IEC 60068-3-3:1991 pdf download.Environmental testing – Part 3-3: Guidance – Seismic test methods for equipments.
Guidance is included in each of the three test methods referred to in this standard but it is specific to the test method. The guidance in this standard is directed towards choosing the appropriate test method and applying it to seismic testing.
This guide applies primarily to electrotechnical equipments but its application can be extended to other equipments and to components
The verification of the performance of an equipment by analysis or by a combination of testing and analysis may be acceptable but is outside the cope of this guide, which is restricted to verification based entirely upon data from dynamic testing.
This guide deals solely with the seismic testing of a full size equipment which can be tested on a vibration table. The seismic testing of an equipment is intended to demonstrate its ability to perform its required function during and/or after the time it is subjected to the stresses and displacements resulting from an earthquake.
The object of this guide is to present a range of methods of testing which, when prescribed by the relevant specification, can be applied to demon strate the performance of equipments for which seismic testing is required with the main aim of achieving qualification.
The choice of the method of testing can be made according to the criteria described in this guide. The methods themselves are closely based on published 1EC test methods.
IEC 60068-3-3:1991 is intended for use by manufacturers to substantiate, or by users to evaluate and verify, the performance of an equipment.
2 General considerations
Two seismic classes have been established: a general seismic class and a specific seismic class. Neither of these classes can be considered to be more demanding than the other. The difference between the two classes lies in the availability of and/or the accuracy in defining the characteristics of the seismic environment. When high reliability safety equipment for a specified environment is required, such as safety related equipment in nuclear power plants, the use of precise data is necessary and, therefore, the specific seismic class is applicable and not the general seismic class. Appendix A contains a flow chart for the selection of the test class (general seismic class or specific seismic class) and four flow charts (Al to A4) covering the possibilities discussed in this guide. To obtain the maximum advantage from this guide it is strongly recommended that the flow charts be studied very thoroughly.IEC 60068-3-3:1991 pdf download.