CCT Certified Calibration Technician and other Metrology Topics
CCT, Certified Calibration Technician and other Metrology Topics • Why would you consider ASQ CCT certification? § Test or calibration lab manager, engineer, technician § Five years work-related experience required (some can be offset by education) § Demonstrate ability to o Understand apply the topics in the Body of Knowledge, BOK; o Use the principles, ideas, procedures, methods, etc; o Analyze information; o Evaluate ideas, data, information, solutions, etc. ASQ Illiana Quality Conference - January 22, 2016, Presented by Alex Klein, alex. klein@arcelormittal. com 1
Examples of early measurements include: • • Artifacts over 20, 000 years old indicated some form of timekeeping. A beam balance dated to 5000 BC was found in a tomb in Eqypt. A 365 -day calendar was begun in 4236 BC by Eqyptians. Units of length, area, volume and weight were defined in Egypt and Babylon about 3000 BC. • 0. 05 % accuracy was achieved by Egyptians in building the pyramids. 2
The history of measurement continued to the recent past. ▪ 732 ▪ 960 ▪ 12 th century ▪ 1266 ▪ 1670 ▪ 1792 ▪ 1795 ▪ 1824 ▪ 1866 ▪ 1875 ▪ 1889 ▪ 1916 ▪ 1954 ▪ 1983 ▪ 1999 The unit of an acre was commonly used. Standards for measurement were established in London and Winchester. ‘Indo-Arabic’ numbers 1 to 9 and the concept of zero introduced. 12 ounces was one pound a gallon of wine weighed eight pounds. The metric system was originated by Gabriel Mouton, a French vicar. Thomas Jefferson proposed a decimal-based measurement system for the United States. The U. S. Mint was formed to produce a decimal currency. France adopted the metric system. George IV established the Imperial System of Weights and Measures (still in use). The use of the metric system is made legal (but not mandatory) in the U. S. The Convention of the Metre was adopted by 18 nations including the U. S. The U. S. received a prototype meter and kilogram to be used as measurement standards. The Metric Association was formed advocating adoption of the metric system in U. S. commerce and education. It became the U. S. Metric Association in 1974. The International System of Units (SI) began and six new metric base units were adopted. Definition of the meter is the length of the path traveled by light in vacuum during a time interval of 1/ 299 792 458 of a second. Refine experiments that link the unit of mass to fundamental or atomic constants in consideration of a future redefinition of the kilogram The Metrology Handbook, chapter 1 3
Metrology may be classified as follows: • Physical metrology – measurement of mass, length, electric current, viscosity, force • Chemical metrology – testing in chemical, medical, pharmaceutical, pathological, forensic, environmental, food and agricultural labs • Legal metrology – measurements related to trade and consumer protection § Consumer: market scales; gasoline pumps; gas, electricity and water meters; taxi meters § Safety and health care: medical scales, syringes, thermometers, radiotherapy equipment, diagnostic equipment, audiometer, glucose in blood meter, equipment used for toxic chemical measurements, radiation measurement § Environment: noise, air, water, vehicle exhaust emissions testing § Law: vehicle speed, breath analyzers for alcohol levels • Industrial metrology – checking conformance of products and services during production and maintenance • Scientific metrology – measurements in testing, research and calibration labs. See Kimothy, page 8 for more information about metrology classifications. 4
CCT, Body of Knowledge, BOK, includes these topics The four-hour open-book exam includes 125 questions. Cost is $ 189 for ASQ members. • • • General Metrology (35 questions) Measurement Systems (22 questions) Calibration Systems (33 questions) Measurement Uncertainty and Applied Math (20 questions) Quality Systems and Standards (15 questions) 5
General Metrology (the science of measurement) includes these topics. • Seven Base SI, International System of Units, and two Supplementary Units § mole, meter, kilogram, second, ampere, kelvin, candela § radian, steradian • Derived SI units: area, volume, frequency, force, pressure, power, volt, velocity, density, etc. • SI multipliers, scientific notation, prefixes and symbols § § § § § 0. 00001 0. 00000001 0. 1 1. 0 100000000. 0 100000. 0 1. 0 x 10 -9 1. 0 x 10 -8 1. 0 x 10 -7 1. 0 x 10 -6 1. 0 x 10 -5 1. 0 x 10 -4 1. 0 x 10 -3 1. 0 x 10 -2 1. 0 x 10 -1 1. 0 x 100 1. 0 x 101 1. 0 x 102 1. 0 x 103 1. 0 x 104 1. 0 x 105 1. 0 x 106 1. 0 x 107 1. 0 x 108 1. 0 x 109 nano- (n) micro- (µ) milli- (m) kilo- (k) Mega- (M) Giga- (G) 6
