This article highlights the timelines for releasing the second generation of the Eurocodes in the evolution program of the Eurocodes structural codes and UK strategy to implementing the expected changes.
The initial article in this update series on the second-generation Eurocodes detailed the goals and current progress of the Eurocodes evolution programme, particularly highlighting European-level activities (See: Eurocode Evolution-What to Expect from the Second Generation).
This follow-up article presents the most recent advancements, emphasizing the national implementation in the UK. It specifically discusses the established common European framework for publishing the second-generation Eurocodes and outlines the UK’s strategy for publication within this framework, including the creation and release of the UK National Annexes.
Timeline for Publication and Transition
The European framework for publication and transition of the second-generation Eurocodes is overseen by the CEN Technical Committee 250 (CEN/TC 250). CEN, the European Committee for Standardization, comprises 34 full National Standardization Body (NSB) members, which include the British Standards Institution (BSI). All CEN members operate under CEN rules, and CEN standards, referred to as ENs (European Standards), are developed in accordance with CEN’s Internal Regulations.
Upon the successful approval of a new standard through its Formal Vote, the CEN Internal Regulations Part 2 define three key dates:
- Date of Availability (DAV): the date when the definitive text of an approved EN is distributed to NSBs by CEN.
- Date of publication (DoP): the latest date by which an EN has to be implemented at the national level by publication of an identical national standard or by endorsement.
- Date of withdrawal (DoW): the latest date by which national standards conflicting with a new EN have to be withdrawn.
In the context of the second-generation Eurocodes, it’s important to explain the meaning of the DoW. Although each second-generation Eurocode is assigned a DoW, the ‘national standard conflicting with a new EN’ in this case is the corresponding first-generation Eurocode. Thus, the DoW for a second-generation Eurocode actually signifies the latest date by which the corresponding first-generation Eurocode must be withdrawn by all NSBs.
Recognizing the interdependent nature of the Eurocodes suite, CEN/TC 250 acknowledged the necessity for a coordinated framework regarding the treatment of the DoP and DoW across all second-generation Eurocodes. Discussions within CEN/TC 250 suggested that different countries are likely to adopt varying approaches to the transition and implementation of the second-generation suite, influenced by national regulations and industry preferences.
Therefore, CEN/TC 250 agreed upon a set of overarching principles for the publication of the second-generation Eurocodes, including:
- Ensuring a fully compatible suite of standards is available at all times for use by industry by setting an appropriate DoP and DoW2.
- Making new and revised Eurocode parts available to NSBs (DAV) as early as possible2.
- Ensuring sufficient time is available between DAV and DoP/ DoW for the development of National Annexes2.
- Ensuring sufficient time is available between DAV and DoP/ DoW to allow for the withdrawal of any conflicting national standards and to update supporting industry guidance material2.
While for CEN standards, the DoP and DoW are usually set automatically based on elapsed time post-DAV, it was evident from that this approach would not meet CEN/TC 250’s agreed principles due to the staggered approvals of the second-generation Eurocode parts over approximately four years. This would require the withdrawal of some first-generation Eurocodes before all second-generation Eurocodes had been published, resulting in an incompatible suite of standards for industry use.
A different approach was therefore proposed: one that provided European consistency of DAV, DoP, and DoW, satisfied CEN/TC 250’s agreed principles, and accommodated necessary differences in national implementation approaches.
To this end, CEN’s Technical Board agreed upon a special derogation for the second-generation Eurocodes, allowing a single common DoP and DoW to be set for all second-generation Eurocode parts, akin to the March 2010 DoW date used for all first-generation Eurocodes.
It’s essential to emphasize that the DoP and DoW establish the most recent deadlines. Establishing a unified and consistent DoP and DoW for all second-generation Eurocodes doesn’t prevent NSBs from implementing them sooner. It allows each NSB the flexibility to adopt their preferred national strategy (such as a ‘big bang’ approach, ‘package-based’ transition, or selective early implementation of specific Eurocode parts) within the overall timeframe set by the DoP and DoW backstop dates.
Throughout the development of the second-generation Eurocodes, CEN/TC 250 has established targets and is actively monitoring progress against a comprehensive publication plan, tracking all stages of the development process for each Eurocode part. Consequently, in 2020, CEN/TC 250 set the target date of October 2025 to approve, via Formal Votes, the final second-generation EN parts developed under EC Mandate M/515.
Over the past four years, CEN/TC 250 has remained committed to its overall program. The approval of the first second-generation Eurocode part (EN 1996-1-13) via Formal Vote occurred in October 2021, and it was made available to NSBs in April 2022. CEN/TC 250 is still on track to meet its final Formal Vote deadline of October 2025.
A final Formal Vote date of October 2025 corresponds to a final DAV of March 2026. CEN/TC 250 has agreed that a suitable minimum time between DAV and DoP is 18 months, and the time required between DoP and DoW is six months. Based on this, the end of September 2027 and the end of March 2028 have been designated as the ‘backstop’ DoP and DoW dates to be used for all second-generation Eurocodes. For all Eurocode parts that receive approval by Formal Vote before October 2025, the time between DAV and DoP will exceed 18 months.
As outlined in Figure 1, the subsequent comprehensive publication framework across Europe was collectively agreed upon and approved by CEN’s Technical Board:
- The definitive text of second-generation Eurocode parts in the official language versions will be distributed by CEN to NSBs as soon as possible after Formal Vote and no later than 30 March 2026 (DAV).
- All second-generation EN Eurocodes will have a DoP of 30 September 2027.
