IEC 60068-2-5:2010

IEC 60068-2-5


®

Edition 2.0 2010-04



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE


Environmental testing –
Part 2-5: Tests – Test Sa: Simulated solar radiation at ground level and guidance
for solar radiation testing

Essais d’environnement –
Partie 2-5: Essais – Essai Sa: Rayonnement solaire simulé au niveau du sol et
guide pour les essais de rayonnement solaire


IEC 60068-2-5:2010

---------------------- Page: 1 ----------------------
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IEC 60068-2-5


®

Edition 2.0 2010-04



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE


Environmental testing –
Part 2-5: Tests – Test Sa: Simulated solar radiation at ground level and guidance
for solar radiation testing

Essais d’environnement –
Partie 2-5: Essais – Essai Sa: Rayonnement solaire simulé au niveau du sol et
guide pour les essais de rayonnement solaire


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
R
CODE PRIX
ICS 19.040 ISBN 978-2-88910-035-4
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 60068-2-5 Ó IEC:2010


CONTENTS


FOREW ORD . 3

INTRODUCTION . 5


1 Scope and object . 6

2 Normative references . 6

3 Terms and definitions . 6

4 General . 7

4.1 Irradiance . 7

4.2 Spectral distribution . 7
5 C o n di t ioning . 8
5.1 Ge n eral . 8
5.2 Temperature . 8
5.3 H umidi t y . 9
5.4 Ozone and other contaminating gases . 9
5.5 Surface contamination . 9
5.6 Mounting of specimen . 9
5.7 Test facility . 9
5.8 Test apparatus . 9
6 Initial measurement . 10
7 Testing . 10
7.1 General . 10
7.2 Procedure A – 24 h cycle, 8 h irradiation and 16 h darkness, repeated as
required . 10
7.3 Procedure B – 24 h cycle, 20 h irradiation and 4 h darkness, repeated as
required . 10
7.4 Procedure C – Continuous irradiation as required . 11
8 Final measurements. 12
9 Information to be given in the relevant specification . 12
10 Information to be given in the test report . 13
Annex A (informative) Interpretation of results . 14
Annex B (informative) Radiation source . 16
Annex C (informative) Instrumentation . 17
Bibliography . 19


Figure 1 – Global solar spectral irradiance at the earth´s surface for relative air mass . 8
Figure 2 – Test procedures A, B and C . 11

Table 1 – Spectral energy distribution . 8
Table C.1 – Calculated spectral distribution values. 18

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60068-2-5 Ó IEC:2010 – 3 –


INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



ENVIRONMENTAL TESTING –



Part 2-5: Tests – Test Sa: Simulated solar radiation at

ground level and guidance for solar radiation testing





FOREWORD

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International Standard IEC 60068-2-5 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This second edition cancels and replaces the first edition of IEC 60068-2-5, published in
1975, and IEC 60068-2-9, published in 1975, and constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
This second edition of IEC 60068-2-5 will make the reading much easier, partly because it
includes guidance for solar radiation testing, previously published in a separate publication,
IEC 60068-2-9, and partly because it now allows the use of all lamps specified in CIE 85 and
published in 1985 by the International commission on Illumination.

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– 4 – 60068-2-5 Ó IEC:2010


The text of this standard is based on the following documents:

FDIS Report on voting


104/500/FDIS 104/515/RVD



Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.


This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.


A list of all the parts in the IEC 60068 series, under the general title Environmental testing,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
 reconfirmed,
 withdrawn,
 replaced by a revised edition, or
 amended.

The contents of the corrigendum of December 2010 have been included in this copy.

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60068-2-5 Ó IEC:2010 – 5 –


INTRODUCTION


This part of IEC 60068 describes methods of simulation designed to examine the effect of

solar radiation on equipment and components at the surface of the earth. The main

characteristics of the environment to be simulated are the spectral energy distribution of the

sun, as observed at the earth's surface, and the intensity of received energy, in combination

with controlled temperature conditions. However, it may be necessary to consider a

combination of solar radiation with other environments, e.g. temperature, humidity, air

velocity, etc.

