1. CONCEPTS OF METROLOGY AND IMPORTANCE OF CALIBRATION
Bangladesh BEST Programme
CONCEPTS OF METROLOGY AND IMPORTANCE OF CALIBRATION
Nihal Gunasekara
Sri Lanka

2. KEY WORDS CALIBRATION – Comparison METROLOGY – Science of Measurement
Bangladesh BEST Programme
KEY WORDS
CALIBRATION – Comparison
METROLOGY – Science of Measurement
TRACEABILITY – Unbroken Chain of Comparisons
UNCERTAINTITY – Error in Measurement
ACCREDITATION – Third Party Ascertain
CALIBRATION INTERVAL – Equipment Remains Reliable

3. Everything has to do with measurement
Bangladesh BEST Programme
WHAT IS METROLOGY
SCIENCE OF MEASUREMENTS
Everything has to do with measurement
Designing
Conducting
Analyzing Results
Experiment
or test
within the Metrology realm
Allowing people to plan their lives and make commercial exchange with confidence
CAN BE SEEN
EVERYWHERE 3

4. METROLOGY Metrology Covers Three Main Tasks:
Bangladesh BEST Programme
METROLOGY
Metrology Covers Three Main Tasks:
The definition of internationally accepted units of measurement
The realization of units of measurement by scientific method
Establishment of traceability chain in documenting the accuracy of a measurement
“Metrology is essential in scientific research”

5. CATEGORIES OF METROLOGY
Bangladesh BEST Programme
CATEGORIES OF METROLOGY
Scientific Metrology – Development of measurement standards
Industrial Metrology – To ensure the adequate functioning of measurement instruments used in industry, production & testing laboratories
Legal Metrology or
Weights & Measures – Accuracy of measurement where these have influence on the transparency of economic transactions, health & safety

6. AREAS OF INDUSTRIAL METROLOGY
Bangladesh BEST Programme
AREAS OF INDUSTRIAL METROLOGY
Mechanical Metrology – Realises , maintains and disseminates the national measurement standards in the areas of Mass, Volume, Pressure and Dimension
Electrical Metrology –– Realises , maintains and disseminates the national measurement standards in the areas of AC/DC, low frequency, time & frequency and temperature

7. LEGAL METROLOGY Services offered by legal metrology are:
Bangladesh BEST Programme
LEGAL METROLOGY
Services offered by legal metrology are:
Mass measurements verification: verification of all mass measuring instruments (balances, trade masses etc.)
Volume measuring instruments : verification of fuel dispensers, tankers , meters etc.
Prepackaging control :verification of quantities in prepackaged products (mass, volume, length, number etc.)

8. Calibration (Old Definition)
Bangladesh BEST Programme
Calibration (Old Definition)
“Calibration is the comparing of an unknown measurement device against equal or better known standard under specified conditions”

9. Calibration Bangladesh BEST Programme
“Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties, and in a second step, uses this information to establish a relation for obtaining a measurement result from an indication ” International Vocabulary of Metrology )
( JCGM 200:2012 – International Vocabulary of Metrology )

10. Bangladesh BEST Programme
Units of Measurement
SI Units published by BIPM(Bureau of Weights and Measures)
Base Units…
Quantity Unit Symbol
Length metre m
Mass kilogram kg
Time second s
Temperature kelvin K
Electric current ampere A
Luminous intensity candela cd
Amount of substance mole mol

11. Metrology Laboratories
Bangladesh BEST Programme
Metrology Laboratories
Primary Laboratories NML, NMI, NPL etc
Reference Laboratories
Calibration Laboratories

12. Measurement Uncertainty
Bangladesh BEST Programme
Measurement Uncertainty
“ non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used”
It arises due to the imperfections in the measurement system
No measurement system is perfect !!!!!

13. Uncertainty An estimate of the possible error in a measurement
Bangladesh BEST Programme
Uncertainty
An estimate of the possible error in a measurement
Type A evaluation
A series of repeated observations is obtained to determine the standard deviation of the measurement result.
Type B evaluation
The evaluation is carried out using available information found in calibration reports, certificates, specifications etc.

14. Calculate combined standard uncertainties Type A Type B
Bangladesh BEST Programme
Expanded Uncertainty
Calculate combined standard uncertainties
Type A
Type B
Exp. Unc. U = Combined Uncertainty X Coverage factor

15. Ishikawa diagram Bangladesh BEST Programme Reference T/C
Digital Thermometer
Calibration (B)
Resolution (B)
Scatter (A)
CJC (B)
Uncertainty of an oven
Test oven
Resolution (B)

16. Gaussian probability distribution
Bangladesh BEST Programme
Confidence Level
Gaussian probability distribution
-kσ  +kσ
68% Within 1σ of mean
95% Within 2σ of mean
99% Within 3σ of mean

17. Metrological Traceability
Bangladesh BEST Programme
Metrological Traceability
”property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty” or
“HOW TO ENSURE THAT TWO MEASUREMENTS OF THE SAME QUANTITIES ARE COMPATIBLE”

