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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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. In this case, the instrument comprises a wet-bulb thermometer only.
Standards Subsctiption may be the perfect solution. 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.
Recent Developments in the Measurement and Monitoring of Climatic Conditions
The memory capacity is a maximum of 25, records or sets, in up to different batches. 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. The measurement of climatic conditions prior to applying a coating is vital to the success of the process, as it is well known that a surface at the dewpoint temperature will have a thin film of moisture over which the paint will be applied.
Standards Awtm from ANSI provides a money-saving, multi-user solution for accessing standards. Please note our new address: Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials.
Link aastm Active This link will always route to the current Active version of the standard. This is particularly the case when the hygrometer has been stored in office conditions and then is used outdoors in different conditions of temperature and humidity. A semiconductor sensor is used to measure the relative humidity so 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.
ASTM grants you a license as follows: We have no amendments or corrections for this standard. Measurement of relative humidity in controlled conditions is not practical for the whirling or sling hygrometer as the presence of an operator in the controlled environment causes errors. Please sign into an account with a subscription to this content, or email for help at support madcad.
ASTM E337 – 15
The accuracy of the electronic measurements can be shown to be as indicated on the calibration certificate and the speed of response of the electronic gauge can show the effects of the presence of humans in the area, particularly if the area is enclosed or the effects of changes in a prevailing wind if the work place is exposed.
The reference values are set using the controls for the chamber and measured independently using calibrated equipment. There were no books found for the applied search filters. The values quoted in table 1 are obtained from the calibration software and can be shown to a resolution of two decimal places.
Similarly the data-logging option can be chosen when a new batch is selected by pressing the clock softkey. 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.
The external thermocouple is also attached to the substrate using a magnet to get a good thermal contact for the surface temperature measurement. Our office will be closed from December 21st until January 2nd No other units of measurement are included in this standard.
The definition of the Dewpoint Temperature is the temperature at which moisture will condense from a body of air at a higher temperature. Table 1 shows the typical measured reference values for these parameters that appear on the calibration certificate.
The method for determining if moisture is present is given in ISO asrm An example of this type of gauges is shown in figure 3. Please first log in with a verified email before subscribing to alerts.
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.
Online orders w337 ship on January 2, The method specified is based on measuring air temperature and relative humidity, calculating the dewpoint temperature, measuring the steel surface temperature, and estimating the minimum surface temperature above the dewpoint temperature that is needed to avoid condensation under the prevailing environmental conditions. 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 s337 the difference between the surface and dewpoint atsm can be calculated for correct paint or not paint decisions to be made.
Register for a trial account. Figure 4 The Electronic Dewmeter with an external thermocouple sensor connected. Content only available by subscription. The default time is 1 minute.
There are several operational aspects of the wet and dry bulb hygrometer method for measuring humidity that influence the accuracy of the measurement including insufficient whirling so steady-state conditions are not reached, contamination of the satm so optimum evaporation conditions for the wet bulb are not achieved, the use of spirit-in-glass thermometer in place of the environmentally unsound mercury-in-glass thermometers.