#  > Petroleum Industry Zone >  > Mechanical Engineering >  >  >  What is the minimum distance between two welding joints?

## polka

Is there anyone knows this? any idea?

See More: What is the minimum distance between two welding joints?

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## coverall

If you are talking for the pipe, minimum length can't be shorter than pipe diameter.

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## gateaux_boy

It call heat effect zone, please see in ASME B31.3 has explain about it.

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## cpchonburi

Try ASME SC-VIII-1,UW9(d)

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## riksha

Polka

Commonly there are not-written rules in piping.
Generally we use 2D or 5x Pipe thk.

for 2D, no problem appear when we applied to small NPS, but could have problem to bigger NPS.

It happen also to 5x Pipe thk, would problem to smaller schedule.

The point how to determine minimum distance is :
Just follow Specification (client spec) or looking for Piping Engineer's advice.

The basic reason is just there is a Heat Affected Zone in every weld joint & we must avoid this from Intersecting to prevent Local Hardening & other effects.

Hope this will help you.

Riksha


ps : if you think this is useful, please simply click "Thanks" button below.

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## victorlachica

50mm from toe to toe. this is the HAZ

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## Ali366

> Is there anyone knows this? any idea?



Polka,

What is your design or construction code?

Where is the welded joint? Is it in a pressure equipment, say piping, pressure vessel, etc. or in a storage tank or steel structure?

If in a pressure equipment, is the weld joint a longitudinal weld or a circumferential joint?

What is the degree/type of NDT?

Cheers,

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## BornToSin

> Polka,
> 
> What is your design or construction code?
> 
> Where is the welded joint? Is it in a pressure equipment, say piping, pressure vessel, etc. or in a storage tank or steel structure?
> 
> If in a pressure equipment, is the weld joint a longitudinal weld or a circumferential joint?
> 
> What is the degree/type of NDT?Z



co-sign that questions for give an approtiate answer

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## polka

I want to put air release valf on pipe.Where should I put them? They should be installed the highest point but at the highest point there is welding joint of elbow. I can cut and put there my valf or I should avoid this joint.If I should avoid how many distance should I avoid from this joint? Same thing is also valid for the lowest point.This point is also on welding joint where should I put these valf.What is the standard for these places?

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## polka

Also there is spiral weldings on pipe.Is there any minimum distance to approach these welds? If I want to weld any other equipment to pipe can we cut these joints and weld them on it?

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## polka

none of these standards are telling that you can not cut a welding joint and put your  equipment there.

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## abhijit.koyande1987

Minimum distance between two weld point should be 11/2" (50 mm) or 5 times pipe or plate thickness which ever is more

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## losmoscas

I'm looking for your information about minimum distance between two weld joint should be 11/2" (50mm) or 5 times pipe diameter, but I could not find this information on any standard. Are there any standart are telling that this?

See More: What is the minimum distance between two welding joints?

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## abhijit.koyande1987

this as per ASME  Sec IX-welding code

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## polka

> Polka,
> 
> What is your design or construction code? Construction code Api 1104
> 
> Where is the welded joint? Is it in a pressure equipment, say piping, pressure vessel, etc. or in a storage tank or steel structure? These welds are for air release valves and for other components like valve,clappe or manholes
> 
> If in a pressure equipment, is the weld joint a longitudinal weld or a circumferential joint? Not a pressure equipment valves or clappes
> 
> What is the degree/type of NDT? 100% x-ray
> ...



I tried to answer your questions.

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## Lucas2008

I in your place. I will install a elbolet and valve the elbolet is a fittings that permit you install the branch in the elbow. this solution is not in the the highest point but i think it is a solution.
otherwise you must have minimum 50 mm at weld. this dimension is a thumb rule. The codes indicate the variables that you keep in mind for taht you can determinate this dimension.
Hope this will help you

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## tacka

50 mm is minimum, only if you dont have space, for pipes up to 4" i advise you to go 75-100 mm, and for diameters above 4" use 1x Pipe Dia.

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## yanda saputra

As per ASME B31.3 para 341.4.1.6.B " when a circumferential weld with an interesting longitudinal weld is examined, at least the adjacent 38mm(1.5 Inch) , of each interesting weld shall be Examined"

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## go6o

It depends also to the NDT.
For example when there is UT, need to have  min. 100mm distance...

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