CLAS Certificate Number 94-02

Company name	Stephens Analytical, Inc.
Company address	Instrument Calibration and Standards Laboratory 8110B Trans-Canada Highway St-Laurent, Quebec Canada H4S 1M5
Contact	Don Sutherland Telephone: 514-332-1616 Toll free: 800-267-7474 Fax: 514-335-6566 Email: labmtl@stephens-analytical.com
Clients served	All interested parties
Fields of calibration	Humidity
Accreditation body	Standards Council of Canada (SCC)
ISO/IEC 17025	SCC file number: 15063 First issued 1987-10-06 Issue 4.3e 2022-06-03

This CLAS Certificate is published by the CLAS service of the National Research Council of Canada (NRC) in cooperation with the laboratory accreditation program of the accreditation body.

The accreditation body recognizes the capability of the named laboratory for being able to perform calibrations as per the listed Calibration and Measurement Capabilities with metrological traceability to the International System of Units (SI) or to standards acceptable to CLAS.

See supplementary notes.

Measured Quantity & Range or Instrument	Expanded Measurement Uncertainty	Type of Service	Remarks
Humidity
Dew Point Temperature
0 °C to 95 °C	0.4 °C	I	For the calibration of humidity measuring instruments using a two temperature, two pressure humidity generator. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3}
0 °C to 95 °C	0.5 °C	I	For the calibration of sources of humidity using a humidity measuring instrument. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3}
Frost Point Temperature
- 19 °C to 0 °C	0.4 °C	I	For the calibration of humidity measuring instruments using a two temperature, two pressure humidity generator. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3}
- 19 °C to 0 °C	0.5 °C	I	For the calibration of sources of humidity using a humidity measuring instrument. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3}
Volume Ratio
0.02 to 1 parts per 10⁶	0.02 parts per 10⁶	I	For the calibration of humidity measuring instruments using gravimetrically verified diffusion cells. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3} ^{Table note 4}
0.05 to 1 parts per 10⁶	0.05 parts per 10⁶	I	For the calibration of sources of humidity using a humidity measuring instrument. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3} ^{Table note 4}
1 to 1200 parts per 10⁶	2 % of reading	I	For the calibration of humidity measuring instruments using gravimetrically verified diffusion cells. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3} ^{Table note 4}
1 to 1200 parts per 10⁶	5 % of reading	I	For the calibration of sources of humidity using a humidity measuring instrument. See Notes ^{Table note 1} ^{Table note 2} ^{Table note 3} ^{Table note 4}

Table Notes

Note 1

There are many units in common use for describing the amount of moisture in a gas. Each industry has it's own preferred unit of measure for moisture. These units fall into two classes, concentration units and temperature units. It is always possible to convert from one concentration unit to another by multiplying by a conversion factor. Conversion from one temperature scale to another is also straightforward.

Return to table note 1 referrer

Note 2

Conversion from a temperature scale to a concentration scale must be done using vapour pressure tables. For accurate work, corrections for pressure and temperature are also necessary. These conversions are best done using tables, charts or computer programs.

Return to table note 2 referrer

Note 3

The user should be aware that chilled mirror hygrometers measure the condensation temperature and that the calculation of the corresponding moisture concentration is valid only if the condensing phase is pure water. Furthermore, the user must also recognize that there is significant difference in the moisture concentration associated with a frost and a dew formed on a mirror at the same temperature. It is common to use the terms dew point and frost point interchangeably. In general, regardless of the terminology used, dew points are implied above 0 °C and frost points are implied below 0 °C, unless stated otherwise.

Return to table note 3 referrer

Note 4

A volume ratio of 0.02 ppm(V) is equivalent to a frost point of -98.2 °C.

Return to table note 4 referrer

Language selection

Language selection