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Pipe thickness

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M Kandasamy

Mechanical
Nov 11, 2016
2
pipe schedule 40 purchased but as per calculation 80. how we can manage now? please let me know your thoughts
 
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Ooops! Shoot the procurement officer?


Dejan IVANOVIC
Process Engineer, MSChE
 
If you need 40, decline 80, inform procurement and buy a now (correct) one.
 
Not sure if you require Sch 80 which is calculated thickness and purchased Sch 40 which if is the case you need to purchase Sch 80 and return Sch 40 probably taking a hit financially depending on your relationship with vendor.

If on the other hand you could either decline/return as XL83NL suggests or use in lieu of Sch 40 if it suits schedule and no flow concerns with smaller ID.
 
You have purchased Sch 40 when it should have been Sch 80.
Unfortunately you have a major problem and nobody can assist you with it.

If it was the other way around you may have been able to get away with it as noted above but basically you have to return the pipe and reorder the correct pipe.
Cheers,
Shane
 
Hold it as surplus stock. You'll probably need it later for something some day. Or build some streetlight posts.
 
Do calculation backwards to find out what your new (reduced) design pressure now is. If it's above what you need to do your duty then ok. If not then change your duty or but some schedule 80 pipe....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
If the calculated thickness was close to S40 then there are some fine tuning of the calculation you could do.

1. reduce corrosion allowance. Is the specified allowance really required? Do you have a long history in this service with little corrosion.
2. Reduce manufactures tolerance. Measure the S40 pipe. I bet it is well within the 12.5% allowance.
3. review the how the design pressure was calculated. Is this conservative?
 
M Kandasamy said:
pipe schedule 40 purchased but as per calculation 80. how we can manage now? please let me know your thoughts


Elaborating on KevinNZ's point 3 - was schedule 80 calculated based on pressure only or did the calculation take into account structural requirements i.e. deflections and thermal loading etc. ?
 
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