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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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. 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.
The reference values are set using the controls for the chamber and measured independently using calibrated equipment. The digital format of the gauge allows sets of reading to be stored in memory for further analysis, reporting or archiving. In this case, the instrument comprises a wet-bulb thermometer only. Please login to your authorized staff account to use this feature.
Online orders will ship on January 2, Figure 4 The Electronic Dewmeter with an external thermocouple sensor connected. Digital humidity gauges have been available for some years but there is now a Dewpoint Meter that is designed specifically to monitor the paint process and that also provides a method for recording and presenting data as proof of the conditions prevailing. 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.
It is therefore essential that the relative humidity RHthe air temperature Ta and the surface temperature Ts are measured quickly and accurately so that the dewpoint temperature Td and the difference between the surface and dewpoint temperatures can be calculated for correct paint or not paint decisions to be made. These temperatures make allowance for the accuracy of the measurement of relative humidity and surface temperature in the field and also deal with any inertia in the evaporation from a surface as it warms up.
These errors accumulate from a number of operational issues such as alignment of the lens in the glass thermometers for optimum position when reading both thermometers, parallax errors when reading the position of the thread relative to the scale on the glass, heat from hands transmitted to the bulbs of the thermometers and resolution of the measurement and the conversion of the readings to rh and dewpoint.
Recent Developments in the Measurement and Monitoring of Climatic Conditions
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. Guidance on the estimation of the probability of condensation prior to paint application. Note — Ta will be the same value as Tdb.
A semiconductor sensor is used to measure the relative humidity wstm the measurement response time is much quicker than the traditional wet and dry bulb method that can take 20 minutes or more to reach steady-state conditions, at which point the temperatures of the bulbs can be read. 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.
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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 strip thermometer. Your Alert Profile lists the documents that will be monitored. The method for determining if moisture is present is given in ISO No items in cart.
We wish you and yours a Happy Holiday Season! The feature in the electronic Dewmeter that displays the calculated wet 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 relative humidity.
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ASTM E337 – 15
Search book title Enter keywords for book title search. You may delete a document from your Alert Profile at any time. This paper describes the latest design and 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.
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.
This sensor can be also be used for measuring the temperature of satm to astk used in the e3377 or for surface temperature monitoring during the process, data-logging. The right to access the electronic files of ASTM Standards is for purposes of viewing for individual use only. There were no books found for the applied search filters.
Figure 3 — Digital Electronic Dewpoint Meter It can clearly be seen that if a surface is cooled sufficiently the surrounding air will eventually asgm up its moisture to the cool surface.
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. Historical Version s – aatm previous versions of standard. The surface temperature is measured either using an integrated K-type thermocouple sensor mounted next to the RH and Air Temperature sensors or by using an optional atsm thermocouple sensor connected via a K-Type connector.
However, the extra resolution provided by the electronic gauge over that of the whirling and sling hygrometers is useful in reports. This arrangement is shown in figure e373. The wireless connection will operate over a distance of up to 15 m.
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.
Data stored in the memory of the Dewpoint Meter can be transferred to a computer operating data management software. This is also true for whirling and sling hygrometers as when these encounter immovable objects such as pillars the tendency is to break the spirit-in-glass thermometers. Please sign into an account with a subscription to this content, or email for help at support madcad.