ASME B89.1.7 pdf download.Performance Standard for Steel Measuring Tapes.
2 DEFINITIONS
accuracy: closeness of agreement between a measured quantity value and a true quantity value of a measurand. Accuracy is a qualitative concept. (VIM 2.13)
i’raduatious: marks or lines perpendicular to the edge of a measuring tape denoting increments of measure.
infrrnwdiate graduatiou: a graduation mark denoting an increment of measure that falls between the major and the minor graduations (e.g., inch or centimeter).
major graduation: a graduation mark denoting the largest increment of measure (e.g., feet or meter).
,naxinum permissible errors (MPE): extreme value of measurement error, with respect to a known reference quantity value, permitted by specifications or regulations for a given measurement, measuring instrument, or measuring system. (VIM 4.26)
minor graduation: a graduation mark denoting the smallest increment of measure (e.g., fraction of an inch, decimal inch, or millimeter).
plumb ba,: when used with a measuring tape, a weight with a tapered or flat tip on the bottom that is suspended from the tape.
tension: a force that tends to stretch or elongate something, or a measure of such a force.
NOTE: The measuw of force in the US. Customary system is the pound (IbI); the measure of force in the SI system is the newton (N). Traditionally, the tension (a force) has been referred to in units of pound.and kilograms. Pound (orpound-force) is proper. In the SI system of units, the kilogram is the unit of mass and the newton is the unit of force, In this Standard. th tension for tapes graduated in SI units is specified in kilograms. in order to maintain continuit of reference to master tape calibration data. The corresponding force in newtons is equal to the applied mass in kilograms multiplied by the acceleration due to gravity g. By convention,
= 9.89665 rn/s2 es.actly. Thus, the force exerted on a tape by a I kg load is 9.80665 N. For highest .1ccuraq the local value of g should be used.
validity conditions: the set of values or range of values of the relevant influence quantities, e.g., environmental conditions, under which the performance specifications are valid.
(c) State the expanded (k = 2) uncertainty associated with the calibrated distance of the reference standard as used at the time of measurement
NOTE This includes both the uncertainty on the cili1’ration certificate and effects such as the prevailing thermal conditions at the time of the calibration, and associated equipment used to transfer the value from the master to thc tape under calibration, for esampie. a microscope carnage system.
(d) Provide an uncertainty budget describing the uncertainty components used to compute the statement of uncertainty. For a master tape, the typical uncertainty components are the calibration uncertaint the uncertainty in the master tape temperature (used to make the nominal thermal expansion correction), and the uncertainty in the coefficient of thermal expansion of the master tape. Additional uncertainty components may include lixturing effects.
(e) Provide documentation of traceability back to an appropriate terminus of the standard used for the reference standard (see section 1-3 for an appropriate metro- logical terminus). For example, for a master tape the calibration certificate would suffice assuming the certificate is from an appropriate metrological terminus.
‘f Show evidence of an internal quality assurance program so that the measurement uncertainty statement for the reference standard is assured. This may be a simple procedure to ensure that the reference standard is periodically recalibrated; other sensors, e.g., the weather station of a reference interferometer, are periodically recalibrated; and the artifact fixturing or other effects are in accordance with the calibration requirements or otherwise taken into account in the uncertainty budget.
1-3 METROLOGICAL TERMINUS
An appropriate metmlogical terminus for the documentation traceability is any one of the following sources (see ASME 889.7.5 for further details):
(a) a calibration report’\ from a national measurement institute (NMI) for the reference length (artifact or instrument) used in the testing.
ASME B89.1.7 pdf download
