POLICY GUIDELINES AND PROCEDURES FOR CEN/TC 250 STRUCTURAL EUROCODES

Transcription

1 Document: CEN/TC 250 N 250 F Ref: 7232: CEN/TC 250 To the Members of CEN/TC 250 Structural Eurocodes Date: 28 December 2003 POLICY GUIDELINES AND PROCEDURES FOR CEN/TC 250 STRUCTURAL EUROCODES NOTE 1 This document is an update of the original document N 250 dated 28 May 1997, revision A dated August 1999 and revision B dated September It has been specifically adapted for use during the CONVERSION STAGE from ENV to EN and is generally based on previously issued documents, CEN/TC 250 resolutions, updated CEN rules and comments and observations from Members. The main changes from the original version are revision of Section 7 (N 250 C), the inclusion of Annexes G, H, J, K (revised in N 250 C), L (revised in N 250 C), M and N (revised in N 250 C), the inclusion of Annex P in N 250 C and the conversion of the document into electronic format. As this is considered a "living" document the latter change will enable it to be loaded onto the CEN web-site which, in future, will aid regular updating. NOTE 2 This document should be made available to Convenors and members of Project Teams via Sub-Committee Secretariat. NOTE 3 This document has been applied in EN 1990 and EN , the first EN-Eurocodes. NOTE 4 Changes made subsequent to N250C are listed after the Foreword. Revisions: N Original 28 May 1997 Rev. A - August 1999 Rev. B - 22 August 2000 Rev C 23 November 2001 Rev D 8 May 2002 Rev D Rev 1 13 June 2002 Rev E 6 May 2003 Rev E Rev1 21 July 2003 Rev F 28 December 2003 CEN/TC 250 N250 F 28 December 2003 Page 1 of 77

2 Foreword to N 250 D (1) Version D of N 250 dated 8 May 2002 contains changes that focus on the conversion of ENVs to ENs. It is available at and supersedes version C dated 21 December 2001, that was also on the Website. The changes recognise the Commission s Guidance Paper L Application and use of Eurocodes, clarify several issues by revision or by new material and update specific guidance that has been superseded. The page after the Frontispiece summarises where the changes have been made. The detail in this Foreword is added to emphasise the importance of this version for the satisfactory completion of Eurocode parts on target. (2) Guidance Paper L (25 January 2002) expresses the common understanding of the Commission and the Member States of the Eurocode programme, and therefore complements N 250. In particular it sets out the purposes of Nationally Determined Parameters (2.1) and how they may be expressed in National Annexes (2.3), when so required by National Provisions. These recommendations correspond to those in the Foreword of EN 1990 and N 250 D (7.16). It is important to express the possibilities for national choices in the correct way, using EN 1990 as a model. Part 3 concerns the use of EN Eurocodes in technical specifications for structural products, a subject not generally developed in N 250 D, apart from 7.6. (3) The changes to the main text included in N 250 B were made to clauses in order to improve clarity, to align with Guidance Paper L and to assist user-friendliness. Clause 7.16 sets out the procedure for the removal of any boxed values used at the ENV stage. (4) Annex D Order voucher for phase 1 of conversions was deleted in N 250 C, as no longer relevant. (5) Annex E Conversion programme with target dates continues to refer to the latest version of CEN TC 250 N 455, so that the reader can access the latest current information on this topic. (6) Annex K Common Sections was revised substantially in N 250 C. The common Foreword is now covered by reference to EN Tables of recommended contents and model clauses cover sections 1 and 2. Examples of the application of the models are now included in N 250 D. Separate models and examples are included now for the fire parts, where it is necessary for them to differ. (7) Annex L Editorial style and form for the Eurocodes has been revised substantially to make it shorter and easier to follow, without altering the scope or intentions in N 250 B (22 August 2000). It now contains much more detailed guidance on editorial matters that was agreed in Detailed information on numbering, format and editing was approved at the ENV stage and remains valid, although not included in N 250. This additional information has been added to N 250. (8) Annex M Translations was out of date. It now reflects current agreements described in CEN BOSS at CEN/TC 250 N250 F 28 December 2003 Page 2 of 77

3 (9) Annex P Examples of the use of Nationally Determined Parameters (NDPs) and National Annexes describes the six types of information that may be given in a National Annex. It complements the framework given in Guidance Paper L. (10) Further amendments to N 250 will continue to be made direct to the website, which will indicate when amendments were last made. We would appreciate feedback on this procedure and on any further needs for clarification but it is important that the guidance is essentially settled so that consistency is achieved as the first Eurocode Parts are finalised in the near future. H Bossenmayer J F A Moore Chairman, CEN TC 250 Chairman, CEN TC 250 WG 1 NOTE N250 D Rev 1 contains the changes listed below. CEN/TC 250 N250 F 28 December 2003 Page 3 of 77

