If an oxygen E-cylinder pressure gauge shows half of its full service pressure, how many minutes will it last at a usage rate of 10 liters per minute?

To determine how long an oxygen E-cylinder will last when the pressure gauge indicates half of its full service pressure, it's essential to know the specifications of the E-cylinder and the calculations involved in using the oxygen at a given flow rate.

An oxygen E-cylinder typically has a full service pressure of around 2000 psi. When the gauge shows half of this, it indicates that the cylinder is at approximately 1000 psi.

The usable oxygen in the cylinder can be estimated based on the pressure, and the general rule of thumb is that 1 cubic foot of oxygen is approximately equivalent to 28.3 liters. At full pressure, an E-cylinder holds around 660 liters of oxygen at 2000 psi. Therefore, at 1000 psi, while the pressure is half, the volume will also be approximately half of the full capacity, equating to about 330 liters of usable oxygen remaining.

Given a flow rate of 10 liters per minute, you would calculate the duration of usage by dividing the total liters of usable oxygen by the flow rate:

330 liters / 10 liters per minute = 33 minutes.

This calculation affirms that the oxygen E-cylinder will last approximately 33 minutes when using oxygen at a rate of 10 liters