WT meaning in flange pipeline. 2

[skengg]

Hello to all,
i have one minor doubt which sound bit naive to you, i have a flange input design condition and need to design based on that.
this is butt welded flange with design pressure, temprature and size given.
But there is one more input which is written WT=25.4mm, what does this mean?

 

[SJones]

Generally, it’s taken as the abbreviation for wall thickness

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[LittleInch]

Second that.

You need to specify the wall thickness (wt) of the pipe you're welding to to avoid a step change on the inner surface.

That's a pretty thick pipe!

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[skengg]

thanks SJones and LittleInch for replying,
i have a Technical data sheet of flange design calculation in which WT=25.4mm but to calculate pipe wall thickness it was shown as pipe wall thickness = 25.4-6= 19.4mm
i couldn't be able to figure out that why they subracted 6 from WT.

 

[LittleInch]

Possibly corrosion allowance?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[skengg]

IT COULD BE

 

[LittleInch]

What exactly are you trying to do?

"Flange input design condition"?

Input into what?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[skengg]

Littleinch, flange design input condition means i have all the flange dimensional parameters along with operating condition information.
i was analyzing mating pipe information, where i have given WT-25.4mm, internal corrosion allowance - 6mm, pipe wall thickness given in the sheet is 25.4-6=19.4mm,
so i was trying to understand that if WT=25.4mm already given then why to calculate pipe wall thickness, they have subtracted internal corrosion allowance to it.

 

[LittleInch]

The calculation of the wall thickness is undertaken normally using pressure, Design factor or provided S value, temperature and metal strength.

then you add manufacturing tolerance then you add corrosion allowance. So in the uncorroded condition, stress is lower, but in fully corroded condition, the stress is still within limits. A CA of 6m is rather extreme though and is at the top end of what could be described as "normal".

So initially the pipe wt will be 25.4 (one inch), but if allowed to corrode fully would only be 19.4mm, but still within design limits.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[skengg]

Thanks, littleinch for clarity, now i understand.