Calibration of Metal Tapes Bench Method

1 Page 1 October 2014 SOP 11 Page 1 of 15 SOP No. 11 Recommended Standard Operating Procedure for Calibration of Metal Tapes Bench Method 1. Introduction 1.1. Purpose Metal tapes are used by contractors, surveyors, and others for... Open at page → 2 Page 2 October 2014 SOP 11 Page 2 of 15 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 11 Page 3 of 15 2.4. Symbols Table 2. Symbols used in this procedure. Symbol Description S Standard X Unknown d0i Initial zero difference d0f Final zero difference X0L Left edge of zero on unknown X0R Ri... Open at page → 4 Page 4 October 2014 SOP 11 Page 4 of 15 bottom of the fabric strap. Check to see that the tape is lying straight on the bench and parallel to the bench scale. Adjust, if necessary. Apply tension using a weight of 10 pounds, unl... Open at page → 5 Page 5 October 2014 SOP 11 Page 5 of 15 tension weights back on the fabric strap, and realign the zero marks on the tape and the bench to coincidence. 2.5.13. Repeat 2.5.8 thru 2.5.12 for every 15 foot (5 meter) section of the... Open at page → 6 Page 6 October 2014 SOP 11 Page 6 of 15 3.6. Calculate the temperature correction, t corr.  )(20 tLt ncorr (6) 3.7. Calculate a correction, C X, for each trial and each scale interval. corrSX tCdC   (7A) Be sure to... Open at page → 7 Page 7 October 2014 SOP 11 Page 7 of 15 root-sum-squared method (RSS), and the expanded uncertainty, U, reported with a coverage factor to be determined based on degrees of freedom, which if large enough will be 2, (k = 2), to... Open at page → 8 Page 8 October 2014 SOP 11 Page 8 of 15 Table 3. Example uncertainty budget table. Component Description Reference us Standard uncertainty for standa rds Calibration report, divide by k sp Standard uncertainty for the proc ess... Open at page → 9 Page 9 October 2014 SOP 11 Page 9 of 15 Appendix A Bench 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 % % Based... Open at page → 10 Page 10 October 2014 SOP 11 Page 10 of 15 Appendix B Table B-1. Temperature Correction Factors for Calibration of Steel Tapes graduated in feet when linear coefficient of thermal expansion for the tape is 0.00001160 / ºC. All va... Open at page → 11 Page 11 October 2014 SOP 11 Page 11 of 15 Table B-2. Temperature Correction Factors for Calibration of Steel Tapes graduated in meters when linear coefficient of thermal expansion for the tape is 0.00001160 / ºC. All values in m... Open at page → 12 Page 12 October 2014 SOP 11 Page 12 of 15 Appendix C Supplemental Information C.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 → 13 Page 13 October 2014 SOP 11 Page 13 of 15 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 → 14 Page 14 October 2014 SOP 11 Page 14 of 15 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 → 15 Page 15 October 2014 SOP 11 Page 15 of 15 metric tapes, the normal load is 5 kg. A load of 10 kg is used to determine the AE value. C.8. AE Value The AE Value (area elongation value) for a tape is determined by first calibrating... Open at page →