Pipe schedule vs Class rating when purchasing fittings/flanges.
Pipe schedule vs Class rating when purchasing fittings/flanges.
(OP)
[edited]
Good morning,
Thank you,
Damon Alfaro
FITTING__________CLASS_____________SCH RAT
CAP______________X_________________N/A
COUPLING_________X_________________N/A
ELBOW, SW________X_________________N/A
ELBOW, THRD______X_________________N/A
BLIND FLANGE_____X_________________N/A
SLIP ON FLANGE___X_________________N/A
SW FLANGE________X_________________N/A
THRD FLANGE______X_________________N/A
WELD NECK FLANGE_X_________________X
WNORIFICE FLANGE_X_________________X
SW RED INSERT____X_________________N/A
THREADED PLUG____N/A_______________N/A
CONC RED, THRD___X_________________N/A
EQUAL TEE, SW____X_________________N/A
EQUAL TEE, THRD__X_________________N/A
RED TEE, SW______X_________________N/A
RED TEE, THRD____X_________________N/A
UNION____________X_________________N/A
ELBOLET, BW______N/A_______________X
ELBOLET, SW______X_________________N/A
ELBOLET, THRD____X_________________N/A
LATROLET, BW_____N/A_______________X
NIPOLET, BW______N/A_______________X
SOCKOLET_________X_________________N/A
THREDOLET________X_________________N/A
WELDOLET_________N/A_______________X
Good morning,
New member here, I am new in my field and currently working on updating the pipe specs at my plant. Part of this project involves setting up new material numbers with short descriptions, which are then sent for purchasing. One of the problems I have run across is not being sure when a pipe schedule needs to be specified alongside the fitting/flange rating. It appears to my novice eyes that SCH rating is needed for BW fittings/flanges, but CLASS rating is needed for SW/THRD fittngs/flanges, with few exceptions. However I know that SCH rating changes the bore size and could cause turbulent flow if not matched. Do manufacturers take this into account? I am running across a large number of different items in the specs (just about every fitting/flange used in a commercial plant), and have access to and have read the relevant ASME, MSS standards, but would like some clarification from someone in the industry. I want to verify what is correct in practice. For example, I can specify that a coupling is 3000 CLASS rating, do I also need to specify that it will be used with SCH XS pipe? Is this information that the distributer needs to get me the correct part? Another example olets, I know that BW olets are rated by pipe schedule, while SW and THRD olets are rated by LB class. Would I need to specify that a 3000 CLASS SW Elbolet would be used on STD x XS pipe? Would it make a difference in the part I received? I have compiled the list below, and would appreciate a reply as to whether I've got it right or not. As you can see from the table below, the majority of the fittings/flanges are classified by CLASS, does this mean that the SCH rating of the pipe is not needed when ordering?
Thank you,
Damon Alfaro
FITTING__________CLASS_____________SCH RAT
CAP______________X_________________N/A
COUPLING_________X_________________N/A
ELBOW, SW________X_________________N/A
ELBOW, THRD______X_________________N/A
BLIND FLANGE_____X_________________N/A
SLIP ON FLANGE___X_________________N/A
SW FLANGE________X_________________N/A
THRD FLANGE______X_________________N/A
WELD NECK FLANGE_X_________________X
WNORIFICE FLANGE_X_________________X
SW RED INSERT____X_________________N/A
THREADED PLUG____N/A_______________N/A
CONC RED, THRD___X_________________N/A
EQUAL TEE, SW____X_________________N/A
EQUAL TEE, THRD__X_________________N/A
RED TEE, SW______X_________________N/A
RED TEE, THRD____X_________________N/A
UNION____________X_________________N/A
ELBOLET, BW______N/A_______________X
ELBOLET, SW______X_________________N/A
ELBOLET, THRD____X_________________N/A
LATROLET, BW_____N/A_______________X
NIPOLET, BW______N/A_______________X
SOCKOLET_________X_________________N/A
THREDOLET________X_________________N/A
WELDOLET_________N/A_______________X





RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
I think you're totally on the wrong track, first you need to have the pipespecs with pipe and schedulenumbers. Then you seek the fittings to it.
Can't you borrow them from another company?
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
you say "Can't you borrow them from another company? ". That is tantamount to theft!!!
All fittings that are to be butt welded to the pipe need to have the schedule specified (e.g. 8"nb Sch40 Class 300 WNRF Flange). For a reducer you need to specify the schedule at the large and small end.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
europipe - Thank you, I have the pipe specs, I am currently in the process of ensuring the material is described correctly for purchasing.
DSB123 - Thank you, I see my mistake, I'm not as familiar as I should be with the codes to recognize the blatant error. My post has been edited. I obviously have more reading to do.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
So, it seems if the flange is to be used with any schedule other than SCH 40 on CLASS 150 flanges, it would need to be noted. For consistencies sake I will note the bore for all flanges other than blind flanges.
Thanks for letting me bounce my thoughts off you guys, and replying so quickly.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
Don't be so dramatic,it's not topsecret. you need to do the calcs anyway.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
It's not being dramatic as you say. It takes time and effort to create pipe specs and then you encourage someone to plagerise the results. Not the professional way forward in my eyes and not something that should be promoted!!!