4 Changes implemented in N 250 D, May Chairmen s introduction added after title page 2. The insertion of this list before CONTENTS 3. Alignment of all text, as far as possible, with the CEN editorial style aligned with published Guidance Paper L 5. Examples of the use of common clauses 1 and 2 added to Annex K 6. Model clause for Fire Parts added to D in Annex K 7. Annex L revised to incorporate detailed editorial guidance agreed at ENV stage. 8. Annex M updated inline with BOSS guidance. 9. Annex P aligned with Guidance Paper L and an example added to Type 6 Changes implemented in N 250 D Rev 1, June Editorial corrections to 7.8 (3) 2. Annex L amended to include uses of informative Annexes 3. Annex M aligned with the latest guidance from CEN, as available on CEN/BOSS 4. Annex P edited to remain in line with Annex L. Changes implemented in N 250 E, May Annex C amended to reflect changes to titles and scopes of EN Eurocode Parts previously agreed by CEN TC Annex M amended to reflect the new responsibilities of TC/SC Secretariats for the three language versions for Formal Vote, as resolved by CEN TC 250 in Stockholm. 3. Annex P amended substantially to provide detailed guidance on the content of National Foreword and a National Annex, while retaining the examples (with minor editorial corrections). 4. A few outstanding editorial corrections. Changes implemented in N 250 E Rev 1, July Annex K edited to reflect revised common clause (2) for EN Eurocode fire Parts. Clauses aligned with CEN editorial style and reference to national regulations amended in common clause 1.3 (1). CEN/TC 250 N250 F 28 December 2003 Page 4 of 77

5 2. Annex L edited to distinguish examples more clearly and improve alignment with CEN style. Clause 5.2 (2) amended to clarify that an informative annex can be made normative only by national provisions. 3. Annex M edited to give fuller details of the procedure for translations, especially in relation to having three language versions for Formal Vote. 4. Annex N edited to combine the first two lists of TCs requiring liaison, together with additional TCs. 5. Annex P edited to improve clarity. Changes implemented in N 250 F 28 December This version of N 250 is shorter as a result of removing the contents of Annexes K, L and M to a separate document, N 600, to accommodate three-language versions of the common Foreword and the revised guidance on editorial style and translations. 2. It is anticipated that the titles of EN Eurocode Parts in Annex C will be rationalised during Formal Vote of the first material parts early in CEN/TC 250 N250 F 28 December 2003 Page 5 of 77

6 CEN/TC250 STRUCTURAL EUROCODES - POLICY GUIDELINES and PROCEDURES Contents 1. Introduction and purpose of guidelines 8 2. The objectives of the Eurocodes and their status 8 3. The role of CEN/TC250 (and its elements.) General CEN responsibilities Specific responsibilities of CEN/TC Meetings and Communication (incl. use of electronic mail) 11 4 CEN/TC 250 Conversion programme and prioritisation The Statement of Intent The Mandate, schedule of works and prioritisation programme Programme and target dates Setting up, briefing and managing project teams Conversion from ENV to EN General (This section contains the information, which is specific to work on conversions) CEN internal procedures Sub-committee procedures Conversion procedure - drafting and editing Guidance for project teams drafting EN Eurocode Parts The users Level of technology Design economy User-friendliness Comprehensiveness of scope and text Organization of EUROCODE parts Consistency and interdependency Format of Text - Principles and application rules Innovative and alternative design Format of Text - standard sequence of sections Format of Text - foreword, standard clauses Format of Text - harmonised editorial style Editing Panels Translations from the working language Relationship with National Regulations Removal of boxed values Safety classification/reliability differentiation Quality Assurance, control and management Liaison/compatibility with other standards 21 CEN/TC 250 N250 F 28 December 2003 Page 6 of 77

7 ANNEXES A B C D E F G H J K L M N P Responsibilities of Chairmen and Secretariats of TCs Conversion Mandate - BC/CEN/10-90 Addendum No. 3 Schedule of titles and scopes for EN stage Void Conversion programme with Target Dates Establishing and Managing Project Teams Pro forma brief for Project Teams Standstill Format of implementing National Standards (incl. Informative National Annexes) Common Sections (see N 600) Editorial style and form for the EUROCODES (see N 600) Translations (see N 600) CEN/TC250 Liaisons National Forewords and National Annexes CEN/TC 250 N250 F 28 December 2003 Page 7 of 77

