Calibration of Industrial Hygiene Instruments. David Silver, CIH. Industrial Hygiene Issues. Accurate & repeatable measurements. Analytical results and confidence limits. Uncover the mystery of annual calibrations. Field calibrations vs. annual calibrations. Successful Outcomes.
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David Silver, CIH
Metrology establishes the international standards for measurement used by all countries in the world in both science and industry
Examples: distance, time, mass, temperature, voltage, values of physical and chemical constants
Direct reading instrument, sampling.
Measurement or analysis.
Results – variability.
Lots of derived units:
Seven base units:
Length: meter (m)
Mass: kilogram (kg)
Force: 1 Newton = 1 kg·m/s2
Time: second (s)
Voltage: 1 volt = 1 m2·kg/s3·A
Electric current: ampere (A)
Frequency: 1 hertz = 1/s
Thermodynamic temperature: Kelvin (K)
Power: 1 watt = 1 kg·m2/s3
Electric Charge: 1 C = 1 A·s
Amount of substance: mole (mol)
Luminous intensity: candela (cd)
One part per quadrillion accuracy!!!
Accurate frequency gives accurate distance and time.
The modern meter:
A metal bar:1889-1960
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
The SI kilogram drifts!
Goal: 10 parts per billion accuracy
Avogadro’s number6.0221415 × 1023
The Kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
Most technologically advanced countries.
From Article I, section 8 of the U.S Constitution:
“The Congress shall have Power To…
…fix the Standard of Weights and Measures;”
Soap bubble meter.
Pump is attached to the top of a volumetric glass tube containing a small amount of liquid soap. While the air flow causes the soap film to move from one volume mark to another, the travel time is measured with a stopwatch. The flow rate can then be directly calculated using the travel time and the known tube volume.