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Up Topic Welding Industry / Inspection & Qualification / Force fit-up
- - By Richman (**) Date 05-24-2009 13:24
Lest the spools has been forcibly fitted-up prior to welding, Is there any stress on the weld joints once it completed and during Hydro testing of line, commissioning, start-up and operation? Incase there is any, what are the effects on the weld area or on the weld joints?
Parent - By Mikeqc1 (****) Date 05-26-2009 17:03
will it be heat treated?
Parent - - By G.S.Crisi (****) Date 05-26-2009 21:10
If the spools have been, as you say, forcibly fitted up prior to welding, chances are (good chances, by the way) they will transmit the stress to the equipment they will be connected to, like pumps, vessels, tanks etc. This is unacceptable, no erection instruction manual will allow it. In the case of rotating equipment, you won't be able to align it.  
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By Richman (**) Date 05-27-2009 09:03
There are heavy wall lines requiring PWHT and others don’t have like for example Stainless steel-Cryogenic lines. There are instance sub/contractor forcibly straighten or pull the lines to install the support and guide at the same time to avoid cutting or rectify the lines. Once they put the guide and the support, the line will stay as it is and if we didn’t see any signs of forcibly fitted-up during line checking and hydro testing. With that case what are the best things to do as a Client or contractor representative to stop this wrong doing since we cannot oversee all the works at sites?  What is the effect on these during comm. and start –up?
Parent - - By Shane Feder (****) Date 05-27-2009 09:16
Richman,
As Giovanni has stated it is totally unacceptable to force fit piping to pumps and equipment.
As the client you must not allow flanges to be bolted up to equipment with any tension on them, the flange must be inspected prior to final bolt up to ensure there is no gap and that the flanges are square to each other.
Do a random check, have the contractor loosen all the bolts on a selection of flanges and if the spools "spring" you have got a problem.
Regards,
Shane
Parent - - By Richman (**) Date 05-27-2009 09:42
Thanks so much for the advise
Parent - By cremx (*) Date 05-28-2009 18:23
You have to contact the equipment´s vendor to verify the allowable loads at flange connections otherwise check the flexibility study if there is; the design takes in consideration some fabrication/construction tolerances; consult the piping engineer
Up Topic Welding Industry / Inspection & Qualification / Force fit-up

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