Calibration Specification for the Equipment of the Environmental Testing for Temperature and Humidity
环境试验设备温度、湿度校准规范
1 Scope
This specification is applicable to the calibration for metrological performance of equipment of the environmental testing for temperature and humidity (hereinafter referred to as environmental testing equipment).
Other similar equipment may also be calibrated by reference to this specification.
2 References
GB/T 2423.4-1993 Basic Environmental Testing Procedures for Electric and Electronic Products - Test Db: Damp Heat, Cyclic
GB 6999-1986 Relative Humidity Tables for Environmental Test
JJF 1071-2000 The Rules for Drafting National Calibration Specification
While using this specification, current valid editions of such documents shall be applied.
3 Terms
3.1 Temperature Deviation
The difference between the displayed temperature average of the environmental testing equipment under stable state and the measured temperature average of the center point in work space.
3.2 Relative Humidity Deviation
The difference between the displayed relative humidity average of the environmental testing equipment under stable state and the measured relative humidity average of the center point in work space.
3.3 Nominal Value
The parameter specified according to the testing method requirements or that predetermined as required when calibrating the equipment of the environmental testing for temperature and humidity.
4 Metrological Performance
See Table 1 for the deviation, uniformity and fluctuation respectively for the temperature and relative humidity.
5 Calibration Conditions
5.1 Environmental Conditions
5.1.1 Temperature: (15~35)℃
Humidity: (30~85)%RH
Atmospheric pressure: (86~106)kPa
5.1.2 Loading conditions
Generally, calibration is carried out under no-load condition; where required by the user, it may be carried out under loaded condition. However, the loading condition shall be descripted.
Table 1
Equipment name Temperature testing equipment Damp heat testing equipment Alternating damp heat equipment
Temperature and humidity range (0~100)
℃ (-60~0)℃
(100~200)℃ (200~300)
℃ (10~60)℃
(20~100)
%RH (10~60)℃
(20~100)
%RH (20~60)℃
(80~100)
%RH
Temperature deviation ±1.0℃ ±2℃ ±3℃ ±2℃ ±2℃ ±2℃
Humidity deviation - - - +2
%RH
-3 ±5%RH +2
%RH
-3
Uniformity Temperature 1.0℃ 2℃ 3℃ 1℃ 2℃ 2℃
Humidity - - - 3%RH 5%RH 3%RH
Fluctuation Temperature ±0.5℃ ±0.5℃ ±2℃ ±0.5℃ ±1℃ ±1℃
Humidity - - - ±2%RH ±3%RH ±3%RH
Notes:
1. The alternating capacity of alternating damp heat equipment shall be inspected.
2. For the temperature and damp heat testing equipment with metrological performance otherwise specified, calibration shall be carried out according to the requirements of relevant technical documents.
5.1.3 Other conditions: the equipment shall be free from strong vibration and corrosive gas at its surrounding, and shall be free from being affected by other cold and heat sources.
5.2 Standard Instrument and Other Equipment
5.2.1 Temperature measurement standard
Temperature measurement is composed of temperature sensor (generally, four-wire system platinum thermistor is adopted) and displayer, and the time constant shall be less than 15s.
5.2.2 Humidity measurement standard
The following instruments may be adopted for humidity measurement:
Digital ventilated psychrometer and gas-pressure meter (the ventilation speed shall be greater than 2.5m/s)
Digital hygrometer (only used for humidity field without alternation)
Dry and wet bulb thermometers① (applicable to the measurement of relative humidity and uniformity under uniform wind speed)
6 Calibration Items and Methods
6.1 Calibration Items
See Table 2 for the calibration items.
Note: the manufacture method of ① dry and wet bulb thermometers shall meet the requirements of Appendix C.
1 Scope
2 References
3 Terms
3.1 Temperature Deviation
3.2 Relative Humidity Deviation
3.3 Nominal Value
4 Metrological Performance
5 Calibration Conditions
5.1 Environmental Conditions
5.2 Standard Instrument and Other Equipment
6 Calibration Items and Methods
6.1 Calibration Items
6.2 Calibration Methods
6.3 Data Processing
7 Calibration Result Expression
8 Recalibration Interval
Appendix A Reference Format for Calibration Record of Environmental Testing Equipment
Appendix B Reference Format for Calibration Result of Environmental Testing Equipment
Appendix C Relative Humidity Measurement with Dry and Wet Bulb Method
Appendix D Uncertainty Analysis for Temperature Deviation Calibration Result of Environmental Testing Equipment
Appendix E Uncertainty Analysis for Relative Humidity Deviation Calibration Result of Environmental Testing Equipment
