Sustainable Land Development Today - January 2009 - (Page 30)

By Jay Tufano Industry Spotlight Spray-Applied Gas Membrane System Instrumental in Methane Mitigation at Playa Vista with methane gas and VOC mitigation systems. Integral to the mitigation systems has been the use of LIQUID BOOT®, a spray-applied membrane that forms a gas-tight vapor barrier. Used along with sub-slab venting and monitoring systems, LIQUID BOOT serves to protect the buildings and Smoke testing ensures that a membrane is impermetheir occupants at Playa Vista from able and free of holes. methane gas and VOC vapor intrusion. membrane, commonly used in landfill Prior to the Playa Vista project, the capping and pond lining. LIQUID BOOT membrane was routinely Many of the buildings at Playa Vista used in Los Angeles for methane gas were designed with pile foundations, mitigation on a per project basis. Two no- consisting of thousands of slab penetratable projects from the early 1990’s in- tions requiring sealing. An HDPE system clude the Los Angeles Library expansion would have required batten strips, penand Chinatown Plaza. In 2000, Los An- etrations “boots”, and welds with no geles established an ordinance that in- guarantee that each penetration was cluded a permanent set of membrane completely sealed. With LIQUID BOOT, testing standards for all buildings the membrane could be spray-applied within the Los Angeles “Methane directly onto each of the penetrations, Zone”, including the development at footings, and pile caps, ensuring a seamPlaya Vista. These tests include VOC less, gas-tight seal. The benefit to weight change and permeability at builders was not only a speedy, fullyhigh concentrations, methane perme- tested system, but one that also saved ability, tensile strength, and long term significant time and cost. durability. For the LIQUID BOOT Thousands of new structures have membrane, a new QA/QC procedure been built at Playa Vista, each of which is called “Smoke Testing” was devel- equipped with a gas mitigation system oped. The Smoke Test involves pump- that follows the LADBS Methane Ordiing non-toxic smoke beneath the nance. Feedback from Playa Vista engiLIQUID BOOT spray-application allows for a gastight membrane installation membrane to verify that it is gas-tight. neers and designers indicates that the As Playa Vista got underway, two systems are performing well. Gary CarIn order to address these public safety different types of membrane systems lin of Carlin Environmental states, “Our and health issues, the City of Los Ange- were approved through LADBS: LIQ- firm is responsible for 59 completed sysles Department of Building Safety UID BOOT spray-applied membrane, tems in buildings at Playa Vista. Overall, (LADBS) enhanced an already-strict which is specifically designed for sub- we and our clients are pleased with the methane ordinance and mandated that slab applications; and High Density performance of the methane systems all structures at Playa Vista be equipped Polyethylene (HDPE), a plastic sheet that are in place.” SLDT The Playa Vista development, located near Marina Del Rey, California, has drawn political opposition over land-use issues and building safety concerns dating back to the 1990’s, which continued through the project’s inception in 2001. At the heart of the public safety concern was naturally occurring methane gas, which is known to be explosive if allowed to accumulate in confined spaces. Of secondary concern was the potential of VOCs in the soil and groundwater left over from the site’s former use as an aeronautics manufacturing facility and runway. Without engineered safety measures the impacted soil could present a danger to the residents and workers of the new Playa Vista community. 30 January 2009 Sustainable Land Development Today

Table of Contents Feed for the Digital Edition of Sustainable Land Development Today - January 2009

Sustainable Land Development Today - January 2009 Contents Our Voice Your Voice The BottomLine SLDI in Focus Calendar Industry Rebound Will Require Balanced Approach What Happened to Fannie and Freddie? Added Value in Entitlements Industry Spotlights Technology Wastewater Innovation Classifieds Advertiser Index Editorial Board SLDT Resources Last Word

Sustainable Land Development Today - January 2009

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