The UK's #1 coded welding company

Nationwide, Code-Compliant and Audit-Ready

In hazardous fabrication and construction environments a weld can be the difference between success and failure on multi-million pound projects or compromise the very existence of an entire facility. In addition, in areas related to pressure systems, structural steel, process equipment, etc., “good enough” is never good enough; you require demonstrable, traceable, documented quality – coded welding by qualified individuals using approved procedures and witnessed by competent inspectors with proven results through testing.

At Kee Engineering we are able to offer nationwide coded welding services that have complete end-to-end quality assurance. We send out our coded welder teams to carry out the welding, develop and control the welding procedures, coordinate welding inspector oversight, arrange the testing, and deliver to you audit-ready documentation from start to finish.

All of our welders are coded, meaning that every one of our coded welders has undertaken an exam in a welding process using a specific method (Welder Approval Test).

Coded welding - explained

Coded welding – also referred to as code compliant welding – is welding that has been performed by a welder that has successfully completed a formal Welder Approval Test to a recognized welding code. Each test approval is specific and binds the welder to a specific welding process, material group and thickness range, and a specific welding configuration or weld configuration.

The welder’s ability to produce welds that meet the required specification, consistently and repetitively under the same job site conditions, is proven through both theoretical and practical tests/exams.

Therefore, this is welding certification based on the welder demonstrating that their skills are sufficient to meet the specified and industry standard requirements.

Find out more by reading our What is Coded Welding article.

Which code applies?

Typically in the UK/Europe coded welding is referenced to recognized standards and/or specific specifications (e.g.):

Additionally, projects may reference:

ISO 9606-2 for aluminum
ISO 3834 for Quality Requirements for Fusion Welding
EN 1090 for structural steel (Execution Class EXC2 or EXC3) for CE/UKCA marking
and internationally may reference ASME IX from the American Society of Mechanical Engineers and the American Welding Society (AWS D1.1) for structural steel.

Irrespective of the code used, the principle remains the same – qualify the individual performing the welding, qualify the procedure, and verify the results of the welding process through inspection and testing to the applicable standard(s), using the appropriate industry standards and requirements.

For pressure equipment many European scopes are aligned to the Pressure Equipment Directive.

Why code compliance is important on actual projects

While a weld may appear to be visually acceptable it can conceal a lack of fusion, porosity or inclusions which will not become evident until subjected to pressure, heat, or vibration. In addition, on pressure vessels, pressure piping, and structurally significant steel connections, hidden defects can place a risk to life, program, and budget.

By employing a coded welding company the risks associated with weld failures are eliminated and assists in meeting your client’s specifications, third-party inspection requirements, and those of your insurers.

Reliability – lower in-service failure rates and extended asset lifespan. When constructed in accordance with a welding code and examined against well-defined acceptance criteria, there will be no risk to life.
Programme certainty – fewer non-conforming products, less rework, and shorter inspection times due to the implementation of adequate QA/QC controls.
Compliance and insurance – code compliance meets the needs of your clients, auditors, and insurers through a clear audit trail and manufacturer’s data records.
Reputation – consistent quality from a certified welding company builds confidence in the regulated industries and safety-critical applications.

Pressure vessel welding and process pipework

Any equipment that operates at pressure or temperature has zero tolerance for weld failure. Spools and headers, heat exchangers, and storage tanks are examples of process equipment that should be coded welded with complete traceability. Examples of typical specifications include P-number groupings, impact-tested materials, and PWHT as necessary.

Structural steel and industrial infrastructure

Welded connections in structures, such as buildings, bridges, stadia, and heavy plant are reliant upon being capable of providing documented assurance that they will functionally perform under load for decades. Coded welding is the only way to ensure documented assurance of the performance of these connections.

Offshore, energy and storage

Offshore Oil and Gas, Renewables, and Bulk Storage operate in corrosive, high stress environments. Foundations, risers, subsea piping, and large tank fabrications require coded welding to ensure durability and continued operation. Duplex and Super duplex Stainless Steels, Nickel Alloys, and Corrosion Resistant Overlays often require strict control of Heat Input.

