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00:13 Feb-23-2006
Luis Marques
Statistics analysis of TML UT measurements

Statistics analysis of TML UT measurements


The selection of our thickness measurement locations (TMLs) is established in accordance with the API 570 guidelines.

Critical Piping circuits are selected in accordance with RECOMMENDED PRACTICE 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry and API RECOMMENDED PRACTICE 580 Risk-based Inspection.

After the base line survey and the first inspection we calculate a corrosion rate based on the TML minimum thickness found in the circuit. With this corrosion rate we define the next inspection survey to define inspection frequency and estimation of the remaining life. After de third inspection survey we are in conditions to define a short term and a long-term corrosion rate, inspection frequency and a more accurate remaining life.

My question is:

Are there any guidelines for the statistics analysis of TML UT measurements?

A piping circuit section should be replaced when a TML of that section reaches the minimum calculated thickness or it should be given a statistics analysis of all TMLs within the whole critical piping circuit to preview the corrosion trend and pipe length replacement?

Comments on this subject should appreciated

Regards

Luis Marques


 
06:38 Feb-23-2006
John Rudlin
Re: Statistics analysis of TML UT measurements ----------- Start Original Message -----------
: Statistics analysis of TML UT measurements
:
: The selection of our thickness measurement locations (TMLs) is established in accordance with the API 570 guidelines.
: Critical Piping circuits are selected in accordance with RECOMMENDED PRACTICE 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry and API RECOMMENDED PRACTICE 580 Risk-based Inspection.
: After the base line survey and the first inspection we calculate a corrosion rate based on the TML minimum thickness found in the circuit. With this corrosion rate we define the next inspection survey to define inspection frequency and estimation of the remaining life. After de third inspection survey we are in conditions to define a short term and a long-term corrosion rate, inspection frequency and a more accurate remaining life.
: My question is:
: Are there any guidelines for the statistics analysis of TML UT measurements?
: A piping circuit section should be replaced when a TML of that section reaches the minimum calculated thickness or it should be given a statistics analysis of all TMLs within the whole critical piping circuit to preview the corrosion trend and pipe length replacement?
: Comments on this subject should appreciated
: Regards
: Luis Marques
------------ End Original Message ------------

You will find guidelines on this subject in a UK Health and Safety Executive document, which you can find on www.hse.gov.uk/research/rrpdf/n016.pdf.

Regards
John Rudlin



 
03:22 Feb-24-2006

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1094
Re: Statistics analysis of TML UT measurements Unfortunately the HSE site does not recognise that document number, John. Could you check out the correctness of your link please. Thanks.


----------- Start Original Message -----------
: : Statistics analysis of TML UT measurements
: :
: : The selection of our thickness measurement locations (TMLs) is established in accordance with the API 570 guidelines.
: : Critical Piping circuits are selected in accordance with RECOMMENDED PRACTICE 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry and API RECOMMENDED PRACTICE 580 Risk-based Inspection.
: : After the base line survey and the first inspection we calculate a corrosion rate based on the TML minimum thickness found in the circuit. With this corrosion rate we define the next inspection survey to define inspection frequency and estimation of the remaining life. After de third inspection survey we are in conditions to define a short term and a long-term corrosion rate, inspection frequency and a more accurate remaining life.
: : My question is:
: : Are there any guidelines for the statistics analysis of TML UT measurements?
: : A piping circuit section should be replaced when a TML of that section reaches the minimum calculated thickness or it should be given a statistics analysis of all TMLs within the whole critical piping circuit to preview the corrosion trend and pipe length replacement?
: : Comments on this subject should appreciated
: : Regards
: : Luis Marques
: You will find guidelines on this subject in a UK Health and Safety Executive document, which you can find on www.hse.gov.uk/research/rrpdf/n016.pdf.
: Regards
: John Rudlin
------------ End Original Message ------------




 
06:42 Feb-24-2006

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1094
Re: Statistics analysis of TML UT measurements I checked out the HSE website and found the document under this link:

www.hse.gov.uk/research/rrpdf/rr016.pdf

Thank you for the pointer, John


----------- Start Original Message -----------
: : Statistics analysis of TML UT measurements
: :
: : The selection of our thickness measurement locations (TMLs) is established in accordance with the API 570 guidelines.
: : Critical Piping circuits are selected in accordance with RECOMMENDED PRACTICE 571 Damage Mechanisms Affecting Fixed Equipment in the Refining Industry and API RECOMMENDED PRACTICE 580 Risk-based Inspection.
: : After the base line survey and the first inspection we calculate a corrosion rate based on the TML minimum thickness found in the circuit. With this corrosion rate we define the next inspection survey to define inspection frequency and estimation of the remaining life. After de third inspection survey we are in conditions to define a short term and a long-term corrosion rate, inspection frequency and a more accurateremaining life.
: : My question is:
: : Are there any guidelines for the statistics analysis of TML UT measurements?
: : A piping circuit section should be replaced when a TML of that section reaches the minimum calculated thickness or it should be given a statistics analysis of all TMLs within the whole critical piping circuit to preview the corrosion trend and pipe length replacement?
: : Comments on this subject should appreciated
: : Regards
: : Luis Marques
: You will find guidelines on this subject in a UK Health and Safety Executive document, which you can find on www.hse.gov.uk/research/rrpdf/n016.pdf.
: Regards
: John Rudlin
------------ End Original Message ------------




 
07:26 Feb-15-2007
Ron
Redgrave I like drink pivo. Thanks


 


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