When to use multiple Pipe Networks?

[soonhui.ngu]

I have stormwater sewers, they can be grouped into 3 disjointed groups ( meaning, there is no way to go from one structure in a group to another structure in another group by traversing the connecting pipes alone).

In this case, should I define one Pipe Network, or 3 Pipe Networks? When do I know when I should define them as one, or as multiple?

[Neilw_05]

I view pipe networks as topologies. Pipes within a network will interact with each other. Pipes not in a network will not interact. If you do not want the pipes to connect to each other, use separate networks. Storm pipes and sewer pipes should be separate networks. I usually create separate networks for existing and proposed networks as well because I don't want my existing pipes and manholes to be changed by proposed pipes. The one downside to this is when you need to connect a new pipe to an existing manhole. Since the parts won't connect you will have to manually apply the appropriate labels. Also the connected pipe  lengths will not dynamically adjust to the outside wall of the manhole. 

[soonhui.ngu]

Not sure what do you mean. Let's say all are Storm pipes, and these storm pipes can be grouped into 3 groups ( you can't go from a structure in a group to another structure in another group by traversing the connecting pipes), and I should set this as 1 Pipe Network or 3?

[Neilw_05]

Again, you need a network for each pipe system that is independent.

[soonhui.ngu]

Thanks, can I use just 1 Pipe Network for 3 independent Pipe systems? Any downsides?

[Neilw_05]

You can use one network but you will have to be careful to keep the parts from connecting to each other. If they do connect you can manually disconnect them. Unless you have a need for them to connect, why not make them separate?

[soonhui.ngu]

If I have one Pipe System, but I have 3 Pipe Networks ( as a result of accidentally connecting them, as you say), then the program will give a warning/error?

[Neilw_05]

The program will not give an error. Why would it? It doesn't know you don't want the parts to be independent. That is why you use separate networks. All parts within a network are designed to interact. 

[Neilw_05 · Accepted solution]

Perhaps you don't understand pipe networks. You can have any number of pipes and structures in a network. They do not have to touch each other to be in the same network. So for example you can have pipes in 2 subdivisions that are not connected in any way, yet they can all be in the same network. You would not have to create separate networks for each subdivision, nor do you have to create a separate network for each run of connected pipes. They can all be in the same network yet not connected to each other. They only connect if they touch another part in the network.

[narce2]

Neil,

The only problem I see with using one pipe network for multiple separate pipes that do not connect is the limitation of having only 1 outfall.  Is this correct?  What problems could this cause, if any?  If it is a problem, how can it be bypassed? 😉

[Neilw_05]

That question is about the analysis of the network. I can't speak to that as I don't do analysis. My comment was about the functionality of the pipes and structures within a network.

[wfberry]

As far as I know there are no limitations on the number of outfalls.

Bi;;

[Charlie.Ogden]

Narce2, a Pipe Network can have as many outfalls as you want to add.  You can have a bunch of disconnected sets of pipes and structures in a single pipe network all with their own outfall at the end of each set. Actually, the pipe network doesn't even care if you have a bunch of outfalls in a set of connected pipes and structures - but hydraulically that doesn't make sense in a direct-step method like FHWA's HEC-22 EGL Procedure which is used in Storm Sewers and the Analyze Gravity Network command.  The outfall is where all the pipes in that connected set of pipes and structures flows toward - and there can only be one for each set. But each set, even in a single pipe network, should each have their own outfall.

You should be able to just have a pipe network for each utility type - and maybe also separate by existing, proposed, or another phase as mentioned above.