National foreword

This British Standard is the UK implementation of ISO 20895:2026.

The UK participation in its preparation was entrusted to Technical Committee CB/203, Design & execution of steel structures.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2026.

Foreword

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This document was prepared by Technical Committee ISO/TC 167, Steel and aluminium structures.

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Introduction

Structural safety is needed in high public occupancy facilities, tall or large-scale structures, and other important facilities. Higher performance is needed for structures subjected to seismic actions. In the case of steel frame structures, integrity of welded joints determines the structural safety of these structures, because welding is often used with beam to column connections, joints of steel members, member assembly, etc. It is especially important to ensure the strength and toughness of the welds.

This document addresses the mechanical testing methods and acceptance criteria for weld metal and heat affected zones. These mechanical properties, coupled with appropriate designs for the seismic force resisting system, proper connection designs and detailing, as well as appropriate weld quality and inspection criteria are essential to ensuring the high structural safety of steel structures of seismic design.

This document specifies the target performance regarding the strength and toughness of welded joints in the acceptance criteria, but does not mention the means for realizing the performance. Rather, the document intends to present the performance-based standards, in recognition of diverse construction methods and the need to promote and disseminate new technologies.

1 Scope

This document defines two performance levels for welded joints, namely Basic Demand and Critical Demand, for longitudinal tensile strength of weld metals, impact toughness of weld metals and heat affected zones (HAZ) to suit the level of seismic performance specifications required for welded steel structures.

This document supplements the provisions of the standards or codes for welding procedure qualification in the application of new steel materials, welding consumables, or complex joints, for welds that require the performance of Basic or Critical Demands as specified by the engineer in the contract.

2 Normative references

3 Terms and definitions

4 Welded joints

4.1 Applicable structural performance

4.2 Mechanical properties of base metal

5 Mechanical testing

5.1 Type of testing

5.2 Test specimens

5.3 Testing procedure

6 Acceptance criteria

6.1 Basic Demand

6.2 Critical Demand

7 Re-testing

8 Test reports

Bibliography

BS ISO 20895:2026

Welded joints performance for seismic steel structures

Current

Published:

30 Apr 2026