Geomembrane Design

ISO 9001:2000 Quality Assurance and Testing

General
Quality control of the installation can be divided into three areas:

Checking the material delivered to site for damage prior to use, checking the sheet identification number with factory QA, and carrying out checks on material thickness and material properties.
Inspection and continuous control of all welding, including weld parameters and full testing of regular trial seams.
Testing of the completed weld seams by destructive and non-destructive methods.

The on-site welding of each material is carried out by special welding processes which are fully monitored and tested. This ensures consistent weld seam quality within a wide range of ambient conditions.

Materials tests and panel sizes are recorded on our QA Report No. 1

Faults and repairs are recorded on QA Report No. 2.

Daily progress, weather and machinery set-ups and test welds are recorded on QA Report No. 3.

Inspection of Welding Seams
The completed weld seams are inspected to ensure a strong water-tight bond.

The principal inspection methods are continuous and non-destructive.

The company's site personnel conduct and record the following inspection of the joints formed.

Visual Inspection of Welding Seam
Visual inspection of the welding surfaces, the welding process and the completed weld is carried out to ensure consistency of weld.
Destructive Mechanical Testing
The procedure is carried out on samples of completed trial welds. Each sample is subjected to tensile testing. At least two specimens are tested, one in the direct tensile mode and one in the peel mode.
Once a destructive weld test has been completed, the sample is viewed to establish where the break has occurred and the weld classified by referring to industry standard charts.
Non-Destructive Air Pressure Testing - For Wedge Welded Joints
The welds are tested for continuity by pneumatic pressurisation of the central void in the double weld. On completion of the weld run, the channel is sealed at one end and the other end is attached to the test equipment. Air pressure is applied to the channel. The system is then allowed to stabilise and is isolated from the air pressure source, and the pressure in the channel monitored. For satisfactory weld, the air pressure should not change by more then 10% of its initial stabilised value.
Non-Destructive Spark Testing - For Extrusion Welded Joints
A copper wire is encapsulated within the weld. A high voltage electric spark is applied above the welded section. The spark will normally spread evenly across the surface of the weld, but will concentrate into any areas where a satisfactory welded seam has not been achieved.
Vacuum Box Testing - For Vulcanised Hot Air Joints
This method is used in areas of complex welding detail, or where other methods are not feasible, and comprises treating the area of the liner to be tested with a soap solution and then using an open- based box producing a vacuum over the soaped area. Leaks are detected by the appearance of bubbles.
Air Lance - For Vulcanised and Hot Air Joints
This method involves forcing a high pressure jet of air along the weld edge and looking for signs of lifting or bubbling.