N.Y.C. Admin. Code § 27-598: § 27-598 Core tests of concrete construction.

The adequacy of the concrete in a building may be ascertained by the recovery and testing of cores. Cores shall be taken and tested in accordance with the procedure described in reference standard RS 10-16. In lieu thereof, cores cast-in-place and originally cured with the parent concrete, or other device acceptable to the architect or engineer designated for controlled inspection and which will produce test specimens simulating the condition of the concrete in place including the size and proportions specified for core specimens may be utilized to demonstrate the adequacy of the concrete in place. The compressive strength so determined shall meet the requirements for strength tests as described in reference standard RS 10-3.