IEC 60068-2-5 pdf download

IEC 60068-2-5 pdf download.Environmental testing – Part 2-5: Tests – Test Sa: Simulated solar radiation at ground level and guidance for solar radiation testing
1 Scope and object
This part of IEC 60068 provides guidance for testing equipment or components under solar radiation conditions. The purpose of testing is to investigate to what extent the equipment or components are affected by solar radiation. The method of combined tests detects electrical, mechanical or other physical variations.
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. IEC 60068-1 , Environmental testing – Part 1: General and guidance IEC 60068-2-1 , Environmental testing – Part 2-1: Tests – Test A: Cold IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Test B: Dry heat IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady state CIE 85:1 985, Solar spectral irradiance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60068-1 , as well as the following, apply. 3.1 air mass path length that light from a celestial object takes through the earth’s atmosphere relative to the length at the zenith where air mass = 1 at the zenith NOTE The air mass is 1 /sin (gamma), where gamma is the elevation angle of the sun. 3.2 black standard temperature BST characteristic value of the specimen surface temperature NOTE Black standard temperature as measured by a black standard thermometer (see ISO 4892-1 ).3.3 black panel temperature characteristic value of the specimen surface temperature NOTE Black panel temperature as measured by a black panel thermometer (see ISO 4892-1 ). 3.4 solar constant rate at which solar energy, at all wavelengths, is received per unit area at the top level of earth’s atmosphere NOTE The value of the solar constant is E 0 = 1 367 W/m 2 . 3.5 optical depth measure of how much light is absorbed in travelling through a medium NOTE A completely transparent medium has an optical depth of zero.
4 General remarks
4.1 Overview The effect of radiation on the specimen will depend on the level of irradiance, the spectral distribution, the location, the time of day and the sensitivity of the material of the specimen. 4.2 Irradiance The irradiance by the sun on a plane perpendicular to the incident radiation outside the earth’s atmosphere at the mean earth-sun distance is known as the solar constant E 0 . The irradiance at the surface of the earth is influenced by the solar constant and the attenuation and scattering of radiation in the atmosphere. For test purposes, CIE 85 gives a value of 1 1 20 W/m 2 for the global radiation at the surface of the earth from sun at zenith; value based on a solar constant E 0 = 1 367 W/m 2 . 4.3 Spectral distribution The standard spectral distribution of the global radiation specified for this test, in accordance with the recommendations of the CIE 85, is given in Figure 1 and in Table 1 .If the source of radiation used for the test does not meet the standard spectral distribution given in Table 1 , the exact spectral absorption data of the material and the exact spectral irradiance of the alternative radiation source in the range from 300 nm to about 3 000 nm and for the solid angle of 2π sr above the specimen surface shall be known or measured.
5 Conditioning
5.1 General During the entire test, the irradiation, the temperature within the chamber, the humidity and any other specified environmental conditions shall be maintained at the levels appropriate to the particular test procedure specified in the relevant specification. The relevant specification shall state which preconditioning requirements are to be applied. 5.2 Temperature The temperature within the chamber during irradiation and darkness periods shall be controlled in accordance with the procedure (A, B or C) specified. During irradiation, the temperature within the chamber shall rise or fall by 1 K/min and be maintained at one of the preferred values given in IEC 60068-2-1 , IEC 60068-2-2 or the relevant specification. NOTE Additionally, a black standard thermometer can be used to control the maximum surface temperature. By ventilation, this temperature can be influenced.