General Metrology (the science of measurement) includes these topics. • Seven Base SI, International System of Units, and two Supplementary Units 7
General Metrology (the science of measurement) includes these topics. • Fundamental constants § § § Speed of light in a vacuum, c = 299 792 458 meters per second Standard acceleration of gravity, g = 9. 80665 m/sec or m·sec-1 Universal or molar gas constant, R = 8. 314472 J·mol-1·K-1 Avogadro’s number, NA, L = 6. 02214199 x 1023 molecules in on mole of a substance Planck’s constant, h = 6. 626070 x 10 -34 J/Hz or J·Hz-1 or J·sec • Common measurements: temperature, humidity, pressure, force, mass, voltage, resistance • Measurement standards and hierarchy • Intrinsic or International Standard, International Bureau of Weights and Measures (BIPM) • National Standard • Primary Standard • Secondary Standard • Working Standard • Measuring equipment 8
General Metrology (the science of measurement) includes these topics. • Other types of measurement standards § Transfer standard is a standard specially designed for ruggedness and portability so that it may be calibrated in one location and used as a reference standard after transportation, with assurance that errors cause be travel were limited to a range of known values. § Intrinsic standard is a standard realized based on standard procedures, well-characterized laws of physics, fundamental constants and invariant properties of materials. Examples: o Josephson-junction-based voltage standards o Cesium atomic standards for time and frequency o The International Temperature Scale of 1990 (ITS-90) § Consensus standard is a standard not traceable to national standards but has an agreed on method for realization of the quantity. Examples: o The Rockwell Hardness Scale that depends on specifying a procedure and an apparatus meeting certain specifications. o New consensus standards for characterization of biomedical nanoparticles are currently under development within ASTM committee E 56 on Nanotechnology. § Derived standard is a standard derived by combining two or more known values from artifact or intrinsic standards to enable a traceable measurement to be made when it is not possible for the measurement to be made using a single standard to realize the measurement. Examples: o Measuring screw threads by combining small threaded wires and a length measuring device such as a bench micrometer o Measuring electrical charge using current and time; each is directly and easily traceable. 9
General Metrology (the science of measurement) includes these topics. • Metrological traceability of a measured result is achieved through • An unbroken chain of comparisons • That connects the local standard to national standards and • Each comparison in the chain has a stated measurement value and its associated uncertainty. • Substitution of standards § Reasons o Calibration standard is past due for calibration or is being calibrated. o Calibration standard became obsolete. o Reference material was consumed. § Select a suitable substitute o o It must be capable of measuring the same parameter at the same level. Resolution must be equal or better. Accuracy and precision (or measurement uncertainty) must be equal or better. It must be available. 10
Measurement Systems include these topics. • Measurement methods: § Direct – a measuring instrument (ruler) is applied to an unknown and a measurement value is read from a scale. § Indirect – the variable of interest is not the one that is actually measured. Examples: o Temperature of an object is determined by measuring the infra-red light it emits at a known wavelength. o Flow in a pipe is measured by introducing an orifice or constriction and measuring the pressure drop across the orifice. § Zero Difference or Null Measurements – comparison between unknown and reference is made by looking for a zero difference between them. Examples: o Using a two-pan balance for mass comparison o Calibrating gage blocks with a comparator § Ratio - Comparison between the unknown and a fixed reference is made by setting up using a divider mechanism and looking for a zero difference. Examples: o Creating intermediate voltage valued using a Kelvin Varley divider and a fixed voltage source o Measuring weight using