How to make choice of the hammer test apparatus？

IEC 60068 provides for three methods of test (the pendulum hammer, the spring hammer and the vertical hammer.) which, as far as is practicable, are intended to give similar results. To obtain repeatable and reproducible results, this test is more dependent on the details of the test apparatus than is usual in IEC 60068 standards.

The choice of the test apparatus depends on the orientation of the surface to be tested and on the energy level. Not all methods can be used in every case. 

It is self-evident that a pendulum hammer can only be used on vertical surfaces without overhangings. 

Similarly the vertical hammer can normally only be used on accessible horizontal surfaces. 

When the specimen cannot be moved or turned, for any reason, the choice is limited. 

The advantage of the spring hammer is that it can be used in any position, provided there is enough room to apply it correctly, and that the specified impact energy does not exceed 2 J. For higher energy levels, aspring hammer would be too difficult to handle, and could even be hazardous for the operator.