RE: 1307] Re: 1305] welding reqd on a weldolet

[Bathula Raghuram (Mumbai - PIPING)]

I am expecting multiple opinions on this issue from the group members but so far none?. please share your experience (no matter whether it is right or wrong after all we are just learning) , since it is long debated and yet not resolved issue. almost on every project I work for I have an issue with weldolet welding/distortion etc..

 

On many occasions in the past I have come across Weldolets which have not been fully welded out to the weld line. One in particular resulted in a near catastrophic failure. In general I find that contractors do not fully weld out weldolets to the weld line generally with the mis-conception that provided they have the same thickness as the branch wall they will be O.K. However they need to meet Thermal Stress Analysis requirements and not just Pressure reinforcement. I am neither a designer nor stress specialist  bur considering Code" SIF's are lower than set-on branch SIF's since they are based upon the assumption that the Weldolet is fully welded out to the weld line. In not fully welding out the Weldolet then the actual SIF's are far greater than the "Code" values. The problem is that in many cases the Pipe Stress Engineer has assumed that the Weldolet is fully welded out whereas in fact the inspector approves cases where this has not occurred. My opinion is that Weldolets should be fully welded out always and if the parent pipe is so thin that distortion is a problem then use some other type of fitting.

there are some client specifications indicate the the extent of weld required for olets for e.g NORSOK standard M-601 states

"The weld bevel of O-lets shall be completely filled up to weld line on the O-lets. Smooth transition between the pipe and the O-lets is required. Notches below the weld line shall be avoided. Prior to welding, sufficient root gap shall be ensured"

 

The problem is that olets are manufactured in a combination of diameter groupings to avoid inventory, resulting some of them will have the reinforcement at branching in excess of what is required. also it is because we get Sch40 fittings for sch10 run pipe, since bonny forge does n't have sch10 in their inventory, is n't it? and end up with more welding.

 

simplest solution would be rather than going thro these complex geometry, we can choose a poorer solution such as with RF pad, after all we can calculate the required thk as per code is n't it?

 

I hope some national/international code will be published soon on the olet geometry.

 

-----Original Message-----
From: material...@googlegroups.com [mailto:material...@googlegroups.com]On Behalf Of HAREESH K V
Sent: Thursday, November 13, 2008 4:25 PM
To: material...@googlegroups.com
Subject: [MW:1307] Re: 1305] welding reqd on a weldolet

can we calculate the weld required based on asme B 31.3, the minimum reinforcement required for the branch opening. If so can you send one example calculation.

also how much weld should be done on a half coupling.

On Thu, Nov 13, 2008 at 1:46 PM, Bathula Raghuram (Mumbai - PIPING) <R.Ba...@ticb.com> wrote:

there is always heated debate on this between me and the vendors. in my opinion what ever is the bevel provided has to be completely filled since it compensates the area of opening (also called as crotch).

also olet manufacturer (since they are the designers) should give these recommendations. you may check the burst test performed on these olets by mfrs, the minimum weld should be the one they welded during burst test.

 

-----Original Message-----
From: material...@googlegroups.com [mailto:material...@googlegroups.com]On Behalf Of HAREESH K V
Sent: Thursday, November 13, 2008 9:11 AM
To: material...@googlegroups.com
Subject: [MW:1305] welding reqd on a weldolet

I want to know how much welding reqd on a weldolet. My client is insisting me to weld the total slope (up to the middle of weldolet) on the weldolet. How the welding to be calculated?

Generally please suggest how much welding reqd on the OLETS.

If available can anyone send pictures of the same.

Regards

Hareesh

[mathu.subramanian]

Interpretation 13-11E of ASME B31.3 will give all options to find out the welding requirement including the one as said by Mr. Raghuram.    

 

Please note that even though the Code allows to use RF pads, nowadays some Clients & PMCs clearly mentions the need of weld ‘O’ lets in the specifications. So, it is unavoidable to use O lets.  

 

Clients & PMCs, they themselves should understand the problem of chance for less welding at the branch connections due to inspectors less design knowledge and clearly specify the weld thickness required at the branch connections in the specifications. This will avoid the weld failure.

 

---

<BR

[Owen Jenkins]

This brings us back to the problem about inspection - what is an inspector using as his guide to what is acceptable? His experience alone, the codes and designs to which the fabricator should be working, or a combination of both? In my view, the fabricator should be working to the client-approved design drawings, details, codes and specifications and it is these that the inspector should be using as his guide to acceptability. Only where they are themselves in conflict or actually wrong and there is no opportunity to discuss with the client's responsible engineer should the inspector be having to make such judgements. It is often a good idea if the inspector is the client's specifying engineer, or someone similarly or better qualified.

