First FM Approved retrofit coating helps mitigate fire hazards for roofs with roof-mounted PV

FM Approvals’ photovoltaic (PV) standards and testing protocols evaluate the performance of products that are designed to mitigate the fire risks associated with roof-mounted PV systems. Products that meet the stated testing requirements and demonstrate the ability to perform as expected can be certified to FM Approvals standards and labeled with the FM APPROVED certification mark.

When examining the PV systems for fire, a significant function of FM Approvals photovoltaics testing is to evaluate the resistance of a product, and its surrounding environment, to both ignition and spread – to ensure the product will not contribute to further propagation when a fire occurs.

One strategy to mitigate the ignition and spread of fires that can impact roofs and roof-mounted PV modules is to apply retrofit coatings. These coatings are particularly useful because they can be applied on top of an existing roof system. For new construction, a complete FM Approved roofing assembly that includes PV modules would not require the use of a retrofit coating. However, applying a retrofit coating when just installing PV over an existing roof in favorable condition can result in the same reduced level of expected external flame spread that is achieved with new construction.

FM Approvals Examination Standard 4484 retrofit coatings for roof-mounted rigid PV module systems states the testing and certification requirements to mitigate fire spread hazards of roof-mounted assemblies, with consideration for the underlying roofing system. Testing evaluates the suitability, performance and reliability of the coating. During testing, the retrofit roof coating is applied to the top surface of the test roofing system in accordance with the coating manufacturer’s specifications. Coatings that resist fire ignition and spread, while not negatively impacting the integrity of the roofing system in any way, can be FM Approved.

In September 2025, AllShield Blue – a mineral-based coating that limits roof system ignition and fire spread, even when applied over roof assemblies containing combustible insulation – became the first FM Approved liquid-based roof coating to be certified to the requirements of FM 4484. AllShield Blue is manufactured by AllShield Coatings BV, based in Rotterdam, Netherlands.

With PV power systems becoming increasingly prevalent in commercial applications, the addition of a roof-mounted system can significantly enhance flame spread over the roof in the event of a fire. Coatings, such as AllShield Blue, are designed to protect the roofing system and prevent or reduce flame spread. The recently completed
FM Approval of AllShield Blue confirms that the product can help mitigate the increased fire hazards posed by roof-mounted PV equipment.

When building owners and other stakeholders are looking to create sustainable facilities and build on existing strategies and protocols to make facilities resilient against fire and all the other risks physical structures face, browsing FM Approved roofing-related products in RoofNav will provide access to comprehensive and diverse solutions that have been tested and certified to our standards of quality, technical integrity, and performance. Click here for a comprehensive listing of the types of roofing assemblies, roof coatings and associated equipment we certify.

With 60,000+ FM Approved products listed in the Approval Guide, FM Approvals’ globally recognized certification process is backed by technical integrity and confirms product performance under real-life conditions. If you manufacture loss prevention products or are in search of a solution to protect your facility from evolving risks, please reach out to us at [email protected] to learn more.