Metrology-2-National Measurement System

Question 1

what place holds physical measurements?

Answer 1

National Physical Laboratory(NPL)

Question 2

Some Physical measurements?

Answer 2

Environmental, Optical Radiation, Radio, Microwave and Acoustics, Mass, Length, Force, Pressure, Colour, Gas Standards

Question 3

What measurements do the National Engineering Laboratory hold?

Answer 3

Gas, Water, Oil and Multiphase Mixtures

Question 4

What do the Laboratory of the Government Chemist do?

Answer 4

Proficiency Testing schemes, Gas Standards, Certified Reference Materials

Question 5

What do the Office for Product Safety and Standards do?

Answer 5

*Trade Measurements
*Type Approval
*Equipment testing
*Mass, Length and Volume calibration
*EMC Testing
*Traceability
*Trading Standards

Question 6

Who is in charge of Laboratory Accreditation?

Answer 6

United Kingdom Accreditation Service(UKAS)

Question 7

What is Measurement Traceability?

Answer 7

*Ability to trace the result of a measurement to a single source that is a national, or more likely, an international standard.

Question 8

What to all industrialised countries typically have?

Answer 8

A National Bureau of Standards

Question 9

Rules when tracing between measurement and NPL?

Answer 9

The traceability chain must be unbroken, usually involving working and transfer standards.

Question 10

What is the Traceability Chain?

Answer 10

1.Instrument/ Measuring Process eg. Micrometer
2. Working Standards eg. Class 2 Gauge Blocks
3. Secondary/Transfer Standards eg. Class 0 Gauge Blocks
4. NPL National Standards
eg. Definition of the Metre
Cost increases with the number

Question 11

What do companies do when they cant afford their own calibration laboratories?

Answer 11

Use outside accredited laboratories for the transfer standards and calibration

Question 12

What are the differences between transfer standards, Measurement Instruments and working standards?

Answer 12

1. 10x difference of accuracy between all of them starting with Transfer standards as the most accurate.
2. Transfer and Working Standards require periodic calibration.

Question 13

What do UKAS accredited laboratories give out?

Answer 13

Guaranteed traceable calibrations to national standards(measurements), with statements of uncertainty.

Question 14

What is the purpose of calibration?

Answer 14

To provide confidence about a measurement instruments accuracy and repeatability.

Question 15

What should calibration be?

Answer 15

Traceable via UKAS accreditation

Question 16

What is calibration also about?

Answer 16

The instrument, but also information handling, data analysis, intervals, uncertainties/error analysis, environment and people

Question 17

What is the error due to the calibration process?

Answer 17

Should be a maximum of ten percent of the permissible error of the instrument or measuring process being calibrated.
10x rule again

Question 19

Calibration environment is difficult to control and is a function of ?.

Answer 19

Temperature, humidity, electrostatic fields, human interaction, pressure, vibration, electromagnetic fields
Calibrator must be aware if all potential sources of error which could affect calibration

Question 20

What may a calibration process involve?

Answer 20

Not just single measurements which are quick but more than likely many measurements across time. Stability is required in these cases.