RE: Assessing/Rerating the On-Line Flange Gasket L eaks Repair

From: <SARE>
Date: Thu Jul 19 2001 - 03:32:00 EDT

section 6.3 (d) and (f) of api 570 Rerating state and i quote

item (d)"rerated piping systems shall be leak tested in accordance with the code to which the piping system was built... unless documented records indicate a previous leak test was performed at greater than or equal to the test pressure for the new condition. An increase in the rating temp that does not effect the allowable tesnile stress does not require a leak test."

Item (f) "rerating is acceptable to the inspector or pipng engineer"

A leak on the flange will mean either you got a busted gasket, damage to the flange face or increase in its operating condition exceeding flange rating (bolt has been ruled out). Wire wrap is normally followed by leak sealing i njection and in moist cases it will leak again after few months. We'll you can re-inject but thats about it. If you then lower your design requirement and u have determined that all piping componet int he sytem are still adequate for the new design changes and item (d) and (f) has been complied with then i guess it meet the rerating stated in api 570. else u plan to install an enclosure and scehdule its refacing or replacement in the very first opportunity or u shutdown the unit and heave the flange repaire/replaced to match new design parameter.

hope this helps. we normally hire the services of furmanite or team inc for wire wrap or leak sealing. we have also some in-house capability to do leak repair using the Plidco system. good luck

-----Original Message-----
From: Samuel Liu [mailto:samuel.liu@amec.com] Sent: 18 July, 2001 10:42 PM
To: 'PipingDesign@yahoogroups.com'
Subject: [PipingDesign] Assessing/Rerating the On-Line Flange Gasket Leaks Repair

Hi, There:

Does anyone know the reference for assessing/rerating the on-line repair of flange gasket leaks, such as Wire Wrap or Crunch Groove? Does API 570 make sense for it?

Thanks a lot,

Samuel Liu
Mechanical Engineer
AMEC E&C Services Limited
PH: 1-780-968-3421
FAX: 1-780-968-3423
Email: samuel.liu@amec.com

Visit our web site at www.amec.com

[Non-text portions of this message have been removed]

---

Piping Design Central
[ http://www.PipingDesign.com ]

---

We hope you find this newsletter useful. If not, you can unsubscribe at:
PipingDesign-unsubscribe@yahoogroups.com Post message: PipingDesign@yahoogroups.com Subscribe: PipingDesign-subscribe@yahoogroups.com

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Thu Jul 19 03:32:00 2001