Repair, Modify, and Extend Life

Repairs to pressure systems, modifications to process lines, and life extension repairs to existing equipment require the same level of control as original construction. Coded welding using an approved procedure during repairs to pressure systems maintains system integrity while minimizing downtime. Controlled sequencing of welding, hot work permits, and isolation plans protect operational facilities from potential hazards during repair operations.

Our Coded Welding System

The four key elements of our welding process, which provide quality welds at all times, are:

Qualified people - the coded welder

All of our Coded Welders have their Welder Approval (which is linked to Process, Position, Material Group and Thickness Range) and this approval is maintained via Continuity Monitoring, Re-validation and Practical Tests.

All of our Coded Welders have demonstrated both theoretical knowledge and practical skills in accordance with the Welding Code and can therefore perform the exact weld that is specified for each task. We maintain records of welder identity, continuity logs and renewal dates to ensure the welder’s approval is always valid.

Approved welding procedures - WPS and PQR

Each and every production weld is performed according to an Approved Welding Procedure Specification. The WPS specifies the essential variables such as Base Materials, Filler Wire/Filler Metal, Pre-heat Temperature, Inter-pass Temperature, Travel Speed, Heat Input etc.

The Procedure is proven by a Procedure Qualification Record (PQR) which details the test pieces and the associated Non-Destructive (NDT) and Destructive Testing. Many Clients refer to the WPQR as the supporting document to the WPS. The WPS provides the framework to produce consistent and repeatable quality welds across shifts and locations.

Quality Control / Inspection

There is visual inspection on an ongoing basis. A qualified welding inspector monitors the quality of the fit-up, root, cap, bead profile and there are no surface breaking defects and WPS.

There are hold points, surveillance and welder identification in place to ensure that every joint can be traced back to the correct Coded Welder, WPS and Material.

Non-destructive testing and verification

The internal integrity of the welded component is proven by NDT as per the Service and Code requirements. The NDT methods employed include Magnetic Particle Testing, Dye Penetrant Testing, Ultrasonic Testing and Radiographic Testing.

In addition, we can also arrange Positive Material Identification, Hardness Testing and Ferrite Checks as necessary. Where necessary, we can also employ Phased Array Ultrasonic Testing or Time Of Flight Diffraction for thicker sections.

The results of the NDT testing are recorded against the Weld Map to facilitate traceability and to demonstrate compliance to the Standard. As necessary, we will coordinate Hydrostatic Testing and Pressure Testing to demonstrate Leak Tightness of Pressure Components.

Materials, Positions and Welding Processes we use

The welding processes we utilise include TIG, MIG/MAG, FCAW and MMA. We also use Orbital Pipe where the process permits. Where possible, we also utilise automated or semi-automatic techniques to enhance repeatability.

Materials – Mild Steel, Carbon Steel, Low Alloy Steels, Stainless Steels (including Duplex and Super Duplex), Nickel Alloys and Aluminium. We also undertake Dissimilar Joints where compatible filler and procedures exist.

Positions – Plate and Pipe in PA, PB, PC, PD, PE, PF and 1G to 6G.

Thickness Ranges – Thin Gauge Platework to Heavy Wall Pressure Components, with appropriate backing, purge control and heat input control.

We frequently work on Hygienic Pipework, Fatigue Sensitive Details, Corrosion Resistant Applications and Specific Joint Designs that require tight control of the process and methods chosen. Typical Root Techniques include TIG Root with MIG/MAG Fill and Cap, Stringer or Weave Beads as specified and Purge Dams for Stainless Pipe.

