New Hydrocarbon Barrier Technology
Puraflex is a new hydrocarbon and chemical resistant barrier membrane designed for containment, separation, environmental and groundwater protection 
projects. Its proven resistance to hydrocarbons and toxic industrial chemicals provides a cost-effective solution for brownfield developments. Environmental Risk Assessments for brownfield sites require a soil analysis to identify concentrations of hydrocarbon and toxic chemical contaminants.
The integrity of any risk assessment therefore relies on the permeation data of separating geosynthetic membranes. Though considered chemical resistant, HDPE and other common homogeneous geosynthetic membrane materials are susceptible to Hydrocarbon permeation
due to the limitations of their chemical resistance spectrum. HDPE is a hydrocarbon and because they are the same species, hydrocarbons permeate more readily
through HDPE membranes. Industrial Textiles & Plastics Ltd, a manufacturer of chemical protective clothing materials resistant to chemical and biological warfare agents, has
developed a new hydrocarbon barrier specifically designed to resist hydrocarbons and toxic industrial chemicals commonly identified in contaminated land
risk assessments. The barrier membrane is an extruded composite comprising protective polymeric layers on both sides of a chemical resistant inner core. The outer surfaces
of the membrane are Non-Polar polyolefinic polymers and like HDPE, insoluble to Polar chemicals but not to Non-Polar hydrocarbons. The concentration gradient for Benzene, a well know carcinogenic hydrocarbon, is linear across a generic 1.5mm HDPE membrane. At a concentration of 100
mg/kg, Benzene permeates at over 500 mg/m2/year. However across Puraflex, there is an abrupt change as the Benzene reaches the Polar core region of the membrane,
resulting in a significantly lower Permeation Rate of less than 0.001 mg/m2/year for the same concentration level. To assist environmental consultants and design engineers, ITP provides Puraflex Permeation Modeller software. Soil analysis data is simply uploaded
into the software and key site-specific variables, including soil temperature, moisture and density are entered. The software calculates predictive permeation
rates for over 200 hydrocarbons which are then imported directly in to environmental risk assessment models (such as the Environment Agency’s CLEA modelling
software) to determine whether the proposed site and the wider environment is suitably protected. Where risk assessments determine that the best design solution is a separation membrane, whether installed under the entire site or the building’s footprint,
Puraflex provides a cost effective, robust and high performance barrier to hydrocarbons and toxic industrial chemicals. Puraflex Permeation Modeller is freely available by contacting Charlotte Shaw, Puraflex Technical Support, Tel: +44 (0)1347 825221 or Email:
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Posted: 17/06/2011 By: Mr Richard Menage