Recycling at issue in ASTM debate over corrugated pipe standard.

The U.S. Environmental Protection Agency is expected to implement by mid-April a Clinton Administration executive order to encourage recycling through federal spending. EPA plans to propose procurement guidelines for federal programs like interstate highway construction that would recommend purchases of sewer and drain pipe containing post-consumer and post-industrial HDPE and PVC. This action would come while a committee of the American Society for Testing and Materials (ASTM) in Philadelphia remains in a seven-year deadlock over a new standard for non-pressure-rated storm-sewer pipe. A key issue dividing the committee members has been specifications on HDPE materials--recycled or virgin--approved for use in such corrugated pipe.

The EPA's move is similar to actions by some states such as Florida, which already requires post-consumer recycle (PCR) content in corrugated pipe for state highway construction. That requirement runs contrary to existing standards of AASHTO (American Association of State Highway and Transportation Officials), which requires only virgin resin to be used.

ASTM's subcommittee F17.62, whose roughly 90 members must reach a nearly unanimous vote to adopt a new standard, has had 10 unsuccessful ballots on drafts of the proposed standard, the most recent in January. The proposed "Standard Specification for Corrugated Polyethylene Drain Pipe with a Smooth Interior Wall and Fittings" covers 4-in. to 48-in.-diam. storm sewers (not building drains) under highways and roads.

ASTM standards are meant to be determined only by objective technical judgments. But some of those involved blame conflicting business interests among subcommittee members for dragging out the process. "The primary issue is that 200 to 250 makers of concrete and steel pipe don't want HDPE to have a standard," says Mark Stuhlreyer, marketing v.p. of Advanced Drainage Systems Inc. in Columbus, Ohio, the biggest maker of corrugated pipe.

One participant notes that so far, the concrete and steel faction has sat on the sidelines and not interfered. So far, says this authoritative source (who spoke off the record), the debate has been mainly between the different plastics factions:

* PVC pipe makers allegedly want to hold onto their strong edge over HDPE.

* Resin companies making high-pressure HDPE pipe grades allegedly want to see those higher-priced materials required (a point that resin companies strenuously deny).

* Independent corrugated-pipe makers, who already use blends of wide-spec and PCR material in agricultural and highway drainage pipe, would like to hold onto the price advantage of using these cheaper raw materials.

The corrugated-pipe standard is significant to more than just resin and pipe makers: On it hangs the future of what could be the biggest single market for recycled HDPE detergent bottles. It's estimated that corrugated pipe makers already use some 400 million lb/yr of HDPE, including over 100 million lb of copolymer PCR, in highway and agricultural drainage pipe (which already has an ASTM standard). Potential PCR consumption in storm-sewer pipe is even greater, if the new standard isn't written to keep it out.

An estimated 90% of the linear feet of sewer and drain pipe installed annually is concrete. Of plastics' share, PVC is dominant. "We want HDPE to get a bigger share, and to be cost-competitive we must be able to use recycle," says Peter Toohy, manager of plastic sales at Chevron Chemical Co., Houston.

Many large, independent corrugated-pipe makers already use PCR in some non-pressure-rated, single- and double-wailed drainage pipe, often at the request of government agencies seeking to support local recycling initiatives. Such pipe makers number some 60 plants nationwide and include Advanced Drainage Systems, Hancor Inc. in Findlay, Ohio; Big-O Inc., Exeter, Ont.; Crumpler Plastic Pipe Inc., Roseboro, N.C.; Prinsco Inc., Prinsburg, Minn.; and Springfield Plastics Inc., Auburn, Ill.

MATERIALS AND TESTING

The main unresolved issue in the ASTM subcommittee is "establishing consensus on technically appropriate material requirements," as one of the participants puts it. On the one hand, corrugated-pipe makers want to tie material selection to field performance requirements of pipe. Espousing a differing view are leading members of the SPI's Plastics Pipe Institute in Wayne, N.J., which includes no corrugated-pipe makers, but does include resin companies that also make pipe--namely, Chevron and Phillips Chemical Co., Bartlesville, Okla. PPI members want material selection to be tied to performance requirements too, but they raise questions on how to establish conformance to those requirements through testing.

