TABLE 4. CHEMICAL AND BIOLOGICAL REQUIREMENTS FOR GEOMEMBRANE (HDPE GEOMEMBRANES)

19. Resistance to highly concentrated liquids

19.1

19.2  changes in mechanical properties

Change in weight

Uniaxial tensile test, yield stress, elongation at yield.

Immersion must be carried out up to constant weight.  Tensile test is then conducted on re-dried samples.

Change in yield stress <10% and in elongation at yield <10%.

DIN 53521, concentrated media, on the basis of Appendix 1, Group A of the NRW Guidelines, Immersion temperature 23° C, for HDPE geomembrane the media 6, 7, 10, and 11 may omitted, see Appendix A.

The tensile tests are carried out according to DIN 53455 with No. 3 samples of the geomembrane at a climate 23/50 and a speed of 50 mm/min.

20.  Resistance to microorganisms

20.1

20.2

20.3

Change in weight

Visual assessment

Changes in mechanical properties

£ 5%

No significant changes

Changes £10%

DIN 53739, Procedure D soil burial test in microbe-active soil, length of test 1 year.

Tensile test in accordance with DIN 53455, see Table 2, 8.2.

21. Resistance to higher animal life

Root strength

No penetration by roots.

Followed DIN 4062, Sec. 5.7, the tests are carried out on the base material and on the weld seams.

22.  Resistance to higher animal life

Resistance to burrowing animals.

Not to be gnawed through or nibbled by animals.

Test method explained in BPG Geomembranes, IFBT, 1982, p. 38, Sec. 3.8 and 4.8.  Tests are carried out at MPA Dortmund using Arvicola Terrestris (water vole).