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– 6 – 60068-2-5 Ó IEC:2010


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 20:1972, Recommendation for the integrated irradiance and the spectral distribution of
simulated solar radiation for testing purposes
CIE 85:1985, 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 where air mass = 1
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).

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60068-2-5 Ó IEC:2010 – 7 –


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


2
NOTE The value of the solar constant is E = 1 367 W/m .
0

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
2
value of 1 090 W/m for the global radiation at the surface of the earth from sun at zenith;
2
value based on a solar constant E = 1 367 W/m .
0
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.

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2 000



1 600



1 200



800
400
0
0,3 0,7 1,1 1,5 1,9 2,3
Wavelength  (mm)

IEC  640/10

NOTE Optical depth of aerosol extinction 0,1 (solid line) and 0,27 (dashes), respectively.
Figure 1 – Global solar spectral irradiance at the earth´s surface
for relative air mass 1
Table 1 – Spectral energy distribution
Spectral Total
*
Ultra-violet B Ultra-violet A Visible Infra-red
region radiation
Bandwidth 320 nm to 400 nm to 800 nm to
300 nm to 300 nm to
400 nm 800 nm 2 450 nm
320 nm 2 450 nm
2 2 2 2 2
Irradiance 4,06 W/m 70,5 W/m 604,2 W/m 411,2 W/m 1 090 W/m
Approximate 0,4 % 6,4 % 55,4 % 37,8 % 100 %
proportion of
total radiation
* Radiation shorter than 300 nm reaching the earth’s surface is insignificant.

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
–2 –1
Spectral irradiance  (Wm mm )

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60068-2-5 Ó IEC:2010 – 9 –


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 or a black panel thermometer can be used to measure the

maximum surface temperature. By ventilation, this temperature can be influenced.

5.3 Humidity


Different humidity conditions, particularly condensation, can markedly affect photochemical

degradation of materials, paints, plastics, etc. If required, the values of IEC 60068-2-78 shall

be preferred.


The relevant specification shall state the humidity and whether it is to be maintained during
a) the irradiation periods only;
b) the periods of darkness only;
c) the whole test duration.
5.4 Ozone and other contaminating gases
Ozone, generated by short wavelength ultra-violet of test sources, will normally be excluded
from the test chamber by the radiation filter(s) used to correct the spectral energy distribution.
As ozone and other contaminating gases can significantly affect the degradation processes of
certain materials, it is important to exclude these gases from the test chamber, unless
otherwise required by the relevant specification.
5.5 Surface contamination
Dust and other surface contamination may significantly change the absorption characteristics
of irradiated surfaces. Unless otherwise required, specimens should be tested in a clean
condition. However, if effects of surface contamination are to be assessed, the relevant
specification should include the necessary information on preparation of surfaces, etc.
5.6 Mounting of specimen
The specimen to be tested shall be placed either on raised support, on a turntable or a
specified substrate of known thermal conductivity and thermal capacity within the chamber as
stated in the relevant specification, and so spaced from other specimens as to avoid shielding
from the source of radiation or re-radiated heat. Temperature sensors should be attached to
specimen as required.
5.7 Test facility

It shall be ensured that the optical parts of the test facility, lamps, reflectors and filters, etc.
are clean.
The level of irradiation over the specified measurement plane shall be measured immediately
prior to each test.
Any ancillary environmental conditions, e.g. ambient temperature, humidity and other
parameters if specified, should be monitored continuously throughout the test.
5.8 Test apparatus
The chamber in which the tests are to be carried out shall be provided with means for
2
obtaining, over the prescribed irradiation measurement plane, an irradiance of 1 090 W/m
2
± 10 % with the spectral distribution given in Table 1. The value of 1 090 W/m shall include
any radiation reflected from the test chamber and received by the specimen under test. It
should not include long-wave infra-red radiation emitted by the test chamber.

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– 10 – 60068-2-5 Ó IEC:2010


Means shall also be provided whereby the specified conditions of temperature, air flow and

humidity can be maintained within the chamber.


The temperature within the chamber shall be measured (with adequate shielding from

radiated heat) at a point or points in a horizontal plane 0 mm to 50 mm below the prescribed

irradiation measurement plane, at half the distance between the specimen under test and the

wall of the chamber, or at 1 m from the specimen, whichever is the lesser.


