10.2 Instrumentation and Measurement:
10.2.1 Calibrate instrumentation and load-measuring devices to 61 % accuracy. In some indirect methods of load measurement, the load on the beam and that indicated may not be quite the same. Better accuracy in load determination is obtained when the magnitude is directly indicated. This can be done by the use of proving rings or load cells at the reactions or at the points of loading, or by adequate mechanical or electronic devices