Pressure reported from a water line, gauge or absolute?

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SUMMARY

The discussion centers on the distinction between gauge pressure and absolute pressure in a water line context. The pressure value of 1630 kPa is identified as absolute pressure, leading to confusion regarding unit conversion. Participants clarify that "psia" denotes absolute pressure, and thus, the correct interpretation does not require adding atmospheric pressure to the gauge reading. The consensus is that pressure gauges typically display gauge pressure unless specified otherwise.

PREREQUISITES
  • Understanding of gauge pressure vs. absolute pressure
  • Familiarity with pressure units (kPa, psi, psia)
  • Basic knowledge of atmospheric pressure (14.7 psi at sea level)
  • Ability to convert between pressure units
NEXT STEPS
  • Research the differences between gauge pressure and absolute pressure in fluid mechanics
  • Learn about pressure measurement tools and their specifications
  • Explore unit conversion techniques for pressure measurements
  • Study the implications of pressure readings in engineering applications
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Students in engineering fields, professionals in fluid dynamics, and anyone involved in pressure measurement and analysis will benefit from this discussion.

EastWindBreaks
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Homework Statement


upload_2017-10-26_4-7-1.png


Homework Equations

The Attempt at a Solution


I thought the pressure in a water line is in gauge pressure, but the solution suggests that 1630 kPa is in absolute pressure, do we always assume absolute pressure unless otherwise specified?
 

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How does the solution imply gauge or absolute? It's simply asking you to change units isn't it?
 
CWatters said:
How does the solution imply gauge or absolute? It's simply asking you to change units isn't it?
I thought psia means psi as in absolute pressure? if it is, then I would need to add 1630 kpa( if its gauge pressure) to atmospheric pressure, which would be 246.42 psi+14.7 psi, but the correct answer is just simply 246.42 psia.
 
EastWindBreaks said:
I thought psia means psi as in absolute pressure? if it is, then I would need to add 1630 kpa( if its gauge pressure) to atmospheric pressure, which would be 246.42 psi+14.7 psi, but the correct answer is just simply 246.42 psia.
A pressure gauge typically gives the pressure in a water line as gauge pressure. So, you are absolutely right in your criticism of question. I would have given the same answer you gave.
 
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Chestermiller said:
A pressure gauge typically gives the pressure in a water line as gauge pressure. So, you are absolutely right in your criticism of question. I would have given the same answer you gave.
haha, I am not sure if i was criticizing the question or just confused, thank you for clarification!
 
I didn't notice the "psia" next to the answer box. The question itself just says psi.
 
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