A new short-term (less than 24-hr) performance test has been proposed as part of the new standard. PPI argues that just because a freshly made pipe specimen--with a surface free of defects--passes a short-term performance test, that same pipe, after scratching and nicking through handling and installation, won't necessarily resist cracking over its intended 50-yr service life under the anticipated earth and other loadings. "In other words, for a short-term test to be accepted as a performance test, there must first be established a reliable correspondence between the test results and actual long-term performance. My point is that this has not yet been done, and until this occurs it will be difficult to defend the |proposed~ product test as a 'performance' test," says Stanley A. Mruk, executive director of PPI and a voting member of the ASTM subcommittee.

The pipe resin itself must have good ESCR to resist slow crack growth, PPI says. PPI notes that if a PCR resin offers inadequate ESCR, it may be upgraded by blending with resin of higher stress-crack resistance to yield an acceptable material. "By such blending, more opportunities for recycling PCR would become available," Mruk notes. He adds that PPI does not propose that PCR be blended with expensive pressure-rated resins such as are used in gas pipe. "You don't need an internal pressure-resistance rating, but you do need crack resistance," explains Paul Petro, president of Chevron's Plexco pipe division in Bensenville, Ill., also a subcommittee member.

Some corrugated-pipe users and makers say higher ESCR is nonsense. "In a gas pipe, one little crack can be catastrophic, but in a storm drain a little localized crack usually isn't a problem," says John Hurd, assistant hydraulic engineer with the Ohio Dept. of Transportation. "The joints in storm sewers don't even have to be water-tight. They only have to be soil-tight. So why would you want to pay for more properties than you need?"

"I fully agree with John Hurd," replies PPI's Mruk. "A little localized crack usually isn't a problem. It is for this reason that most of us agree that PE drain pipe need not be made of the same highly crack-resistant materials as are used for gas pipe. However, to ensure that the crack, if it develops, stays localized (continuing crack growth could result in structural failure of the pipe), most of us also agree that the materials used for drain piping must have a minimum measure of long-term crack resistance. How much crack resistance, and how to define it, are the crux of the issue regarding the new ASTM standard."

Bill Altermatt, Hancor marketing director, replies that the ESCR level required by AASHTO for 2-6 in. drains (AASHTO M294) has been successful for many years. "To apply gas-industry constraints to these products does a disservice to the taxpayer." Mruk says gas-pipe resin is not at issue here. "Neither PPI nor any resin interest known to me has ever pushed for the use of stress-rated materials for non-pressure drain pipe. |That~ would indeed be a waste of money, as well as a misuse of stress-rated resins." There are other high-ESCR materials that could meet drain-pipe requirements, he says.

"There should have been more discussion," adds Mruk, "but that wasn't possible once the sides crystallized into their positions. Maybe one side (PPI and member resin companies) is being too conservative and the other (corrugated pipe makers) isn't being conservative enough." Hancor's Altermatt counters, "Being conservative isn't the issue at all. We're confident our current offering is conservative."

HOW MUCH PROOF?

As the ASTM standard process dragged on, eventually the Environmental Protection Agency got into the act. The EPA's regional Chicago office and the Ohio Departments of Transportation and Natural Resources funded independent testing at the University of Toledo, Ohio, Polymer Institute of corrugated pipe containing up to 75% PCR. A report issued last year said these pipe samples passed the test proposed in the new standard (a modification of ASTM D1693), as did pipe made of virgin resin (see PT Sept. '93, p. 25). "The EPA-funded study validates the potential for PCR use in this market," says Hancor's Altermatt.

PPI's Mruk agrees with Altermatt "in principle" but doesn't feel the Toledo tests answered all questions. The proposed new ASTM drain-pipe standard requires ESCR tests for the material in both flat-plaque form and as finished pipe. The Toledo PCR blends failed the material test (unmodified ASTM D1693) but passed the product test. Mruk feels that passing both tests is important.

Mruk adds that PPI, with funding from the American Plastics Council, is trying to devise a test for determining resistance to slow crack growth "that all parties can agree on." PPI is investigating a so-called "Notched Constant Tensile Load Test" developed at Drexel University in Philadelphia and approved by EPA for predicting performance of geomembranes. This relatively new, 100-hr test was developed, Mruk says, because ASTM D1693 did not prove precise enough in qualifying geomembrane materials.