Green Roofs - Living Architecture Monitor - Winter 2017 - 30

STANDARDS

REVISED DESIGN STANDARD
MINIMIZES FIRE RISKS
SPRI UPDATES VF-1 FIRE DESIGN STANDARD FOR VEGETATIVE ROOFS
BY MICHAEL ENNIS

The steady advance of vegetative (green) roof designs within mainstream
construction under the International Building Code requires regular
updating of key design standards. As part of this industry wide effort, the
American National Standards Institute (ANSI) re-approved the updated
VF-1, "Fire Design Standard for Vegetative Roofs" as an American National
Standard on May 11, 2017.

reen Roofs for Healthy Cities and Single-Ply Roofing
Industry Inc. (SPRI), the trade association representing
commercial roofing system manufacturers and component
suppliers, initially collaborated on VF-1. The standard
was developed by SPRI in 2007 and first approved as an ANSI
standard in 2010. The document was created to provide a design and installation reference for roofing professionals to help
eliminate the risk of fire on vegetative roofs.
"Updates to the VF-1 Standard included collaboration between
all industries and segments involved with vegetative roofing"
says Brian Davis, chair of SPRI's VF-1 Review task force.
"This, in turn, helped to create the best, most comprehensive
document possible for the industry to reference and design
with."
Vegetative roof designs continue to evolve, with plant types,
growing media, system complexity and usage, such as rooftop
gardens. When updating the VF-1 Standard, SPRI needed to
consider changes relating to external fire design and fire spread
based on the American Society for Testing and Materials
(ASTM) E108 - 17, "Standard Test Methods for Fire Tests of
Roof Coverings."
"Some of the key changes included new definitions and
clarifying or removing some of the previous explanations and
classifications, as well as additions to the VF-1 commentary
section," says Davis. "Some of the most important changes
revolved around firebreaks, fire barriers, border zones, and area
dividers, to name a few."
The updated standard describes and provides more in-depth
definitions of the three main categories of vegetative roofs-

LIVING ARCHITECTURE MONITOR / WINTER 2017 / 30

extensive, intensive, and semi-intensive. The standard also
adds the spread of fire requirements that include combustible
features that are part of the vegetative roof design, but not part
of the building structure. Roof planters are one example.
The section on "Spread of Fire, Protection for Large Area
Roofs" is more robust, with specific references to FM Global
recommendations (FM Global Loss Prevention Data Sheet
1-35-Green Roof Systems), which also coincides with the
International Building Code "General Building Height and
Area Limitations." The new document also refers to German
Landscape Research, Development and Construction Society
(FLL) requirements. This includes FLL's definition of a "hard
roof" and its assertion that a vegetative "hard roof" can be considered equivalent to an ASTM E108 Class A Fire Classified
roof assembly under certain conditions.
Vegetative roof technology has also been the subject of greater
research efforts over the last seven years, as shown by the
14 references included in the new document, compared to
only four references in the 2010 version. The 2017 version of
ANSI/SPRI VF-1 provides clearer criteria for minimizing the
risk of fire on green roofs through prudent design and mandatory maintenance requirements. The updated VF-1 standard is
available for a free download at www.spri.org
Mike Ennis, RRC, joined the Single-ply Roofing Industry (SPRI)
trade association in 1993. He has chaired various SPRI committees
and task forces, and served as president from 2004 to 2006. He
became the group's technical director in 2007. Ennis can be reached
at info@spri.org.
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Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Winter 2017