a beam balance scale § Transfer – When the measuring equipment cannot be moved, a calibrated standard is transported to the location and the calibration is performed. § Differential – The desired measurement result is the difference between two quantities. o A two-pan balance can measure differences o When measuring temperature using a thermocouple, an electrical signal is directly related to the temperature difference between the two ends of the sensor o LVDT (Linear Variable Differential Transformer), a probe than can move in one direction and sensor for measuring dimensions § Substitution – When an instrument can only sense and display one measurement, but it is necessary to compare a reference standard to an unknown, the two measurements may be made by substitution. Example: mass measurement using a single-pan balance 11
Measurement Systems include these topics. • Sources for measurement methods: Methods may have been specified by the customer, published in international or national standards, by technical organizations, in scientific texts and journals, or specified by the manufacturer of the equipment. For example: § § § § § American Society for Testing and Materials, ASTM ▪ Underwriter’s Laboratories, UL International Organization for Standardization, ISO ▪ American Public Health Association, APHA International Electrotechnical Commission, IEC ▪ Association Connecting Electronics Industries, IPC International Special Committee on Radio Interference, CISPR ▪ International Safe Transit Association, ISTA International Federation of Clinical Chemistry, IFCC ▪ European Telecommunications Standards Institute, ETSI Japanese Industrial Standards, JIS ▪ American Petroleum Institute, API Euronorm, EN ▪ German Institute for Standards, DIN American Association of Textile Chemists and Colorists, AATCC Federal Motor Vehicle Safety Standards, FMVSS Society of Automotive Engineers, SAE Department of Defense, MIL STD National Academy of Sports Medicine, NASM Customers American Association of State Highway Transportation Officials, AASHTO Environmental Protection Agency, EPA American Water Works Association, AWWA Water Environmental Federation, WEF Technical Association of Paper and Pulp Association, TAPPI 12 § What agency, organization, customer, … defines the standard test methods for your testing?
Measurement Systems include these topics. • Measurement characteristics: variation, sensitivity, repeatability, reproducibility, bias, linearity, stability, resolution • Measurement data considerations: recording, format, readability, suitability for use, rounding, storage, retention, access, confidentiality • Go to Quiz 1. • Specification terms and characteristics for IM&T equipment and standards; specifications were discussed in The Metrology Handbook, Chapter 21. § Tolerance is a design feature that defines limits within which a quality characteristic is supposed to be on individual parts. § Specifications define the expected performance limits of a large group of substantially identical finished products – all units of a specific model of digital thermometer. Customers use specifications to determine the suitability of a product for their applications. A product that performs outside specifications when checked (calibrated) is not used until adjusted or repaired and checked again. Specifications may be used to estimate the uncertainty of the measurement being made. 13
Measurement Systems include these topics. • Specification terms and characteristics for IM&T equipment and standards § Two types of specification limits: o One-way – Lower specification limit, LSL, or upper specification limit, USL. Examples: ü An appliance safety tester was designated to detect a leak of 1 m. A, -25 %, + 0 % ü Product was heat treated at 1000 o. C min (minimum) o Two-way – LSL and USL. Examples: ü Voltage, 500 m. V +/- (0. 005 % + 10 µV); LSL = 499. 965 m. V and USL = 500. 035 m. V ü 1. 000 m. W, LSL = 0. 631 m. W and USL 1. 585 m. W ü Rockwell hardness standard block, B scale: 55. 58 +/- 1. 0 HRBW ü 2 in gage block has a specification of +8 μinch, -4 μinch § Some descriptors are used to specify measurement ranges or limits for measuring equipment. o o o o Percent or fraction of full scale, percent or fraction of range, percent or fraction of reading Parts per million (ppm) of full scale or range or reading Number of counts Resolution or minimum display increment Temperature, humidity and other environmental limits for operation and storage Minimum warm-up time Sample preparation or equipment preparation requirements (e. g. , exercise force gages before use) 14