8 1 Introduction and purpose of guidelines (1) The construction industry, together with the Commission for the European Union, EFTA and CEN, are expecting and hopeful of rapid progress towards the publication of EUROCODE parts with EN status. These should be clear and practical, in the pursuit of the objectives referred to in 2. (2) The EUROCODES will achieve full acceptance and success by achieving strength from their quality and ability to meet the expectations of them, irrespective of their status through legislation or regulation. (3) These guidelines reaffirm the objectives, the principles, and the means by which these are to be achieved, and record the administrative and procedural steps involved. CEN/TC250 welcomed the establishment of the guidelines, and confirmed the principles included. (4) These guidelines (including the Annexes) should therefore be followed by Project Teams converting ENVs to ENs by amending/editing. The Sub-Committees and the TC itself will have regard to these principles in their overview and management of the work. (5) In respect of the drafting, editing and publication of documents (at ENV or EN stage) the objective is to quickly achieve what is good and practicable, rather than incur delays by seeking theoretical perfection. Repeated and belated attempts to incorporate last minute research results or alternative ideas must be avoided. (6) The conversion from ENV to EN must be a simpler and more constrained process than the original drafting of the ENV, and must proceed effectively in accordance with the agreed programmes and procedures. The experience gained from the drafting, experimental use and application together with comments received during and at the end of the ENV period should facilitate conversion to EN, using the ENV as the first draft, within programme. (7) The Annexes give details of the relevant CEN procedures and rules for the work of CEN/TC250, and the agreed procedures of the TC for the management of the work. 2 The objectives of the Eurocodes and their status (1) As stated in the Commission's original objectives, the intention of the EUROCODE programme is to establish a set of common technical rules for the design of building and civil engineering works, which will ultimately replace the differing rules in force in the various Member States. (2) The Special Agreement between CEN and the European Commission (BC/CEN/03/89) specified that the EUROCODES are intended to serve as reference documents to be recognized by the authorities of the Member States for the following purposes:- CEN/TC 250 N250 F 28 December 2003 Page 8 of 77

9 a) As a means of compliance of building and civil engineering works with the Essential Requirements as set out in Council Directive 89/106/EEC, particularly Essential Requirement No.1 - Mechanical resistance and stability and Essential Requirement No.2-safety in the case of fire. b) As a basis for specifying contracts for the execution of construction works and related engineering services. NOTE. relates to Council Directive 71/305 Public Procurement. c) As a framework for drawing up harmonized technical specifications for construction products. In addition, the EUROCODES are foreseen to:- d) Improve the functioning of the single market for products and engineering services, by removing obstacles arising from different nationally codified practices for the assessment of structural reliability. e) Improve the competitiveness of the European construction industry, and the professionals and industries connected to it, in Countries outside the European Union. (3) The EUROCODES are technical documents which are written by technical people for use by technical people in various sectors of the Construction Industry including designers, regulators and approvers, producers of components and materials, specifies, constructors and educators. CEN/TC250 aims to encourage the optimization of input and comment from all potential users. All sectors in each Member State should be provided with the ongoing opportunity to make input to their National Standards Body and hence, via National Technical Contacts and National Delegations, to CEN/TC250 and its SCs. The TC250 has also established contacts with recognized European professional and trade bodies. (4) It is important to recognize that there is a clear and vital distinction between design codes and national regulations. The relationship between them has caused concern, and led to lengthy discussion. CEN/TC250 is fully aware that the harmonization of National Regulations is not within the scope of the National and European Standards Bodies. CEN/TC250 is responsible for, and committed to, the formulation of documents, which can be implemented WITHOUT AMENDMENT in all Member States. These Policy Guidelines point the way to resolving this matter by combination of EUROCODE drafting and action at National level (see Section 7.15). 3. The role of CEN/TC250 (and its elements) 3.1 General CEN responsibilities (1) In 1994 CEN/CS issued a statement, which confirms the responsibilities of each part of the CEN hierarchy, including Technical Committees, their Chairmen and Secretariats. The relevant extracts are attached at Annex A. CEN/TC 250 N250 F 28 December 2003 Page 9 of 77

