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ASHRAE Standard 126 Method of Testing HVAC Air Ducts and Fittings (ANSI/ASHRAE/SMACNA Approved), 2008
- FOREWORD
- 1. PURPOSE
- 2. SCOPE
- 2.1 This standard may be used to determine the structural strength, dimensional stability, durability, and leakage characteristics of HVAC air ducts and fittings.
- 2.2 This standard does not cover:
- 3. DEFINITIONS
- 4. NOMENCLATURE
- 5. INSTRUMENTS
- 5.1 Accuracy and Precision. Measurements shall be made with an instrument or instrument system, including read-out devices, that meets the accuracy and precision requirements specified in Sections 5.2 through 5.5. The systematic error in an instrumen...
- 5.2 Temperature Measurement
- 5.3 Pressure Measurement
- 5.4 Flowmeters. Flowmeters shall have an accuracy of 2% (of reading).
- 5.5 Dial Indicators. Dial indicators shall have jewel bearings, a suitable range, and 0.01 mm graduations.
- 6. TESTS
- 6.1 Tests to be conducted are listed below. A specific test specimen may be used for more than one test at the sponsor’s discretion.
- 6.2 Individual tests may be omitted by the sponsor.
- 6.3 When required by the sponsor, a leakage test shall be conducted before and after an individual test. If a specific test specimen is to be used for a group of tests, a leakage test may be conducted before and after the test series. Exclusive leaka...
- 7. LEAKAGE TEST
- 7.1 Test Specimen and Test Pressure. The duct assembly and test pressure shall be specified by the sponsor. The ends of the duct assembly shall have sealed end caps.
- 7.2 Test Setup
- Figure 1 Generic leakage test setup.
- 7.3 Test Procedure
- 7.4 Leakage Rate Correction
- 8. STRUCTURAL TESTS
- 8.1 Deflection Under Pressure
- Figure 2a Deflection measurement locations for externally reinforced ducts (rectangular ducts).
- Figure 2b Deflection measurement locations for externally reinforced ducts (flat oval ducts).
- Figure 2c Deflection measurement locations for externally reinforced ducts (round ducts).
- Figure 3 Deflection measurement locations for unreinforced ducts.
- 8.2 Deflection Under Superimposed Loads
- Figure 4 Test specimen loading.
- 8.3 Impact Test
- Figure 5 Sandbag details. Reproduced with permission of Underwriters Laboratories, Inc.4
- Figure 6 Test specimen impact configurations and strike points.
- 8.4 Tension Test
- 8.5 Bending Test
- Figure 7 Tension test setup.
- Figure 8 Bend test setup.
- 8.6 Pressure Cycling Test
- 8.7 Burst/Collapse Test
- 8.8 Puncture Test
- Figure 9 Puncture test apparatus.
- Figure 10 Puncture test specimen strike-point locations.
- 9. DURABILITY TESTS
- 9.1 General. The temperature and relative humidity tests shall be conducted sequentially using the same specimen.
- 9.2 Temperature Test
- 9.3 Humidity Test
- 10. REPORT
- 11. REFERENCES
- informative APPENDIX A— COMMENTARY
- informative APPENDIX B— LEAKAGE TEST SETUPS AND EXAMPLE PROBLEM
- B1. LEAKAGE TEST SETUPS
- B1.1 Laminar Flow Test SetupB-1
- Figure B-1 Example of leakage measurement by a laminar flow system for positive pressure tests.
- Figure B-2 Example of leakage measurement by a laminar flow system for negative pressure tests.
- B1.2 Orifice Tube Test Setup
- Figure B-3 Example of leakage measurement by an orifice tube system for positive pressure tests.
- B2. Example Problem
- B2.1 Recorded Test Data
- B2.2 Atmospheric Air Density Calculation
- B2.3 The measured leakage rate (Qa) determined by a laminar flowmeter is 5.093 L/s at 0.750 kPa. The leakage rate referenced to standard air density is 4.86 L/s, calculated as follows:
- B3. REFERENCES for APPENDIX B
- B4. BIBLIOGRAPHY for APPENDIX B
- informative APPENDIX C— RECOMMENDED ACCEPTANCE CRITERIA
- C1. Deflection under pressure (8.1)
- C2. Deflection under Superimposed Loads (8.2)
- C3. Impact (8.3)
- C4. Tension (8.4)
- C5. Bending (8.5)
- C6. Pressure Cycling (8.6)
- C7. Burst/Collapse (8.7)
- C8. Puncture (8.8)
- C9. Temperature (9.2)
- C10. Humidity (9.3)
- informative APPENDIX D— BIBLIOGRAPHY [Go to Page]