Talk:Nominal Pipe Size

message: I am really surprised to see this entry. Good work. Excellent effort.
THIS IS VERY HELPFULLYItalicTHANKS FOR YOU SUPPORT text''''
Very Useful information. I had been looking for this information for months. Now that I have this info, life becomes so much easier.. Very good work, thank you...
Kindly arrange the table converter from NPS to DN  —Preceding unsigned comment added by 122.161.30.137 (talk) 07:27, 9 November 2007 (UTC)
thread_title:  Thank you contributors! 

message: Lamps and light fixtures here in the U.S. use standard pipe nipples of size "1/8-IP". I googled "1/8-IP" and found that these are nicely explained at , which says that they come from a 19th-century standard for wrought iron pipe by a company called Briggs. Their cited source is "Standard Pipe and Pipe Threads." Transactions of the American Society of Mechanical Engineers, volume 8, Page 29. I suspect that maybe this IP standard evolved into NPS, but I do not know that as fact. It would be great if someone who works in engineering related to pipe could work this info into this article or whichever other article would be logical. I won't have time to read and research into this, but maybe someone who is already well versed in this field can contribute the info to Wikipedia without too much time expenditure. — ¾-10 16:37, 21 November 2007 (UTC)
replies: text: Well, the article already mentions iron pipe size, which seems to be what you're talking about.--Yannick (talk) 01:27, 22 November 2007 (UTC)
replies: text: Ah, OK, upon rereading iron pipe size, I find that it is probably referring to one and the same thing. Thanks. One thing I don't get. According to American Machinists' Handbook, 2nd ed, pp 42-43, the Briggs threads are actually taper threads, for sealed joints; but yet they are used in lamps and light fixtures today as a non-taper thread. (You can buy nipples in any length, from ½" to 12", with all threads perfect, i.e., full and not tapering). I guess there is nothing to "get"—it is what it is—but I am surprised that they effectively took a taper thread standard and morphed it into what is essentially a machine screw thread standard. And the major diameter is .375, rather than .405. Essentially it is a little ⅜-27 machine screw thread, standard to nothing but lamps and light fixtures. I wanted to just buy some cap screws with this thread, but now I see why my light fixture was made stupidly to begin with: you can't buy them. It looks like I may have to make them the ole-fashioned way, with the quick-change gear-box set to 27 and a blank turned to .375. I didn't expect to have to do this simple job from scratch. I am a little miffed that we are still bound to this size in 2007. I vote for abolishing it tomorrow. To hell with maintaining backwards compatibility with any legacy light fixtures; let the antiquarians turn custom threads when they need them—I want mine in a box from McMaster-Carr! Oh well, it is late and I will stop ranting! — ¾-10 03:07, 22 November 2007 (UTC)
replies: text: Hmmm. There's a straight (non-tapered) version of the NPT called NPSM that's used for hoses and mechanical joints. But that .375 diameter doesn't sound right. I agree with abolishing legacy threads; let's just settle on M10 for light fixtures... (I'm well aware that would not be popular in the Western hemisphere.)--Yannick (talk) 04:41, 22 November 2007 (UTC)
thread_title:  Lamp pipe (nipple) threads: 1/8-IP, 1/4-IP 

message: This is the pipe that your shower head screws onto. The OD is 5/8" (.625). What is the name of this thread? I can't figure out this pipe size and pipe thread standard BS. Any help out there? — ¾-10 18:48, 12 January 2008 (UTC)
thread_title:  What is the thread called on a (U.S.) standard shower riser with OD of 5/8" (.625) 

message: I would like to see a brief paragraph added regarding extra heavy and double extra heavy along the same lines as XS and XXS, perhaps following the first paragraphy under History.  I think this would be particularly helpful for anyone perusing a pipe table who is trying to make sense of it all.  I've seen a number of vendor sites that explain this already.  I'll add it to my to-do list, but anyone else who agrees is free to take a shot at it.--CheMechanical (talk) 21:16, 17 August 2008 (UTC)
thread_title:  XH, XXH 

message: STD, XS, and XXS: these abbreviations are used by structural engineers as they are listed in their reference books for common steel shapes.  At least by my experience in the US.  Structural engineers prefer steel columns and the like described by call-outs based on dimensions rather than what the bursting strength of it would be if used as a pressure pipe only.
Electrical: We might also mention that the NPS standards is also used in electrical fittings in the US in PVC and regular steel electrical conduit (not EMT etc).  Except, that the threads on fittings and conduit are not tapered (possible exception of full lengths of standard steel conduit).  This lack of tapering allows the use of bushings, locknuts et cetera, although they are not water tight.  The PVC fittings are typically glued, although male and female threaded adapters are made.  This is similar to the 1/8" and 1/4" nipples (previously discussed) that grew out of the use of gas fittings for lights, and even the term keyed and keyless lights and lampholders that grew out of the use of gas luminaires. 
Perhaps someone should also edit the article to mention that these nominal pipe sizes are based on the use of steel pipe, and they were extended to brass and PVC pipe, but do not hold true for copper! Copper pipe in the US at least, comes in different thickesses, and the outside diameter is based on the nominal size plus 1/8".  That is, 1/2" copper plumbing pipe (not refrigeration tubing) is exactly 5/8" outside diameter. 
There is also standard for PVC pipe below schedule 40, for irrigation use called PS125 or something like that.  Outside diameter matches NPS.
CPVC and PEX pipe (and the old PB pipe) do not match NPS, but use different standards WonderWheeler (talk) 06:08, 8 May 2009 (UTC)
thread_title:  STD, XS, and XXS; Electrical; Copper  

