Reduced bore ball valve

[mobarez]

Our company is EPC contractor for a crude oil transmission plant between storage tanks. Based on maximum liquid velocity limitation=2 m/s, the pipe size is 48” for the main lines from tanks to manifold.
now for sizing on/off motorized ball valves, could we use reduced bore ball valve instead of full bore? Is there any especial analysis needed to find whether we could use the reduced bore ball valve, or just we should mention the bigger pressure drop in reduced bore type (which is usually not huge relative to several elbows we have in the line).
In the other hand, Our client insists on using full bore ball valves. Because of big amount of difference between the prices, we have a solution: using 48”/36” reducer + 36” full bore ball valve + 36”/48” reducer instead of a reduced bore (48”/36”) ball valve.
So, is there any technical difference or standard prevention or practical notes applicable to this solution relative to reduced bore ball valve?

 

[BigInch]

The client's requirements might be based on pigging pipelines, in which case reduced bore could be trouble and your 48/36 solution won't go down well. Find out exactly why the client prefers full bore first and work your solution around that reason.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[zdas04]

If I was your client I would be questioning my decision to hire you about now. There are long-term operating reasons to avoid reduced bore ball valves and many companies have come to regret using them to cut original capital in the past. You haven't given much detail on the application, but if the line is very long there is a good chance that they'll want to smart pig it someday--that isn't happening with your pair of reducers idea.

The client wants full bore valves. They have a reason for that desire. Wasn't that requirement included in their original bid documentation? I would say you are not really acting in their best interest by not honoring their requirement.

David

 

[mobarez]

Thanks for your contribution. The plant is designed base on ASME B31.3 and it is not a pipeline system, so no other rules of pigging is applied. we are not asked to design based on pigging probability, Each line starts from tanks, passing the roads using several elbows and ends to manifold with maximum length 500 meters.
We are believing the client wants the best technically, while spending such a money just for omitting the pressure drop related to reduced bore ball valve is not reasonable for EPC contractor, when this pressure drop is not significantly relative to all the line and elbows pressure drop. even we could minimize the pressure drop in the other points such as using long radius elbows.
So we are evaluating such a solution, is there any technical problem?

 

[pennpiper]

It sounds like mobarez's EPC company might have bid this job "Lump-Sum" based on using reduced port valves (at a lower cost) and now they are stuck with it.

 

[BigInch]

Exactly. They're trying to get variations on the specs they should have read and understood first, so they can .... make more money.

The "technical problem" is one of the following,

1. Not having read the client specs before bidding,
2. Not proposing to use reduced port, or reduced size valves in the proposal that you submitted.
3. Looking foolish when you propose to do that now.

Good luck!

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[JLSeagull]

Does the client specification require full bore valves? Is this requirement a personal preference or unspecified project requirement? The written project specifications rule. After that your project management team can do the claims negotions.

Reduced bore valves are commonly used for intra-unit applications. Many exceptions exist such as piggable lines, low pressure compressor suction piping, offshore bridges, ... .

 

[gerhardl]

Everything is already said, but let me add the view from another angle:

This is really about ethics. In earlier times, when standards were not that detailed, simple contracts involving handcraft parts often had the wording 'general work to be done based on solid handcraft practise'.

This interpreted and understood as the solid, normal, knowledgeable way 'masters' in the handcraft did the work and that 'everybody' recognized and knew.

Drawing the modern parallell: for a pipeline in this length and dimension as described here, the discription 'ball valves' (from either end user or bidder) will imply full bore.

Deviation from this with reduced bore, even if the reduced bore valves are top quality, is a standard below normal, and not the 'normal handcraft practise'.

Another point:

if the description in itself for the pipeline and valves (and pumps?) from the end-user or yourself (contractor/bidder)at this stage is uncomplete and giving doubt about allowable dimensions:

why not (if time) propose to rework and put some solid pipeline engineering QA into the process (third part?) to see if pipeline dimension and valves with the pipeline could be reduced one dimension and/or are laid out and described correct for the process?

If yes for total reduction, this could be a win/win situation for both parties.