Large Diameter Pipeline PCCP Valves and access entry points

[richcrow1]

Since there are no general standards for large diameter pressure pipelines. I was wondering what would be a good rule of thumb to use for minimum valve distance for a transmission line of let's say 72 inch RWM PCCP? Also, what minimum distance would you use for access entry points; some call them manholes? I assumed a min. distance of 3,000 feet for butterfly valves seperation and still not sure about access entry points. Maybe OSHA has a regulation on it. Most stuff I've been finding has been on gravity lines.

If there is any other guidance you can provide in designing large diameter pipelines? It would be greatly apprecaited.

In fact, it would be nice if they devoted a section of the forum just to large diameter pipelines.

Thank you all,

South Florida
Junior Engineer

 

[coloeng]

Without knowing more details about what this pipeline is for, how many connections it has to it, etc. it is difficult to say what the reasonable distance between valves would be, however, 3,000 foot separation between valves seems to be way too close together for this size of line. It would be best to discuss this with entity that the pipeline is being designed for. 72-inch butterfly valves are not exactly cheap, but you probably want to be able to isolate sections of the pipeline. You should typically evaluate where you think you would need the valves based on how much of the pipeline you could reasonably have out of service at one time.

 

[richcrow1]

Thank you coloeng,

I agree with you fully but before meeting with the client and the design team, I was looking for a second opinions and better judgment. I'm just a junior engineer. Thank you though for your appreciated follow up.

There are no branch connections just a transmission line from point A to B. It's 27,600 LF of pipeline. Also, it's for raw water transmission.

Thank you all,

South Florida
Junior Engineer

 

[civilperson]

A valve at each end and one in the center should make engineering sense. 13000 foot spacing.