The British Geomembrane Association (BGA) approached TWI regarding raising the standards within the landfill lining industry in the UK. They believed that standards were dropping as the industry became more competitive.
Annually, over 20 million tonnes of waste are dumped into landfill in the UK. To protect the environment, landfill sites are lined with clay and a welded polyethylene sheet, commonly known as a geomembrane. The primary function of the polyethylene sheet is to collect leachate from the rubbish in order that it can then be reprocessed.
The polyethylene sheet used in the lining process is available in limited widths and therefore has to be welded on site. Two processes are used, wedge welding to weld the sheets together and extrusion welding for hole repair.
The approval testing of welding personnel for lining systems fabrication is covered by draft European prEN13067 - Approval testing of plastic welding Personnel. TWI Certification Ltd, TWI and BGA worked together to expand the existing CSWIP Plastic Welder Examination scheme to cover people working on geomembranes. A training course was developed that will be used by all BGA member companies ensuring autonomy across the industry.
The first full examination was run in Spring 2000 at TWI and successful candidates were awarded a CSWIP certificate.
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