What is the minimum distance between two welding joints?

[polka]

Is there anyone knows this? any idea?

[coverall]

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

[gateaux_boy]

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

[cpchonburi]

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

[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.

[victorlachica]

50mm from toe to toe. this is the HAZ

[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,

[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

[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?

[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?

[polka]

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

[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