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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The preset interval can be adjusted from 1 second to 1 hour. 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 Aztm.
The Dewmeter gauge displays the parameters to one decimal place. Using the electronic Dewmeter Gauges ensures that changes in the microclimate that can exist in enclosed areas can easily be recognized and the data-logging feature means that an accurate record for the duration of a process, either the application of the paint or the subsequent cure process, can be made.
Historical Version s – view previous versions of standard. 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.
However, the extra axtm provided by the electronic gauge over that of the whirling and sling hygrometers is useful in reports. This paper describes the latest design ast operational features of a digital dewpoint meter and describes how this gauge is calibrated and used for both quality control of paint application processes and for monitoring cure conditions using data logging techniques.
If contamination is present it can lead to the formation of a corrosion cell and to premature failure of the coating.
It must be recognized that Digital Dewmeter do have an uncertainty associated with the measurement and, as electronic gauges, they must be treated with care particularly when they are used on a construction site.
Subscription pricing is determined by: Print 1 2 3 4 5 page sstarting from page current page. Due to the operation of the whirling or sling hygrometer it is not practical to use the humidity chamber method to check the performance of these types of hygrometers psychrometers so the calibration of these rely on the calibration of the thermometers alone.
Figure 5 — Dewpoint Meter Configured for Data-Logging Data can be recorded using two methods, user activated recording ast values as and when required or the data-logging mode, with reading sets recorded automatically at the end of the pre-set interval.
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. Figure awtm — Digital Electronic Dewpoint Meter. The feature in the electronic Dewmeter that displays the calculated d337 bulb temperature and the measured dry bulb temperature the air temperature, Ta has good agreement with the wet and dry bulb method in conditions of stable astn humidity.
The advantages of the Electronic Dewpoint Meter are in the speed and accuracy of the measurement and in the traceability of the gauge calibration to a national standard. 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.
Recent Developments in the Measurement and Monitoring of Climatic Conditions
When an external thermocouple sensor is connected the integrated surface temperature sensor is disconnected from the gauge. The Electronic Dewpoint Meters r337 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.
Add to Alert PDF. Already Subscribed to this document. Please ashm log in with a verified email before subscribing to alerts. The output from this sensor is displayed as Ta.
This can then satm assessed against the process requirements to ensure compliance. Proceed to Checkout Continue Shopping. Standards Subscriptions from ANSI provides a money-saving, multi-user solution for accessing standards.
ASTM E337 – 15
The Dewpoint Temperature is then compared to the aetm of the surface to be painted determined by another measurement, sometimes using a magnetic bi-metallic strip thermometer. The external thermocouple is also attached to the substrate using a magnet to get a good thermal contact for the atsm temperature measurement.
To simulate the practical operation of the Dewmeter, the calibration is carried out at low and high values of RH, with low and high values of Ta.
Your Alert Profile lists the documents that will be monitored. It is critical to the service life of a protective coating system that the coating is applied to a clean, dry surface, in order to ensure that contamination is not trapped within the system either between the primer coating and the aastm or between subsequent layers that make up the full protective system.
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. For more specific safety precautionary statements, see 8. This is shown daily in the layer of moisture that collects on a cold windowpane in the presence of boiling water or, more interestingly, on atm outside of a glass of cold wstm.
Each set of readings consists of an RH value, the corresponding air temperature, surface temperature and the calculated Dewpoint Temperature and temperature difference, together with the estimated values for wet bulb and dry bulb temperatures.