AASHTO PP 57:062009) Standard Practice for Establishing Requirements for and PerformingI Equipment Calibrations, Standardizations, and Checks.
3.2. calibration, n—a set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or between values represented by a material measure or a reference material, and the corresponding values realized by standards (VIM, Section 6.11).
3.2.1. Example—Balances (measurement instrument), Dynamic Shear Rheometer (measuring system), Pycnometer (material measure).
3.2.2. Discussion—The purpose of calibration is to ensure that measurements made by the laboratory are traceable to the International System of Units (SI). Where traceability of measurements to SI units is not possible or relevant, measurements must be traceable to certified reference materials, agreed methods, or consensus standards. Uncertainty estimates obtained during calibration are used to judge if an instrument is suitable for its intended purpose. There is a need to re-establish traceability or recalibrate only when instrument measurements drift out of control [as determined through verification of calibration (Section 3.10)].
3.3. check, n—a specific type of inspection and/or measurement performed on the physical properties of equipment and materials to determine compliance or otherwise with stated criteria.
3.4. correction, n—value added algebraically to the uncorrected result of a measurement to compensate for systematic error (VIM, Section 3.15).
3.4.1. Discussion— Because the systematic error cannot be known perfectly, the correction can only be an estimate.
3.5. correchon factor, ii- —numerical factor by which the uncorrected result of a measurement is multiplied to compensate for systematic error (VIM, Section 3.16).
3.5.1. Discussion—Because the systematic error cannot be known perfectly, the correction factor can only be an estimate.
3.6. standard. n—material measure, measuring instrument, reference material, or measuring system intended to define, realize, conserve, or reproduce a unit of one or more values of a quantity to serve as a rcfcrcncc (VIM. Section 6.1).
3.7. standardization, n—a process that determines (1) the correction or correction factor to be applied to the result of a measuring instrument, measuring system. material measure, or reference material when its values are compared to the values realized by standards, (2) the adjustment to be applied to a piece of’ equipment when its pertbrmance is compared with that of an accepted standard or process.
3.7.1. Discussion—Standardization in case (1) is a simplified f’orm of’ calibration that estimates systematic error but does not identify random error. Standardization, therefore, does not address all of the elements of uncertainty of measurement and does not lead to traceable measurements. An example of case (2) standardization is adjusting the number of blows of a mechanically operated hammer so it applies the energy equivalent to that of a manually operated hammer.
3.8. traceability, n—the property of the result of a measurement or the value of a standard whereby it can be related to stated refirences, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties (VIM, Section 6.10).AASHTO PP 57 pdf download.