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
Flange class ratings to ASME B 16.5 are steps - correct terminology is ASME class xxx or API xxxx. Common terminology used is e.g. 600lb, #600, but for MTos and orders use the correct designation.
In general you need to specify the connecting pipe when it is being butt welded to the fitting.
Socket weld and threaded connections should only require the OD, which is unaffected by wall thickness.
The example you quote may be an odd ball or maybe if the wall thickness is small, they machine the bore back to match the ID?
If in doubt tell them what it is.
Schedule numbers and descriptions like STD, XS, XXS etc exist for piping. Pipelines and some long piping runs could easily use wall thicknesses which don't correspond to a standard schedule or descriptor like BI says.
Also some piping systems will have pipe wall thickness which are not valid for the flange rating. You don't need to have the design pressure of a system fixed by the flange rating. Some companies do this, but if you don't need the metal, it's a waste buying it. E,g, you can have a design pressure of 70 bar, which needs a class 600 flange, but has pipe of a thickness only for 70 bar.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
Please show me where in ASME B16.5 a flange is designated as 600LB or #600 ? Flanges are designated Class 600 (without the Lb or #)
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
ASME#followed by class designation, such as "ASME#600" should be used to eliminate any confusion from WOG 2000 LB (actually psi) ratings which are working pressure limit based, such as this valve here using a "WOG 1500" and "WOG 2000" (in psi) ratings,
http://www.astech-valve.com/s/en/2/product/Three-P...
Using numbers alone, without any accompanying ASME or WOG designation, risks generating dangerous errors.
While IT geeks might prefer to state minimal information MY personal preference is to state everything, even if it might appear to be somewhat redundant. I'd rather be redundant than have somebody confuse 1500# with 1500
size
item
spec and number,
pressure rating, with unit
OD
WT, with unit
std schedule when applicable,
bore when applicable
material spec
EXAMPLE:
16", FLANGE, RFWN, ASME B16.5 #600, 16" OD x 0.250" WT, SCH40, Bore 15.500", ASTM A105N
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
It may be accepted custom "in your neighbourhood" to use LB or # but actually it is incorrect. Nowhere in ASME B16.5 does it refer to 150Lb or 150# - if it does then please correct me!! As an Engineer you should move with the times - years ago people used to use Lb or # but times have moved on and engineering should use the correct designation. It's the same as people still using ANSI B16.5 - there is no such standard as ANSI B16.5 - do a search on any Standard site if you do not beleive it.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
Not Sorry
Sorry ... obviously I ment toI did type "ASME" B16.5You are free to practice any method you like, I am only saying what I have found to work extremely well in eliminating any possibility of confusion over many years ... including 2015. 2016 hasn't finished yet.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
Sorry no Caffeine today - don't like the crap!!
I am just making the point that when designating a Flange the "correct" way is Class 600 - end of story and you cannot correct me on that score unless you can point me to where it is otherwise stated in ASME B16.5 - and you cannot. You may want to add the Lb or # but it is incorrect - and remember as engineers we should be striving for accuracy!!! You and others, by using Lb or # are just purpetuating the error. Unless you can "prove" that i am wrong in what I am stating then please consider the discussion closed. You can continue to use the incorrect way to specify flanges!!!!
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
As you like.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
I use class all the time and correct those under me to do the same, but they need to know when others talk to them that, like it or not, class, lb , pound or # are interchangeable in many peoples mind and writing when referring to ASME B 16.5 flanges.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
Previous versions of the code used "300 pound" quite widely to mean what is now called "300 class". It isn't in the current code, but it sure is in common usage. Just last month I told a construction superintendent that we were going to use "ASME B16.5 600 Class" flanges and he wrote it down as "ANSI 600 lb". Is it standard? No. Is it right? "Right" is so subjective. Was there communication? Hell yes, and that is the purpose of all of this stuff.
The OP got a lot of useless factoids slung in his face (and to his credit he accepted the garbage with humility, he comes across very well) when he was asking fair questions with a goal of clearing up some information that is fuzzy in many people's minds. Useful questions and the thread started out with useless answers. In my limited experience (I've only been doing this stuff for 36 years), prior to the current version of ASME B16.5, "Class" referred to "Thread pressure rating in psig". The current version of ASME B16.5 muddies that a lot. "Schedule" refers to a pipe or fitting inside diameter.
Failing to match ID of a fitting to the ID of a pipe creates fabrication problems, but it does not "create turbulence". It is fascinating to watch flow visualizations (not models, film of actual flow in a pipe with different wall thickness) of changing wall thickness. The distance from the edge of one boundary layer across the pipe to the edge of the other changes about half the change in the pipe ID and requires extreme magnification to even see.
As to non-standard pipe and fitting ID, if you are spending enough money, the foundries will make you anything you want. BigInch has worked on some jobs with a pipe budget rivaling the GNP of many countries. With that kind of purchasing power, he is careful not to waste pipe wall thickness and tries to run his design closer to real physical limits than is common in smaller projects (and he doesn't pay a premium for non-standard pipe and fittings due to the size of the orders). I would never expect to be able to get a non-standard pipe size for a project with a pipe budget under $10 million USD without paying a significant premium and waiting for a future mill run. Non standard pipe sizes should not be part of the OP's database.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Pipe schedule vs Class rating when purchasing fittings/flanges.
http://www.saginawpipe.com/steel_pipe_chart-2.htm