psia=psig+atmospheric pressure
where, atmospheric pressure = 14.7psi
therefore
psig=psia-atmospheric pressure
psig=100-14.7
psig=85.3psig
psia to psig psig - 15 15 - 15= 0 psig
70 psig
psig
14.7 psia represents standard atmospheric pressure, or 1 atm. PSIA is just psi with atmospheric pressure taken into account also.
55 psig +15=70
psia to psig psig - 15 15 - 15= 0 psig
70 psig
psig
PSIA is Pounds per Square Inch Absolute, as opposed to PSIG which is PSI Gauge. PSIA is absolute pressure. For example, normal atmospheric pressure is about 14.7 PSIA, so a PSIA device connected to atmosphere would read 14.7. PSIG is relative pressure, so if system pressure is 15.7 PSIA, and atmospheric pressure is 14.7 PSIA, then PSIG would be 1.0
PSIG refers to pound/force per square inch gauge, while PSI measures the pressure relative to a vacuum. If you want to convert a figure from PSIG to PSI, you would need to add 14.7psi to your PSIG figure, which will give you your PSIA result.
add atmosperic pressure to gage pressure to convert to psia one atm standard = 14.7 psi
psia IS the abbreviation. It stands for Pounds per Square Inch Absolute. When determining a pressure, you are typically measuring it with something that is subjected to atmospheric pressure (1atm~14psia) just like you and I. So say you inflate your tires to 35 psi and check it with a tire gauge. That reading is the GAUGE pressure, or psig. Typically, gauge pressures will not use the G at the end because people tend to be good enough at noticing that there's a difference between "psi" and "psia" and start to ask questions. The ABSOLUTE pressure is the gauge pressure plus the atmospheric pressure. Expressed in equation form, this looks like: psia = psig + atm -or- psig = psia - atm In the case of a vacuum, where there is less than atmospheric pressure, an absolute gauge will read positive values while a typical gauge will read negative values. The equation still holds true. Example: Absolute pressure = 4 psia 1 atm ~ 14 psia What is the gauge pressure? -10 psig 4 psia - 14 psia = -10 psig
The difference between Absolute Presure and Gauge Pressure is 14.7psi. So zero gauge pressure (0psig) = 14.7 psia. 600 psig = 614.7 psia. Calibrate the tranmitter so 4mA is obtained at 14.7 psig and 20mA is obtained at 614.7psig. The span will be 600 psi in both cases.
30 PSIG is about equal to 45 PSIA. Saturation temperature from the steam tables at 45 PSIA is about 274°F. So the steam would be 274°F, or hotter if superheated.
(psi x 6.89476 = kPa). So, 70 psi x 6.89476 = 482.633 kPa
The perfect answer requires understanding of the density of the water at different temperatures and pressures at all levels of depth. NOTE: The distinction between PSIG and PSIA is that PSIG is pressure as compared to local (atmospheric) pressure which becomes negative for a vaccum (pressure less than the local pressure). O PSIA is a perfect vacuum and normal atmospheric pressure is ~14.7 PSIA (0 PSIG when referenced to atmospheric local pressure) Without getting too "deep" into the perfect answer, using an approximation thumbrule of 1/2 psi increase per 1 foot of water depth, the answer is approximately 328 PSIG or ~ 343 PSIA.
Psig (pound-force per square inch gauge) is a unit of pressure relative to atmospheric pressure at sea level. By contrast, psia measures pressure relative to a vacuum (such as that in space). Most pressure gauges, such as tire gauges, are calibrated to read zero at sea level, because most applications require the difference of pressure. At sea level, Earth's atmosphere actually exerts a pressure of 14.695948804 psi. If a pressure gauge is calibrated to read zero in space, then at sea level on Earth it would read 14.695948804 psi. Thus a reading of 30 psig on a tire gauge, represents an absolute pressure of 44.695948804 psi.