tonyespinoza
Premium Member
sorry for the newbie question...
anyone know the max flow rate of a 1.5" drain?
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kzooreefer
New member
I don't think there is really an answer to the question as it all depends upon how you are moving the water through it. By gravity or with a pump? I've gotten well over 30-gpm out of a well using a 1-hp pump through 1.5" and 1.0" diameter schedule 40 pvc with no problem. I think it would also depend upon the material the drain is made of and what type of fittings are used as to the pressures it could handle.
tonyespinoza
Premium Member
got it -- i'm planning to gravity feed a skimmer (BK 300 Ext) and just trying to wrap my head around what kind of throughput is possible. i know other folks are running about 550GPH through this skimmer in a similar sized system.
TheH
New member
I have heard that a 1" drain maxes 600gph by gravity as well. Although I would imagine that this would depend on the pressure of the water pressing down on it which would itself depend on the height of the water?
However, if we hold this constant I imagine we can do something like this?
Area of Circle: (r^2) * PI
C * (1^2) * 3.14159 = 600gph, therefore C = 191
and
191 * (1.5^2) * 3.14159 = 1350gph?
However, if we hold this constant I imagine we can do something like this?
Area of Circle: (r^2) * PI
C * (1^2) * 3.14159 = 600gph, therefore C = 191
and
191 * (1.5^2) * 3.14159 = 1350gph?
tonyespinoza
Premium Member
thanks guys - i knew someone out there could help me figure it out!
kzooreefer
New member
what i've found through googling is that the maximum velocity through pvc pipe (schedule 40) should not exceed 5 feet per second. from the charts in the link below for 1.5 inch diameter pipe that comes to approximately 30 gpm or 1800 gph. though you can get a lot more flow than this through the pipe from what i've experienced first hand but you run the risk of bursting the pipe.
http://www.engineeringtoolbox.com/pvc-pipes-friction-loss-d_802.html
http://www.engineeringtoolbox.com/pvc-pipes-friction-loss-d_802.html
kzooreefer
New member
TheH your equation for the radius of a circle is off, r = 1/2 diameter so Area of a Circle = pi x (1/2 d)^2. So C in your first equation actually equals 764 but somehow the math for the 1.5 inch diameter pipe still comes out to 1350 gph (22 gpm) which seems fair for gravity flow.
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