Carlo1023' you wrote:
"Is it acceptable to use a two piece ball valve as an alternative to an end entry ball valve? "
The previous answer is quite correct. And in addition, it is not possible for anyone out here to be able to answer you.
First, We do not know the commodity, the maximum operating pressure or the maximum operating temperature.
Second, we do not know the material or the pressure being specified for this line class
Third, we do not know the type of plant this valve will be installed in.
Forth, we do not know the applicable Design Code that applies to this plant.
Fifth, we do not have the Make, Model number, material or trim for the two valves in question.
Sixth, we do not know who you are in the long chain of responsibility for this valve.
- Are you the Piping Material Engineer responsible for valve selection?
- Are you the mechanical contractor responsible for the purchase and installation of the valve?
.- Are you a valve supplier who is responsible for filling the valve order?
Guys, pardon me for leaving out the details.
Here's my reply to pennpiper's questions:
1. Commodity = Sanitary sewer
Design Temp = 100degC; Oper Temp = 50degC
Design Press = 13barg; Oper Press = 2.5barg
2. CS A216 GR. WCB; 150# RATING
3. Petrochemical plant
4. As per ASME B31.3
5. Body and trim materials are both the same for the two
valves. The only difference is that of their body
body design. One is a two-piece body while the other is
end-entry design.
6. I'm a piping materials engr responsible for reviewing
bids from vendors. As per client specs, either end entry
or split body is acceptable but I just want to know your
opinion about this one.
I hope I have also indirectly answered Mike Halloran's question. Thanks in advance!
The short answer is that both designs are built to the same API standard and both passed. Beyond that is a lot of marketing about being able to repair them in place, etc. In my experience ball valves are rarely repaired in place (people in my industry tend to replace them and send a damaged valve to a shop for reconditioning or to scrap. The repairability in place feature has only been important on the rare welded-in valves that I've installed.
Neither a 2-piece or end-entry valve can be repaired in place. THere's not a hard and fast rule her but a 2-piece valve would be more likely to have a full bore than an end-entry valve. End-entry valves are much more likely to have a "regular port" (one reduction:e.g.: 3" ball in a 4" body.
With sewage as the fluid of concern, I would think that full-port ball valves would be useful, if not the sector-type valves. Sector valves have the advantage of not collecting contaminants in the body cavity
Could it possibly be that the petrochemical works has used its normal valve standard (petrochemical) also for the sanitary sewer service?
Is this standard and selection necessary?
If heating to sterilizea or process at 100 deg C (Real max temperature?) and 2" with normal sewer sludge (real fluid?), pigging to clean inside pipeline walls from burnt on fat residues would probably be necessary. Full bore would be highly recommendable, and why not 3-piece ball valves to be able to swing out, inspect and change the section with the ball.
At lower real temperature (70 deg C and lower), and higher dimension (2 inch and up) the normal European selection would be soft sealing gate-valves or knife-gate valves, epoxy outer and partly inner coated. (Epoxy coating normally limited to the 70 deg C.)
Materials would be SS316 for the small ballvalves, PTFE seats and floating ball, for the larger valves mentioned nodular cast iron body, same for gate, but elastomer (NBR normally) coated, trim SS/gun metal, and SS for the knife and stem for the knifegate valve.
