If someone is at sea level and they put ten pounds of air pressure into a container does the container now have 10 + 14.5 = 24.5 pounds of air pressure. Do we not add the atmospheric pressure? Seems like the container had 14.5 in before the ten was added. I have a feeling there is a simple something I am over looking here. How much air pressure is in the container.
there are two different conventions that people use to express pressure. "absolute pressure" includes the contribution of atmospheric pressure and "gauge (also spelled "gage") pressure" does not. So a sensor that is calibrated to read gauge pressure will indicate zero on the readout when it is sitting in ambient air at 14.7 PSI, and its readout will specify PSIG, meaning pounds per square inch GAUGE. A sensor that is calibrated to read absolute pressure will read 14.7 PSI when it is sitting in ambient air and its readout will specify PSIA, meaning pounds per square inch ABSOLUTE.
This means that (PSIG) = (PSIA-14.7)