Re: [MW:29523] Query related to Pressure testing of Existing piping/equipment - Looking for a right recommendation based on International Standard/ Guidelines

Check ASME B31.1-137.4.5 and 137.5.5 as an example. The holding time is a minimum of 10 minutes.

On Sat, Apr 27, 2019 at 6:22 AM ViNo Varughese <vinopvarghese@gmail.com> wrote:

Dear All,

I have read recently an Oil & Gas Journal regarding the hydro test Vs holding time and looking for more insight from Experts from different industries. There are few questions which I would like to get more clarity on -
1. What should be the recommendation for pressure testing of existing piping line which is repaired due to leak? Whether we should follow the Construction code or should we limit just above the MAOP? Is there any criticality rating based on which we need to consider the pressure test value, eg: H2S service.

2. Many times our Operation colleague request to consider the closure weld principal where we can do additional NDT on the welded joints instead of pressure testing. I do understand that NDT cannot be replaced with pressure testing. However, there are good chance of having a defect opened up which is on the verge of failure when the line is tested at 1.5/1.3 times the design pressure. How to deal with such situations when Asset Plant has been in Operation since 25+ years?

3. There is reference in the same Oil & Gas Journal - " A study of the causes of failures of Defects that Have Survived a Prior Hydrostatic Test". Appreciate if someone holds a copy of this article and please share in forum.

4. I think there is no International code referring to holding time of pressure testing. Just would like to get a reconfirmation on this.

Hope to see view from Experts all around different industries. I am sure it's a very routine repair in almost all of the Plants/Company and will add value to each one of us.

Best Regards
Vino

--
https://materials-welding.blogspot.com/
https://www.linkedin.com/groups/122787
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
Visit this group at https://groups.google.com/group/materials-welding.
For more options, visit https://groups.google.com/d/optout.

--
https://materials-welding.blogspot.com/
https://www.linkedin.com/groups/122787
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
Visit this group at https://groups.google.com/group/materials-welding.
For more options, visit https://groups.google.com/d/optout.

Re: [MW:34105] SA266 GR4N 4 Cycle SPWHT

Hi, You are correct, Minimum refers to the one cycle for which this part will expose until final work shop PWHT. hence mill test certificate shall include this. Max. SPWHT, refers to additional cycles of heat treatment that are reserved for future repairs during equipment lifetime. Again, these simulated no. Of cycles shall be specified in MTC. The idea is we need to make sure that steel mechanical properties are not compromised upon exposure to multiple repairs (i e 4 cycles in your case). One could say, if steel is subjected to 4 cycles and is ok, then it should by defacto be good for one cycle, yet, this is wrong assumption cause mechanical problems and microstructure of materials varies accordingly based on no. Of cycles for which material will expose. This is apparent in alloy steel and especially for impact test values as an example. In your case, this forged CS with properties before PWHT can be understood to be " as forged" condition (i.e. Wit...

Heat tint (temper) colours on stainless steel surfaces heated in air // Heat tint

Introduction The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change. Oxidation resistance of stainless steels However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases. The colours formed can only be used as an indication of the temperature to which the steel has been heated. Factors affecting the heat tint colours formed Steel composition The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colou...

Materails FAQs

Q: What are equivalents for standard Q 235 B (and Q 235 A) for U-channels? (asked by: boris.vielhaber@vait.com) A: DIN Nr. = 2393 T.2, 2394 T.2, EN 10025 W. Nr. DIN 17007 = 1.0038 Design DIN 17006 = RSt 37-2, S235JRG2 (Fe 360 B) Q: What is St DIN 2391 BK material? (asked by: dmcandrews@automaticstamp.com) A: Precision steel tubes, cold-finished/hard. Q: What is C.D.W. Boiler Tube? (asked by: montydude123@yahoo.com) A: Cold Drawn Welded Boiler Tube. Q: WHAT IS W.Nr. 1.4301? PLS TELL US IN EASY LANGUAGUE (asked...

Materials & Welding

Search This Blog