Flammability Testing of Standard Roofing Products in the Presence of Stand-off Mounted PV Modules — Solar ABCs Interim Report

Download the one-page Summary (PDF, 214KB) or the full report (PDF, 2.34MB).

Overview

One-page summary report cover of Flammabilty Testing of Standard Roofing Products in the Presence of Stand-off Mounted PV Modules
The Solar America Board for Codes and Standards (Solar ABCs) released an Interim Report that was developed in partnership with Underwriters Laboratories Inc. (UL) to investigate whether and how the presence of stand-off mounted PV arrays may affect the fire class rating of common roof covering materials.  In particular, these tests were initiated in response to questions from stakeholders about the language in the UL Guide Card that stated that PV modules may or may not reduce the fire class rating of roof coverings when modules of a lower rating are installed above a roof covering with a higher rating.  All tests were conducted by UL in Northbrook, IL, with assistance from representatives of Solar ABCs.

Why the Report is Important

As the number of rooftop photovoltaic (PV) systems increases, addressing questions and concerns about fire safety of PV systems have never been more vital.  Code officials and the solar industry want to better understand whether the presence of a rooftop PV system affects the fire class rating of the roof. This Interim Report details tests conducted to date and recommendations for future research.

Solar America Board for Codes and Standards Recommendation

Further collaboration between the Solar ABCs, UL, the solar industry and fire safety officials will continue with more research aimed at PV safety improvements.  Based on the current round of testing, reviews and comments by the PV flammability working group and the steering committee of the Solar ABCs, our recommendations are as follows:

  1. At present, field experience and thorough review of fire incident data do not indicate an urgent need to revise current practice with regard to code requirements.  A major task in the next round of research will be to quantify the potential risk identified by the test results.
  2. Further investigation is required to refine the pass/fail criteria for a fire performance test for systems that includes roofing materials as well as the PV array. In addition, tests should be conducted to identify effective means of mitigating fire spread by this roof/PV system.   (The recommended tests are presented the Interim Report.)
  3. Meetings should be held with fire safety authorities, the solar industry and other interested stakeholders to discuss these tests results and determine future test requirements, as needed.
  4. Results of these tests and of subsequent stakeholder meetings should be communicated to the UL 1703 Standards Technical Panel for their consideration regarding impact of these results on that test standard.

Media and Other Inquiries Contact:

Larry Sherwood, Solar ABCs Project Administrator, 303-413-8028