With very few exceptions, building products must comply with accepted industry material standards. These standards allow differentiation among similar products; demonstrate specification compliance, and establish accepted thresholds for safety and quality. Amazingly, until recently, there have been no American green roof standards. In the absence of American standards, responsible providers of green roof materials and systems would typically demonstrate compliance with the German FLL standards, which are little-known in the general design and construction industries.
Within the past few years, the ASTM convened a Green Roof Task Force to create green roof standards. Charlie Miller, P.E., President and founder of Roofscapes, Inc., has been a very active member of this Task Force from the beginning. He is the primary author of four of the five standards recently published and listed below. We are very proud to be such an integral part of the movement to standardize green roofs in the United States.
The methods described in the new ASTM standards establish a common basis for comparing fundamental green roof properties, such as maximum weight and moisture retention potential. These methods are designed to measure critical material properties for green roof materials under conditions similar to those encountered in the field, this way, a roofing company can be able to guide itself with looking at these methods.
Roofscapes, Inc. has incorporated these ASTM standards in all of its Roofmeadow® specifications, and encourages all other green roof providers to do the same. The tests referenced in these standards can be run at a number of American laboratories including:
Agricultural Analytical Services Laboratory
Penn State University
University Park, PA 16802
GAI Consultants, Inc.
1055 Westlakes Drive, Suite 200
Berwyn, PA 19312
Turf Diagnostics & Design
613 E. Street
Linwood, KS 66052
The five new standards are in the Annual Book of ASTM Standards, Volume 04.12.
E2396 Standard Testing Method for Saturated Water Permeability of Granular Drainage Media [Falling-Head Method] for Green Roof Systems
E2397 Standard Practice for Determination of Dead Loads and Live Loads Associated with Green Roof Systems
E2398 Standard Test Method for Water Capture and Media Retention of Geocomposite Drain Layers for Green Roof Systems
E2399 Standard Test Method for Maximum Media Density for Dead Load Analysis*
E2400 Standard Guide for Selection, Installation, and Maintenance of Plants for Green Roof Systems
*Method E2399 includes tests to measure moisture retention potential and saturated water permeability of media.
To purchase any of these standards, visit the Penn State is the leading Tester in FLL and ASTM guidelines.
Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V. (FLL) Richlinien für die Planung, Ausführung and Plege von Dachbegrünung
Now you know why we just call them the “FLL Guidelines.”
The FLL is the Research Society for Landscape Development and Landscape Design (Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V.). For over 15 years, the German FLL Guideline for the Planning, Execution and Upkeep of Green-Roof Sites have been the only source of reliable information for green roof designers – German or American.
The Guide covers all aspects of green roof design, including (but not limited to) designing appropriate media (engineered soil) for different applications; selecting plants palettes, and managing drainage. The FLL has also developed specific tests:
- To determine the root resistance of waterproofing materials and root-barriers,
- To evaluate water-holding capacity of media, or
- To estimate maximum weight of green roof media.
Until similar American standards are published by the ASTM or other American standard-setting organizations, the FLL guidelines and test procedures represent the only accepted standards for green roof materials. Potential purchasers of green roof systems should determine if these systems comply with FLL recommendations.
The FLL Guideline for the Planning, Execution and Upkeep of Green-Roof Sites is only available in an electronic .pdf format directly from FLL. The company is currently updating their on-line store and expect the Guidelines to be available through their website soon. If you require a copy of the FLL Guidelines for Green Roofs immediately, please contact Michael Fuchs of FLL directly with your request.
The Approved American National Standard (ANSI) and the Single Ply Roofing Industry (SPRI), in cooperation with Green Roofs for Healthy Cities (GRHC), have jointly developed a Wind Design Standard and a Fire Design Standard for vegetative roofing systems. The Wind Design Standard provides a method of designing wind uplift resistance of green roofs, and the Fire Design Standard provides a method for designing external fire resistance for green roofs. These organizations presently are drafting a standard for investigating resistance to root penetration on green roofs.
Roofmeadow has participated as a reviewer for the ANSI/SPRI standards pertaining to green roofs, including the Wind Design Standard and the Fire Design Standard. We continue to advise ANSI and SPRI on the root-resistance standard that is in progress.