A small breath still is x 5 at 40m/130ft.but it doesn’t?
Tidal volume is NOT the same as vital capacity….
A big breath will be 2.5 litres, so I guess I could re-do my calculations...
- Surface: 0.7litres hose / 2.5 litres lungs = 28% of a full breath.
- 40m/130ft/5ata: 1.05 litre hose / 12.5 litres lungs = 8.4% of a full breath.