Schedule/Thickness of Pipe Component/Fitting in Piping Material Specification

Could you clarify where this 'M' appears:

Is it, for example, in the site building schedule / parts list

or the plant specification schedule

or the actual component specification such as ASME B16.11.

I'm not sure that the first two options are correctly named but you get the idea.

Drew

In my view it is just a typographical error. For carbon steel materials, the alphabet N is used which indicates it has been normalized. I trust this resolves the matter.

This 'M' occurs in the piping material specification.
http://tenders.hpcl.co.in/tenders/tender_prog/tenderfiles/31/Vol%20II%20Scope%20of%20Work/Job%20Specsl/Pipeline/6544-00-16-71-SP-02.pdf
Please refer page no. 8 in the PDF on the link given above. For Flange the first two rows under the column Sch/thk have the value of M. It is also given for other components like elbows, nipple, reducer etc. I want to know what this 'M' specifies?

Metric ?

It can't be metric since all the sizes are given in inches..

Sorry, I can't find any reference to 'M' in any of the ASME specs relating to wall thickness. The only thing we did find was in an old 'Tubesales' catalogue where they used 'M' to denote 'Mechanical' in one instance and bored-out bar in another.

Drew

Manufactor trade mark. Manufactor simbol'

WP

It can't be manufacturer trademark also.. Because the organisation whose logo we see in the PMS is actually and EPC and consultant. Not a manufacturer..

Can anybody let me know what is the practice in your own organisation? What is specified in the sch/thk column in the PMS used in your organisation?

May be

In plumbing fittings, the "M" or "F" usually comes at the beginning rather than the end of the abbreviated designation. For example:

• MIPT denotes Male Iron Pipe Thread;
• FIPT denotes Female Iron Pipe Thread

WP

STD is Standard, aka Schedule 40. XS is Extra Strong, aka Schedule 80, but I haven't found M (yet). There's also an XXS, which is Double Extra Strong.

Yes, JohnDG. You are right. From what I have discussed with piping engineers they say, that if M is written then it is understood that the schedule of the component/fitting will be decided by seeing the size of the fitting. The schedule of the pipe of that particular size range will be the schedule of the component/fitting for that particular size range.
You can see the schedule of pipe can vary for different sizes. So will the schedule of the component/fitting.
Otherwise, if M is not mentioned then the schedule of the component/fitting should be specified separately.
While some have said that it means that the thickness of the component/fitting is medium.

Looking further at your lists, it is only the pipes that have schedule numbers against them, it is the fittings that have the 'M'.

A fitting wouldn't normally have a schedule number, it would have a class rating which is derived from the schedule of the pipework that joins it.

Is it possible that your engineers meant that you should look at the schedule of each of the pipes joining the particular fitting and 'M'atch the fitting to suit it?

Just a thought.

Drew

You don't state the material of the pipe but, if it copper tubing "M" designates thin wall copper pipe. "L" and "K" are thicker walled and can be bent easier.

Also, at least in the USA, fittings don't have a letter designation for each pressure rating. They are marked with the maximum allowable non-shock pressure (psig) and temperature ratings for steel pipe flanges and flanged fittings according the American National Standard ANSI B16.5 - 1988. The classes includes, in psi: 150; 300; 400; 600; 900; 1,500 and 2,500. The most common class for general use is 150 for sched 40 pipe.

Some piping arrangement will use fittings and pipe with rating higher than necessary to extend the time between necessary replacements. This is often done on steam and steam condensate piping.

Perhaps the "M" is a manufacturer's code such as the colored threads used to designate the manufacturer of some wires or the unique stamps used on gas cylinders to designate the last hydrostatic tester (usually on the shoulder area of the cylinder).

Good Luck, Old Salt

This 'M' occurs in the piping material specification. http://tenders.hpcl.co.in/tenders/tender_prog/tenderfiles/31/Vol%20II%20Scope%20of%20Work/Job%20Specsl/Pipeline/6544-00-16-71-SP-02.pdfPlease refer page no. 8 in the PDF on the link given above. For Flange the first two rows under the column Sch/thk have the value of M. It is also given for other components like elbows, nipple, reducer etc. I want to know what this 'M' specifies?

.

.
What do the engineers from the company that produced the above report have to say what the "M" means?

Contact the people that wrote that PDF!

Type M fitting Goggle that. It is a type classification on how the fitting is machined.

M used mostly for high pressure hydraulics.

Per Note 104:

"WALL THICKNESS FOR LINEPIPE USED IN VARIOUS SECTIONS SHALL BE AS PER TABLE-1 OF ANNEXURE-I (GENERAL

NOTES) OF THIS DOCUMENT."

Suggest reviewing that document.

I would contact the pipe manufacturer because they are allowed to stamp pipe with whatever alphanumeric characters desired. Often manufacturers have a proprietary code to identify Quality Control, Date of Manufacturer, Plant location, ETC.

Type 'M' in this instance refers to the threads. Specifically to a metric thread profile.

Consider component(s) offered by "SPIR STAR". See page 17 of their catalog.

[https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=

rja&uact=8&ved=0CE0QFjADahUKEwiBt5vvwqvIAhUSO4gKHW3QCeY&

url=http%3A%2F%2Fwww.spirstar.de%

2Fgetasset.php%3Fasid%3D2038&usg=AFQjCNFplggCo0LMx2_

hBB8WTirigWYA1g&sig2=PKzNajQjeS1vPn7poop7LQ&bvm=bv.104317490,d.cGU]

Then refer to Wikipedia entry "ISO metric screw thread".

I think "M" stands for "matching the pipe schedule"

For example if you had a 4"-600# ANSI Weld neck flange, and the 4" pipe was sch 40, you would buy a weld neck flange machined to sch 40.

What would be the advantage of NOT specifying the schedule of the weld neck flange?

The only thing I can think about is you could have the same stock code number for the same size flanges with different schedule.

I doubt if that was the intent.

Looks like you are getting ready to submit a bid; why don't you raise a clarification to the client? If you cannot, here is the answer...

"M" stands for "1000", "2M" for '2000'

Here in this case, it refers to "Class Designation"

Good Luck!

Regards,

Srijit

----------------------------

Practice makes man perfect

No, I am not submitting a bid. Actually this PMS has come directly from the client. They have specified that it means match to pipe. However, I had encountered two schools of thought. Hence I wanted to get as much information as I can to really get to the depth of this issue. It seems that Match to pipe is the correct scenario, in this case.

I agree that "It seems that "M" means "Match to pipe" is the correct scenario". However, I think this practice is okay during the early development of a Piping Material Specification(PMS) development when an experienced Senior Engineer is showing apprentice junior engineers how to develop a full PMS. The senior uses the "M" where appropriate and lets the juniors fill in the right data.

The "M" Code version (of a PMS) should never make it outside of the development phase. The Client Approval on the AFC (Approved for Construction) version should be the completely defined version.

I can see that two years down the road some purchasing agent will get his hands on a copy of a PMS with "M" code along with instructions to buy 10- 6" 90degree Ells with "M" wall. He and the vendor will have lunch and have lots of fun telling jokes about what the "M" stands for.

Do it once, and Do it Right!