The equipment qualification of safety important items in nuclear installations is a vital part of the facility design basis. The process includes qualification for functional capability, seismic conditions, environmental conditions, and electromagnetic interference effects over the full range from normal operating conditions to accident conditions. It should be proven that the equipment that is relied upon to perform safety functions can perform these functions even in the event of design extension conditions. Moreover, quality assurance during testing, manufacturing process, installation, and maintenance is an integral element of this.