The baseline set of 217Plus models published by the Reliability Information Analysis Center (RIAC) does not have a separate model for PCBs. PCB related failure rates are accounted for in the “lambda solder joint” factor that is included as part of each component model (resistors, capacitors, etc.). If you are adding a separate contribution for PCBs, you may be double counting the PCB failure rate contribution. You should check with Relex to see how they are implementing the PCB model in their implementation of the RIAC 217Plus models.