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, 2024
- ASHRAE Online Bookstore
- Addenda
- Errata
- ANSI/ASHRAE Standard 195-2024 [Go to Page]
- Contents
- Foreword
- 1. Purpose
- 2. Scope
- 3. Definitions [Go to Page]
- 3.1 This section provides definitions of key terms used in this standard. For terms not defined, refer to the definitions listed in ASHRAE Terminology of Heating, Ventilation, Air Conditioning, and Refrigeration. 1.
- 3.2 The nomenclature in Table 1 is used throughout this test method.
- 4. Instrumentation [Go to Page]
- 4.1 Temperature Measurement. Temperature measurements made to support determining the reference airflow are covered in Section 4.3. This section applies to other temperature measurements taken during testing.
- 4.2 Pressure Measurement. Refer to Section 5.3 for pressure measurements made to support determining the reference airflow.
- 4.3 Airflow Measurement. The reference airflow measuring system shall be calibrated annually, in the range of use, by comparison with a national measurement standard (e.g., a NIST standard). The reference airflow measuring system shall be calibrated ...
- 4.4 Electrical Measurement
- 4.5 Automatic Data Acquisition. Test data shall be automatically gathered from the prescribed sensors or instruments and logged for analysis and reporting purposes.
- 5. Test Setup [Go to Page]
- 5.1 Inlet to Terminal. The nominal test condition is a straight, hard inlet to the terminal. The inlet to terminal is a minimum of 10 duct diameters. The inlet duct dimensions shall be the same size as terminal inlet, i.e., no transitions.
- 5.2 Outlet from Terminal. The outlet from terminal is a minimum of 3.5 straight duct diameters. Downstream duct size shall match the terminal unit outlet, i.e., no transitions. A flow resistance (e.g., damper) may be installed downstream of this duct.
- 5.3 Airflow Reference. A reference airflow measuring system, conforming to Section 4.3, shall be installed a minimum of 10 duct diameters upstream of the air terminal.
- 5.4 Ambient Air Temperature Sensor. The ambient air temperature sensor shall not be in the airstream. It shall be located within 12 in. (30 cm) of the controller and shall be representative of the temperature of air surrounding the controller.
- 5.5 Airstream Temperature and Humidity Sensors. The airstream temperature sensor and humidity sensor shall be located in the airstream of the air terminal. They shall be located between 3 and 8 diameters upstream of the air terminal.
- 5.6 Static Pressure Drop (ΔSP). The static pressure drop (i.e., differential static pressure) across the air terminal shall be measured. The high pressure port shall be located 1.5 equivalent duct diameters upstream of the air terminal. The low pres...
- 5.7 Flow Probe Signal (for systems that include a velocity pressure flow probe). If tees are available in the tubing between the flow probe and the controller, they shall be used in order to measure the flow probe signal with a reference pressure sen...
- 5.8 Controller. The controller shall be mounted and connected per the manufacturer’s instructions. All control and measurement tubing and connections shall be tested for leakage. Maintain integrity of tubing throughout the test.
- 5.9 Ductwork Leakage. Every joint of the ductwork between the reference airflow station and the unit under test must be sealed and tested. A duct pressure test shall be conducted at 6.0 in. of water (1500 Pa). The measured leakage rate shall be less ...
- 6. Test Methods [Go to Page]
- 6.1 Calibration. The SUT is calibrated on the test installation, with the intention that the calibration process used in the lab represents the one that will be used in a field installation. The reference airflow measuring system, used for the system...
- 6.2 System Performance Test Methods. The test specifier may specify that all of the following test methods be performed or only one or more of the test methods. For each test method specified, the method must be followed in its entirety, and all othe...
- 7. Controller-Only Tests
- 8. Test Report
- 9. References
- Normative Appendix A: Standard Terminal Unit
- Informative Appendix B: Rating Conditions [Go to Page]
- B1. System Performance Test [Go to Page]
- B1.1 Accuracy
- B1.2 Zero Drift. DSPstpt and Qstpt shall be values at which the system also passed the accuracy test. The Zero drift test is passed if the following tolerance conditions are met during all subtests:
- B1.3 Stability—Low Flow. ΔSPstpt and Qstpt shall be values at which the system also passes the accuracy test. The stability test is passed if the following tolerance conditions are met during all subtests:
- B1.4 Stability—Max Flow. ΔSPstpt = 0.6 in. of water (150 Pa) or twice the pressure required to reach Qmax.
- Informative Appendix C: Exemplary Test Facility and Guidance for Measuring Air at Low Flow Rates [Go to Page]
- C1. Instrumentation [Go to Page]
- C1.1 Temperature
- C1.2 Pressure
- C1.3 Relative Humidity
- C1.4 Air Velocity Reference
- C1.5 Voltage
- C2. Data Acquisition
- C3. Test System Capability
- C4. General Guidelines for Measuring Airflow
- Informative Appendix D: Application of the Controller-Only Test [Go to Page]
- D1. Example [Go to Page]
- D1.1 I-P Units
- D1.2 SI Units [Go to Page]