18. How Do We Get Traceability ?
Bangladesh BEST Programme
How Do We Get Traceability ?
Common point of reference
My laboratory
Your laboratory
Their laboratory 18

19. NMI: The Link Organisation to the International Arena
Bangladesh BEST Programme
NMI: The Link Organisation to the International Arena
International standards
National Metrology Institute
National community that is using measurements 19

20. HIERARCHY OF MEASUREMENTS
HIERACHY OF MEASUREMENT STANDARDS
Bangladesh BEST Programme
HIERARCHY OF MEASUREMENTS
Primary Standards
Traceable to BIPM
Secondary Standards
Working Standards
Instruments
Used in Lab/ Industry

21. Metal fixed-point Bangladesh BEST Programme Number Substances State
Defining temperature K oC 1 2 3 4 5 6 7 8 9 Hg
H20 Ga In Sn Zn Al Ag Au Cu T M F
273.16
0.01
961.78

22. Analytical &Top loading
Bangladesh BEST Programme
CALIBRATION HIERARCHY OF MASS STANDARDS
BIPM Kilogram
National Kilogram
Class E1, E2,F1, F2
Masses
Analytical &Top loading
Precision
Balances
OIML M1,M2,M3
OIML R47
TRADE MASSES
Platform & Top loading balances
Weighing
Bridges

23. EXAMPLE Bangladesh BEST Programme MASS COMPARATOR Traceable to
Prototype 1kg
Calibrate
Traceable to
Analytical Balance
Transfer
USE
Set of Classes E2, F1, F2, and M1
BIPM Prototype 1kg
Traceable to
SI Units 23

24. GAUGE BLOCK COMPARATOR
Bangladesh BEST Programme
GAUGE BLOCK COMPARATOR
Primary Standard
Traceable to
Laser interferometer
Compare
USE
Grade K set
Calibrate
Grade 1 set

25. 1. Performance Test on a Incubator at 35 + 0.5 oC
Bangladesh BEST Programme
Examples
1. Performance Test on a Incubator at oC
Set Temp. oC
Indicator Value
Measured Mean value
Expanded Uncertainty
Min
Max
Near Sensor
Upper
Middle
Lower
34.5
34.6
34.9
34.7
34.2
 0.2

26. 2. Performance Test on a Water Bath at 50 oC
Bangladesh BEST Programme
2. Performance Test on a Water Bath at 50 oC
Set Temp. oC
Indicator Value
Measurement
Locations
Measured Mean Value
Expanded Uncertainty
Min
Max
48.0
49.5
50.0 C P Q R S
50.1
50.2
 1 S P C R Q
Uniformity : 0.61 oC
Stability : oC

27. Reference and Auxiliary Equipment
Bangladesh BEST Programme
MASS
Reference and Auxiliary Equipment
COMPARATOR BALANCES
CLASS E1 1 kg
CLASS E1 SET
CLASS E2 SET
CLASS F1 SET
CLASS F2 SET
CLASS M1 SET

28. What is Calibration interval ???
Bangladesh BEST Programme
CALBRATION INTERVALS
What is Calibration interval ???
Period of time of use to ensure the equipment remains reliable
Interval is too short : Calibration $$$$$
Interval too long : Risk of bad measurements

29. Capable of achieving required accuracy
Bangladesh BEST Programme
CALBRATION INTERVALS
ISO Requirements:
Capable of achieving required accuracy
Comply with specifications relevant to test/calibration method
Use under established calibration programme
Therefore need to :
Define required accuracy
Identify the equipment that can affect it
Manage all equipment under a calibration programme

30. RECOMMENDED CALBRATION INTERVALS
Bangladesh BEST Programme
RECOMMENDED CALBRATION INTERVALS
N No single correct answer Calibration represents an instantaneous snapshot of actual condition
Depend upon
Level of stress - subjected
Stability of past calibration
Allowable tolerance range
Required accuracy
Quality Assurance Requirements

31. RECOMMENDED CALBRATION INTERVALS
Bangladesh BEST Programme
RECOMMENDED CALBRATION INTERVALS
Final Analysis Period between two calibrations
Determined & Monitored
USER HIMSELF

32. HOW TO ESTABLISH CALIBRATION INTERVAL
Bangladesh BEST Programme
HOW TO ESTABLISH CALIBRATION INTERVAL
Consider influencing factors and existing knowledge : eg
Accuracy sought & consequences of error
Manufacture’s recommendations
Accommodation & environment
Purpose and usage
Maintenance & servicing
Trends from previous calibration
Frequency of checks
Etc. etc. etc. ….
Ref. - ILAC – G 24 : Guidelines for determination of calibration interval of
measuring instruments

33. RECOMMENDED PRACTICES
Bangladesh BEST Programme
RECOMMENDED PRACTICES
Calibration at (planned) periodic intervals to ensure acceptable accuracy & reliability
Shorten the intervals when results of previous calibration suggest it
May lengthen intervals on basis of demonstrated performance
Documented procedure for assigning and adjusting calibration intervals
Fully documented re-calibration system 33 33

