Do you need to do a hydraulic design, or a pressure design calculation?
Your post is too vague to even let contributors properly assist you.
Recommend you read the faq of this forum first.
I think you might really want the velocity rather than the speed. Search the forums on that word and you'll find some recommended values to start off with.
Want to know the do's and don'ts of Eng-Tips? Read FAQ731-376.
English not your native language? Looking for some help in getting your question across to others or understanding their answers? Go to forum1529.
thanks for your answers, I am designing a piping, I've read the ASME B31.4, I need the diameter and I have the flow (GPM), I suppose exist a rate of velocity for diesel, gasoline or hidrocarbons in general. Could you tell me where I find that?
You won't find it in any standard or specification. As a very basic GUIDE only, for long pipelines (>40 kms) start with 2 to 2.5 m / sec. Inside plants start with 4 to 5 m/ sec.
This then needs to be checked with a pressure drop calculation to determine how much pressure you need and how much power. Higher velocity means a smaller pipe, but higher power needed. Use the guide numbers above to get you a rough size and then look at options for at least one pipe size up and down from there. You may find a big difference in power requirements.
Remember pipelines are designed, not chosen by data like this and there are many many other things to consider.
Good luck.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way