Polyethylene Pipe Heads for Heyday

Almost one-third of treated water in Canada is lost before it reaches the consumer, and the main culprit is leaky pipes, according to the National Research Council of Canada (NRC).

But while this continent-wide problem may be bad news for the consumer, it’s good news for plastics.

LEAKS AND GEEKS

Adoption of biomodal polyethylene (PE) pipe, like PE100, is increasing in North America, Carl Baker, technical service and development, pipe at the Dow Chemical Co., in Houston, Tex. said.

That’s because PE100 pipes are less likely to leak than their concrete, metal and unimodal PE counterparts. In particular, PE100 pipes are increasingly used to transport treated water in areas on the West Coast of the U.S. where water is scarce, he noted.

Bimodal PE pipe has also been given a boost by a new ASTM standard for the material, Heather Lau, North American market manager for pipe, fittings and geomembranes at the Dow added. “Traditional materials still dominate the market, [but] the use of plastics is growing to avoid cracking and crumbling.”

PE pipes, however, are nothing new. The technology — primarily high-density PE (HDPE) — is already accepted in some industries.

“If you look at any industry that can’t afford to have leaks, such as natural gas, they exclusively use PE pipes, except for high-pressure situations where steel is used,” Baker said.

“What we’re seeing now is PE100 are replacing unimodal PE grades, as well as traditional materials, because of the materials’ slow crack growth rate, improved resistance to rapid crack propagation (RCP) and increased strength,” Lau added.

Oil and gas in particular would benefit from PE100 pipe, Baker said, although so far adoption has been slow in North America.

Last year, Mississauga, Ont.-based KWH Pipe Canada Ltd. signed a three-year contract to provide U.S. utility, Public Service Electric and Gas Co. in Newark, N.J. with gas pipes varying from two to 12 inches (in.). This was the first utility in North America to switch to bimodal PE pipes, Paul Van Warmerdam, president of KWH Canada, noted at the time. The pipes are in production at KWH Canada’s facility in Huntsville, Ont.

The use of high-density polyethylene (HDPE) pipe in the oil and gas markets is on ther rise, however, and not just with bimodel but also with unimodal, as a replacement for both concrete and PVC, according to Andreas Trk, product manager, pipe at Krauss-Maffei Corp. in Florence, Ky.

Krauss-Maffei was involved in developing a reinforced PE pipe for China’s oil wells, Trk said, and now the same type of plastic PE pipe with fibre reinforcement is being made in Canada. “This is a special solution for the oil and gas industry,” he noted.

VINYL ADVANTAGE

Despite the increased usage of PE pipe, polyvinyl chloride (PVC) remains the dominant plastic pipe material, accounting for over two-thirds of plastic pipe demand by weight, according to a 2003 report from the Freedonia Group Group, in Cleveland, Ohio. The report provided forecasts through the end of 2007.

“PVC is popular because of its low-cost, durability, strength and ease of extrusion allowing it to make inroads against non-plastic pipe materials,” the report said. “Demand for HDPE pipe will benefit from use as small-diameter pipe in natural gas transmission, as a conduit for electrical and telecommunications applications and as corrugated pipes for drains and sewers.”

But PVC experienced and unexpected boost in the pipe market in late 2005 and early 2006 after storms devastated the U.S. Gulf Coast, Trk noted. “Most companies did a good business with PVC (polyvinyl chloride) pipe because of the hurricanes (Katrina and Rita), so it’s a stable to a slow-growing business,” he said.

The report also forecasted that worldwide demand for plastic pipe will increase by more than four per cent through 2007, outpacing gains for overall pipe demand.

WIDER MARKETS

But regardless of PVC’s continuing dominance, industry insiders say that PE is moving on to larger markets — particularly, large-diameter markets.

“The HDPE pipe market has been resurrected and growing at a rapid pace,” Wendell Whipple, business manager, profile, at Pawcatuck, Conn. based Davis-Standard LLC, said. “[Although] medical tubing is the strongest market that we have been involved in.”

And industry acceptance of large diameter HDPE is growing in North America, P.J. Buriak, sales manager for the PE Pipe Division at AMC in McPherson, Kan., said. This adoption has been fuelled in part by new resin grades formulated specifically for the market as well as the success of large diameter HDPE pipe extrusion lines in Europe, he noted. Growth is occurring primarily in mining and drain-water where large-diameter HDPE is replacing concrete, ductile iron and corrugated metal, he added.

