For more than a decade, the American National Standards Institute/Underwriters Laboratories Standard 1703 (ANSI/UL 1703) has been the safety and regulatory standard to certify the fire resistance of flat photovoltaic modules and panels. However, field failures and cases when fire had a different impact on modules than anticipated - due to installation; interaction with the host structure; and/or environmental conditions, such as extreme weather - led to an update in fire resistance testing and classification requirements.

These changes took effect in California on Jan. 1 and will be in place for the rest of the U.S. in 2016, if not sooner. This has created another demand: to better understand the testing and certification requirements that ensure the fire resistance of PV modules.

There are two types of PV panel modules that are installed on roofs today - one is secured to roofs using mounting and racking systems, and the other is integrated into the building, acting as a part of the roof itself. For those secured by mounting and racking systems, recently revised standards have led to a shift in fire resistance certification. As a result, panels will not be able to be tested separately from the other components for much longer.

The revised version of ANSI/UL 1703 no longer bases the fire rating on the PV module alone, but on a combined “system rating” as defined by the PV module type and the mounting and racking system. Under the revisions, stand-alone PV modules and PV modules with mounting and racking systems in combination with the roof must receive a fire rating, which is denoted by a Class A, B or C designation.


Testing and classification

PV module systems that are not integrated into the building fall into two categories: 1) the PV module alone, independent of mounting systems and roof covering, and 2) the PV module, mounting system and roof covering, as one unit. Under the revised standard, individual PV panels will be required to obtain a classification “type” based on construction review and testing. Whole systems - which include the PV module, mounting system and roof covering - will be tested together.

An independent PV module is subject to testing under UL 1703 Section 31.1, where it is classified by construction as one possible type. The verification of type comes from testing the panel for spread of flames and resistance to a burning brand.

A PV module with a mounting system and roof covering is subject to testing under UL 1703 Section 31.2. If a panel is not yet type-tested under UL 1703 Section 31.1, it will be tested for spread of flames to verify its surface characteristics, as above. If the panel has been type-tested, this step will be skipped. In either event, the system is then tested for spread of flames and, for systems intended for a roof with a steep slope (greater than or equal to a 2:12 ratio), tested for burning brand resistance.

Based on these tests, PV systems will receive a fire rating classification, which is based on the roof coverings and slope.



Steep vs. low slopes

As noted previously, there are different testing requirements for roofs with steep slopes (greater than or equal to 2:12) and ones with low slopes (less than 2:12). The requirements are based on the composition of the roof and its spread of flame and burning brand resistance.

Roof composition. Because the composition of the roof must be taken into account, “typical” roof materials are used during fire-resistance testing. Depending on the slope, there are various requirements for plywood, insulation and other materials, as follows:

Spread of flames testing. Regardless of slope, spread of flames testing will consist of two tests conducted on the panel surface - unless the panels have already been type-tested - and two tests conducted on the system, with the following requirements:

Burning brand testing. The slope-specific requirements for burning brand testing are as follows:


Ensuring compliance

In order to ensure compliance with these revised standards, manufacturers can employ several best practices.

First of all, familiarize yourself with the revised ANSI/UL 1703 standard and any other standards that apply to the products you offer. Make sure you understand the implications for your products in all of the environments where they are likely to be installed.

After getting a panel type-tested, understand which rack systems and installations are compatible with your type. In general, familiarize yourself with the products and new technologies in the mounting and roofing product industries to ensure compatibility with PV panels.

Be prepared not only to test panels, but also to redesign products to fit with available mounting systems and new mounting systems coming to market. Additionally, be prepared to re-design and re-evaluate products that may present safety concerns or that may not pass fire-resistance testing.

PV testing and certification experts have the knowledge and experience to assess PV technology according to current standards. They are often looking ahead to new technological developments and changes in the industry to continually adapt in the future. Additionally, experts on both solar panels and the building materials used in roofing installations can be assets to the design stages, as they can ensure the best materials and product design to help mitigate risks, such as flammability.

Consider third-party testing. Partnering with a nationally recognized test laboratory and or a certification body testing laboratory can ensure that your products are being tested by experts in the industry and can help get your product to market faster. These groups can often review, test and certify products more quickly, given their expertise and knowledge of the industry.

As previously noted, the new testing standards have already taken effect in California and are quickly approaching for the rest of the U.S. Yet, these changes come at a time when residential and commercial customers are increasing their demand for solar panels.

This potential opportunity for the industry is coupled with the challenges of new standards, meaning that testing and certification are more important than ever to a manufacturer’s bottom line - presenting the opportunity for growth and success.


Sunny Rai is vice president of renewable energy at Intertek’s office in San Francisco, where he provides strategic direction for the company’s photovoltaic, wind, smart grid and semiconductor businesses. Greg Allen is engineering team leader for the openings group at Intertek’s Middleton, Wis., location, with a focus on hardware testing, fenestration testing and fire-resistance testing.

PV Fire Testing Standards

Manufacturers Must Get Ready For New PV Fire Testing Standards

By Sunny Rai & Greg Allen

Real-world failures and unanticipated effects from fires have spurred revisions to ANSI/UL 1703.











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