the job with fewer people because you don’t need someone there feeding you 20-foot pipes, which can be really difficult to maneuver in tight spaces.

How do builders respond to PEX?

JC: The custom homebuilders in my area wanted only copper until about a year ago. Now, the high-end custom builders exclusively request PEX, and the other custom builders are slowly coming around. Some of this demand is driven by homeowners who request PEX for the improved water quality and speed of delivery. Because the tract builders have always been into cost savings, they’ve already latched onto PEX.

Tell me about using PEX in your commercial work.

JC: On the commercial end, we’ve started doing value engineering with our customers, installing PEX in the slab, rather than overhead. By installing PEX in the slab, you’re able to cut costs for all thread, clevis hangers, beam clamps and pipe insulation, so you don’t need an insulation sub like you do when pipes are in the attic. We are able to offer all those savings to the owner, and pocket the difference between the copper and PEX costs.

We can do this because these are bid-type jobs, so every contractor has to bid according to the engineered specs. If they call for copper, we have to bid copper. But in the past six months, we were able to bring our value engineering idea to the owner three times, and all three times the owners took it over copper. Our clients were really happy with us. They were able to save $3,000 to $8,000, and we were also able to make some extra money on top of just winning the bid.                  

For more information on PEX water distribution piping and to find a list of manufacturers, visit www.pathnet.org. Click on Tools, then Tech Inventory to find a detailed discussion of the technology, installation videos, a list of manufacturers, field evaluations and a comprehensive design and installation guide.

Asa Foss writes about better building practices on behalf of the Partnership for Advancing Technology in Housing (www.pathnet.org). Path is administered by the U.S. Department of Housing and Urban Development.