ASHRAE 41.1 2013
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ASHRAE Standard 41.1-2013 Standard Method for Temperature Measurement
Published By | Publication Date | Number of Pages |
ASHRAE | 2013 | 16 |
ANSI/ASHRAE Standard 41.1-2013 prescribes methods for temperature measurement as well as for testing heating, refrigerating, and air-conditioning equipment and components.
PDF Catalog
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4 | FOREWORD 1. PURPOSE 2. SCOPE 3. DEFINITIONS |
5 | 4. CLASSIFICATIONS 4.1 Temperature measurements shall be made with an instrument or instrument system, including read-out devices, meeting the accuracy and precision requirements in the test plan. Temperature-sensing methods that are within the scope of this standard i… 4.2 The response time for liquid-in-glass thermometers is too long to be used in transient testing. 4.3 In no case shall the smallest scale division of the instrument exceed twice the specified precision. For example, if the specified precision is Ā±0.05Ā°C (Ā±0.10Ā°F), the smallest scale division shall not exceed 0.10Ā°C (0.20Ā°F). 4.4 Where accuracy better than Ā±0.30Ā°C (Ā±0.50Ā°F) is specified, the instrument shall be calibrated by comparison with a National Institute of Standards and Technology (NIST) calibrated primary or secondary (transfer) standard or shall itself be si… 4.5 Whenever two temperature-measuring instruments are used to measure a temperature difference of less than 5Ā°C (9Ā°F), the investigator shall recognize the effect of individual instrument accuracies on the accuracy of the calculated temperature di… 5. REQUIREMENTS 5.1 Test Plan. A test plan is a document or other form of communication that specifies the tests to be performed and the required measurement accuracy for each test. Sources of the test plan include, but are not limited to, (a) the person or the orga… 5.2 Values to be Determined 5.3 Airstream Temperature Measurements Figure 1 Mixing device. |
6 | Figure 3 Mixing device. Figure 3 Mixing device. 5.4 Liquid Temperature Measurements |
7 | Figure 5 Methods for ensuring thorough mixing in liquids. 5.5 Refrigerant Temperature Measurements 6. instruments 6.1 Derived Measurements. Measurements are categorized as either primary measurements or derived measurements. A primary measurement is one that is obtained directly from the measurement sensor (e.g., liquid-in-glass thermometer). A derived measureme… 6.2 Calibration 6.3 Electrical Measurements. Electrical measurement (resistance, voltage, and current) errors shall be less than 0.1% when used to derive a temperature measurement. When not defined by the test plan or method of test standard, the portion of the tota… 6.4 Pressure Measurements. Pressure measurement errors shall be less than Ā±1.0%. If absolute pressure sensors are not used, ensure that the pressure measurement uncertainty calculations include the barometric pressure correction to obtain absolute p… |
8 | 6.5 Time Measurements. Time measurements shall be within Ā±0.5% of the elapsed time measured. This accuracy shall include any uncertainty errors associated with starting and stopping the measurement. 7. temperature test methods (informative) 7.1 Liquid-in-Glass Thermometers 7.2 Thermocouples |
9 | TABLE 1 Limits of Error of Thermocouples and Extension Wiresa, b 7.3 Thermocouple Circuits |
10 | 7.4 Resistance Temperature Devices 7.5 Thermistors 7.6 Infrared Pyrometers |
11 | 8. UNCERTAINTY ANALYSIS 8.1 Accompanying the measurement of temperature shall be an estimate of the uncertainty of the measurement. This is referred to as an error analysis, as outlined in ANSI/ASHRAE Guideline 2, Engineering Analysis of Experimental Data.2 8.2 The random errors in temperature measurements are associated with the ability to resolve a reading from the instrument. The random error estimate determined in a measurement shall be compared with the least scale division for reading the instrume… 8.3 The larger estimate of instrument uncertainty as determined in Section 8.2 and 8.3 shall be used in the estimate of the error propagation for any derived temperature measurement. Alternatively, a more rigorous approach to estimating the random er… 8.4 Calculation examples for estimating the uncertainty for two types of temperature measurements are provided in Informative Annexes B and C. 9. TEST REPORT 9.1 Test Identification 9.2 Unit under Test Description 9.3 Instrument Description 9.4 Ambient Conditions 9.5 Test Conditions 9.6 Test Results 10. REFERENCES INFORMATIVE ANNEX Aā bibliography |
12 | INFORMATIVE ANNEX Bā Example of an uncertainty estimate for a temperature measurement with an rtd |
13 | INFORMATIVE ANNEX Cā example of an uncertainty estimate for a temperature measurement with a thermocouple |