- All second-generation EN Eurocodes will have a DoW of 30 March 2028.
Developments within the UK
In the UK, the responsibility for the Eurocodes lies with two BSI committees: B/525, which handles buildings and civil engineering structures, and B/526, which handles geotechnical design. To help with the transition to the second-generation Eurocodes and to guide the strategic planning and delivery of UK Eurocodes projects, BSI has formed the Eurocode Strategic Steering Group (ESSG) (B/525/-/6), including the Chairs of B/525 and B/526.
B/525 and B/526 have agreed on the approach to publishing the second-generation Eurocodes in the UK. This approach aligns with the European framework for publication and reflects UK regulatory practice. The details are outlined in the UK National Foreword to each second-generation Eurocode part (for example, see the National Foreword to BS EN 1996-1-1:20223).
Typically, National Forewords contain background and procedural information, which, while important, doesn’t directly impact day-to-day use of a standard. However, this isn’t the case for the second-generation Eurocodes. It’s crucial that designers are familiar with and understand the UK National Forewords to the second-generation Eurocodes.
The UK National Foreword explains that the second-generation EN Eurocodes are expected to be published in the UK between 2023 and 2026. It further explains that these standards are being published by BSI as soon as possible after they are made available by CEN to allow users to prepare for the transition from the first-generation to the second-generation. Therefore, the UK is choosing to accelerate the Declaration of Performance (DoP) significantly ahead of the European backstop date of 30 September 2027.
The Date of Withdrawal (DoW) is also specified in the National Foreword, aligned with the European backstop date. Specifically, the National Foreword to each second-generation Eurocode part will state that the corresponding first-generation Eurocode part will be withdrawn at the end of March 2028.
It was acknowledged that the period between the publication of a second-generation Eurocode part and the withdrawal of the corresponding first-generation Eurocode could create a period of coexistence, leading to a risk of confusion among designers about which version to use.
The UK National Foreword addresses this risk by stating clearly that until March 30, 2028, standards ‘should be considered as the applicable standards for building and civil engineering works constructed in the UK unless otherwise specified by the relevant authority or in the specification for a particular project’. Extended periods of coexistence are unusual for standards, so the terminology used by CEN and National Standards Bodies to explain the status of standards may not intuitively account for such a possibility.
Thus, designers may encounter designations such as ‘current, under review’ or ‘current, superseded’ for the status of first-generation Eurocodes, whereas second-generation Eurocodes are typically labeled as ‘current’ only.
The crucial point is that until the end of March 2028, both first- and second-generation Eurocodes have the status of ‘current’, although the first-generation documents are given a special ‘current’ status indicating they will be withdrawn on a defined date after the corresponding second-generation Eurocode is published.
The fact that the second-generation Eurocodes are also ‘current’ is recognized in the UK National Foreword. Although generally, the first-generation standards should be considered applicable until the end of March 2028, the UK National Foreword further states that the use of provisions in the second-generation Eurocodes in conjunction with first-generation Eurocodes ‘is not precluded’.
However, it is emphasized that the use of provisions in the second-generation Eurocodes alongside first-generation Eurocodes ‘should be undertaken with care and should only be done when users are satisfied that it will not result in a lower level of reliability than the minimum level set in the first-generation Eurocodes and associated UK National Annexes’.
This statement places an obligation on designers to ensure the appropriateness of using provisions from the second-generation Eurocodes alongside the first-generation ones. It’s hoped that authoritative industry bodies will develop interim guidance to assist designers and approval authorities, especially in cases where the second-generation Eurocodes cover matters not addressed in the first-generation standards, thus offering potential benefits in using this new content.
The UK National Annexes
National Annexes are crucial for implementing the Eurocodes nationally. They specify the national choices allowed by the Eurocodes, and the UK National Annexes detail these decisions for UK building and civil engineering works.
The development of these National Annexes for the second-generation Eurocodes is handled by BSI Committees B/525 and B/526, often delegating the work to specialist subcommittees.
Preliminary work on these National Annexes usually starts as soon as a stable European draft is available, typically a CEN Enquiry draft. However, the National Annex can’t be finalized until after a standard’s final version is approved through a Formal Vote. As a result, the publication of UK National Annexes will inevitably lag behind the publication of each BS EN Eurocode part.
The second-generation National Annexes will be significantly improved over the first-generation ones. ESSG and BSI have created comprehensive guidelines to enhance ease of use and address inconsistencies in style found in the first-generation UK National Annexes.
One key improvement is the inclusion of complementary information. For the first-generation Eurocodes, National Annexes could only reference non-contradictory complementary information (NCCI) published separately. This condition has been relaxed by CEN/TC 250, allowing complementary information to be included directly in the second-generation National Annexes, as long as it doesn’t alter or contradict any provisions of the Eurocodes.
The UK plans to take advantage of this change, adding complementary information to National Annexes where it significantly enhances usability. However, to avoid an overload of information, guidelines have been set on what can and cannot be included. Exclusions cover general background information and interpretations of Eurocode clauses.
Also See: Principles of Design to the Eurocode
Sources & Citations
- S. Denton & M. Angelino (2021) ‘Eurocode Evolution – Preparing for the Second Generation.’ Professional Guidance Notes. The Structural Engineer 101(12).
- S. Denton & M. Angelino (2021) ‘Eurocode Evolution – Latest Development and the UK Approach.’ Professional Guidance Notes. The Structural Engineer 106(3).
- Second Generation of the Eurocodes – What’s new. The European Commission reports. (Available: Second generation of the Eurocodes: what is new?| Eurocodes: Building the future (europa.eu)
