Specifying Pipe Schedules for Fittings
Specifying Pipe Schedules for Fittings
(OP)
thread378-416204: Pipe schedule vs Class rating when purchasing fittings/flanges.
The poster for the original thread referenced above was trying to standardize the information contained in some internal company database for the various fittings used in their building. Part of the challenge was when to include pipe schedules as relevant information.
This post is a word of caution regarding pipe schedules. My Tioga Pipe chart lists (3) different columns of information under the same "schedule designation" heading. Anecdotally, I think these different schedule names came from the different industries that all used pipe. Depending on who you are talking to, you may hear any or all of the designations get used.
Many different pipe schedule designations can refer to the same wall thickness of pipe. But, this is not true for all designations in all sizes. For example, in Nominal Pipe Sizes (NPS) 8 and smaller, Sch.STD = Sch.40 = Sch.40S and Sch.XS = Sch.80 = Sch.80S. When you reach NPS 10, the rules change. The NPS 10 Sch.STD = Sch.40 = Sch.40S is still true. But, NPS 10 Sch.XS = Sch.80S = 0.500" wall thickness, which does not equal NPS 10 Sch.80 = 0.594" wall thickness.
It may not be necessary to provide a wall thickness along with the schedule designation on smaller pipe sizes. But, including it can save confusion (and huge headaches) when you get into larger sizes. As one poster said, (paraphrasing) "it is better to give someone more information", they can always disregard the extra details. But, when you don't give them enough, you are forcing them to guess/make up those details or contact you for the rest of the information they need. The latter is a waste of time. The other is dangerous.
Steve
The poster for the original thread referenced above was trying to standardize the information contained in some internal company database for the various fittings used in their building. Part of the challenge was when to include pipe schedules as relevant information.
This post is a word of caution regarding pipe schedules. My Tioga Pipe chart lists (3) different columns of information under the same "schedule designation" heading. Anecdotally, I think these different schedule names came from the different industries that all used pipe. Depending on who you are talking to, you may hear any or all of the designations get used.
Many different pipe schedule designations can refer to the same wall thickness of pipe. But, this is not true for all designations in all sizes. For example, in Nominal Pipe Sizes (NPS) 8 and smaller, Sch.STD = Sch.40 = Sch.40S and Sch.XS = Sch.80 = Sch.80S. When you reach NPS 10, the rules change. The NPS 10 Sch.STD = Sch.40 = Sch.40S is still true. But, NPS 10 Sch.XS = Sch.80S = 0.500" wall thickness, which does not equal NPS 10 Sch.80 = 0.594" wall thickness.
It may not be necessary to provide a wall thickness along with the schedule designation on smaller pipe sizes. But, including it can save confusion (and huge headaches) when you get into larger sizes. As one poster said, (paraphrasing) "it is better to give someone more information", they can always disregard the extra details. But, when you don't give them enough, you are forcing them to guess/make up those details or contact you for the rest of the information they need. The latter is a waste of time. The other is dangerous.
Steve
Quote: "Sometimes, the biggest problems are caused by the smallest things. Pay Attention!" (Unknown)





RE: Specifying Pipe Schedules for Fittings
The different pipe designations of the wall thickness, i.e. STD/XS/XXS and Sch.40/80/160, are developed in the different time through the history. As a result, some of them have the same actual wall thickness. The proper pipe thickness can be ordered from either designation. In this case, the better for the simple description of the design and PO.
The Schedule number with the suffix "S", i.e. Sch.40S/80S, is used for stainless steel pipe.
RE: Specifying Pipe Schedules for Fittings
In most cases, the more accurate the better. Unfortunately, people learn and stick to generalizations. If I ask for a A312 TP316 pipe don't quote me "stainless pipe"
Thanks,
Ehzin
RE: Specifying Pipe Schedules for Fittings
I agree that it can be quite odd and thickness I'd better but schedule is so ingrained in the piping world you're not going to change it.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Specifying Pipe Schedules for Fittings
RE: Specifying Pipe Schedules for Fittings
Ehzin, there is so much information (or misinformation) available that there is room for error even between professionals. You said it yourself. An RFQ asking for A312 TP316 pipe should never get a bid offering "stainless pipe." I suspect this story is based on your real world experience. Arguing that the sales rep was not a true professional (no matter how accurate that might be) does not advance the topic of conversation.
LittleInch is exactly on point. New engineers learn how to deal with the ingrained knowledge of prior generations that they inherit/adopt it themselves before passing it on to those who follow them. Changing it is as likely as the United States dropping Imperial measurements and adopting the metric system across the board.
Thanks to everyone for posting their thoughts.
Quote: "Sometimes, the biggest problems are caused by the smallest things. Pay Attention!" (Unknown)
RE: Specifying Pipe Schedules for Fittings