Selecting appropriate inspection, measuring, and test equipment 4.11.2a

Selecting appropriate inspection, measuring, and test equipment (4.11.2a) 

The standard requires the supplier to select the appropriate inspection, measuring, and test equipment that is capable of the accuracy and precision necessary. 

There are two categories of equipment which determine the selection of equipment general-purpose and special-to-type equipment. It should not be necessary to specify all the general-purpose equipment needed to perform basic measurements, which would be expected to be known by appropriately trained personnel. You should not need to tell an inspector or tester which micrometer, vernier caliper, voltmeter, or oscilloscope to use. These are the tools of the trade and they should select the tool which is capable of measuring the particular parameters with the accuracy and precision required. However, you will need to tell them which device to use if the measurement requires unusual equipment or the environmental conditions prevailing require that only equipment be selected that will operate in such an environment. In such cases the particular devices to be used should be specified in the test or inspection procedures. In order to demonstrate that you selected the appropriate device at some later date, you should consider recording the actual device used in the record of results. With mechanical devices this is not normally necessary because wear should be detected well in advance of there being a problem by periodic calibration. 

With electronic devices subject to drift with time or handling, a record of the device used will enable you to identify suspect results in the event of the device being found to be outside the limits at the next calibration. A way of reducing the effect is to select devices that are several orders of magnitude more accurate than needed. (See later under Action on equipment found out of calibration.) 

On occasions you may require a measurement capability that exceeds the known state of the art, such accuracy and precision that no available device can achieve. If under contract to a customer you should inform your customer of this situation so that you can negotiate the measures needed to develop the technology required. (See Part 2 Chapter 2 on Identifying new measurement capabilities.) 

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