This part of GB/T 16422 specifies specifies methods for exposing specimens to open-flame carbon-arc lamps in the presence of moisture to reproduce the weathering effects that occur when materials are exposed in actual end-use environments in daylight or daylight filtered through window glass.
This part is applicable to the evaluation of weather resistance of plastics and the comparison test of weather resistance between plastics under the condition of carbon-arc light source exposure.
The specimens are exposed to filtered open-flame carbon-arc light under controlled environmental conditions (temperature, moisture). Various filters are described.
Specimen preparation and evaluation of the results are covered in other national standards for specific materials.
General guidance is given in GB/T 16422.1.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 16422.1-2006 Plastics — Methods of Exposure to Laboratory Light Sources — Part 1: General Guidance (ISO 4892-1:1999, IDT)
ISO 4582 Plastics — Determination of Changes in Color and Variations in Properties after Exposure to Daylight under Glass, Natural Weathering or Laboratory Light Sources
ASTM G 152 Standard Practice for Operating Open Flame Carbon Arc Light Apparatus for Exposure of Nonmetallic Materials
3 Principle
3.1 Specimens of the materials to be tested are exposed to glass-filtered open-flame carbon-arc light, to heat and to moisture continuously or in repetitive cycles.
3.2 The exposure conditions may be varied by selection of:
a) the light filter;
b) the type of exposure to moisture/humidity;
c) the length of exposure to light and moisture/humidity;
d) the temperature of the exposure;
e) the relative lengths of the light and dark periods.
The effect of moisture is usually produced by controlling the humidity of the air or by spraying the test specimens with demineralized/deionized water or by condensation of water vapour onto the surfaces of the specimens.
3.3 The procedure may include measurements of the irradiance and radiant exposure at the surface of the specimens.
3.4 It is recommended that a similar material of known behaviour (a control) be exposed simultaneously with the test specimens to provide a reference standard for comparative purposes.
3.5 Intercomparison of results obtained from specimens exposed in different apparatus should not be made unless an appropriate statistical relationship has been established between the devices for the particular material tested.
