Fullbored or Restricted bored ball vave?

[Siagians]

For a pump or compressor configuration, the isolation ball valves located in the suction (eg; 8 in)and discharge lines (eg; 6 in) are specified for full bored (FB) by the client. (1) Are there engineering fundamental reasons for FB instead of restricted bored (RB) as the RB calculated pressure drop considerably very small or neglectable compared to the cost different?. (2) and why for the recycle line is not required for a FB size?. Appreciated any opinions. Regards.

 

[zdas04]

It has been a few years since I priced them, but at that time the RB in your terminology (they are usually called "normal bore") was actually more expensive than the FB. Has that changed back?

For pump suction/discharge valves I'm not sure that it matters which one you use. The restriction of the RB valve is pretty insignificant. For in-line valves that someone might need to pig through it is a big deal.

I've never heard of eliminating the recycle line because of using a full bore over a normal bore, it doesn't ring true for any reason that I can think of.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[stanier]

Full bore valves are generally used in pipelines where pigging may be required. A customer may specify full borevalves to be consistent for the whole project.

Reduced bore valves generally cost less as the amount of material in the body is reduced. This is particulalry so in exotic materials.

I have found for large projects that you can negotiate pricing such that overall there is not much difference in pricing.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[MortenA]

The RB valve costs less - and also iportant is that the valve will have an outside size comparble to the pipediameter. This mean that it will fit easier into a piping system e.g. where more than two piperuns are i parallel etc. A FB valve will be larger than the pipe and thus e.g. a parallel pipe will have to take this into consideration.

Best regards

Morten

 

[zdas04]

I have to call BS on that one Morton. A full port valve body is about the same diameter as the flange on the ends of the valve. If you are stacking pipelines close enough together that you are worried about the diameter of the valve body (i.e,. you are putting the flange for one valve against the body of the adjacent valve) then you are never going to be able to unbolt a valve and your risk of damaging a line while working on a valve is too great. If you are talking about welded valves, there is no way to get a welding rod in a space that tight. Also, if the pipes ever go into the ground the risk of stray currents and cathodic interference becomes a near certainty.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[PeterIgg]

My two pennies worth:
Reduced bore valves are generally cheaper than the full bore version.
[li]The pressure drop across a well designed reduced bore ball valve tends to be negligible in the scheme of things.[/li]
[li]Smaller, lower (Class 150 / 300) class valves are often one piece, end entry which can make them more compact than the two/multi piece equivalent. Full bore valves are almost inevitably two/multi piece design.[/li]
[li]Smaller ball = lower operating torque which can mean smaller (cheaper) actuator or smaller wrench/handwheel.[/li]
[li]One piece design inherently has fewer leak paths.[/li]

 

[Siagians]

Many thanks for the comments and/or opinions. Regards.

 

[2mainer]

It all depends on the CV required, Period!

 

[zdas04]

It all depends on the CV required, Period!

.

Really? Period? No other considerations at all? What about a requirement to pig? What about liquid lines running partially full? What about the risk of creating a liquid trap in lines that run intermittently? I have actually never, not once, seen a situation where there was only one consideration in an Engineering decision. Not a single time. Ever. Period (no exclamation point, I don't think they belong in Engineering discussions).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[stanier]

I managed to purchase a large number of full bore valves at a discount as the manufacturer was stopping production. These were cheaper than reduced bore valves than another supplier. Their Cv was of course larger but they would do the job as they were only isolation valves. So Cv is not the only criteria. In fact it rarely is for a ball valve.

Generally the piping specification will identify the type of valve to be used. If a valve meets specification, is common on the plant (ie not introducing a new line needing spares) and is cost effective then buy it.

it would appear in the OP that the client has specified full bore. then the contractor should supply same. It could be the client is prepared to pay for standardisation. If this is what appeared in the tender documents then perform the contract and stop wasting your time.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[rneill]

there are a number of situations where it would be common to require full bore valves (e.g., relief valve flowpaths - in and out, meter runs, pigging). Many operators have specifications where they list the situations in which they require the use of full port valves. However, if this is not a "special" situation where a full port valve, or very low Cv, is specifically necessary then typical practice would be to purchase (or at least specify) regular port.

