Designing Commercial Sewage Lift Stations Part 1: How To Determine Flow Rate

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By Chris Edmondson

Sometimes codes just aren’t very helpful.  Take Section 712.4.2 of the International Plumbing Code (IPC) and its insight into the selecting flow capacity for a sewage and ejector pumps:

712.4.2 Capacity. A sewage pump or sewage ejector shall have the capacity and head for the application requirements.

(Thanks, IPC….)

Clearly, having the proper flow is necessary to efficiently discharge wastewater from a commercial plumbing system – but how do you determine the flow rate for the sewage system so you can properly size the pump? 

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Pump Affinity Laws Are Key To Saving Money in a Hydronic System

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What are the pump affinity laws and why are they so important? 

Pump affinity laws define the mathematical relationship that exists between pump speed, flow, total head, and power consumption.

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How to Read a Pump Curve - Part 3

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 Pump selection can have dramatic impact on the overall operating cost of a hydronic system.  Consulting several pumps curves prior to the selection of a pump is the key to minimizing these operating costs.   In this blog we will discuss the factors that impact pump efficiency and how pump curves can be used to take the guesswork out of efficienct pump selection. 
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How To Read A Pump Curve - Part 2

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One of the most important lines on a pump performance curve is the Net Positive Suction Head (NPSH) curve.  Discreetly applied either below or above the pump performance and efficiency curves, this single plotted line is the key to avoiding cavitation. Required NPSH or NPSHR for a given pump increases with flow.  So, using the pump curve shown in Figure 1, we can see that the NPSHR for this Model 1510 B & G pump with a 8” impeller and 800 GPM and 33 Feet of Total Head is 12 feet of head. 
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How To Read A Pump Curve – Part 1

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If a picture is worth a thousand words then a pump curve must be worth several thousand.

 Make no mistake, there’s a lot of information on a centrifugal pump curve like the one shown here.  It’s no wonder that many newly practicing engineers are a little intimated by them.

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