34. CALIBRATION OF VOLUMETRIC GLASSWARE
Bangladesh BEST Programme
CALIBRATION OF VOLUMETRIC GLASSWARE
FLASKS
CYLINDERS
BURETTES
PIPETTES
ACCURACY CLASSES
CLASS A – Higher grade
CLASS B – Lower grade

35. Gravimetric Method – IS0 4787 -2010
Bangladesh BEST Programme
Example - Pipettes
Nominal capacity(ml)
Limit of Error (ml)
Class A
Class B 1 25
100
200
0.008
0.03
0.08
0.1
0.015
0.06
0.15
0.2
METHOD
Gravimetric Method – IS
(Laboratory Glassware- Volumetric instruments- Method of Testing of capacity and for use)

36. ANALYTICAL BALANCES – Using a Calibrated Weight
Bangladesh BEST Programme
IN-HOUSE PERFORMANCE CHECKS
(During Calibration Interval)
ANALYTICAL BALANCES – Using a Calibrated Weight
INCUBATORS - Using a Calibrated Thermocouple
GLASS THERMOMETERS- Ice Point

37. Importance of Calibration
Bangladesh BEST Programme
Importance of Calibration
Assurance of accurate of measurements
Ability to trace measurements to International standards
International acceptance of test/calibration reports
Correct diagnosis of illness (medical reports)
Consumer protection (legal metrology)
Meeting the requirements of ISO 9000 and 17025 37

38. Technical Competence of Calibration Laboratories &
Bangladesh BEST Programme
How we ensure
Technical Competence of Calibration Laboratories
&
Measurements are traceable to SI Units
ACCREDITATION

39. Defined Criteria for Laboratory Accreditation Metrology Laboratory
Bangladesh BEST Programme
Organization
Laboratory Quality System
Qualified personnel
Range of the work capabilities and test methods
Laboratory practices and management system
Reliable standards and measuring devices
Laboratory facilities
Adequate measuring capabilities
Traceability maintenance
Calibration records
Satisfactory completion of internal audits

40. QUALITY SYSTEM ISO/IEC 17025
Bangladesh BEST Programme
QUALITY SYSTEM ISO/IEC 17025
QUALITY MANUAL
PROCEDURE MANUAL
METHOD MANUAL
FACILITIES MANUAL
SAFETY MANUAL

41. ACCREDITED LABORATORY
Bangladesh BEST Programme
ACCREDITED LABORATORY
IMPLEMENTATION OF ISO 17025
MANAGEMENT REQUIREMENTS
TECHNICAL REQUIREMENTS
TRACEABILITY
MAINTENANCE OF ENVIRONMENTAL CONDITIONS
TRAINED STAFF 41

42. ENVIRONMENTAL CONDITIONS
Bangladesh BEST Programme
ENVIRONMENTAL CONDITIONS
TEMPERATURE
HUMIDITY
AIR VELOCITY
FREE OF VIBRATION
ILLUMINANCE 42

43. ACCREDITED MASS LABORATORY
Bangladesh BEST Programme
ACCREDITED MASS LABORATORY
ENVIRONMENTAL CONDITIONS: TEMPERATURE: 23 ± 0.5 0C , HUMIDITY : 50 ±10%

44. ACCREDITED TEMPERATURE LABORATORY
Bangladesh BEST Programme
ACCREDITED TEMPERATURE LABORATORY
ENVIRONMENTAL CONDITIONS: TEMPERATURE: 23 ±1 0C , HUMIDITY : 50 ±10% 44

45. ACCREDITED VOLUMETRIC LABORATORY
Bangladesh BEST Programme
ACCREDITED VOLUMETRIC LABORATORY
Temperature : 20 ±1 °C Humidity : 60 ±10%

46. CONTENTS OF CALIBRATION CERTIFICATE
Bangladesh BEST Programme
CONTENTS OF CALIBRATION CERTIFICATE
NAME AND ADDRESS : CUSTOMER/ LABORATORY
METHOD
CONDITION RECEIVED
IDENTIFICATION
DATE OF CALIBRATION
DATE OF RECALIBRATION ?
CALIBRATION RESULTS
UNCERTAINTY OF MEASUREMENT
TRACEABILITY
ENVIRONMENTAL CONDITION 46

47. SAMPLE OFSCOPE OF ACCREDITATION
Bangladesh BEST Programme
RANGE C.M.C
ONE MARK PIPETTE to
GRADUATED PIPETTE to
BURETTE to
VOLUMETRIC FLASK to
GRADUATED MEASURING CYLINDER 0 to
SAMPLE OFSCOPE OF ACCREDITATION
CALIBRATION mL

48. Bangladesh BEST Programme
Accredited Metrology Facilities
Ensure
Traceable Measurements
Technical Competency
Industries
Better Place in Global Market
ISO Certified QMS
Products
Quality Life

49. Bangladesh BEST Programme
“Calibration of laboratory equipment is important to obtain reliable test results”
Thank you