Handover Documentation provided

While compliance is proven in metal, compliance is also proven on paper. Your Turn Over Pack will be prepared for Audit and will contain:

Welding Procedure Specifications with Procedure Qualification Records or WPQRs.
Welder Qualification Certificates, Welder Approval Continuity and Assessment Records.
Material Certificates and Heat Numbers for Full Traceability and Batch Control.
Weld Maps Linking Joints to Personnel, Procedure and Materials.
Inspection and NDT Reports detailing Acceptance Criteria and Results (VT, MT, PT, UT or RT as specified).
Fit-Up, Pre-Hot and Inter Pass Temperature Records as required.
Heat Treatment Charts for PWHT as necessary.
Calibration Certificates for Measuring Devices and Welding Sets.
Manufacturers Data Records (MDRs) and Inspection Test Plans (ITPs) to the particular specification.
Where required, ISO 3834 Quality Records and EN 1090 Execution Class documentation for Structural Work.

National Mobilisation Capability

Success is built into preparation. We will mobilise to your programme, site constraints and permit regimes and then deploy the correct coded welder with the correct approvals, calibrated equipment and consumables.

Our national footprint enables us to respond quickly, scale up and maintain quality wherever you are in the country – fabrication shop, live plant or remote site. Site rams, inductions, confined space and hot-work controls are included in our method statements to enable safe and compliant delivery. We will coordinate permit to work, lock out tag out and client hold points as part of the plan.

How long does coded welding approval last

Welder Approval is maintained by performing welds within the approved range. Many approvals require six-monthly sign-off and periodic revalidation. If Continuity Breaks or if you need a different range, you may need to re-test. Our Quality Team monitor Continuity to ensure that each Coded Welder remains Current for the Jobs we Deliver. Where required, we can expand Scope by Adding Positions, Thickness Ranges or Materials to cover upcoming work.

Frequently used terms - quick reference

Coded Welding – Welding completed by a Coded Welder to a Recognised Welding Code with full documentation.
Coded Welder – A Welder who has passed Practical Tests and currently holds Welder Approval for a Defined Range.
Welding Code – The Rule Set e.g. BS EN, EN ISO, ASME IX or AWS D1.1 that defines Qualification and Acceptance Criteria.
Welding Procedures – WPS and PQR/WPQR that Control Variables to ensure Consistent Welds to the Specification.
Welding Inspector – The Competent Person who verifies Compliance, Acceptance Criteria and Traceability.
Testing – NDT and Mechanical Testing that Prove Internal and External Quality to the Required Standard. Examples of Testing include Bend Tests and Impact Tests where specified.

Why choose Kee Engineering for coded welding

Experienced Coded Welders with Current Approvals for TIG, MIG/MAG, FCAW and MMA
Procedure Development and Qualification to BS EN, EN ISO, ASME IX and relevant ISO or BS Standards, including PED Aligned Pressure Scopes
Welding Inspector Oversight, Welder Identification and Full Weld Mapping for Clear Traceability
NDT to the Service and Code, UT and RT for Pressure Vessels and Pressure Pipework, with MT and PT for Surface Breaking Defects
Full Turn Over Packs for Client, Insurer and Regulatory Audits, Including ITPs and MDRs
National Mobilisation, Out of Hours and Shutdown Support with Responsive Resourcing
Sector Experience in Oil and Gas, Power, Renewables, Water, Pharmaceutical, Food, Construction and Heavy Industry in the UK

Example Scopes and Materials/Methods

A typical Kee Engineering scope would include carbon and mild steel spools in 5g, with TIG root and MIG/MAG fill and cap; stainless pipework in hygienic service using tig with purge control; aluminium fabrications using a suitable welding method for thin-gauge sections; and/or nickel alloy work where a particular specification demands tight control of heat input and inter pass temperature.

Each job is matched to the correct coded welder approvals and controlled through the appropriate wps with documented essential variables.

Work with Kee Engineering

Your critical assets deserve proven, documented weld quality. Kee Engineering delivers coded welding that is compliant by design – qualified people, approved procedures, rigorous inspection and testing and clear documentation from start to finish. For pressure vessels, structural steel, storage tanks and process pipework, we help you meet the welding code efficiently and to the highest quality.

Please contact our team for a no obligation discussion about your project and we will propose the right approach, the right approvals and a mobilisation plan that protects your programme and your reputation.