2" pipe and GPM

[mmcguire]

Is it true that a 2" pipe can only push 73 GPM so a pump that can push more will be useless?

[eljefe281]

That "limit" is on velocity. High velocity fluids have the potential for damaging plumbing systems.

Generally speaking, I believe designers want to keep fluid velocities below 7 feet per second, especially in plastic pipe.

Really, you can move much more than 73 gpm, but it's not a good idea.

[mas985]

Actually, there is no real hard limit to flow rates or velocity in a PVC pipe. The numbers quoted are recommendations and suggest damage may occur when exceeding those so called limits.

However, pools have been built for years with over sized pumps and undersized plumbing and exceeding velocity limits of pipes. What happens in these situations is that over many years, the pipes start to leak. PSI ratings for schedule 40 pipes is usually well over 100 psi so there is little chance of pipe bursting but the high velocity in the pipe will slowly wear out the pipe.