ASTM E Standard Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures). Find the most up-to-date version of ASTM E at Engineering ASTM-Epdf – Download as PDF File .pdf), Text File .txt) or read online.
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Need more than one copy? This can then be assessed against the process requirements to ensure compliance.
Caution should be taken when handling mercury and mercury containing products. The Electronic Dewpoint Meters can be placed in the humidity chamber and the measurements monitored using the data output feature to achieve calibration against another relative humidity gauge that is separately calibrated for trace-ability. The definition of the Dewpoint Temperature is the temperature at which moisture will condense from a body of air at a higher temperature.
Our office will be closed from December 21st until January 2nd The digital format of the gauge allows sets of reading to be stored in memory for further analysis, reporting or archiving.
The reference values are set using the controls for the chamber and aastm independently using calibrated equipment. Data can be recorded using two methods, user activated recording of values as and when required or the data-logging mode, with reading sets recorded automatically at the end of the pre-set interval. Calibration of the Electronic Dewpoint Meter is carried out in a temperature controlled humidity chamber, whereas the calibration of the wet and dry bulb hygrometers is limited to assessing the accuracy of the spirit in glass thermometers.
Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials.
This sensor can be also be used for measuring the temperature of materials to be used in the process or for surface temperature monitoring during the process, data-logging.
The output from this sensor is displayed as Ta. The method for determining the Relative Humidity and hence the Dewpoint Temperature that has been most commonly taught to Paint Inspectors is the Wet and Dry Bulb method, commonly called the Whirling or Sling Hygrometer.
Recent Developments in the Measurement and Monitoring of Climatic Conditions
Link to Active This link will always route to the current Active version of the standard. However, the hygrometers described in this method use mercury in glass thermometers, which are no longer acceptable under Restriction of Hazardous Substances RoHS legislation round the world.
The air temperature is measured using another semiconductor sensor mounted close to the RH sensor to minimize any differences in conditions. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
D337 temperatures make allowance for the accuracy of the measurement of relative humidity and surface temperature in the field and also deal with e37 inertia in the evaporation from a surface as it warms up. The Dewpoint Temperature is then compared to the temperature of the surface to be painted determined by another measurement, sometimes using a magnetic bi-metallic aatm thermometer.
In this case, the instrument comprises a wet-bulb thermometer only. The value of the Dewpoint Temperature mainly depends on the Relative Humidity of the air, that is the volume of moisture contained in the air at a asttm temperature compared to the maximum s337 of moisture that this volume of air could contain if it were saturated at that temperature. Please sign into an account with a subscription to this content, or email for help at support madcad.
Subscription pricing is determined by: The method for determining if moisture e37 present is given in ISO Figure 5 — Dewpoint Meter Configured for Data-Logging Data can be recorded using two methods, user activated recording of values as and when required or the data-logging mode, with reading sets recorded automatically at the end of the pre-set interval. Data stored in the memory of the Dewpoint Meter can be transferred to a computer operating data management software.
Even when an Electronic Dewmeter is taken from a warm office or car to a cold environment, an accurate reading of rh can be obtained in less than 30 seconds.
The values quoted in table 1 are atm from the calibration software and can be shown to a resolution of two decimal places. The estimated values for the wet bulb temperature Twb and the dry bulb temperature Tdb can be displayed by selecting these parameters from the Display menu in preference to two of the usual set, e.
The PC version of the software also offers features for analyzing data, for reporting and for archiving date for future analysis or comparison.
ASTM E337 – 15
No other units of measurement are included in this standard. If contamination is present it can lead to the formation of a corrosion cell and to premature failure of the coating.
Surface temperature measurements are also made at low and high values and the external temperature measurement is checked at four values across the range.
This standard is not included in any packages. No other units of measurement are included in this standard. Figure 3 — Digital Xstm Dewpoint Meter It can clearly be seen that if a surface is cooled sufficiently the surrounding air will eventually give up its moisture to the cool surface. Examples of these measurement devices are shown in figures 1 and 2 below.