IRR Explanation

IRR (Internal Round Robin)

The IRR program allows a laboratory to carry out additional tests within its own structure when it has several machines or operators performing the same type of tests. The objective is to evaluate these additional resources. The results are then compared to the acceptance classes defined by the PT Program for the relevant kit. The IRR specimens and the PTP kit come from the same material batch, ensuring consistency in evaluation.

This process makes it possible to verify the consistency of results between different machines and operators, and to ensure the overall reliability of internal testing.

For example, Company Bob has two tensile testing machines (A and B) and two operators (1 and 2). It first participates in the PTP 2025 of this test, with machine A and its main operator (1), by ordering one PTP kit of 5 specimens.

To also evaluate machine B and operator 2, the company orders two IRR sets from the same batch than PTP kit 2025 (3 specimens each). Operator 1 performs 3 tests on machine B, while operator 2 carries out 3 tests on machine A.

In total, Company Bob therefore receives:

• 1 PTP kit of 5 specimens

• 2 IRR sets of 3 specimens each

The laboratory will then receive the PTP 2025 report, followed by its IRR report for each operator.

Thus, Operator 1 can identify malfunctions between Machine A and Machine B, or observe whether the testing method between Operator 1 and Operator 2 is consistent.