pensfan84
New Member
The water line coming off of my main shutoff is 1/2" - am I able to increase the pipe to a larger size right after the main shutoff without losing much pressure?
Water Lines - Increasing Pipe Size
- Thread starter pensfan84
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pensfan84
New Member
Well...I'm installing a new bathroom on the second floor and the house currently has 1/2" throughout - it's old and starting to get deposits in spots and causing problems with pressure.
Also, I looked at the main shutoff a little closer and saw that it's actually 1" coming into the house and has a threaded reducer to 1/2". I can simply replace the fitting.
I'm trying to prevent the water temperature from changing in the shower when someone flushes the toilet, and a few master plumbers I've spoken to advised me that putting in larger water lines and then install 1/2" takeoffs for each fixture - is this not the case?
Also, I looked at the main shutoff a little closer and saw that it's actually 1" coming into the house and has a threaded reducer to 1/2". I can simply replace the fitting.
I'm trying to prevent the water temperature from changing in the shower when someone flushes the toilet, and a few master plumbers I've spoken to advised me that putting in larger water lines and then install 1/2" takeoffs for each fixture - is this not the case?
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A larger pipe size will have less pressure loss due to friction than a smaller pipe at the same flow. Therefore you will have more pressure available to your fixtures with a larger pipe. Your static pressure will remain the same. I'm not a plumber , so I don't know if this will help ypur problem with the toilets.
ChuckS
New Member
So he doesn't get the cold shower when someone flushes. So you can run two facets simultaneously.
Basement_Lurker
One who lurks
Temperature fluctuations in your shower are only going to be solved once and for all by upgrading your shower valve to at least a pressure balanced unit...are you sure you were talking to master plumbers?
Upsizing your lines will definitely allow for more water on demand if you have a big household and tend to run a few fixtures at the same time.
Upsizing your lines will definitely allow for more water on demand if you have a big household and tend to run a few fixtures at the same time.
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hj
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pipe size
Increasing the pipe size will just insure that whatever amount of water is available at the point of increase will arrive at the faucet. ANY restriction ahead of that point will still affect volume, and thus pressure, in the new section. If this is a new tub/shower installation, you MUST use pressure balanced valves and these will automatically control the situation when someone flushes the toilet.
Increasing the pipe size will just insure that whatever amount of water is available at the point of increase will arrive at the faucet. ANY restriction ahead of that point will still affect volume, and thus pressure, in the new section. If this is a new tub/shower installation, you MUST use pressure balanced valves and these will automatically control the situation when someone flushes the toilet.
pensfan84
New Member
Terry,
Based off of the link you gave me, I fit into the 1' per branch category.
would you then recommend 1" to supply the main branch, then each area (e.g. kitchens, bathrooms, laundry area) be reduced to 3/4", and then again to 1/2" for each fixture? or what way would you recommend?
Based off of the link you gave me, I fit into the 1' per branch category.
would you then recommend 1" to supply the main branch, then each area (e.g. kitchens, bathrooms, laundry area) be reduced to 3/4", and then again to 1/2" for each fixture? or what way would you recommend?
Lakee911
I&C Engineer (mostly WWTP)
Well, you can if you want hot water to arrive quickly and you have no recirculator....
Pressure loss depends on velocity, with more at higher velocity.
http://www.engineeringtoolbox.com/pe-pipe-pressure-loss-d_619.html
Cold water in plastic pipe,
ID = 0.5", 4.8 GPM, 5 ft/sec, 8.8 psi drop per 100'
for copper pipe,
http://www.engineeringtoolbox.com/pressure-loss-copper-pipes-d_930.html
http://www.engineeringtoolbox.com/pe-pipe-pressure-loss-d_619.html
Cold water in plastic pipe,
ID = 0.5", 4.8 GPM, 5 ft/sec, 8.8 psi drop per 100'
for copper pipe,
http://www.engineeringtoolbox.com/pressure-loss-copper-pipes-d_930.html
What most plumbers do, is work the chart backwards, and increase pipe size on the way back to the street.
So for instance, if you need 1/2" pipe to two plumbing fixtures, like a tub and lav, then you would increase to 3/4" when you get to the third fixture.
After a while, you will be adding more fixtures, and at some point you will be at 1"
It doesn't hurt cold to be too large, but most plumbers keep to the chart for hot water.
But even oversizing would be better then running a three bath home in 1/2" like your was.
The last time I saw that?
It was a house being "flipped" by carpenters for resale.
The home sold for over $500K and had no water anywhere.
Trying to suck water through a 1/2" straw and a pineapple shake.
Most plumbers will run 1/2" hot for lav and tub, and 3/4" cold to the bathroom, splitting down to 1/2" for the individual fixtures.
At some point, you're at 1" for the main branch.
So for instance, if you need 1/2" pipe to two plumbing fixtures, like a tub and lav, then you would increase to 3/4" when you get to the third fixture.
After a while, you will be adding more fixtures, and at some point you will be at 1"
It doesn't hurt cold to be too large, but most plumbers keep to the chart for hot water.
But even oversizing would be better then running a three bath home in 1/2" like your was.
The last time I saw that?
It was a house being "flipped" by carpenters for resale.
The home sold for over $500K and had no water anywhere.
Trying to suck water through a 1/2" straw and a pineapple shake.
Most plumbers will run 1/2" hot for lav and tub, and 3/4" cold to the bathroom, splitting down to 1/2" for the individual fixtures.
At some point, you're at 1" for the main branch.
Last edited:
Lakee911
I&C Engineer (mostly WWTP)
Cwhyu2
Consultant
aalina you know that you are repling to threads that are years old!
Bluebinky
Member
Larger pipes reducing pressure is an old wives tale.
Like others have said -- if done correctly, larger pipes should help, and a better shower valve will also help.
Another thing that can help is to take-off for the toilets from a point before the split between hot and cold.
Like others have said -- if done correctly, larger pipes should help, and a better shower valve will also help.
Another thing that can help is to take-off for the toilets from a point before the split between hot and cold.
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