Last year, for example, McPherson, Kan.-based American Maplan Corp. (AMC) installed its first 63-in. HDPE pipe line in the U.S. and sold several more this year. The company also has a 78-in. HDPE pipe extrusion system in development, following in the footsteps of its sister firm, Battenfeld Extrusionstechnik GmbH (BEX) in Bad Oyenhausen, Germany, which has already delivered a 78-in. diameter HDPE pipe line extrusion system to a customer in Europe.

PE-RT TAKES THE HEAT

PE pipe isn’t just for applications in infrastructure. It’s also snaking its way between the floors of new homes, commercial buildings and industrial sites in cold parts of the continent.

Radiant heating has only recently taken off in North America but has been popular in Europe for some time, according to Warwick, R.I. based Guill Tool & Engineering Co.’s Bill Conley. In the past year, the North American radiant floor heating markets grew between eight and 12 per cent, Dow’s Heather Lau noted.

Once considered a luxury, the proliferation of radiant floor heating is fueling a demand for crosslinked PE (PEX) pipes used in this application.

To tackle this growing market, Dow recently released Dowlex 2324 to the North American market. The grade is designed specifically for pipes for radiant heating as a replacement for PEX; it is the only non-crosslinked PE of raised temperature resistance (PE-RT) on the North American market that has a hydrostatic design rating at 18- degrees Fahrenheit, she said.

“You can subject this material to higher temperatures, and because it is not crosslinked, it is flexible enough for this application,” Lau said.

Two types of pipe for radiant floor heating applications are currently produced — the more common three-layer and five-layer.

Three-layer PEX pipe consists of an EVOH — an oxygen barrier to protect corrosion of metal components — inner layer, an adhesive centre and a PEX outer layer.

A five-layer pipe would be constructed with PEX on the inside, a layer of adhesive, an EVOH, another adhesive and another layer of PEX on the exterior.

Guill Tool’s Conley said the majority of its customers manufacturing PEX tubing are producing three-layer tubes, but it does have a couple of customers involved in five-layer.

And the market is far from saturated. Companies participating in the PEX pipe market are performing very well and there is still room for more players, he added.

FOR PROFILE EXTRUDERS, wood-plastics composites (WPCs) decking and fencing, as a wood replacement, are definitely hot applications at the moment.

The wood-plastics composite (WPC) deck market seems finally to be reaching maturity, Wendell Whipple, business manager, profile at Davis-Standard LLC in Pawcatuck, Conn., said. “The vinyl fence market is experiencing particularly solid growth,” he added.

Andreas Trk, product manager, pipe, at Krauss-Maffei Corp., in Florence, Ky., agreed, and noted the U.S. trend to replace gutter fences — the fences used to pen in horses in farms — with PVC fences as an example. “Normally they have to be replaced ever three to four y
ears and PVC is very stable in contrast,” said.

Trk also noted that the use of foam brings materials costs down without affecting performance because screws and nails behave the same way in foam as they do in pressure treated wood.

New technologies are helping bring down the costs of WPC decks and fences. For example, foam made from wood- or organic-reinforced polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP) is the hottest trend in the manufacture of WPC decking and fencing profiles, Trk said.

John Effmann, director of sales and marketing and Entek Manufacturing Inc. in Lebanon, Ore., expects to see more elaborate WPC profiles in housing applications, and also predicts North America will start to see a trend towards hollow WPC profiles, a strategy already being employed in Europe where wood has been scarce. And although many WPC startups died as quickly as they were born, the sector is still in growth mode and will see more startups before widespread consolidation, Effmann said.

Polyvinyl chloride is losing marketshare in the siding market, stable in the window market and growing in the fencing market as a wood replacement.

The vinyl fence market is experiencing solid growth, Whipple agreed.

In the U.S., there is a trend to replace gutter fences — the fences used to pen in horses in farms — with PVC fences. “Normally they have to be replaced ever three to four years and PVC is very stable in contrast,” Trk noted, making it an area ripe with opportunity for profile extruders.