Pipe fittings-Manufacturing/Quality Assurance

OD

-wall thickness

x2

=ID.

Theoritical OD - Theoritical Wall Thickness = Theoritical ID

(However this differs from the nominal bore bu just a tiny amount)

These are based on the semi-prehistoric practices. Now any way for the pipes - you have the OD controlled (eg 1" will have 33.4mm or 1.315")

This will be a 1" pipe irrespective of the wall thickness (it may be upto 9mm or so, but still it will be called NB25)

A chart for your reference (Google and you will find millions of them)

I sorry to disagree NB is used and in the context of nominal bore only. Only, as I mentioned, now it does not really match with the actual bore and as I mentioned based on the wall thickness (which of course is to be precise defined by the 11 odd schedules- or 16 in the expanded)

Just to have a few links where NB is used

http://www.metals4u.co.uk/detail.asp?cat_id=165&prd_id=2955

http://www.nero.co.uk/tube_pipe~nominal_bore_nb_schedule_40s

etc. or

WIKI

http://en.wikipedia.org/wiki/Nominal_Pipe_Size

Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures.^[1] Pipe size is specified with two non-dimensional numbers: a nominal pipe size (NPS) based on inches, and a schedule (Sched. or Sch.). NPS is often incorrectly called National Pipe Size, due to confusion with national pipe thread (NPT). For other pipe size standards, see pipe (material) - sizes. The European designation equivalent to NPS is DN (diamètre nominal/nominal diameter), in which sizes are measured in millimetres.^[2] The term NB (nominal bore) is also frequently used interchangeably with NPS.

However these are only terminologies since neither NB nor NPS nor DN actually equals to the actual diameter ID or OD or even the mean. These are as I mentioned terminolgies from bygone era. Though this logic does not apply to tubes where 40mm tube means the OD is 40mm.

As far as 12" Vs > 12" is concerned, as I have mentioned in another thread, quite a few months back, the pipe ODs and the NPT sizes are linked, which was standardised first, I don't know, but it is likely that once the NPT sizes were fixed the pipe OD were totally fixed.

Upto 12" being common at that point of history, there was no manipulation possible there, since any changes would have had effect in the ones supplied to the old system However the larger, and the uncommon ones could be changed/ frozen in inception) and that was done. Now NPT 14" has the dia 14" where as for 12" it is 12.75"

Yes you can find places where people and companies have used NB (Nominal Bore) to define pipe, BUT that does not make it right!

The repeat use of an incorrect term does not make it correct.

Okay, though you may disagree you can't show "NB" as an internationally acknowledged pipe standard, so I offer these common Pipe & Equipment common Abbreviations and Acronyms:

obviously you are limited to the US abbreviations, which does not make the world.

where is the BS and BSPT?

you can't show "NB" as an internationally acknowledged pipe standard,

I have already attached links from UK

http://www.nan-long.com/Metal%20Steel%20Technology%20Summary/Diameter_Nominal-Nominal_Bore-Nominal_Pipe_Size.htm (China)

More countries required?

http://www.engineeringtoolbox.com/pipes-tubes-d_347.html

Nominal Bore (NB) may be specified under British standards classifications along with schedule (wall thickness).

It is just like UNC and NPT does not make the world. And that way Meter, Kg, Metric Threads are not standard either, nor is ISO or EPV Directives.

Standards are made from usages and NB is world wide (may be except a region) accepted terminology.

I can refer to any number of books referring to NB just for an example -

"Guide to European Pressure Equipments"

Nozzle sizes are specified as a nominal pipe size in inches (e.g.6" NB or 6" NPS) or in milimeters (e.g. DN150). : page 30

Screwed connections over 4"NB are not generally used in pressure vessels and... (Page 40)

And as per any number of wrong usages do not make a standard- the usage of DN (diameter Nominal _{meaning Nominal Bore in english}) or NPS which do not correspond to OD, ID, Mean diameter or any portion of mechanical calculation are completely wrong terminology.

can you take your 6" NPS and the schedule (or thicknsess) and sit down and do the calculations on the strengths?

Take 6" as what ? Schedule as what ?

We are unnecessarily going into semantics of a thing that is basically unscientifically defined (NPS and Schedules for you, other terminologies for lesser persons) and I don't know wy to argue about a thing that is basically wrong, just to say you are completely wrong and I am 0.001% more right than you?

You asked...

You are confusing vendor designations and or vendor classifications with standards.

*Result of a search for IHS/Global "NB" Pipe

*Result of a search for IHS/Global "NB"

*Note: No, none referenced results returned??