6 Initial measurement


The specimen shall be submitted to the visual, dimensional and functional checks prescribed
by the relevant specification.
7 Testing
7.1 General
During exposure, 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 or IEC 60068-2-2 or the
relevant specification.
In procedure A, the temperature within the chamber shall start to rise 2 h before the
irradiation period starts.
During the darkness period in procedures A and B, the temperature within the chamber shall
fall approximately with 1 K/min and be maintained at +25 °C. If the required temperature is
lower than 25 °C, the temperature shall be maintained at the required temperature.
The requirements for irradiation, temperature and time relationships are given in Figure 2.
Throughout the specified test duration, the temperature within the chamber shall be
maintained within ±2 °C of that shown for the appropriate procedure.
2
The level of irradiance should be 1 090 W/m ± 10 % or specified in the relevant specification.
Acceleration of the test by increasing the irradiation above this level is not recommended. The
total daily irradiation approximating the most severe natural conditions is simulated by
procedure A with a duration of exposure to the standard irradiation conditions of 8 h per day.
Thus, exposure for periods in excess of 8 h will effect acceleration over natural conditions.
However, continuous exposure of 24 h per day, procedure C, might mask any degradation
effects of cyclic thermal stressing, and this procedure is therefore not generally recommended
in this instance.

The specimen shall be exposed, for the duration called for in the relevant specification, to one
of the following test procedures (see Figure 2).
7.2 Procedure A – 24 h cycle, 8 h irradiation and 16 h darkness, repeated as required
2
This gives a total irradiation of 8,96 kWh/m per diurnal cycle, which approximates to the most
severe natural conditions. Procedure A should be specified where the principal interest is in
thermal effects.
7.3 Procedure B – 24 h cycle, 20 h irradiation and 4 h darkness, repeated as required
2
This gives a total irradiation of 22,4 kWh/m per diurnal cycle and is applicable where the
principal interest is in degradation effects.

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60068-2-5 Ó IEC:2010 – 11 –


7.4 Procedure C – Continuous irradiation as required


A simplified test, applicable where cyclic thermal stressing is unimportant and photochemical

effects only are to be assessed. Also for the assessment of heating effects on specimens with

low thermal capacity.

Procedure A


1 cycle


T
2


T
1
Irradiation
0 8 Time  (h) 24



Procedure B
1 cycle
T
2
T
1
Irradiation
0 Time  (h) 20 24


Procedure C
T
2

T
1
Continuous irradiation
0
Time  (h)


Key
T lower temperature (25 °C if not otherwise specified)
1
T upper temperature (40 °C if not otherwise specified)
2
Figure 2 – Test procedures A, B and C

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– 12 – 60068-2-5 Ó IEC:2010


8 Final measurements


The specimen shall be submitted to the visual, dimensional and functional checks prescribed

by the relevant specification.



9 Information to be given in the relevant specification


The relevant specification shall contain the following details as far as they are applicable:


a) exposure time to radiation;

b) black standard temperarure or black panel temperature;
c) power of radiation;
d) duration of the test;
e) state of operation;
f) preconditioning;
g) number of specimens;
h) humidity if relevant;
i) type and scope of initial measurement;
j) test procedure;
k) temperature during the test;
l) period of operation;
m) type and scope of intermediate measurement;
n) recovery;
o) type and scope of final measurement;
p) criteria for evaluation;
q) description of specimen support used for testing.

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60068-2-5 Ó IEC:2010 – 13 –



10 Information to be given in the test report


When this test is included in the relevant specification, the following details shall be given,

where applicable:


a) Test laboratory (name and address and details of

accreditation – if any)


b) Test dates (dates when test was run)

c) Customer (name and address)
d) Type of test (procedure A, B, C)
e) Required values (temperature, humidity, radiation, etc.)
f) Purpose of test (development, qualification, etc.)
g) Test standard, edition (IEC 60068-2-5, edition used)
h) Relevant laboratory test procedure (code and issue)
i) Test specimen description (drawing, photo, quantity build status, etc.)
j) Test chamber (manufacturer, model number, unique id,
etc.)
k) Performance of tes
...