Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: LittleJohn on March 31, 2014, 12:24:06 PM
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VERY Interesting, about the velocity of water
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This is for all of you who will be designing a style & piping this spring and summer; hopefully this information will help you with water erosion issues, potential noise issue and a good starting point for a solid design
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2 fps is darn slow. Where is this info from?
Neal
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What is the size of copper they are referring to?
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Was looking for some other water velocity info and stumble upon this
http://www.engineeringtoolbox.com/copper-pipes-water-velocities-d_1081.html (http://www.engineeringtoolbox.com/copper-pipes-water-velocities-d_1081.html)
I would guess this applies to all sizes! But I do agree 2 ft/s is slow :o, but again water over 140F is HOT :o; plus if I remember from high school the hotter the fluid the more capacity the fluid has to hold dissolved minerals.
...maybe this is why everyone is running PEX these days ;D -> don't have to worry about erosion with plastic pipe, I DON'T THINK
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The pex does erode too, and this is a detail where you will see the pex c fail much quicker than pex A. It does take a gross velocity to eat thru, but it does happen, like on systems where an oversized circ runs 24/7 , thru a small pipe.
2fps is the standard design goal for hydronic systems, no matter what sizing and design program or book you read. This is where air separators are designed to work, beyond 4fps they can't separate air from the fluid. Provides good hydraulic separation or invisibility between other zones and pri/sec piping configurations. Its a lot more than just erosion. Swing checks, spring checks, zone valves push open at speeds above 4fps.
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The pex does erode too, and this is a detail where you will see the pex c fail much quicker than pex A. It does take a gross velocity to eat thru, but it does happen, like on systems where an oversized circ runs 24/7 , thru a small pipe.
2fps is the standard design goal for hydronic systems, no matter what sizing and design program or book you read. This is where air separators are designed to work, beyond 4fps they can't separate air from the fluid. Provides good hydraulic separation or invisibility between other zones and pri/sec piping configurations. Its a lot more than just erosion. Swing checks, spring checks, zone valves push open at speeds above 4fps.
There is a lot of BTU difference between 2fps and 4fps though...
Neal
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How many GPM is in 2 feet per second?
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How many GPM is in 2 feet per second?
a chart i have that i found on the net (so no gaurenty that it is 100 percent correct ) say 1 inch pex can safey be operated between 2 and 4 FPS ??
2 FPS = 3.8 gpm and 4 FPS = 7.5 gpm
1 inch pex-al-pex ...
2FPS = 5.2 gpm and 4FPS =10.4 gpm
i would wager that most of us (or well over 50 percent) are running closer to the 4 FPS than the 2 FPS. if you are heating a house and your domestic water you likely couldnt do it on cold nights at 3.8 gpm...especially if you are running cooler temps than 175 or 180. i would guess there are more guys running standard 1 inch pex than there are pex al pex