The 2023 edition covers a broader range of sizes and modern air-device types, including displacement ventilation underfloor outlets , which were less common when the 2006 version was written. Instrumentation Accuracy:
Requires the use of omnidirectional anemometers for measuring throw, spread, and drop. Major Changes in the 2023 Update ashrae standard 702006 pdf updated
| Feature | 70-2006 | 70-2020 (Updated) | | :--- | :--- | :--- | | | HCFCs, HFCs, NH3 (Ammonia) | Added A2L (mildly flammable) and A3 (highly flammable) refrigerants like R-32, R-454B, and propane (R-290). | | Test Uncertainty | +/- 5% allowed | +/- 3% for critical flow; added rigorous uncertainty analysis protocol. | | Instrument Calibration | Annual calibration suggested | Mandatory traceable calibration to NIST every 6 months. | | Backpressure Correction | Simplified method | New complex correction factors for valves with built-in backpressure compensation. | | Reporting | Basic data sheet | Mandatory electronic data logging with a minimum 1 second sampling rate. | The 2023 edition covers a broader range of
"Reaffirmed" (RA) indicates that the 2006 technical content was reviewed by a committee and found to still be accurate and relevant without needing major changes. | | Test Uncertainty | +/- 5% allowed
