SPRI, in cooperation with ANSI, has released its 2023 revision of the VF-1 standard, effective April 3, 2023. Titled “External Fire Design Standard for Vegetative Roofs,” the VF-1 was created to “provide a minimum design and installation reference for those individuals who design, specify, and install vegetative roofing systems.” This standard is meant to be used in conjunction with the manufacturer’s installation instructions or requirements for a vegetative roof system.

The 2023 revision has additional definitions in the document from the previous version and editorial revisions to improve the consistency in SPRI’s library of ANSI standards, as well as general readability. The VF-1 standard was streamlined to remove design requirements or recommendations that were not specific to external fire design of vegetative roofing systems, such as wind design, and instead directs the user to the appropriate standards where appropriate. Citations were added to help better reference any potentially necessary or helpful design considerations.

A few examples of major changes that were added to the VF-1 are noted below:

  1. VF-1 previously stated “a root barrier shall be installed if the roof covering has not been tested for root penetration resistance”, but provided no guidance on how to test for root penetration resistance. The section has been updated to reference ANSI/SPRI VR-1.
  2. Updated the standard to reference both ASTM E108 and UL 790 test methods since both test methods are referenced in the building code. Previously, the standard only referenced ASTM E108.
  3. Additional clarity around Border Zones, Firebreaks, and Area Dividers.

The 2023 version of the VF-1 standard can be viewed on SPRI’s website at https://www.spri.org/standards/, along with all the other standards published by SPRI. Standards such as the VF-1 are referenced by designers and local building code committees and regulatory authorities.

Please note: This post is not exhaustive in listing all of the revisions made to the previous version of the VF-1. The 2023 revision of the VF-1 should be read in its entirety to fully understand all the minimum external fire design requirements and considerations when installing a vegetative roof system.

Photo credit to Hydrotech A Sika Company