reservoir and Booster pumps

[swazimatt]

I am in the process of designing a new industrial precinct that will require a storage for firefighting and a pump to supply the network.
The idea is that the reservoir will be supplied by the network, but this will be the same network that the pump discharges into (as a booster pump and fire pump), how do i prevent the pump from short circuiting and flow just looping back into the tank

I have modelled it in EPANET and find the only way i can reduce the flow back into the tank is by restricting the tank supply diameter to 50mm. This seems very small for a 1000m3 tank with 250mm dia pipe from the pump into the network.

Is there a good source that i can read up on regarding networks with booster pumps

 

[pierreick]

A sketch, please
Pierre

 

[LittleInch]

You simply need to add in a no return valve between the point where the pump connects into the network and the upstream point where the pond supply is made.

But yes, a sketch or diagram would aid matters for sure.

 

[swazimatt]

Sketch attached
View attachment scan_mzf_2025-02-24-16-20-43 (002).jpeg
The current stage is the part in blue, but this forms part of a 115Ha precinct. This stage is about 20Ha and (while not shown on the sketch) we have a minimum of 150mm dia pipes on each side of the road, making it quite easy for water to loop around the block and fill the reservoir at almost 50% rate the pump is pumping out (100+l/s for fire flows)
I am not sure if there is a way i can correctly model the flow into the reservoir using epanet (possibly as an emitter?) without reducing it to a restricted pipe (40mm diameter). This seems wrong for a 750m3 reservoir

 

[pierreick]

Hi,
Add NRV (non-return valves) to your system to prevent backflow.
You may want to use ON/FF actuated valves interlocked with the start /stop of the pumps and feed back to PLC/DCS (more expensive)
Pierre

 

[LittleInch]

Just do the same,e as you have on the others and feed the reservoir from the incoming supply and either add the nav as shown or just feed it direct.

 

[hydrae]

Make the fill valve pressure sustaining in addition to level control.
I do not know your pressure readings so as an example ( I am used to imperial units so I will convert to bar)
pumps start at 3 bar
pumps regulated to 3.3 bar
fill valve regulated to 3.7 bar

so
if pressure at the tank is greater that 3.7 bar they fill
if pressure at the tank is less than 3.7 they do not fill

The pressure will be between 3.3 and 3.7 under all expected scenarios

EPAnet has pressure sustaining as an option on a control valve
Hydrae

 

[swazimatt]

Just do the same,e as you have on the others and feed the reservoir from the incoming supply and either add the nav as shown or just feed it direct.

I did think of this option but the reason the council has requested we ringmain all three precincts at the end of the project is to provide some redundancy and also in case one of the pumpstations fail. If we use a non-return valve on the ring main from Pct B to Pct C we will not be able to provide flows in reverse. It would also be about 1000m of supply pipe

 

[swazimatt]

Make the fill valve pressure sustaining in addition to level control.
I do not know your pressure readings so as an example ( I am used to imperial units so I will convert to bar)
pumps start at 3 bar
pumps regulated to 3.3 bar
fill valve regulated to 3.7 bar

so
if pressure at the tank is greater that 3.7 bar they fill
if pressure at the tank is less than 3.7 they do not fill

The pressure will be between 3.3 and 3.7 under all expected scenarios

EPAnet has pressure sustaining as an option on a control valve
Hydrae

Not sure if this is the right way round, but possibly a flow control valve? The average daily flow for the full Prct C is only about 4l/s so if i restrict the flow to about 7.5 l/s the tank should fill with 12 hours.
This flow would be fine in a 75mm dia pipe so maybe there is no issue using a smaller pipe diameter to control the flow into the tank
My epanet model currently does not include and "assisted" flow from the pump at Prct B so possibly overthinking this