Equipment specifications
| Volume accuracy | ATS/ERS standards (currently 3.5% accuracy over an 8-L volume using test gases, with a testing syringe accuracy of 0.5%) |
| Gas analysers | Linear from zero to full span within ±0.5% of full span. Stable over the duration of the test with drift <±0.5% of a measured gas |
| Circuit resistance | <1.5 cmH2O·L−1·s−1 at a flow of 6 L·s−1 |
| Demand-valve sensitivity | <10 cm H2O required for 6 L·s−1 flow through valve and circuit (if compressed gas source used) |
| Timer | ±1.0% over 10 s (100 ms) |
| Apparatus/valve filter VD | <0.350 L |
ATS: American Thoracic Society; ERS: European Respiratory Society; VD: dead space volume.