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ASHRAE Standard 41.3-2022 -- Standard Methods for Pressure Measurements (ANSI Approved), 2022
- ANSI/ASHRAE Standard 41.3-2022 [Go to Page]
- CONTENTS
- FOREWORD
- 1. PURPOSE
- 2. SCOPE
- 3. DEFINITIONS
- 4. CLASSIFICATIONS [Go to Page]
- 4.1 Pressure Categories. The types of pressures used in this standard are listed below and shown in Figure 1.
- 4.2 Pressure Measurement Instrument Types. Pressure measurement instrument types that are within the scope of this standard include, but are not limited to, the following:
- 4.3 Pressure and Pressure Difference Measurement Conditions. Pressure and pressure difference measurement test conditions that are within the scope of this standard shall be classified as one of the types in Sections 4.3.1 and 4.3.2.
- 5. REQUIREMENTS [Go to Page]
- 5.1 Test Plan. The test plan shall be one of the following documents:
- 5.2 Alternative Pressure Measurement Types and Units That Shall Be Reported. Table 4 lists the alternative pressure measurement types and units that shall be measured and reported if specified in the test plan in Section 5.1.
- 5.3 Accuracy or Measurement Uncertainty. A selected pressure measurement or pressure difference measurement instrument shall meet or exceed the required pressure or pressure difference measurement system accuracy or measurement uncertainty that is sp...
- 5.4 Pretest Pressure or Pressure Difference Uncertainty Analysis. If required by the test plan in Section 5.1, perform an analysis to establish the expected uncertainty for each pressure or pressure difference test point prior to the conduct of that ...
- 5.5 Post-Test Pressure or Pressure Difference Uncertainty Analysis. If required by the test plan in Section 5.1, perform an analysis to establish the pressure or pressure difference measurement uncertainty for each pressure or pressure difference tes...
- 5.6 Steady-State Test Criteria. Pressure and pressure difference test data shall be recorded at steady-state conditions unless otherwise specified in the test plan in Section 5.1.
- 5.7 Unsteady Pressure Measurements. If required by the test plan in Section 5.1, pressure and pressure difference test data shall be recorded
- 6. INSTRUMENTS [Go to Page]
- 6.1 Instrumentation Requirements for All Measurements
- 7. PRESSURE MEASUREMENT AND CALIBRATION METHODS [Go to Page]
- 7.1 Pressure Measurement Instruments. Pressure measurement instruments that are within the scope of this standard include the types that are described in Sections 7.1.1 through 7.1.12.
- 7.2 Vacuum Instruments. Vacuum instruments that are within the scope of this standard include, but are not limited to, the instruments that are described in Sections 7.2.1 through 7.2.8.
- 7.3 Pressure Calibration Instruments. Pressure calibration instruments that are within the scope of this standard include, but are not limited to, the instruments described in Sections 7.3.1 through 7.3.4.
- 8. UNCERTAINTY ANALYSIS [Go to Page]
- 8.1 Post-Test Uncertainty Analysis. A post-test analysis of the measurement system uncertainty, performed in accordance with ASME PTC 19.11, shall accompany each pressure measurement and pressure difference measurement if specified in the test plan i...
- 8.2 Method to Express Uncertainty. All assumptions, parameters, and calculations used in estimating uncertainty shall be clearly documented prior to expressing any uncertainty values. Uncertainty shall be expressed as
- 9. TEST REPORT [Go to Page]
- 9.1 Test Identification
- 9.2 Unit Under Test (UUT) Description
- 9.3 Instrument Description
- 9.4 Measurement System Description
- 9.5 Test Results. If specified in the test plan in Section 5.1, report the following test results in the units specified in Table 4:
- 10. NORMATIVE REFERENCES
- INFORMATIVE APPENDIX A: INFORMATIVE REFERENCES AND BIBLIOGRAPHY
- INFORMATIVE APPENDIX B: PRESSURE TRANSDUCER UNCERTAINTY EXAMPLE [Go to Page]
- B1. EXAMPLE
- B2. TEST CASE 1 [Go to Page]
- B2.1 Instrument Application 1. The pressure transducer in Section B1 is combined with a data acquisition to measure a refrigerant compressor discharge pressure at 100 °C (212 °F). A reading of 3103 kPa (450 psia) is recorded as 4.5 V.
- B2.2 Instrument Application 2—Analog Comparison. An analog precision gas pressure gage is used to measure the same discharge pressure. The gage has a pressure range of 0 to 3447 kPa (0 to 500 psia) and a resolution of 13.47 kPa (2 psia) between sca...
- B3. TEST CASE 2 [Go to Page]
- B3.1 Instrument Application 3. The pressure transducer in Section B1 and the data acquisition system in Section B3.1 are used to measure the pressure in an exhaust plenum. The air is at 35°C (95°F) and the measured pressure is 105 kPa (15.2 psia).
- B3.2 Instrument Application 4—Analog Comparison. An analog precision gas pressure gage is used to measure the same airflow. The gage goes from 0 to 138 kPa (0 to 20 psia) and has a resolution of 1.38 kPa (0.2 psia) between scale markers. For the in...
- INFORMATIVE APPENDIX C: FLUID FLOW PRESSURE MEASUREMENT BASICS
- INFORMATIVE APPENDIX D: PRESSURE COMPENSATION REQUIRED FOR AN ELEVATION DIFFERENCE [Go to Page]
- D1. PRESSURE COMPENSATION REQUIRED FOR AN ELEVATION DIFFERENCE
- D2. Example
- INFORMATIVE APPENDIX E: PRESSURE MEASUREMENT VOLUME
- INFORMATIVE APPENDIX F: PRESSURE UNITS CONVERSION TABLE [Go to Page]
