Calculating Pressure Difference for Indoor Plumbing

In summary, In order to have water reach the sinks and showers in an indoor plumbing system, the water has to travel vertically up the pipe. The pressure at the sinks and showers will be lower than the pressure at the house's plumbing system, due to the height of the water and the pressure loss due to friction in the pipes.
  • #1
Idea04
194
1
with indoor plumbing, let's say you have 40psi entering the house. The water has to travel vertically to the sinks and showers. Now I know with a foot of height equals a certain psi downforce. But If the water travels 20 feet or so upward, I'll just throw a number out there 10 psi pressure difference. Would you have 30psi reaching the sinks or showers? And would you have to calculate the amount of flow reaching the destination from the 30psi when its been reduced by the pressure difference?
 
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  • #2
There would be a certain amount of pressure loss (head) due to the height of water which acts downward with gravity (weight). When the water is flowing, there is another loss due to friction in the pipes, and the pressure drop depends on the length of pipe. If the water velocity is low, then the pressure drop is likely not very significant.
 
  • #4
So if the velocity is low then with friction loss is not very significant. But the pressure drop from head, Is accounted for and that is just subtracting the pressure head off the initial pressure. But would you calculate the flow from the pressure reduced after the head loss.
 
  • #5
I would suggest you reword your question, I can't make heads or tails of what you are asking in your last post. :confused:
 
  • #6
sorry. With head I mean the pressure that is applied to the water by gravitational pull. So basically the water reduced pressure when rising vertically. So the vertical rising water is affected by gravity. I know how to determine the pressure differece when gravity is pulling downward with vertical rising fluids because its the same as water flowing downward by gravity. But the water reaching higher ground to sinks or whatever has lower pressure. Is it the lower pressure value that you use to determine the velocity of the water. For example 40psi cityline then rising 20 or so feet could have around 10psi downward pull. Is 30psi the figure to use to determine flow reaching the sink.
 
  • #7
As the water rises up the building, it will loose pressure. You are correct that it looses pressure because of the decreasing hydrostatic term.

Provided that you have a single pipe that does not branch out, the flow will be the same value at any point along the pipe, because mass is conserved.

Are you familiar with the bernoulli equation for incompressible fluids?
 
  • #8
Thank you very much. I do understand now. I have heard of the bernoulli equation but have not studied them. I really appreciate your time in helping me. Thanks again.
 

1. How do you calculate pressure difference for indoor plumbing?

To calculate pressure difference for indoor plumbing, you need to know the flow rate of the water in gallons per minute (GPM) and the diameter of the pipe in inches. Then, you can use the formula ΔP = (0.002083 x Q^2 x L) / D^5, where ΔP is the pressure difference in pounds per square inch (PSI), Q is the flow rate in GPM, L is the length of the pipe in feet, and D is the diameter of the pipe in inches.

2. What is the unit of measurement for pressure difference?

The unit of measurement for pressure difference is pounds per square inch (PSI). This is a common unit of pressure used in the United States for measuring the force exerted by liquids or gases on a given area.

3. How does pressure difference affect the flow of water in indoor plumbing?

The pressure difference in indoor plumbing affects the flow of water by determining the direction and speed of the water flow. A higher pressure difference will result in a faster flow of water, while a lower pressure difference will result in a slower flow. It is important to have the correct pressure difference in order to maintain a constant and adequate water flow for household use.

4. What factors can affect the pressure difference in indoor plumbing?

There are several factors that can affect the pressure difference in indoor plumbing. These include the diameter and material of the pipes, the height and layout of the building, the elevation of the location, and the water source and supply pressure. Any changes in these factors can impact the pressure difference and may require adjustments in the plumbing system.

5. How can you measure the pressure difference in indoor plumbing?

The pressure difference in indoor plumbing can be measured using a pressure gauge. This device can be attached to a faucet or other plumbing fixture and will display the pressure in PSI. It is important to regularly check the pressure difference to ensure that it is within the recommended range for efficient and safe water flow.

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