Calibration of Steel Tapes Tape to Tape Method

1 Page 1 October 2014 SOP 12 Page 1 of 12 SOP No. 12 Recommended Standard Operating Procedure for Calibration of Metal Tapes 1 Tape-to-Tape Method I. Introduction 1.1. Purpose Metal tapes are used by contractors, surveyors, and o... Open at page → 2 Page 2 October 2014 SOP 12 Page 2 of 12 Table 1. Environmental conditions. Temperature Requirements During a Calibration Relative Humidity (%) Lower and upper limits: 18 °C to 22 °C Maximum changes: < ± 1 °C / 24 h and ± 0.5 °C... Open at page → 3 Page 3 October 2014 SOP 12 Page 3 of 12 2.3.3. Equipment, see Figure 1, to apply tension to the tapes under test, consisting of the following. 2.3.3.1. Spring scales (two); one capable of indicating a load of 10 pounds and the... Open at page → 4 Page 4 October 2014 SOP 12 Page 4 of 12 Figure 2. Calibration of Spring Scales. 2.4. Symbols Table 2. Symbols used in this procedure. Symbol Description S Length of the Standard Tape at the calibration interval LX Length of the... Open at page → 5 Page 5 October 2014 SOP 12 Page 5 of 12 2.5.3. Stretch the test tape and standard tape parallel to each other on a reasonably flat surface. The evenness of the surface is less important than the parallelism of the tapes. The tw... Open at page → 6 Page 6 October 2014 SOP 12 Page 6 of 12 3. Calculations 3.1. Calculate and record A – B – C + D for each trial, then record the value of R, the range of these values (difference of highest and lowest) for each scale interval. T... Open at page → 7 Page 7 October 2014 SOP 12 Page 7 of 12 Uncertainty) for the complete standard operating procedure for calculating the uncertainty. 5.1.1 The expanded uncertainty for the standard, U, is obtained from the calibration report. Th... Open at page → 8 Page 8 October 2014 SOP 12 Page 8 of 12 Appendix A Tape-to-Tape Method Data Sheet Date Environmental parameters Metrologist Before After Unc/ability to measure Test No. Temperature °C °C sp in Pressure mmHg mmHg df Humidity % %... Open at page → 9 Page 9 October 2014 SOP 12 Page 9 of 12 Appendix B Supplemental Information B.1. Cleaning To clean a steel tape before calibration, first wipe the tape with a soft cloth; then with a soft cloth saturated with alcohol to remove... Open at page → 10 Page 10 October 2014 SOP 12 Page 10 of 12 throughout the entire length of the tape. Also, tapes may be calibrated and used when supported in catenary types of suspension. In these cases, the tape is supported at equidistant poin... Open at page → 11 Page 11 October 2014 SOP 12 Page 11 of 12 when the zero graduation is to the observer’s left. When viewed through a microscope, some graduations will appear to have irregular edges. The portion of the graduation to be used for c... Open at page → 12 Page 12 October 2014 SOP 12 Page 12 of 12 lb feet feetlb feet lblb AE 333 83 012.0 000 1 100 )992.99 004.100( ) 10 20(     It is recommended that the AE value be determined over the longest interval that is convenient to me... Open at page →