scope:

VDI/VDE 3528 Part 1 presents recommendations on how the design objectives applicable to I&C systems important to safety1) can be achieved when equipment of different qualification depths is used. It illustrates opportunities to compensate for the lack of documentation on the avoidance of latent faults which is associated with a downgraded qualification level by corresponding design of the I&C systems important to safety, with the result that the effects of that latent faults can be tolerated. This requires the use of products which are dissimilar to each other and for which dissimilarity has been demonstrated.

This standard contains recommendations on how the demonstration of dissimilarity between devices and the basic qualification required should be managed. The qualification achieved by that demonstration corresponds to design variant 2 in VDI/ VDE 3528 Part 1.

This standard is applicable when the dissimilarity is to be used as a means of increasing the tolerance of the effects of latent faults.