Minimum Distance Between Welds as per International Codes and Standards

Welding is a fabrication process that permanently joins two or more pieces of metal together. It is one of the most common joining techniques used in the manufacturing industry and is used to create products of all shapes and sizes. Welding involves the use of heat and/or pressure to melt the two pieces of metal together and then fuse them. There are several different types of welding processes, including arc welding, MIG welding, TIG welding, and oxy-acetylene welding. Each process has its own advantages and disadvantages, so it is important to select the most appropriate process for the particular application.

Arc welding process is an arc welding process in which an electric arc is used to produce coalescence of metals. The process uses a consumable electrode that is continuously fed into the weld joint. The arc is generated between the electrode and the workpiece, which produces an intense heat that melts the metals and causes them to join together. The process can be used on a variety of metals and alloys and is used to weld components in a wide range of industries.

Minimum Distance Between Welds as per International Codes and Standards

The minimum distance between welds depends on the type of welding process being used. Generally, the minimum distance between welds is determined by the type of material being welded, joint design, and welding process parameters. For example, the minimum distance between fillet welds is typically 1/16 inch (1.6 mm). However, this can vary depending on the material, joint design and welding process.

Standard / Spec.	Minimum Distance Between Welds
ASME SEC VIII Pressure Vessel Code-2017	Longitudinal welds 5t unless circumferential welds are tested by RT up to 4" on each side If impact test as per UCS-66 required the min distance cannot be exempted by RT. No Limit for Circumferential
ASME IX. 2013	Longitudinal welds 5t unless circumferential welds are tested by RT up to 4" on each side In vessels with two or more courses, longitudinal joints of adjacent courses staggered or separated 5t, t= thickness of thicker plate.
ASME B31.3 - 2016	5t or 30 degrees off for Longitudinal. No Limit for Circumferential
ASME B 31.4-2016 ASME B31.8 - 2016	1/2 ND between miter crotches Consideration shall be given to the toughness characteristics and quality of all seam welds in repair welds.
API 5L/ISO 3183-2012	Longitudinal: 50-200 mm Circumferential. 1500mm
API 650-2014	5t between vertical welds
BS 2633-2006	4t, where t= nominal thickness of the pipe
BS 4515-2006	4t, where t= pipe thickness
BS 2971-2009	Agreed by parties
BS PD 5500 - 2014	Longitudinal welds, 4t or 100mm
AS 4458	Circumferential 4t or 30 mm Non-pressure parts: the lower of 3t or 40 mm The exception is made when the first weld is subject to PWHT
AS 4041-2006	4t or 40 mm
EN12952-5 -2001	But weld of tubes: 2D for t<250 .where D = Outside diameter of tube 500 for t>250; where t= Drum or Head thickness Spacing between attachment weld and Main joint weld min 40mm. Branch opening and Main weld: 2t for t<25 50 for t>25 If not practical, cross completely and ground flush and perform NDT
TOTAL GSEPPVV 171-2012	Longitudinal 30 degree staggered. Circumferential: 500mm
SHELL DEP 61.40.20.30-2011	Circumferential: lD or 500mm Between branch/attachment and girth 4t or 100mm
ARAMCO 32-SAMSS-004-2008	Welds of shell-head and head-skirt to be separated min 1 inch
ARAMCO SAES-W-012-2008	Longitudinal welds of adjacent pipe joints shall be 100 mm. Butt welds 20 mm or 3t whichever is greater.