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On 14 June the M25 committee met during the AWWA conference and exhibition in San Francisco to discuss modifications of the manual on "Flexible-Membrane Covers and Linings for Potable-Water reservoirs". Members present were Doug Hilts, Chairman (HCG), Skip Neal (Layfield Environmental Systems), Dave Martin (Layfield), Danny Joe McCullough (Watersaver), Peter Hartman (Cincinnati Water Works), Ian Peggs (I-CORP INTERNATIONAL) , and John Stubbart (AWWA). Non-members present were Peter Bond (Stevens Geomembranes) and Richard Martin (NSF International).
Initial discussions centered on the durability problems with PP geomembranes and GRI’s provisional withdrawal of the GRI.GM18 standard. Ian Peggs and Doug Hilts described data collected from PP projects around the world and proposed the need to generate some basic performance data to demonstrate to installers, engineers, and regulators that PP is still a viable liner and floating cover material. Other topics included: the place of warranty conditions in the manual, black versus colors, the need for a liner action leakage rates (assuming that zero could not be guaranteed), the associated need for appropriate underdrain collection and gas venting systems, the need for electrical leak location surveys, consistent terminology (e.g. replacing flexible membrane liner with geomembrane), the impact of wind uplift, and updating photographs in the manual.
Doug has already incorporated a number of recommendations in an update of the manual and will be preparing a final document in a few weeks.
Please send additional comments to doug.hcg@veizon.net.