message: Subject line says it all.
Thanks.  —Preceding unsigned comment added by 72.42.86.250 (talk) 14:36, 21 June 2009 (UTC)
thread_title:  NPS 3/4" and 1" seem to be missing from the tables 

message: I notice some of the thicknesses reported in the tables found on this page do not follow sizing trends. I'm pretty sure some of them are incorrect(see NPS 12 sch 40 and below). Does anybody have the actual thicknesses for these pipes?  —Preceding unsigned comment added by 67.137.125.106 (talk) 00:15, 29 December 2010 (UTC)
thread_title:  Incorrect Thicknesses on Tables 

message: The article on nominal pipe sizes mentions PVC and CPVC “in the same breath” but does not say that the actual sizes differ even though the sizes stamped on the pipe are the same, ½ inch for example. The CPVC (yellowish tint) is a true ½ I.D. but the white PVC is about 5/8. Supposedly the CPVC was developed because PVC cannot take hot water. CPVC is being used in central Florida because the copper pipe laid in the slab of homes is developing pinhole leaks. I don’t feel qualified to edit the article but would appreciate it if someone could append a comment to it noting that PVC and CPVC pipe designated with same size are incompatible with regard to fittings. Dbvogt (talk) 00:06, 17 August 2011 (UTC)
thread_title:  CPVC versus PVC 

message: in NPS 10 - 24 it is incorrectly labeled as 40s/STD.  STD changes depending on the size of the pipe.  a 24" pipe STD size is 20 and a 10" pipe STD size is 40s.  — Preceding unsigned comment added by 52.129.8.49 (talk) 16:36, 15 May 2012 (UTC)
thread_title:  STD Sizes 

message: The "Application" section begins with this sentence "Based on the NPS and schedule of a pipe, the pipe outside diameter (OD) and wall thickness can be obtained from reference tables such as those below, which are based on ASME standards B36.10M and 5.19M."  I can not find an ASME Standard numbered "5.19M".  Should "5.19M" be "B36.19M" instead?  — Preceding unsigned comment added by 12.0.152.114 (talk) 14:29, 31 May 2012 (UTC)
replies: text: Yup, that was vandalism from last January. Fixed.--Yannick (talk) 17:53, 31 May 2012 (UTC)
thread_title:  ASME Standard Number 

message: I removed the OD tolerances note (just under the first table) because it references a specific product type (Ni-Fe-Cr-Si Steel Pipe); it's in general incorrect. The correct standard is ASTM A999 if anyone wants to correct the numbers and the reference.
Bobxii (talk) 18:53, 3 June 2013 (UTC)
thread_title:  OD Tolerances 

message: ASME B36.10M-2004 does not define wall thicknesses for Schedule 5 pipe in NPS 1/8, 1/4, and 3/8. Nor does ASME B36.19M-2004 define wall thicknesses for these sizes in Schedule 5S, though it does have entries for them. Yet there seems to be a widespread belief, including in this article, that these wall thicknesses are defined. Where do those numbers come from?
Similarly for 3½ NPS XXS, this combination of size and weight is not defined in the referenced standard.
Cstaffa (talk) 17:43, 10 April 2017 (UTC)
thread_title:  Schedule 5, 3/8 NPS and smaller 

message: There is also a 1/16" size. OD 5/16", 27 tpi.
agb 173.233.167.50 (talk) 22:56, 27 January 2023 (UTC)
thread_title:  Additional size 

message: "Non-dimensional number" is an interesting usage; is it an engineering term of art? It could be easily confused with dimensionless number, something completely different. If "non-dimensional number" isn't a term of art, perhaps we could use another formulation like "approximate dimension"? — The Anome (talk) 08:29, 2 June 2024 (UTC)
replies: text: It's probably a nonce term, not an established jargon. I think it was written that way to try to emphasize that the number in an NPS size is not a size in inches (or any other unit of length) of any of the pipe's dimensions. But there must be a clearer way of saying that, if that's the intention. Indefatigable (talk) 16:23, 3 June 2024 (UTC)
thread_title:  "Non-dimensional number"