Does anyone remember controversy in the 2006 Major League Baseball World Series regarding pitcher Kenny Rogers?
The center of the controversy stemmed around whether or not Rogers put pine resin on the ball because it not only would be a league violation, but because it potentially had long-term implications in the outcome of the Series. Although not in the same spotlight as the World Series, resin has been the focal point of many heated debates between CQA and installer throughout my career—specifically the resin used to manufacture geomembrane and extrusion welding rod.
What do the specifications mean when they state something like “extrusion rod must be of the same base resin as the geomembrane sheet”? Does this simply mean any HDPE welding rod will work for any HDPE sheet?
For years, my standard CQA practice included taking inventory of all of the welding rod the installer had on site; and for years, this meant that the welding rod resin needed to match the geomembrane sheet—Solvay HDPE sheet needed Solvay HDPE welding rod; Union Carbide or Phillips HDPE welding rod was unacceptable. I can’t even count the number of times an installer showed up with HDPE welding rod from a different manufacturer than the geomembrane sheet resin! The good thing for the installer (they did not see it this way) was that I was on top of it before deployment began, which meant the problem could be addressed prior to the need for extrusion welding.
In many cases, the installer chose to wait a day or two to begin deployment, so any extrusion seams or repairs performed could be considered permanent. Likewise, many times an installer was sent to a site to perform a repair caused during cover soil placement, only to be delayed a day or two because they brought the incorrect welding rod.
To this day, my standard practice has not changed regarding inventorying the welding rod; you might be surprised how many times a crew has LLDPE rod instead of HDPE rod. But as for the base resin of the extrusion rod matching the base resin of the geomembrane: this is virtually non-existent. For one thing, most of the welding rod is only branded by the manufacturer’s name, so the person reviewing the material certifications would need to look into this—it is not something that can be quickly identified in the field. Another thing is that the more recent interpretation by many engineers of the statement “extrusion rod must be of the same base resin as the geomembrane sheet” is that this simply means HDPE sheet must be welded with HDPE welding rod.
Some questions immediately come to mind (but to which I could not find any quick answers). Does this mean a welding rod produced by Agru is universally acceptable for use on GSE sheet, or visa versa (assuming same density of materials—LLDPE rod for LLDPE sheet, HD rod for HD sheet, etc.)? Does using a welding rod manufactured by a competitor have any implication on either the installation warranty, or the manufacturers warranty?
While the Kenny Rogers controversy was only a short-term distraction in the 2006 World Series (his Tigers won the controversial game but ultimately fell to the Cardinals), I am curious to hear your thoughts on whether the extrusion resin issue also was a short-term concern that is now outdated, or whether it is an ongoing concern that perhaps should be back in the spotlight.
In most of the cases, the manufacturer offer the welding rod as a complement, so its not worthy to him offer only the welding rod and not the liner.
Also, its a “subtile” way of saying its formulation for the membrane is enough different (and better) from the rest of manufacturers, and this is why it does not fit with other membranes or welding rods.
Paco,
Thank you for your feedback! These are excellent points!