High-density polyethylene (HDPE)-based solar mounting systems were all the rage a few years back. Not only were they the lightest ballasted mounts on the market, many of them could be stacked and easily moved, making them cheaper to ship and quicker to install. But as fire safety became more of a concern, it became clear that plastic, which can melt, probably wasn’t the best base for a solar system.
Here are how non-metallic mounting manufacturers—Sollega, Ecolibrium, Renusol America, DynoRaxx, Patriot Solar—are changing their business plans with the enforcement of new fire ratings.
Sollega manufactures the InstaRack (a one-piece mounting unit made of HDPE) and the FastRack 510 (its new mount made of Ultramid glass-reinforced nylon from BASF). Elie Rothschild, sales manager, said the company is phasing out the InstaRack because of its HDPE skeleton, but it can still be used on ground-mounts and rooftop projects outside of California—until other states take on fire safety standards.
Chemical producer BASF approached Sollega two years ago in anticipation of the new UL fire requirements. The Ultramid material was introduced to the company as a replacement for HDPE and has a substantially higher relative thermal index (RTI) rating, meaning it’s much stronger and less vulnerable to high temperatures. The FR510 has less parts and is more cost-effective than the InstaRack since the company has turned to injection molding. Sollega expects the FastRack to ultimately replace the InstaRack, and demand has already turned in favor of the new product.
Sollega is scheduled for UL 2703 and UL 1703 flame spread testing just after press time.
“We have a high safety factor with everything we do,” Rothschild said. “We don’t want to meet the requirements, we want to exceed them.”
Ecolibrium‘s EcoFoot2+ is a step up from the original EcoFoot made of HMWPE (high molecular weight polyethylene). The new version is made of chemical supplier Styrolution’s Luran S acrylonitrile styrene acrylate (ASA) polymer, which is modified with acrylic ester rubber that increases strength and performance when exposed to heat. Just prior to Solar Power International 2014, the EcoFoot2+ received a Class A fire rating.
In 2011, Renusol America introduced the Renusol CS60—the first one-piece mounting system made from 100% recycled HMWPE. President and CEO Bart Leusink said the company began exploring other mounting options after seeing a trend for larger modules. Manufacturing a 72-cell version of the product required the mount to be larger and thicker to support the heavier modules, and the high cost of oil at the time made it cost-prohibitive to continue with plastic. So Renusol went the aluminum route, and introduced the Renusol EW system (a rail-less, ballasted system for east-west module orientation) at Solar Power International 2014 and launched this February.
The Renusol CS60 has morphed into a ground-mount product for landfills and other challenging terrain. Since it won’t be used on roofs in the future, there is no need for fire safety testing. The Renusol CS60 has also influenced Renusol’s new Renusol GS system for ballasted ground-mounts.
“We came up with a custom-designed ground-mount system based on the CS60 product, the GS system,” Leusink said. “We’re expanding the plastic product line but it’s for ground-mount applications.”
The DynoRaxx Evolution flat roof system is not HDPE-based, but it is unique to the mounting market. Made of fiberglass reinforced plastic, the Evolution FR and the Evolution FR Generation 2.0 are non-conductive and fire resistant. The fiberglass mounts will not expand or contract through heat cycling. DynoRaxx will undergo fire testing soon, and founder Nathan Rizzo said he expects no difficulties with receiving a positive fire rating.
Patriot Solar Group
Patriot Solar, mostly a manufacturer of metallic ground-mounts, also has a ballasted roof-mount—the Spider ST. Made of injection molded HDPE, the product was a Department of Energy 2012 Sunshot Award winner. Dylan Pugh, sales and marketing associate, said Patriot Solar planned for the fire rating requirements and designed the Spider ST to meet the tests, which it has passed. While most polymer-based roof-mounts use a HDPE compound that isn’t the strongest, Patriot went with a polypropylene injection molding process that allows the Spider ST to pass all certifications. SPW