1Scope and object 13
2Normative references 13
3Terms and definitions 15
4Application of tests for non heat-dissipating specimens versus tests for heat-
dissipating specimens 15
4.1General 15
4.2Ascertaining high or low air velocity in the test chamber 15
4.3Non heat-dissipating specimens 17
4.4Testing of heat-dissipating specimens 17
4.5Temperature monitoring 17
4.6Packaging 17
4.7Diagrammatic representations 17
5Test description 19
5.1General 19
5.2Test Ab: Cold for non heat-dissipating specimens with gradual change of
temperature 19
5.2.1Object 19
5.2.2General description 21
5.3Test Ad: Cold for heat-dissipating specimens with gradual change of
temperature that are powered after initial temperature stabilization 21
5.3.1Object 21
5.3.2General description 21
5.4Test Ae: Cold for heat-dissipating specimens with gradual change of
temperature that are required to be powered throughout the test 21
5.4.1Object 21
5.4.2General description 21
5.4.3Energizing the specimen 23
6Test procedure 23
6.1Confirmation of performance 23
6.2Working space 23
6.3Thermal radiation 23
6.4Specimen with artificial cooling 23
6.5Mounting 25
6.6Severities 25
6.6.1Temperature 25
6.6.2Duration 25
6.7Preconditioning 25
6.8Initial measurements 25
6.9Conditioning 25
6.10Intermediate measurements 27
6.11Final temperature ramp 27
6.12Recovery 27
6.13Final measurements 27
7Renseignements que doit fournir la spécification particulière 26
8Renseignements que doit fournir le rapport d’essai 28
Figure 1 – Diagramme complet des essais A: Froid 18
1 Scope and object
This part of IEC 60068 deals with cold tests applicable to both non heat-dissipating and heat- dissipating specimens. For non heat-dissipating specimens, Tests Ab and Ad do not deviate essentially from earlier issues. Test Ae has been added primarily for testing equipment that requires being operational throughout the test, including the conditioning periods.
The object of the cold test is limited to the determination of the ability of components, equipment or other articles to be used, transported or stored at low temperature.
Cold tests cover by this standard do not enable the ability of specimens to withstand or operate during the temperature variations to be assessed. In this case, it would be necessary to use IEC 60068-2-14.
The cold tests are subdivided as follows:
Cold tests for non heat-dissipating specimens
with gradual change of temperature, Ab;
Cold test for heat-dissipating specimens
with gradual change of temperature, Ad,
with gradual change of temperature, specimen powered throughout, Ae.
The procedures given in this standard are normally intended for specimens that achieve temperature stability during the performance of the test procedure.
Temperature chamber(s) are constructed and verified in accordance with specifications IEC 60068-3-5 and IEC 60068-3-7.
Further guidance for dry heat and cold tests can be found in IEC 60068-3-1 and general guidance in IEC 60068-1.
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.
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
IEC 60068-2-14, Basic environmental test procedures – Part 2-14: Tests – Test N: Change of temperature
IEC 60068-3-1, Environmental testing – Part 3: Background information – Section one: Cold and dry heat tests
CEI 60068-3-5, Essais d’environnement – Part 3-5: Documentation d'accompagnement et guide – Confirmation des performances des chambres d'essai en température
CEI 60068-3-7, Essais d’environnement – Part 3-7: Documentation d'accompagnement et guide – Mesures dans les chambres d'essai en température pour les essais A et B (avec charge)
CEI 60068-5-2, Essais d’environnement – Part 5-2: Guide pour la rédaction des méthodes d'essais - Termes et définitions
CEI 60721 (toutes les parties), Classification des conditions d’environnement