formula for 1" or smaller pvc volumes 3

[lalvarez]

i need to figure out what the volume in GPM of a 1" pvc pipe 36" long at 3 ft/sec is. help please show math. also for a 3/4" pvc pipe same lenght and ft/sec.

 

[kenvlach]

You need 180 feet of pipe ( 3 ft/sec x 60 sec/minute).
Cap one end, stand upright on a scale to get the dry weight, then fill with water and re-weigh. Weight of water is 8.32487 pounds per gallon at 68 degrees F (measured in air at sea level). To double-check, empty the filled pipe into measuring buckets.

It's also theoretically possible to use the ID (inside diameter) of the pipe to calculate the volume. One US liquid gallon, by law = 231 cubic inches. If you know the pipe schedule (Schedule 40 is commonly used), search for pipe dimension tables.

 

[BRIS]

Q = v x A

A = Pi x R^2

D = 1 in = 0.083 ft

R = D/2

V = 3 ft/sec

1 cubic foot = 7.48 gallons (US ?)

1 minute = 60 seconds


flow = 7.3 GPM

The length of the pipe is not relevant

Do you really need to ask this ?

 

[kenvlach]

Dimensions of schedule 40 & 80 PVC and CPVC Pipes [note: same as for steel pipes]

http://www.engineeringtoolbox.com/pvc-cpvc-pipes-dimensions-d_795.html

 

[katmar]

BRIS, I am sure that Ken only specified 180 ft of pipe to simplify the horrifically complicated math involved in this problem. In fact any multiple of 180 ft (eg 360 ft etc) could be used. The only alternative for lalvarez, if he doesn't want to use so much pipe, is to use his high school math and his brain.

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[BRIS]

Katmar - I didn't see ken's response before making my facetious comments. The horrendous maths result from working in imperial US units. We don't have a problem working in SI units, always providing the pipe ID is not specified to some US schedule.

Brian

 

[kenvlach]

BRIS, 'imperial US units' is confusing. Imperial inches & gallons are slightly larger than the US measures.
Best avoid advanced mathematics - simply empty the water from 180 feet of pipe into a large, graduated bucket.

 

[CorBlimeyLimey]

 

[waross]

But Imperial ounces are smaller, not larger than US ounces.
This is a point that Canadian educators were never aware of with the result that generations of Canadian students were taught the wrong conversion from imperial gallons to US gallons.
respectfully

 

[JohnBreen]

All,

Once we have the flow in imperial GPM, can we make it veddy veddy British and calculate the flow in furlongs per fortnight?

Please show the math.

regards, John.

 

[jartgo]

Furlongs per fortnight only gives us a unit of velocity. We'll need to know the other two dimension units you require in order to calculate a flow rate. The simplest would obviously be cubic furlongs per fortnight, will that suffice?

 

[BRIS]

Acre feet per fortnight are the correct units for volume. You don't get many down a 0.045 chain long 25mm diameter pipe.

 

[JohnBreen]

Ahhh yes,

I meant to suggest that we calculate the flow VELOCITY in furlongs per fortnight? However, mass flow calculated in cubic furlongs per fortnight has a certain veddy British charm. I like it.

Regards, John.

 

[BRIS]

I hate to disappoint but all this wealth of knowledge and mathematical analyses are wasted. The guy posting the question has not logged in since posting on the 8th August.

My intensive research into determining the mathematical relationship between diameter and area of a pipe is wasted.

 

[CorBlimeyLimey]

He's probably been too busy assembling 180' of pipe ... and trying to find a ladder long enough to reach the top to fill it.

 

[dicksewerrat]

Probably an Architect student

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com