Measurement Systems include these topics. • Specifications continued § Some equipment has several sources of error and the specification will include more than one mechanism. o Baseline specifications describe the basic performance of the instrument and may include terms for output, scale and floor, Nominal value +/- (output + scale + floor), where: ü output = a percentage or parts per million (ppm) of the nominal value. ü scale = a percentage or ppm of the range or full-scale value. ü floor = a specific value expressed using the applicable SI units. ü Examples: • Voltage output range: 0. 000 m. V to 320. 000 m. V; 12 -month accuracy: +/- (0. 006 % of output + 4. 16 µV floor) • Voltage range: 10. 00000 V; 12 months: +/- (0. 0035 % of reading + 0. 0005 % of range) • Fluke 87 V Industrial Multimeter: See specifications. o Modifier specifications may indicate differences in performance relative to time, ambient conditions, load or line power. o Qualifier specifications describe the factors that may affect the usability of the IM&T equipment such as operating and storage conditions and altitude. § Why is this important? You may need to replace equipment; that may require comparing 15 specifications for the existing and potential replacement equipment.
Measurement Systems includes these topics. • Error is the difference between the measured value and the true value. • Error sources: identify and correct for drift, bias, operator error, environment. • Measurement assurance program, MAP is a program or plan to ensure that there is on-going confidence in testing and calibrations performed. It is a program for a measurement process that qualifies the total uncertainty of measurements with respect to a national or other designated standard and demonstrates that the total uncertainty is sufficiently small to meet the user’s requirements (NIST). Some elements include: § Schedule traceable calibration of standards. § Perform MSAs, measurement system studies; Gage R&R studies: Examples: o Empirically-derived composite measure of preventive care practices (overall preventive care counseling index, OPCi) of HIV medical care providers in thirteen managed care clinical settings using gage R&R, bias, linearity, stability and process capability (2015) o MSA for service industry: a simple approach presented by HUMANA at ASQ World Conference (2008) o Attribute gage R&R for qualitative responses from call center for a credit card company fielding incoming calls from customers with account inquiries: Graded recorded conversations on a 1 to 5 scale for friendliness, accuracy and suitable advice; used Kappa (agreement) and Kendall’s Coefficient of Concordance (level of disagreement) published by Minitab (2002) o Expanded gage R&R using multiple gages presented by Minitab o Attribute gage R&R for categorization of incoming mail in digital mailrooms, Outsource Magazine, April 2011 o Gage R&R for measuring width of product using a tape measure. See GR&R. o MSA for an iron temperature measurement system; reference “Chart My Gage”. See MSA. § Measure check standards in the same manner as specimens and control chart the results. o Use to predict or change calibration intervals. o Eliminate the need to trace back when something goes wrong. 16
Measurement Systems includes these topics. • Measurement assurance program, MAP continued: § Perform proficiency testing and interlaboratory comparisons. § Compare reference standards against check standards and working standards. § Continuously evaluate measurement uncertainties associated with the standards and test and calibration processes. § Perform replicate tests or calibrations using the same or different methods. § Retest or recalibrate retained items. § Implement a quality system in accordance with recognized standards such as ISO/IEC 17025, ANSI/NCSL Z 540 -1 and Z 540 -3, or another applicable standard. § Standardize, document and regularly review test and calibration procedures. § Train calibration and testing personnel. § Evaluate competence of personnel. § Implement a formal internal audit program. § Control chart and analyze results in a timely manner. • Go to Quiz 2. 17
Calibration Systems includes these topics. • Calibration procedures should include: 18
