This part of ISO 1920 specifies a method for taking cores from hardened concrete, their examination, preparation for testing and determination of compressive strength. The part of ISO 1920 does not give guidance on the decision to drill cores or on the locations for drilling nor does it provide procedures for interpreting the core strength results. NOTE It is recommended that before coring, full agreement should be reached by all parties on the need for core testing and how the results should be interpreted.