According to a recent report by the International Energy Agency (IEA), about 190 gigawatts (GW) of new photovoltaic (PV) generating capacity was commissioned worldwide in 2022, accounting for 60 percent of the increase in global renewable energy capacity. Nearly 200 GW of new PV capacity is forecast for 2023.
Solar PV is becoming the lowest-cost option for new electricity generation in much of the world due to the rising cost of fossil fuels. The IEA notes that in 2021 China accounted for 38 percent of solar PV generation growth, followed by the United States with 17 percent and the European Union (EU) with 10 percent.
Utility-scale PV power plants were responsible for 52 percent of global solar capacity in 2021, followed by residential with 28 percent and commercial and industrial (C&I) with 19 percent.
The range of customers encompassed by the C&I market includes large corporations to local small businesses, as well as municipal facilities, schools, universities, hospitals, and many others.
FM Approved PV
Recently, FM Approvals granted its first certification for a roof-mounted rigid PV system under Approval Standard 4478, Examination Standard for Roof-Mounted Rigid Photovoltaic Module Systems, to Sika Sarnafil, based in Lyndhurst, New Jersey, USA.
The new FM Approved Sika SolaRoof® System is the culmination of five years of research and testing by Sika Sarnafil and Centroplan GmbH, its global partner for rooftop solar system design and installation (fig. 1).
From 2018 to 2022, with an 18-month break due to the Covid 19 pandemic, Sika and Centroplan representatives worked in close collaboration with FM Approvals engineers and laboratory staff at the FM Global Research Campus in West Glocester, Rhode Island, U.S.
A series of tests were carried out at FM Approvals' Fire Technology and Natural Hazards laboratories in accordance with the requirements of FM 4478 and FM 4470, Standard for Single-Ply, Polymer-Modified Bitumen Sheet, Built-Up Roof (BUR) and Liquid Applied Roof Systems for use in Class 1 and Noncombustible Roof Deck Construction.
Collaborative effort
"In partnership with Centroplan, the Sika SolaRoof with Sika Sarnafil roof assemblies have been installed in thousands of facilities throughout Europe and other regions," notes Jon Jensen, Sika product manager (fig. 2). "We sought FM Approvals certification because they are the industry standard for roofing systems in North America and in many other countries. We knew it would be good for our business, but it did require more trial and error than we were used to."
The FM Approved Sika SolaRoof system is listed in FM Approvals’ RoofNav.com roof specification tool. The new system features the Sika SolarMount-2 (SSM2), a new version of the mounting system developed during the FM Approvals certification program to meet rigorous fire and wind uplift tests.
According to Centroplan USA CEO Rocco Gerhardt, "We began testing using the first version of our SolarMount racking system, the SSM1. We were disappointed in both the fire and wind uplift tests, resulting in a redesign to create SSM2, which passed all subsequent tests. When we entered the U.S. market, we had two options: do what everyone else does or do better by choosing FM Approvals. It's well known that they conduct the toughest testing in the industry. By achieving FM Approvals certification, customers know our product is going to work and provide the resilience and performance they expect."
No cost increase for FM Approved PV
What about cost? "The cost for our Sika SolaRoof system will be the same as our other solutions. This new design is optimized when it comes to installation and logistics," Gerhardt explains.
It's interesting to note that the Sika SolaRoof racking system attaches to the Sika Sarnifil® PVC single-ply membrane via a unique PVC injection-molded Sika SolarClick mount that allows the rack to be hot-air welded to the roof membrane without any penetrations. This reduces the chance of leakage and eliminates the need for ballast in most cases.
Materials engineer Cy Ketchum was a member of the FM Approvals team that assisted Sika and Centroplan during their test programs in West Glocester. "There were definitely lessons learned along the way, on both sides," Ketchum notes. "As essentially our first full program under FM 4478, it took us a bit longer than it normally does to assemble the solar panels, racking system and membrane roof build-up. After a few iterations, we got quite good at it and much faster!"
Centroplan, a member of Germany's Pohlen Gruppe, carried out its own successful solar roof Approval program under FM 4478 for standing seam metal roofs. The company, whose U.S. headquarters is in California, earned the FM Approved mark soon after Sika.
"The Sika SolaRoof system is more flexible in how you can arrange the solar panels since it can be hot-air welded to the PVC membrane in almost any arrangement," Ketchum says. "The Centroplan system clamps directly to the standing seams in the metal roof, so it has to conform to that orientation for the most part."
According to Centroplan’s Gerhardt, the firm is one of the largest full-service solar roofing companies in the EU and is also actively rolling out its operations across North America and China. "We are here in the U.S. and in China because Sika is very interested in establishing a strong base in the solar roofing in these markets."
Sika's Jon Jensen, who is based in the company's Canton, Massachusetts facility, notes, "FM Approvals helped us move the program along. We got bogged down a little during Covid, since everything shut down, but FM Approvals has been a true partner to us in this first-ever program."