 

Needless to say, education and training are all part of this. In my experience, some inspectors are excellent, being well educated, properly trained and with real practical experience. Such individuals are also more expensive than others. If a company buys its inspection services purely on price, sooner or later they will suffer the consequences.

 

For those that don't have a copy, the Bonney forge Olet catalogue is available here: http://www.bonneyforge.com/OletCat.PDF

 

It gives a pretty good idea of where the weld metal should go. They should know - they invented the things.

 

Owen Jenkins.

[Pathmanan Ganesan]

Please refer bonny forge web site for weldolets welding sequence and full welding requirement.

 

Weldolets shall be welded to the extent applicable as per the manufacturer recommendations. If not, design calculation shall be provided by the design engineer to provide basis and  customer to approve.

 

Regards,

 

P.M.Ganesan

Site QC Manager

QA&C Department

 

Kharafi National

P.O. Box: 24081, Safat – 13101, Kuwait

Mob: +965.7202358

Email: p.ga...@kharafinational.com

Website: www.kharafinational.com

---

<BR

[HAREESH K V]

Sir,
Can we come to a conclution regarding this topic.?

Can any of the other members reply on this topic.

[narayanam kameswararao]

Dear all,

 

Yes, this is always an issue yet to be resolved. The consultant Foster Wheeler ,  with whom I interacted, did not give satisfactory answer, but said if the weld thicknes is same as of branch pipe thickness ,, it is OK.  But it did not sound correct to me for the simple reason  if that is the case, why to specify  welodolets in the specification and spend money on them.We can simply and directly weld branch lines to main line. 

 

To my knowledge these weldolets replaces reinforcing pads/compensating pads that are otherwise required for a branch connection. Regarding welding requirement , there is a contour on the weldolet and welding is  to be done upto that line. I too experinced failure of a weldolet welded equal to  the thickness of branch pipe/ V- groove provided.

 

Finally I suggest that wellding to be done upto the contour provided on the weldolet.

 

Regards,

 

Kameswara Rao N

---

From: HAREESH K V <haree...@gmail.com>
To: material...@googlegroups.com
Sent: Saturday, 15 November, 2008 2:01:43 PM
Subject: [MW:1315] Re: 1308] RE: 1307] Re: 1305] welding reqd on a weldolet

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[Bathula Raghuram (Mumbai - PIPING)]

Update on this issue:

Pipe Fabrication Institute released PFI Standard ES-49, “Guideline for Installation of Integrally Reinforced Branch Outlet Fittings”, which covers in detail the basic welding procedure and recommended weld deposit criteria for OLET^® fittings.

Additionally, B31.1 “Power Piping” revised, clarifying the governing criteria used for weld size determination and provides depictions of some acceptable weld profile for “Integrally Reinforced Branch Outlet Connections”.

The revisions are Paragraph 127.4.8 and the addition of Figure 127.4 .8 (E) showing acceptable details for integrally reinforced branch connections.

[praveen alavandar]

Hi Raghuram,   You were right about the olet's welding, there is always been a debate here on the extent of welding.   Your Norsok M601 is one good reference.   Please see below a different view from BP Spec (GIS 42-102),   If set on integrally reinforced branch connections are used, it should be noted that the wall thickness of the connection may well be in excess of that necessary to provide the required level of reinforcement. Consequently, no reinforcement contribution is necessary from the weld metal, and the deposition of a branch weld with an excessive throat thickness may lead to unacceptable distortion of the main run pipe. The engineering design should provide guidance on the sizing of branch welds if using this type of fitting and on the need for controlled weld profiles if the branch is on severe cyclic duty. If set in integrally reinforced branch connections are used, fit up, jigging, and developing an overall welding sequence, should minimise the extent of any "sinking". The use of integrally reinforced branch connections on thin wall pipes, sch. 10 and below, should be avoided.   Again it is open for debate, it will always be better to follow the recommendations from the client spec. when identified. When dispute arises then a proper analysis from engineering design can be supported, which again will be subject to the client's approval.   Regards,   Praveen A  --- On Thu, 6/30/11, Bathula Raghuram (Mumbai - PIPING) <R.Ba...@ticb.com> wrote:

--

[박종민(PARK, JONG MIN)]

Dear Experts

 

We will make structural tanks with duplex and super duplex stainless steel.

 

As I know line heating on duplex steel is forbidden.

 

Is there any other method to straighten the deformed duplex stainless plate?

 

Best regards,

 

JM

[Dick Overkleeft]

Dear Sir,

 

Some years ago we built a dss chemical tanker, and at that time we tested flamestraightening of flat panels by spot heating  ( by hand) and watercooling down, directly after upheating until the steel is cherry red. Although it is normally not acceptable because of fear of structure modification and posible carbonizing of the dss, it showed in the laboratory test that the grain size and the structure had not changed.

It is not to be expected that either corrosion resistance as well as impact value is changed due to the straightrening.

