Calibrations of Pi Tapes Bench Method

1 Page 1 October 2014 SOP 23 Page 1 of 11 SOP 23 Recommended Standard Operations Procedure for Calibrations of PI Tapes Bench Method 1. Introduction 1.1 Purpose PI tapes are circumferential measuring tapes that are wrapped around... Open at page → 2 Page 2 October 2014 SOP 23 Page 2 of 11 2. Methodology 2.1. Scope, Precision, Accuracy The precision and accuracy attainable depend upon the care exercised in aligning the tape on the length bench, and the skill acquired in the... Open at page → 3 Page 3 October 2014 SOP 23 Page 3 of 11 vernier scale which comes closest to lining up with a graduation on the main body is the value to be added to the reading. The vernier allows readings to be made to the nearest 0.001 in,... Open at page → 4 Page 4 October 2014 SOP 23 Page 4 of 11 2.3.3 Another point that must be taken into consideration is that the tape was tested for accuracy on a flat horizontal surface but now it is curved around an object. The tape becomes tem... Open at page → 5 Page 5 October 2014 SOP 23 Page 5 of 11 2.6. 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 → 6 Page 6 October 2014 SOP 23 Page 6 of 11 5 m length bench, fabric strap will be be used to effectively lengthen the tape so that the tension weight is properly suspended below the rollers of the length bench. 2.7.5. Lay two ther... Open at page → 7 Page 7 October 2014 SOP 23 Page 7 of 11 2.7.13. Repeat 2.7.9. thru 2.7.12. for every 15 foot (5 meter) section of the tape requiring calibration. This will require repositioning the tape, aligning the last measured interval gra... Open at page → 8 Page 8 October 2014 SOP 23 Page 8 of 11 corrSX tCdC   (7) 3.8. Calculate and report the mean, XC, of the two corrections for each interval. 3.9. Calculate the length of tape under the 10 pound load. XnXCLL  (8) 3.10. As ap... Open at page → 9 Page 9 October 2014 SOP 23 Page 9 of 11 enough will be 2, (k = 2), to give an approximate 95 percent level of confidence. See NISTIR 6969, SOP 29 (Standard Operating Procedure for the Assignment of Uncertainty) for the complete... Open at page → 10 Page 10 October 2014 SOP 23 Page 10 of 11 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 → 11 Page 11 October 2014 SOP 23 Page 11 of 11 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 →