Can you please give your valued interpretation of IAF MD 5 Section 3.5 when the scope and control of processes are same thru 24 hours and the shifts are rotating in a continuous or batch chemical plants?
The standard IAF MD:2013 clearly says that extent of auditing depends on processes performed in each shift and level of applied control. Since the performed processes are identical, under identical conditions and identical SOPs it is enough to audit one shift and provide evidences of same process controls and workers competence in unaudited shifts. In this way you apply the Evidence-based approach, principle from ISO 19011:2011 standard, clause 4 f).
By using established methods of identification and traceability, you can provide evidences that product requirements are met in every shift.
All mentioned above can be used as justification for not auditing odd shifts.