If straightness is an issue, you may try to perform a flame straightening procedure, with additional testing in cooperation with yor client.

2011/7/12 박종민(PARK, JONG MIN) <carp...@dsme.co.kr>

[HAREESH K V]

Dear All,

This question was raised by me in 2008, when i faced the problem. At last i made it clear from the manufacturers PDF file (http://www.bonneyforge.com/OletCat.PDF) that it should be welded to full penetration as in their picture (given by Mr.Raghuram), as they have explained their research and strength considerations for designing the same. Now i am inspecting those welds based  on the same.

The second question which raised, of availability of Sch40 instead of sch 10, certainly it will bend the header pipe and a cost and time burden to welding. This matter to be discussed in detail and wish to have some serious comments. Also i hope a communication with Bonney forge will also solve the issue of "how much to weld?" in such cases.

Thanks in advance,

Hareesh K V

Neo Stucto Construction Ltd

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----------------------
Hareesh K V
+91-9447625012

[Raghuram Bathula]

another interpretation (13-11E) for referanace

On Tuesday, December 18, 2012 4:30:12 PM UTC+5:30, Materials & Welding wrote:

Interpretation (22-22) attached for reference

[MW]

New revision of B31.3-2014 edition added Fig. 328.5.4F Acceptable Details for Integrally Reinforced Branch Connections

On Friday, November 14, 2008 at 12:49:30 PM UTC+4, Bathula Raghuram  wrote:

I am expecting multiple opinions on this issue from the group members but so far none?. please share your experience (no matter whether it is right or wrong after all we are just learning) , since it is long debated and yet not resolved issue. almost on every project I work for I have an issue with weldolet welding/distortion etc..

 

On many occasions in the past I have come across Weldolets which have not been fully welded out to the weld line. One in particular resulted in a near catastrophic failure. In general I find that contractors do not fully weld out weldolets to the weld line generally with the mis-conception that provided they have the same thickness as the branch wall they will be O.K. However they need to meet Thermal Stress Analysis requirements and not just Pressure reinforcement. I am neither a designer nor stress specialist  bur considering Code" SIF's are lower than set-on branch SIF's since they are based upon the assumption that the Weldolet is fully welded out to the weld line. In not fully welding out the Weldolet then the actual SIF's are far greater than the "Code" values. The problem is that in many cases the Pipe Stress Engineer has assumed that the Weldolet is fully welded out whereas in fact the inspector approves cases where this has not occurred. My opinion is that Weldolets should be fully welded out always and if the parent pipe is so thin that distortion is a problem then use some other type of fitting.

there are some client specifications indicate the the extent of weld required for olets for e.g NORSOK standard M-601 states

"The weld bevel of O-lets shall be completely filled up to weld line on the O-lets. Smooth transition between the pipe and the O-lets is required. Notches below the weld line shall be avoided. Prior to welding, sufficient root gap shall be ensured"

 

The problem is that olets are manufactured in a combination of diameter groupings to avoid inventory, resulting some of them will have the reinforcement at branching in excess of what is required. also it is because we get Sch40 fittings for sch10 run pipe, since bonny forge does n't have sch10 in their inventory, is n't it? and end up with more welding.

 

simplest solution would be rather than going thro these complex geometry, we can choose a poorer solution such as with RF pad, after all we can calculate the required thk as per code is n't it?

 

I hope some national/international code will be published soon on the olet geometry.

 

-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com]On Behalf Of HAREESH K V
Sent: Thursday, November 13, 2008 4:25 PM
To: materials-welding@googlegroups.com
Subject: [MW:1307] Re: 1305] welding reqd on a weldolet

can we calculate the weld required based on asme B 31.3, the minimum reinforcement required for the branch opening. If so can you send one example calculation.

also how much weld should be done on a half coupling.

[salman cader]

Halo there...as my experience as a welder and a inspector..depending on what product the pipe is carrying,  some inspectors will not querry how the weldolet is welded maybe the pipe is just used for structural purposes...but if you doing it for hi pressure products or any hazardas material then i suggest you do a full out weld or what the code allows....also to prevent distortion there are welding techniques to combat that lets say a pipe is a clock and we using the clock as an analogy .... you weld from 12 to 3.......then from 6 to 9.....then 3 to 6 then 9 to 12...evening  the heat out....but like any bevel butt you apply the same theory as two pipe being joined....

