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
From: Hareesh K VDate: 2018-10-27 06:32Subject: Re: [MW:28508] Re: 1307] Re: 1305] welding reqd on a weldoletDear Sir,Please refer ASME B31.3 latest edition regarding the same. (If your design code is ASME B31.3)Regards,Hareesh K V--On Fri, Oct 26, 2018, 11:42 AM 'Dom' via Materials & Welding <materials-welding@googlegroups.com> wrote: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--
On Friday, 14 November 2008 17:49:30 UTC+9, Bathula Raghuram (Mumbai - PIPING) 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-----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.
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
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
https://materials-welding.blogspot.com/
https://www.linkedin.com/groups/122787
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