ASTM D7238-06

The use of this apparatus is intended to induce property changes associated with the end use conditions, including the effects of the UV portion of sunlight, moisture, and heat. Exposures are not intended to simulate the deterioration caused by localized weather phenomena, such as atmospheric pollution, biological attack, and saltwater exposure.

Note 3—Refer to Practice G 151 for cautionary guidance applicable to laboratory weathering devices.

Variation in results may be expected when operating conditions are varied within the accepted limits of this method.

Test data for one thickness of a geomembrane can not be used as data for other thickness geomembranes made with the same formula (polymer, pigment and stabilizers) since the degradation is thickness related.

Note 4—It is recommended that a similar material of known performance (a control) be exposed simultaneously with the test material to provide a standard for comparative purposes. When control material is used in the test program, it is recommended only one coupon be used for each UV exposure period to allow for OIT testing.

1.1 This standard covers the specific procedures and test conditions that are applicable for exposure of unreinforced polyolefin geomembranes to fluorescent UV radiation and condensation.

Polyolefin geomembranes include high density polyethylene (HDPE), linear low density polyethylene (LLDPE), flexible polyproplyene (fPP), etc.

1.2 Test specimens are exposed to fluorescent UVA 340 lamps under controlled environmental conditions. UVA 340 lamps are standard for this method.

Other types of fluorescent UV lamps, such as UVB-313, can also be used based upon discussion between involved parties. However, if the test is ran with another type of fluorescent UV lamps, such as UVB-313, this should be considered as a deviation from the standard and clearly stated in the test report. UVB-313 and UVA-340 fluorescent lamps generate different amount of radiant power in different wavelength ranges; thus, the photochemical effects caused by these different lamps may vary.

1.3 This method covers the conditions under which the exposure is to be performed and the test methods for evaluating the effects of fluorescent UV, heat and moisture in the form of condensation on geomembranes. General guidance is given in Practices G 151 and G 154.

1.4 The values listed in SI units are to be regarded as the standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.