Welding Certification, A Basic Guide 

The requirement for weld procedures and the coding of welders is specified in application standards such as:
  • BS 2971 Class 2 Arc Welding of Carbon Steel Pipework  {Gas Pressures less than 17 barg}
  • BS 2633 Class 1 Arc Welding of Carbon Steel Pipework 
  • BS 4677 Arc Welding Of Austenitic Steel Pipework. 
  • BS 806 Boiler Pipe Work (Refers to BS 2971 and BS 2633) 
  • PD 5500 Unfired Pressure Vessels (Formally BS5500) 
  • BS 2790 Shell Boilers 
  • BS 1113 Water Tube Boilers 
  • BS 5169 Air Receivers 
Application Standards
All the above application standards require welding procedures to EN ISO 15614 Part 1 (Formerly BSEN 288-3) and welders coded to BSEN 287 Part 1. Some applications of BS 2971 and BS 5169 permit welders to be qualified without procedures to BS 4872, a less stringent standard. 
The application standard may require tests in addition to those required by welding standards, for example most UK boiler and pressure vessel codes require all weld tensile tests for plate qualification above 10mm. 

UK pressure systems regulations
Items that come under the UK pressure systems regulations must be 'properly designed and constructed so as to prevent danger', and items that are repaired or modified should not give rise to danger. The Health and Safety Executive Guidance Booklet to the regulations interprets this statement as meaning the manufacture or repair of any item should be carried out to suitable codes and recommends the use of British Standards or other equivalent National Standards. 

European Pressure Equipment Directive
For inspection category 2 and above all welding procedures and welder qualifications have to be approved by a Notified Body (an Inspection Authority Notified by a European member country under the Directive), or a Third Party Organisation similarly approved under the Directive. All qualifications approved by these organisations have to be accepted by all parties for work carried out under the directive providing they are suitable for the application and technically correct. 

Welding Procedure Specifications
This is a simple instruction sheet giving details of how the weld is to be performed, its purpose is to aid the planning and quality control of the welding operation. EN ISO 15609 (formerly EN288 Part 2) specifies the contents of such a specification in the form of a list of items that should be recorded, however only relevant information need be specified, for example only in the case of a procedure requiring heat input control would there be a necessity to quote travel speed or run out length for manual processes. 

A weld procedure specification may cover a range of thicknesses, diameters and materials, but the range must be specified and be compatible with the rest of the parameters on the document. I suggest that you produce a new WPS for each type of joint and keep to the ranges of thickness and diameters specified in the welding procedure standard. 

Welding Procedures
Welding procedures are required when it is necessary to demonstrate that your company has the ability to produce welds possessing the correct mechanical and metallurgical properties. 
A welding procedure must qualified in accordance with the requirements of an appropriate welding procedure standard such as EN ISO 15614 Part 1 as follows:- 
  1. Produce a welding procedure specification as stated above. 

  2.  
  3. Weld a test piece in accordance with the requirements of your specification. The joint set up, welding and visual examination of the completed weld should be witnessed by an Inspection Body. The details of the test such as the welding current, pre-heat etc., must be recorded during the test.

  4.  
  5. Once the welding is complete the test piece must be subject to destructive and non destructive examination such as radiography and mechanical tests as defined by the welding procedure standard. This work can be carried out in any laboratory but the Inspection Body may require to witness the tests and view any radiographs. 

  6.  
  7. If the test is successful you or the test body complete the appropriate documents which the test bodies surveyor signs and endorses. The necessary documents are as follows:- 
E1 Welding Procedure Approval Test Certificate
This is the front sheet and only gives details of what the procedure can be used for. i.e. its range of approval. 
E2  Details Of Weld Test
This gives details of what actually took place during the test weld it is similar to a WPS but should not include ranges of welding parameters. 
E3 Test Results
Details of NDT and Mechanical testing Results 
E4 Welder Approval Test Certificate. 
This is the welder approval part of the qualification.
Note The E1, E2, E3, E4 designations are used by some Inspection Authorities to refer to the individual forms. Examples of these forms are given in annexes of EN ISO 15614 and EN287.

Forms E1, E2, E3 may be referred to as the WPAR (Welding Procedure Approval Record) or WPQR (Weld Procedure Qualification Record).

In general a new welding procedure must be qualified for each of the following changes subject to the individual requirements of the appropriate standard used:- 
  • Change in parent material type. 
  • Change of welding process 
  • The diameter range for pipe given by the welding standard is exceeded. Typically 0.5xD to 2xD. 
  • The thickness range is exceeded. Typically 0.5xt to 2xt. 
  • Any other change required by the welding standard. 
Welder Approval
Once the procedure is approved it is necessary to demonstrate that all your welders working to it have the required knowledge and skill to put down a clean sound weld. If the welder has satisfactorily completed the procedure test then he is automatically approved but each additional welder must be approved by completing an approval test to an appropriate standard such as EN 287 part 1 as follows:- 
    Complete a weld test as stated in 2) above. The test should simulate production conditions and the welding position should be the position that the production welds are to be made in or one more severe
    For maximum positional approval a pipe inclined at 45 degrees (referred to as the 6G position) approves all positions except vertical down. 

    Test the completed weld in accordance with the relevant standard to ensure that the weld is clean and fully fused.
    For a butt weld this is normally a visual examination followed by radiography. 

    Once the test is completed the E4 form has to be completed by you or the test body and signed by the test bodies surveyor. 

    Note The above changes that require a new welding procedure may also apply to the welders approval, refer to the standard for precise details. 
ASME 9
ASME 9 as far as the pressurised systems regulations are concerned can be considered as equivalent to EN ISO 15614-1 /EN 287. However it may not be contractually acceptable. The advantage in using ASME is that generally fewer procedure tests are required particularly when welding pipework. 

Welder Approval Without A procedure
BS 4872 is for the qualification of welders where a weld procedure is not required either by the application standard that governs the quality of production welds or by contractual agreement. Typically applied per BS2971 for welding of boiler pipework less than 17 bar g and 200°C. Basically the same rules mentioned above for the welder approval apply. 

Acceptance Standards
In general welds must show a neat workman like appearance. The root must be fully fused along the entire length of the weld, the profile of the cap should blend in smoothly with the parent material and the weld should be significantly free from imperfections. Reference should be made to the acceptance standard for precise details. 

Its a good idear to ensure that you can achieve the appropriate standard before you call in an Inspection Body. Penetration defects and lack of fusion can often be easily detected by sectioning welds and bending them. 
 
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  Page last updated 21 March 2008