Calibration Systems includes these topics. • Standardization and adjustment methods § Spanning - Used to define a specific range for an IM&TE; Involves bringing an IM&TE measurement readout scale in agreement with intended range of the unit via adjustments, changing component values or firmware correction. Helps ensure that a unit’s high, low and mid-range measurement responses correspond to its high, low and midrange measurement readout values. Examples: o o used to set up the range of a pressure gauge calibrate a balance (0 to 1000 g) calibrate a refractometer calibrate force (0 to 30000 lbs) § Nulling - Comparison made when the nominal value of the UUT and the reference are the same. Example: Use of a two-pan balance - This is the modern version of the ancient Egyptian scales. This scale incorporates two pans on opposite sides of a lever. The object to be weighed can be placed on one side and standard weights are added to the other pan until the pans are balanced. The sum of the standard weights equal the mass of the object. § Zeroing - An IM&TE measurement readout offset present in the absence of an applied signal is excluded from measurements via hardware adjustment or algebraic cancellation. Examples: o Zeroing a height gauge on a surface plate before measuring the height of gauge blocks placed on the plate o Zeroing a balance, micrometer, etc. § Linearization - IM&TE is corrected for a linear response such that a step change in an applied signal will result in a corresponding step change in the IM&TE indication. Also, correct a nonlinear output using a linear responding measuring device. Examples: o o Strain gauge Load cell meters Nonlinear measurement sensors used to make high temperature measurement Frequency 19
Calibration Systems includes these topics. • Industry practices and regulations – Measurement and calibration methods apply to the situation in this order: 20
Calibration Systems includes these topics. • Environmental factors affecting calibrations must be understood and controlled: Temperature, humidity, air density or contamination, dust, electrostatic interference, magnetic interference, electromagnetic interference, drafts or air movement, local gravity • Calibration processes for IM&TE: § § Process flow for the item to be calibrated Information Roles and responsibilities Scheduling • Validation – See ISO/IEC 17025. • Records management – See ISO/IEC 17025 and calibration procedure requirements. • Calibration reports and certificates – See ISO/IEC 17025 and calibration procedure requirements. • Go to Quiz 3. 21 • See calibration certificate.
Measurement Uncertainty and Applied Math includes these topics. • Uncertainty is: § the parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand. § an estimate characterizing the range of values within which the true value of the measurand lies. • Uncertainty budget contributors (Consideration is required by A 2 LA. ) § For measurements: o Repeatability of the method o Resolution of the result indicated by the measuring equipment o Uncertainty of the reference standard § For calibrations: o o o Repeatability of the method Resolution of the result indicated by the measuring equipment being calibrated Uncertainty of the reference standard Stability of the reference standard Environmental factors 22
Measurement Uncertainty and Applied Math includes these topics. • Uncertainty determination and reporting § Define the measurement model for the measurement process. § Consider sampling, sample preparation, measurement, data collection and analysis, data display and interpretation of results, test environment and conditions, measurement equipment, resolution, calibration of the measurement equipment, calibration standards. § Identify the contributors to uncertainty. § Estimate the contribution to uncertainty from each contributor. § § § § Standard uncertainty, Variance Combined uncertainty Coverage factor Expanded uncertainty Distributions: Normal, Expanded, Rectangular, Triangular, U-shaped, Digital-step Divisors used to calculate standard uncertainty from the estimated of uncertainty. Record details about the sources for the information and estimates of the contributions to uncertainty. 23
Measurement Uncertainty and Applied Math includes these topics. • Uncertainty determination and reporting – See examples: § Length measurement using a tape measure § Calibration of a 1 inch micrometer • Technical and applied mathematics § § § Scientific and Engineering notation English/ Metric conversions Ratios – percent, decibels (d. B) Linear interpolation and extrapolation Rounding, truncation and significant figures Order of mathematical operations Algebraic equations Number bases Volume and area Angular conversions Graphs and plots - slope, intercept and linearity of data Go to Quiz 4, 5 and 6. 24
