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

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
1scope and object
This part of lEC 60068 provides guidance for testing equipment or components under solarradiation conditions.
The purpose of testing is to investigate to what extent the equipment or components areaffected by solar radiation.
The method of combined tests detects electrical, mechanical or other physical variations.
Normative references
The following referenced documents are indispensable for the application of this document. Fordated references，only the edition cited applies. For undated references, the latest edition ofthe referenced document (including any amendments) applies.
IEC 60068-1，Environmental testing – Part 1: General and guidanceIEC 60068-2-1，Environmental testing – Part 2-1: Tests – Test A: ColdIEC 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 stateCIE 85:1985,Solar spectral irradiance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in lEC 60068-1, as well asthe following, apply.
3.1
air mass
path length that light from a celestial object takes through the earth’s atmosphere relative tothe 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 temperatureBST
characteristic value of the specimen surface temperature
NOTE Black standard temperature as measured by a black standard thermometer (see lSO 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 lS0 4892-1).3.4
solar constant
rate at which solar energy,at all wavelengths， is received per unit area at the top level ofearth’s atmosphere
NOTE The value of the solar constant is E。= 1 367 W/m2.3.5
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.
4General remarks
4.1overview
The effect of radiation on the specimen will depend on the level of irradiance, the spectraldistribution, the location, the time of day and the sensitivity of the material of the specimen.
4.2lrradiance
The irradiance by the sun on a plane perpendicular to the incident radiation outside the earth’satmosphere at the mean earth-sun distance is known as the solar constant Eo-.
The irradiance at the surface of the earth is influenced by the solar constant and theattenuation and scattering of radiation in the atmosphere.For ‘test purposes,CIE 85 gives avalue of 1 120 W/m2 for the global radiation at the surface of the earth from sun at zenith;value based on a solar constant Eo= 1 367 W/m2 .
4.3Spectral distribution
The standard spectral distribution of the global radiation specified for this test,in accordancewith the recommendations of the CIE 85, is given in Figure 1 and in Table 1.