 

[zdas04]

rneil,
How big a sample did you get your "typical practice" from. I've purchased something like $20 million worth of ball valves and never specified anything but full port. Even on "non-piggable" lines since I am quite paranoid that somewhere down the line someone will want to run a smart pig in the line. I don't even order them for launcher/receiver kicker/bypass lines because I'm concerned that the reduced port valve might get used in the wrong place by a field hand who doesn't pay enough attention.

I know other Engineers that never specify type of valve and are content to get whatever the supply house is clearing off the shelves.

Others spend a lot of time agonizing over the decision and end up putting full port everywhere except kicker/bypass lines on pigging equipment.

I don't know any Engineers that preferentially specify normal port valves. But that is a really small sample of my 45 clients with probably 250 Engineers.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[rneill]

David,

I think you are talking about pipelines predominantly and my experience is predominantly plant piping and it is from that perspective that I responded. I agree that full port may be a more logical choice on pipeline projects.

To answer your question about my background, I have worked offshore platform projects in Nigeria, Angola and Eastern Canada, and have done onshore work in the United States and Western Canada for over 20 years. These projects have ranged from small facilities to multi-billion dollar facilities. Much of this work was on staff with one of the largest international Oil & Gas Companies (within the top 3 or 4 anyway) and their specifications stated that regular port valves were to be used unless you meet one of the listed criteria (special cases). As a consultant, I now work with a number of different oil and gas operators in the area of specification development (mostly for plant facilities) and none of these companies have a stated preference for full port valves. They will accept regular port except for specific situations. That said, one of my current clients is a pipeline company and they do not have a stated preference for full port valves either?

When you have to buy hundreds (if not into the thousands) of ball valves ranging in size from 3/4" to 24" for multi-platform offshore complex and there is a grand total of about 8 incoming/outgoing pipelines and less than 24 ball valves which need to be through conduit / full port for pigging, you aren't going to buy all full port valves just to be safe. You're going to buy technically acceptable, and more cost effective, regular port valves and invest in qualified inspection staff to ensure that valves are installed where they are supposed to be installed. Even if you could get the full port at a competitive price, we are extremely concerned with weight control on offshore structures and we would not want the extra weight of all those full port valves that were not techncially required.

Anyway, the original poster's question was about pump and compressor station valves and so this should fall into the category of plant valving and I'm quite comfortable in using regular port valves in most plant applications.

 

[zdas04]

rneil,
I wasn't questioning your knowledge or experience. You generally sound like you know what you are talking about.

In this thread several people have made black and white statements on subjects that I see as very gray. "Typical practice" implies a widespread practice across industries. I was looking for clarification on how big your sample was. I've been doing gathering and mid-stream for a long time and don't know of this typical practice.

When I teach a module on valves in my upstream facilities class I've never had anyone question my preference for full-bore ball valves (I do prefer them because I've seen too many "never to be pigged" lines require retrofitting pigging facilities). Maybe in this one subject they suddenly got polite (since they question everything else I say)?

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[pennpiper]

Everyone seems to have their own terminology.
In cases like this I have always used the following:
"Full Port" and "Reduced Port"

I get confused when other terms are used.



prognosis: Lead or Lag

 

[zdas04]

"Normal port" is a marketing term for "Reduced Port". "Bore" is a synonym for "port" (or vice versa?).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[stanier]

Valve Selection Handbook - Engineering Fundamentals for Selecting the Right Valve Design for Every Industrial Flow Application (5th Edition)Title Edited by: Smith, Peter; Zappe, R.W. © 2004 Elsevier

This is available from Knovel electronically. Members of IMechE can access it via their electronic library. I am sure other professional associations have access also.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/