There need no be any water at all! The capacity of the pipe is 8.11 litres approx.
6.5 gallons, if it is full of water. (if this is a trick question, and the pipe is empty or full of dirt or something, then not 6.5 gallons)
The radius is half of the 4 inch diameter. Therefore, the radius is 2 inches.
Pipe with a Nominal Bore of 4 inch (100mm) Outside Diameter 114.3mm
2 1/4 inch is 9/4 inch long pieces, so if pipe is 36 in long then 36/divided by 9/4 is 36 times 4/9 = 16 pieces
The volume of water in a 4-inch diameter, 1-foot section of pipe is 0.6528 gallons of water.
100
The volume of the pipe is (pi) x (radius)2 x (length)= (pi) x (2)2 x (120)= 1,507.964 cubic inches = 6.528 gallons (rounded). I have no way of knowing how much water may be in it.
A standard water line PVC pipe typically has a width (diameter) of either 1/2 inch, 3/4 inch, 1 inch, or 1.5 inches.
The volume of water in a pipe can be calculated using the formula: V = πr^2h, where V is the volume, r is the radius of the pipe (which is half the diameter), and h is the length of the pipe. Given a 4-inch pipe, the radius is 2 inches, and converting to feet, it becomes 0.167 feet. Therefore, the volume of water in a 4-inch pipe that is 10 feet long is approximately 7.89 cubic feet.
The volume of this pipe is 261.8 cubic feet.
By calculating the areas of circles with diameters 6 and 4 and comparing those: pi3^2=pi9 pi2^2=pi4 pi9/pi4=9/4=2.25 So the 6 inch pipe holds 2.25 times as much as the 4 inch pipe.
111 gallons of water.
There need no be any water at all! The capacity of the pipe is 8.11 litres approx.
6.5 US gallons of water.
If the old steel pipe was half inch, it is recommended to replace it with half inch copper pipe to maintain consistent water flow. Using a larger diameter pipe (3/4 inch) may lead to reduced water pressure and inefficient operation. Stick to the half inch size for best results.
It is based on the flow area, which is proportional to the square of the diameter. 2 squared = 4. 4 squared = 16. So, the 4 inch pipe can take 16/4 = 4 times the volume of the 2 inch pipe. It might be less confusing if you had picked sizes other than 2 and 4. This is a rough calculation, since pipe inside diameters are not the same as nominal sizes, but close enough for most purposes.