Quality System and Standards includes these topics. • Quality management systems § Management responsibility, customer focus, employee training and development, purchasing, document control, records control, corrective/ preventive action § Continuous improvement of the quality management system • Quality control tools – flow charts/ process maps, check sheets, Pareto diagrams, cause and effect diagrams, scatter diagrams, control charts and histograms • Quality audits – See ISO 19011. • Corrective action for nonconformities/ deficiencies § Identify and segregate nonconforming IM&TE materials. § Assess the impact of out-of-tolerance IM&TE. • Professional conduct and ethics – See ASQ Code of Ethics, http: //asq. org/aboutasq/who-we-are/ethics. html 25
Quality System and Standards includes these topics. • Occupational safety requirements – Work environment, hazardous communication, housekeeping • Quality standards and guides § ISO/IEC 17025, ANSI/NCSL Z 540. 3, ISO 15189, ISO 15195 § CLIA, Clinical Laboratory Improvement Amendments – Centers for Medicare and Medicaid Services, CMS, regulates laboratory testing performed on humans § ISO 9001, ISO/TS 16949. ISO/IEC 10012, ISO 13485, ISO 22000 § ISO Guide 99, international vocabulary of metrology § NCSL calibration laboratory manager’s guidebook § ISO/IEC Guide 98 -3, guide to the expression of uncertainty in measurement § ANSI/NCSL Z 540 -2; NIST Technical Note 1297, UKAS M 3003 § Cooperative organizations: ILAC, IAF, NACLA, APLAC, EA, ANSI, IRCA, ASQ § Accrediting Body, AB: A 2 LA, NVLAP, IAS, LAB, ACLASS, SCC, UKAS, JAS-ANZ, In. Metro § Accredited organizations: TRA Certification (IAS) , Exemplar Global formerly RABQSA (JASANZ and In. Metro) 26
References and resources • www. asq. org, American Society for Quality, ASQ; http: //asq. org/cert/calibrationtechnician/references • ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories • The Metrology Handbook, Jay L. Bucher, editor, ASQ, 2012 • The Uncertainty of Measurements: Physical and Chemical Metrology, S. K. Kimothy • Basic Metrology for ISO 9000 Certification, G. M. S. De Silva, 2002 • Managing the Metrology System, C. Robert Pennella, 1992 • www. qualitycouncil. com, Quality Council of Indiana (CCT Primer, $ 70 and Solutions, $35, 2010; Exam $ 70, 2012, Instructor, $ 50, 2015) • The Quality Calibration Handbook, Jay L. Bucher • ISO 10012, Requirements for measurement processes and measuring equipment • ISO Guide 99, International vocabulary of metrology -- Basic and general concepts and associated terms (VIM), contains the internationally accepted definitions for metrology terms. • ISO Guide 98 -1, Introduction to the expression of uncertainty in measurement • ISO 9001, ISO/TS 16949 27
References and resources • www. nist. gov, National Institute for Standards and Technology, NIST • www. a 2 la. org, American Association for Laboratory Accreditation, A 2 LA • www. iso. org, International Organization for Standardization • www. ncsli. org, National Council of Standards Laboratories, NCSL • www. ilac. org, International Laboratory Accreditation Council – Published guidance documents about reporting compliance with specifications, measurement uncertainty, calibration intervals • www. citac. cc, Cooperation on International Traceability in Analytical Chemistry – Guides about traceability and measurement uncertainty • www. european-accreditation. org, European Accreditation – Published guidance documents for consistent accreditation among EU and outside countries. • www. eurolab. org, European Federation of National Associations of Measurement, Testing and Analytical Laboratories - Guide to the evaluation of measurement uncertainty for qualitative test results • www. isobudgets. com, Rick Hogan, metrologist and engineer, provides consulting, training, papers and a blog about ISO/IEC 17025 accreditation and measurement uncertainty. • Calibration: Philosophy in Practice, Fluke, 1994 28
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Fluke 87 V Specification 30
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MSA for measurement of iron temperature 33
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