As manufacturers may use different variables for calculating typical air capacity, we have created an online calculator to assist operators estimate air capacity of their SWBA. 

For typical variables:

Cylinder Volume for SWBA should be are under 500mL. 

Cylinder Pressure for SWBA is generally 207 (bar) for aluminum cylinders and up to 300 (bar) for composite carbon fibre.

Breathe volume is typically around 1500mL.

Breathing rate should be calculated no less than 20 breaths per minute.