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[Dom]

IS 1.4 times the thickness a good gauge for example 5.54 mm wall look for a throat thickness of about 8.5mm 

[Dom]

HI im a supervisor for a company in perth and was wondering if im correct, we are welding a 2" thredolet onto a 2" pipe as you can imagine is wraps around the pipe a bit, im reading the spec(b31.3) as 1.4 times the thickness of the pipe run thickness, i dont want to over weld it the fitting is a sp97 

[Hareesh K V]

Dear Sir,

Please refer ASME B31.3 latest edition regarding the same.  (If your design code is ASME B31.3)

Regards, 

Hareesh K V

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[munee...@gmail.com]

Yes agreed, basically there’s always been a debate between company and contractors, anyhow in most stringent case root fusion should be visualized 100%, if you go with contractors or sub-contractors inspection, definitely Olets will least have fusion and in many case you will find unfused, as a matter of fact i do visualize the outer part olet and contemplate on my own acceptance if i feel the outside deposition is enough or need some pass, if not i will definitely ask the guys to fill or i make punch regardless of fabrication, but again i am telling you in my surveillance, i never leave Olets root confirmation then to outside filling.

 

Basically, prime or sub both will avoid this as cost impact and ask the reference, anyhow controlling is not a matter just by codes, as special quality man takes the control wherever by his means regardless of code.

 

So for me these both have to meet the requirements, inside and outside.

 

Definitely, distortion acts big scenario here, in my last project contractor had so much trouble with me just because of distortion especially in this scenario where we have olets, so the problem is not just good tactical welders but also design of selecting thinner membranes and to set a standard on OLETS, we hope have a R&D and with setting standards with precise requirement.

5.1.1 When wall thickness ratio of joined pipes is less than or equal to 1.5, joint design details shall comply with the respective ASME B31 design code.
5.1.2 When wall thickness ratio of joined pipes is greater than 1.5, end preparations and geometry shall comply with ASME B16.25 “Butt Welding Ends.”
5.1.3 For all four piping codes stated in paragraph 5.1.2 above, refer to Figure 434.8.6(a)-(2) in ASME B31.4 or Figure 15 in ASME B31.8 for graphic details of joint designs.
5.1.4 When the wall thickness of the fitting or pipe at the welding end exceeds the wall thickness of the matching pipe resulting in an unequal external and/or internal diameters, the welded joint design shall comply with Figure 434.8.6(a)-(2) of ASME B31.4 (regardless of the design code).

Design and pressure rating of ASTM A234 and ASTM A420 fittings shall be established by proof testing per ASME B16.9 Section 9 or by mathematical stress analysis per ASME B31.3 Section 304.
5.1.2 Design and pressure rating of MSS SP-75 fittings shall be established by proof testing per MSS SP-75 or by mathematical stress analysis per ASME B31.3 Section 304. No portion of elbows shall be thinner that the minimum wall thickness of the mating pipe.
5.13 A drawing will be prepared for all fittings showing the overall dimensions including the required thicknesses in all areas.

Circumferential Welds
Circumferential welds are not allowed except to attach extensions such as those mentioned in Paragraph 5.4 and straight tangent ends that are specified in the purchase order. Circumferential welds are never allowed in the crotch area

The branch outlet of tees shall be extruded or forged to the run and shall have a smoothly curved transition between run and branch. Welded-on branch connections (set-on or stub-in) are prohibited. However, lengthening of an extruded outlet by means of a circumferential weld in the cylindrical part of the branch will be permitted.
When tees are fabricated from plate, the weld seams shall be parallel to the axes of the run and the branch.

Visual Examination and Dimensional Check
General appearance, workmanship and fit-up shall be acceptable in accordance with ASME B31.3 Paragraph 344.2. Weld surfaces shall show a smooth contour. Dimensions of the fitting shall be checked against ASME B16.9, MSS SP-75 or approved Vendor's Drawings.

Regards,

M.Muneeb

---

[Shyam Krishnan]

Dear All,

I would like to explain my experience on Root fusion of Weld Olets.I faced similar problem that during inspection ,we could see in complete root fusion at olets. (Process-GTAW+SMAW). Which  have solved using Gas lens in TIG Torch, so that it allows more Tungsten electrode extension due to lamellar flow of argon Gas. even in smaller Weldolets has been taken trails and established the parameters including tungsten extension.Welders are also given much training to get desired results.Some times the outlet is small like 1/2 '' , root fusion has been checked via portable boroscope which can be connected to mobile phone.

Thanks &regards

Shyam Krishnan A P

[sandeep kumar]

Thanks Mr. Raghuram for sharing obviously most commonly inspected weld joint in pipeline but easily to be ignored by many inspectors. 

This same issue I faced in past while doing visual inspection & I had to en-compose additional measures such as:

1. Ensure a weld penetration higher the minimum WT of the weldolet.  

2. Smooth weld transition for fillet welds & no concave fillet welds were accepted, preferably convex surface.

3. Train welders, inspectors about the importance of minimum weld size requirements for fillet welds and then how to check the size in case of weldolet.

4. Root penetration inspections of welds.

This is apart from code reference but the basic that must be put in control to eliminate weld joints failures.

Thanks & regards

Sandeep Kumar