Racking Manufacturer Survey

Solutions for Low-Slope Commercial Roof Applications

Mounting systems for low-slope, commercial roof applications are wide ranging and represent one of the most rapidly evolving equipment groups. Solutions range from preengineered products to customized racking systems. Since 2009, nine new players have entered the market, nearly doubling the number of manufacturers. Many have several distinct product lines.

To generate this article, we sent surveys to 24 manufacturers that have developed solutions for low-slope commercial roof applications. Some of these manufacturers were not even on our radar when we started our background research. Four did not respond to our requests for company and productspecific information.

Survey questions addressed topics ranging from product line overviews and suitable array capacities for a given racking system to integrated equipment-grounding provisions and wire management options. Because structural engineering requirements vary from project to project, often significantly, we also queried manufacturers regarding the specific array design, engineering and permitting support services offered.

The manufacturer overview table on page 57 provides basic information on the companies behind the racking systems. Because racking can represent significant shipping and freight costs, US and Canadian manufacturing and warehousing locations are included in the table when the manufacturer provided this information.

This article is intended to serve as a starting point to help determine the right rack for the right project. As always, the devil is in the details.

LOW-SLOPE RACKING SYSTEM MANUFACTURERS

While it is not possible to cover the intricacies of the dozens of racking systems available for low-slope roof-mounted arrays in a single article, we have assembled company and product line overview information for 20 primary players in the market.

Applied Energy Technologies (AET). The Rayport Roof Ballasted System manufactured by AET is the only stainless steel racking system available for low-slope roof applications, making it a sound option for corrosive coastal environments. Modules are installed in landscape format on support rails that can be ordered with tilt angles ranging from 0° to 30°. Support rails are connected to ballast tray assemblies, which are in turn secured to assemblies at the front and the rear, creating a monolithic array structure. AET does not offer product-specific wire management options.

The Rayport system is designed to be compatible with all framed modules. AET offers the Rayport Frameless Module System for thin-film module technologies as well. A spacer bar is utilized during installation to set the support rails at the correct spacing for a given module model. One common bolt size is used for all racking joints. Holes for rack grounding lugs are provided on the back of each support rail. EPDM rubber pads protect the roofing material from abrasion damage.

The Rayport Roof Ballasted System and Rayport Frameless Module System are suitable for project capacities of 20 kW and larger. Both systems carry a limited 15-year warranty. Full array layout and loading analysis and layout drawings are provided with each Rayport system.

Cooper B-Line. The ARISTA Monolithic Solar Mounting System is a low-slope rooftop solution from Cooper B-Line. Recycled rubber DURA-BLOCK supports serve as the system base, elevating north-south strut rails off of the roof membrane and helping to reduce roof wear. The base strut can be ballasted in place or mechanically attached. Preassembled 90° strut fittings are used to attach vertical uprights to the base strut. Preassembled angled strut fittings (10°, 20° or 30°) at the top of these uprights are used to anchor the tilted east-west rails that support the PV modules. The use of preassembled components eliminates loose parts on the jobsite and decreases labor time in the field. Expansion splice plate assemblies for interconnecting base struts are designed to accommodate material expansion and contraction while maintaining system strength.

Because the ARISTA Monolithic Solar Mounting System is strut based, it is compatible with standard strut fittings and accessories. This enables a wide range of mounting options for conduit, combiners and other accessories. Cooper B-Line offers many BOS components, including cable management solutions and electrical enclosures. The racking system accommodates both portrait and landscape module orientations. In addition to the standard ARISTA system, Cooper B-Line can also provide an array of custom engineered mounting solutions upon request.

The ARISTA Monolithic Solar Mounting System is covered by a 10-year warranty on material and workmanship, and a 5-year warranty on the finish. Cooper B-Line offers design, engineering and permitting support for its mounting system, which received structural validation through a certified third-party wind-tunnel test.

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