S1 When strength is used as a basis for acceptance of concrete, standard specimens shall be made in accordance with Practice C 31/C 31M. S2The specimens shall be cured under standard moisture and temperature conditions in accordance with the applicable provisions of Practice C 31/C 31M. S3 The technician performing the strength test shall be certified as an ACI Concrete Strength Testing Technician, Concrete Laboratory Testing Technician-Grade II or by an equivalent written and performance test program covering the relevant test methods. S4If acceptance is based upon compressive strength test results, the certification requirement is satisfied by certification as an ACI Concrete Laboratory Testing Technician-Grade I or by an equivalent written and performance test program.