To successfully redirect water away from your job site, you must understand how to size your pipe properly when bypassing. If you incorrectly size your pipes, they’ll affect the performance of the entire pumping system. On the same hand, sizing pipes is essential because contractors must indicate the pipe sizes in their plans when they submit bids for their projects.
What is Bypassing?During new construction or repairs, companies must pump wastewater around the pipes that require maintenance to prevent overflows. To do so without disrupting the normal flow, they create a temporary pipeline so fluids effortlessly flow through the pipes and discharge downstream to another location. Bypass systems work great for various applications, particularly when you need to divert sewage through pipes in infrastructures and openings. You can also use a bypass system to repair storm drains and sanitary drains, which have been installed separately since the 1930’s.
How to Size Your Pipe Properly When BypassingFirst, you need to know exactly how much and where the flow will come from and where it needs to discharge. Take note of the distance of the area you’ll work in to estimate the length of pipes suitable for the job. Bypass pipes can be one size smaller than main pipes, but larger pipes are typically more ideal for longer distances, Discharge piping should be vented for longer distance piping, so adjust your pipes if needed. Additionally, the size of the pipes must match the peak flow, or the pipeline’s highest daily flow, if the pipe is too small it will create too much TDH or pressure on the pumps and drastically lower the performance of the pumping system; failure to consider the peak flow may result in costly spills. You must also take friction loss and static lift into consideration. Friction loss happens when you increase the line size through the bypass to the receiving point of the system. Static lift is the height at which the water rises in the pipes before it reaches the pumps. Finally, don’t forget to think about the overall bypass system design when you select suction and discharge pipes. Diameter plays a huge role in the pipes you use, as they must be large enough for the flow. The equation for pipe diameter is the square root of four multiplied by the flow rate divided by Pi multiplied by velocity. It’s also crucial that you’re familiar with the fluid’s temperature and viscosity which is the measurement of internal friction or thickness of the fluid flowing through the pipe. The less viscous the fluid, the more easily it can travel from one end of the pipe to the other. To reduce friction and velocity, you need to make sure all the pipes for your operation are the proper size.
Poiseuille’s LawΔP=8μLQ/πR⁴ Physicists and engineers use Poiseuille’s law to predict the velocity of water through a pipe. They use the equation mentioned above, where:
- ΔP = the velocity of the fluid
- μ = the dynamic viscosity, or the force a fluid needs to flow and overcome its own friction
- L = the length of the pipe
- Q = the volume of the fluid
- R = the pipe’s radius