Reduced vs Full Port Ball Valve Class 600
Reduced vs Full Port Ball Valve Class 600
(OP)
Good day! I have a question in regards to ball valves.
I just took over a project for a Process Plant and I'm checking the selection of valves. When I came to ball valves 600# our specification says to be "Reduced Bore" but our three vendors (all very well known and respected) had offered "Full Bore".
Is this standard for 600#?
Thanks for your help!
I just took over a project for a Process Plant and I'm checking the selection of valves. When I came to ball valves 600# our specification says to be "Reduced Bore" but our three vendors (all very well known and respected) had offered "Full Bore".
Is this standard for 600#?
Thanks for your help!





RE: Reduced vs Full Port Ball Valve Class 600
Reduced bore is often cheaper to produce. Often used by producers and vendors to offer a cheaper solution, especially for smaller sizes, but can be found for all.
Depending on pressure class, exact type and construction this is more a question on what is available, cheapest and best adapted to the technical conditions and total requirement.
Ask the suppliers for additional information, and why they offer this solution. Depending on the project status you could either check if 'reduced bore' is a technical requirement (probably not) - or you could recheck the whole piping system and see if the piping and valve sizing is optimized or could be reduced down to next dieameter.
Such specs are often 'leftovers' from previous projects, and need to be revised from time to time according to commercial availability of products and what is happening in the real world
RE: Reduced vs Full Port Ball Valve Class 600
I've never found a technical reason for installing reduced bore ball valves, the reason was always economic. If the full bore valves are actually less expensive then there becomes zero reasons for using the reduced bore valves.
Finally, if you thing there is ever any possibility of running a smart pig in a line don't even consider reduced bore valves. While cleaning pigs will usually traverse reduced bore valves (I saw one once in a 42-inch line that required 2 hours for the pig to deform itself enough to go through the first valve on a river crossing, then went through the valve at the other sided of the river in a few seconds--I don't think it did a very good job of cleaning under the river) smart pigs won't.
David
RE: Reduced vs Full Port Ball Valve Class 600
A few situations require the full bore valve besides pipeline pigs. Examples also include low pressure compressor suctions. This applies anywhere that additional pressure drop is a problem. Full port valves are normally used where inserting sample probes, injection quills, etc.
RE: Reduced vs Full Port Ball Valve Class 600
Actuated regular port valves are significantly less expensive than full-port valves because the full-port valve requires more torque, thus a larger-more expensive actuator...
RE: Reduced vs Full Port Ball Valve Class 600
RE: Reduced vs Full Port Ball Valve Class 600
The point about the actuator is only true if you are desiging close to torque limits in very clean service. In nasty service (which is all I ever see) I typicilly use a safety factor of about 3, so going to full port reduces that safety factor to about 2.9 with the same actuator, no big deal.
David
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Reduced vs Full Port Ball Valve Class 600
A full port is what I like because a) we often pig through many of our lines, and b) it induces less pressure loss than reduced port. If my vendor has dealt with me often enough, they know this and will assume that I either mis-typed, or got a junior guy to do the datasheet who doesn't know my preference.
A reduced port valve usually requires lower torque to close, in the same ANSI class. This is a saving on the actuator, in addition to the cost of the valve.
Without more info, it is tough to say why your vendor has done this.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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RE: Reduced vs Full Port Ball Valve Class 600
Given zdas04 argument re. the normal safety factor to full bore valves dosnt it then sound like "conservatism" that we (my self included) still allmost by defaul specify reduced bore - and offers some time to specify exactly those valves that need to be FB? Maybe it would be cheaper to say: All below size XX ==FB (unless specified)?
Best regards
Morten
RE: Reduced vs Full Port Ball Valve Class 600
RE: Reduced vs Full Port Ball Valve Class 600
RE: Reduced vs Full Port Ball Valve Class 600
I do not exactly understand your question - would you post it differently again.
In the mean time, I will explain a bit more what I meant.
With regards to safety factor, I usually add about 25% to the required torque, and then find the actuator that can do the job. For a reduced port or full port, the percentage increase is the same - hence, there is still an actuator savings in price.
Like David has mentioned, my preference is for full port ball valves, as it serves the purpose most often in my industry. Again, this is a personal preference.
Hope that clarifies my earlier response.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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RE: Reduced vs Full Port Ball Valve Class 600
I just looked up the last actuator I bought and the safety factor was 2, not 3. I may have been waxing poetic above.
David
RE: Reduced vs Full Port Ball Valve Class 600
RE: Reduced vs Full Port Ball Valve Class 600
Reduced port valves in 'made to order' exotic materials (F51, titanium etc.) will still be cheaper, however commodity type carbon steel valves with 316 trim would be more readily stocked as full port as in a pinch, most client's either need a full port or they don't really care. This is likely driving the production of the full port valves and thus a reduction in cost.
Andy
RE: Reduced vs Full Port Ball Valve Class 600
FB are only required for compressor inlet (or similar), PRV inlet/outlet or a line to be pigged or probed, as mentioned by others.
It is not good economic practice to blindly use FB valves regardless of cost. Remember, an engineer can do for a dollar what any idiot could do for five.
I cannot think of any application where a FB cannot be provided instead of a RB. Some manufacturer's do not make RB for small valve sizes.
The actuator sizing issue is very interesting because the cost impact is potentially huge.
Most customers of ours list a 130-150% actuator sizing margin although there is potential for David's experience. Would it be prudent to use 130-150% for clean service (i.e. gas or clean liquid) and 200% for dirty service (i.e. oil with BS&B)? I suppose it depends on experience with specific processes.
Donald
RE: Reduced vs Full Port Ball Valve Class 600
RE: Reduced vs Full Port Ball Valve Class 600
JLSeagull's cynicism aside, experience in the particular service is truly key to properly spec-ing an actuator. In clean, dry, gas with an operating dP significantly less than the design dP (i.e., for an ANSI 150 valve, the maximum dP is probably around 280 psig, but many 150 ANSI systems have a normal operating pressure closer to 100 psig, so operating a shut valve with normal pressure on one side and vented on the other results in 100 psid instead of 280) you will almost always be fine with 110%, but change any of the parameters and you could be in trouble.
David
RE: Reduced vs Full Port Ball Valve Class 600
Best regards
Morten
RE: Reduced vs Full Port Ball Valve Class 600
Hoping I'm not wrong.
RE: Reduced vs Full Port Ball Valve Class 600
Sorry to say this time you are wrong... at least in respect with the spec...
We specify (bearing in mind this spec is 8 years old!) BS5351 Ball Valves Reduced Bore 600#.
I don't have any objection with full bore valves for this application (process plant... no pigging, no probe going trough, etc.. only shut on-off valve) but I got three different offers for a Full Bore valve (from three different manufacturers) and I was wondering whether the "standard practice" had changed (and so should my specification) or it was more an economical issue.
I thank you all guys for your answers (it was much more than I expected, as I also learnt/refreshed some other things beside my question)
RE: Reduced vs Full Port Ball Valve Class 600
No worries.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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