Pressure Vessel Minimum/Retirement Thickness 2

[fronten]

Hello,

I have been trying to calculate the "Remaining Life" for some pressure vessels but I cannot find a formula to calculate the minimum/retirement thickness.

Can someone help me to locate such a formula.

Thanks in advance,
Fronten

 

[metengr]

fronten;
The remaining life of a pressure vessel has to be quantified based on the in-service damage mechanism. What is the specific damage mechanism - general wastage from corrosion, erosion/corrosion, fatigue, creep,..... or combination of the aforementioned?

Once you have responded to the above, the proper evaluation method can be selected. For more guidance, I would refer you to the National Board Inspection Code (2004 Edition, 2005 Addendum). Review RB-9000, this section was completely re-written by our subcommittee to address concerns related to remaining service life of pressure retaining items.

 

[jte]

Don't want to be remiss and leave out API-579 (soon to be API/ASME 579).

jt

 

[fronten]

Metengr,
I went through RB-9000 as you suggested and the formula under RB-9110 (Method for Estimating Inspection Intervals for Exposure to Corrosion) is what I was working with.

My problem was to obtain the "t required" - (minimum allowable thickness for the limiting section).

Can you or anyone for that matter help me to find calculations to obtain "t required" values.

jte,
I don't have a copy of the API codes.

fronten

 

[SnTMan]

fronten, if you can contact the vessel manufacturer(s) they may supply you with the original mechanical calculations which should contain all the information you need.

Otherwise you will need to identify which code / standard (including edition) the vessels were designed to, and get your equations from there. You can then perform the calculations yourself.

Regards,

Mike

 

[jte]

fronten-

If you're planning on staying in the fitness for service arena then I'd strongly suggest that you buy a copy of API/ASME-579 when the new edition comes out. I'm not sure when it will, but suspect it's due within six months or so. 'Course, that is in addition to your local primary code of construction (ASME VIII-1 for many/most of us) and an inspection code such as NB-23 (or, in a few cases, API-510). The codes aren't cheap, but neither are failures. 'Course, the free advice you and I are getting from the anonymous folks on this we site is priceless!

jt

 

[dtn6770]

Refer to ASME Sec. VIII, UG-27 Thickness of Shells Under Internal Pressure and UG-32 Formed Heads, and Sections, Pressure on Concave Side. Both contain the equation for determining required thickness as functions of internal pressure, diameter, maximum allowabel material stress, etc.

 

[metengr]

My problem was to obtain the "t required" - (minimum allowable thickness for the limiting section).

The design rules in the original code of construction. Original in this case does NOT mean the year it was built, it only refers to the specific construction code (a later edition can be used).

 

[stanweld]

fronten,
Please note that you may repair wasted areas and damaged locations of vessels and thus avoid retirement.

The remaining life or "need to repair time" may be dictated by changes in the process during the vessel's life. Minor process changes can drastically affect the remaining life; therefore, it is important to know the full operating history of the vessel. The current corrosion rates may be significantly greater than the lifetime corrosion rate.

 

[fronten]

Stanweld,

The set of formulas that I have shows how to calculate the current corrosion rate as well as long as the long term corrosion rate. The greater of the two will be used to calculate the remaining life however I need to calculate the minimun thickness to complete calculations for the remaining life and that is what I can't do at the moment.

Fronten

 

[metengr]

fronten;
Are you trying to re-rate this vessel, based on your other post????? Design minimum wall thickness calculations for unfired pressure vessels are in the ASME B&PV Code book, as mentioned above. What is the problem??

 

[LSThill]

jte (Mechanical)

Please, Do you know when: (API/ASME-579 when the new edition comes out). Do you have any details. Date?,



L S THILL

 

[LSThill]

TECHNICAL NOTE: (2006 Conference paper)

IPEIA INTERNATIONAL PRESSURE EQUIPMENT INTEGRITY ASSOCIATION

2006 Conference paper
Conference Summary

http://www.ipeia.com/default.asp?prime=Past Conferences&webpage=216

“P-91 and Beyond – New Welding Technologies” William Newell, Euroweld, Ltd. PRESENTATION

"The Effect of Emerging NDE Technology and the Plant Inspector” Mark Koens, Petro-Canada PRESENTATION

“The Interpretation of the NACE MR0175 / ISO 15156 Standard” Ray Goodfellow, Pangea Solutions PRESENTATION

"Pressure Relief Developments in the Next Decade” Valerie Magyari, The Equity Engineering Group, Inc. PRESENTATION

'A Moment is all it takes to change a life forever.” Mel Camilli, WorkSafeBC

"Integrity Operating Windows (IOW’s)” John Reynolds, Shell Global Solutions US PRESENTATION

“Beyond RBI in the Next Decade: Safe and Reliable Operation within Boundaries (Materials Operating Envelopes)” Gerrit Buchheim, The Equity Engineering Group, Inc. PRESENTATION

“Environmental Stress Cracking of a Shell and Tube Heat Exchanger in High Temperature Boiler Feed Water Service” J.Moen, Dow Chemical Canada Inc. / G.Roemer, IRISNDT Corp. PRESENTATION

“The API 579 Fitness For Service Standard: The current state of the technology & a ten year look ahead.” D.Osage / B.Brown, The Equity Engineering Group, Inc. PRESENTATION
"Managing Pressure Vessels with Known Flaws” Ana Benz, IRISNDT Corp. PRESENTATION

“Fitness For Service and Life Extension of Pressure Retaining Equipment in the Pulp and Paper Industry” Craig Reid, Acuren HANDOUT, PRESENTATION

“Issues Affecting the Short Fatigue Life of Pressure Equipment” B Wright / C Allevato, Stress Engineering Services, Inc. PRESENTATION

“Surface Engineered Coatings in Pressure Vessels” Dale Homeniuk, Inotec Coatings and Hydraulics Inc. PRESENTATION

“Industrial Rope Access” Trevor Paananen, RAE Engineering and Inspection Ltd. PRESENTATION

“Advances in Acoustic Emission Testing for On-Stream Inspection” Sam Ternowchek, CONAM / QSL Plus PRESENTATION

“Qualificaton of Phased Arrays to ASME Section V Codes” Michael Moles, Olympus NDT Canada PRESENTATION

 

[jte]

Leonard-

The next edition of API/ASME 579 will allegedly be released in January. I'm not sure whether that means "released to the printer" or "shipping to the public." So, figure somewhere between a month and six months before you get your hands on it.

jt

 

[LSThill]

jte (Mechanical)

Team Members

Thank you for the update on the next edition of API/ASME 579.

 

[0707]

My thought in this matter is that, you should calculate your MAWP (maximum allowable working pressure), this will give a thickness. Then you should scan your vessel for real measured thickness and see if your actual thickness is higher or lower than your MAWP (maximum allowable working pressure) thickness, then you are in condition to extrapolate a corrosion rate to see how much time you have until vessel retirement.

Good luck

Luis Marques

 

[stanweld]

fronten:
To calculate the minimum thickness, use either the design or current operating temperature/pressure of the vessel and use the equations in ASME VIII, Div.1 to solve for T. Verify minimum thickness of the vessel with UT or other thickness measuring equipment.

This assumes that the vessel is not operating in creep, fatigue or SCC [potential] service. Metal loss due to corrosion is your only concern.