Abstract: In 2022, driven by global energy transition and carbon neutrality goals, the PV industry continued its high growth trajectory. As the "skeleton" of PV power plants, the mounting structure industry underwent deep adjustments against a backdrop of raw material price fluctuations and intensifying market competition. Among various solutions, the L-Foot mounting system for metal roofs, leveraging advantages such as easy installation, high reliability, and wide applicability, not only became a "dark horse" in the distributed PV market in 2022 but also achieved breakthrough progress in technological innovation and patent layout, leading a technological transformation for PV installations on metal roofs.

Keywords: L-Foot metal roof mount; PV mounting structure; distributed PV; metal roof installation; PV patent

I. 2022 Market Background: Distributed PV Boom Drives Surge in Demand for Metal Roof Mounts

In 2022, global newly installed PV capacity maintained rapid growth. According to industry data, the market size of PV mounting structures in China reached RMB 19 billion in 2022, an increase of 8.6% year-on-year. With the in-depth development of metal roof resources such as industrial and commercial factories, warehouses, logistics centers, and agricultural greenhouses worldwide, the requirements for mounting systems in distributed PV scenarios have become increasingly stringent. Metal roofs, due to their varying slopes and different materials (e.g., trapezoidal sheet, standing seam, corrugated sheet), pose challenges for traditional installation methods, including leakage from drilling, insufficient load capacity, and low installation efficiency.

Against this backdrop, the L-Foot metal roof mounting system emerged as a solution. Using an L-shaped bracket to connect the roof and PV rails, this solution offers high flexibility, lightweight design, and excellent waterproof performance, becoming a key technological path to solving the challenges of metal roof installations.

II. 2022 Technical Review: Modular Design and Easy Installation Become Mainstream

In 2022, several leading mounting structure companies launched upgraded L-Foot systems, focusing on improving installation efficiency and enhancing structural stability.

(1) Kseng Launches All-Scenario L-Foot Solution

In November 2022, at the All Energy Australia exhibition in Melbourne, Kseng showcased its roof-mounted products for the Australian distributed PV market, including ballasted flat roof mounts, tile roof hooks, and lightweight, high-quality L-Foot systems. Its L-Foot system uses aluminum alloy 6005-T5 and SUS304 stainless steel, capable of withstanding wind loads up to 60 m/s and snow loads up to 1.4 KN/m². It is compatible with both framed and frameless PV modules, meets the Australian AS/NZS 1170 standard, and comes with a 10-year warranty. With selling points of "low price, easy installation, and light weight," the solution quickly gained a foothold in the Australian residential and commercial & industrial (C&I) market.

(2) AceClamp Launches Ready-to-Install L-Foot Kit

In August 2022, AceClamp released an L-Foot PV installation kit (Part#: 5058-LF) specifically designed for single-lock standing seam metal roofs. The product features a highly pre-assembled design, eliminating cumbersome on-site re-tightening steps. With a universal L-shaped foot, it is compatible with various PV modules and clamps and supports flexible height and width adjustments. Additionally, the product has passed rigorous third-party testing, ensuring long-term reliability under extreme temperature and weather conditions.

(3) IronRidge and SnapNrack Deepen Product Portfolios

As veteran players in the mounting structure field, IronRidge continued to promote its Slotted L-Foot system in 2022. The design highlights a vertical slot that allows pre-assembled hardware and rails to slide in easily, effectively compensating for minor unevenness in metal roofs. All systems are UL 2703 certified. SnapNrack, in turn, deepened its partnership with S-5! to launch the "All Purpose L Foot" series, combining S-5!'s professional metal roof clamps with SnapNrack's L-Foot accessories, providing installers with a complete, ready-to-use solution.

(4) Comparison of PV Mounting Installation Efficiency: From Complexity to Simplicity

Traditional L-Foot systems require on-site positioning, drilling, installing EPDM waterproof washers, and screwing wood screws to fix the L-Foot, followed by connecting rails and PV modules. In 2022, QuickBOLT's Throne (17747) mount disrupted the traditional process by integrating the L-Foot directly into the base. Installers no longer need to purchase and assemble the L-Foot and base separately. This design not only simplifies logistics but also eliminates the risk of over-tightening fasteners that could damage the roof, saving installers "minutes per mount and hours per project."

III. Patent Race: S-5! and Unirac Build Technological Moats

In 2022, intellectual property competition in L-Foot and related metal roof mounting technologies was particularly fierce.

S-5!: Global Leader's Patent Harvest

As the global leader in metal roof attachments, S-5! enjoyed a bumper patent year in 2022. On the occasion of the company's 30th anniversary, S-5! announced it had added 14 new patents in a single year, bringing its total patent portfolio to 112. These new patents cover key markets including the United States, China, Europe, and Australia, and include the S-5-ZH™ Mini clamp for round bulb seams, as well as rail-less direct attachment solutions in conjunction with the PVKIT®, further consolidating its dominant position in the metal roof PV mounting technology field.

Unirac: Click-On Tool-Free Installation Technology Patented

In February 2022, Unirac was granted an invention patent titled "Click-on tower and l-foot mount for attaching solar panels to a roof" (Patent No.: US 11,251,743 B2). The patent describes a tool-free "click-on" mounting structure that uses a spring-loaded snap mechanism to quickly attach and detach the L-Foot mount to the roof base, and supports height adjustment after installation, greatly simplifying the installation process and reducing tool dependency.

IV. Installation Essentials and Industry Trends

Synthesizing industry developments in 2022, the following points are critical for L-Foot metal roof mounting system installation: first, ensure waterproof sealing with EPDM rubber washers; second, perform rigorous load checks in accordance with standards such as AS/NZS 1170; and third, prioritize highly corrosion-resistant materials like aluminum alloy and stainless steel to withstand harsh outdoor environments.

Looking ahead, with the increasing penetration of trackers and the popularization of BIPV (Building-Integrated PV), L-Foot mounting structures will continue to evolve toward modularization, lightweight design, and maintenance-free operation, potentially playing a key role in an even wider range of complex metal roof scenarios.