10 (2) For the purposes of these guidelines for CEN/TC250, the position may be summarized as follows: a) CEN/TC250 AND ITS CHAIRMAN. It is the responsibility of CEN/TC250 and its Chairman to manage all the work, including establishment of general policies, programmes and strategies for the structural EUROCODES, and to oversee their implementation. Also to support and guide the Sub-Committees in achieving those policies objectives in the drafting work. b) COORDINATION GROUP. The Coordination Group continues to be active in the areas of technical and programme coordination increasingly as the work of conversion from ENV to EN progresses, so that TC250's policies are implemented in a consistent and coordinated way. The CG addresses technical issues (including, for example, the consistent treatment of values), and will continue to have a vital role to play in this and in monitoring progress and advising TC/250. The Coordination Group has established Horizontal Groups for Bridges and for Fire and has a coordinator for definitions and symbols. The rapid response required during PTs work on conversions may need special actions by the CG. c) SUB-COMMITTEES AND THEIR CHAIRMEN. The responsibilities of Sub-committees and their Chairmen are to undertake and manage the work delegated to them by TC250 within their Terms of Reference and agreed timescales. They have a vital responsibility for establishing technical policies, strategies and coordination of matters exclusive to their work (without overriding established TC250 general policies, etc.) but must refer wider matters to the TC or CG. They also have responsibility for liaison and cooperation with the other TC250 SCs, related TCs in CEN, and other European and International Standards Organizations, as well as with relevant European professional and trade Associations. d) PROJECT TEAMS. Project Teams comprise recognized experts in the relevant field of work producing agreed or consensus drafts, thus warranting the confidence of TC250 in the technical validity of their work, but it is important for PTs to follow these guidelines as the agreed policies of CEN/TC250. This requirement should be included in PT's Terms of Reference provided by the SC at the time they are established. If difficulties arise, these should be reported to the SC or SC Chairman for consideration and reference to TC250 (or CG) when necessary. 3.2 Specific responsibilities of CEN/TC250 (1) The European Commission and CEN have recognized on several occasions that it is vitally important to achieve coherence in the European Standards system, and in terms of structural design there must be consistency across materials/products so as to avoid public safety being compromised between materials/products or types of construction, particularly in times of competitive pressures. Consistency should not inhibit or prevent innovation, but the maintenance of an adequate safety regime is a prime necessity CEN/TC 250 N250 F 28 December 2003 Page 10 of 77

11 (2) The Special Agreement between CEC and CEN (reference BC/CEN/03/89) states:- With a view to the realization of the existing work programme and its further development, CEN will set up a Technical Committee 'Structural EUROCODES' with overall responsibility for all CEN work on structural design codes. It is understood that no structural design codes will be prepared within other CEN Technical Committees.' (3) CEN has formally accepted and established this principle by means of resolutions of BT and the former BTSI. This has been strongly confirmed at the BTSI meeting in May 1995 when it was reiterated that a proper safety regime can only be achieved by CEN/TC250 having exclusive responsibility for structural design/calculation rules. This implies that almost all rules relating to structural reliability and safety will be contained in the Structural EUROCODES. It may exceptionally be convenient, or even necessary, for these rules to be published in a product standard (for example, when the EUROCODES are not planned to cover a particular specialized subject, or it is technically necessary to bind the design rules into the performance specification in a product standard). But it is recognized that CEN/TC250 must monitor and agree these exceptional cases. (4) The CPD as a New Approach Directive requires that construction product standards are performance based, i.e. the performance criteria govern the design or validation of the product. The achievement of structural safety is crucial (reference to the CPD, Essential Requirement No. 1, mechanical resistance and stability). In order to undertake design of products on a performance basis, there is no general alternative to the application of codified design rules and in the European context, these will be the EUROCODES. (5) In addition, for a product or range of products simplified design procedures may be developed. It is essential for these to be on a consistent basis, so as to provide consistent reliability, and this is achieved by reference to the EUROCODES. Whilst the EUROCODES are in the ENV status, it is appreciated that this exclusivity may be difficult to operate. (6) However, after conversion and publication as ENs the EUROCODES will be fully placed to cover these aspects, within the established policy of consistency of the treatment of safety, under the control of CEN/TC250, subject only to decisions on the application of a period of coexistence. 3.3 Meetings and communication (1) Whenever possible work of the TC, SCs and PTs shall be conducted by correspondence. Use of electronic document transmission is encouraged, e.g. fax and . Each action shall be given a response deadline. Electronic communication is particularly encouraged for use by Project Teams to assist in rapid work progress and compliance with tight target dates. NOTE CEN is undertaking a study of the optimum computerized drafting and transmission systems, which will be distributed to CEN/TC250 when completed. (2) Meetings shall be held only when necessary to have face-to-face discussion in order to reach decisions and agree the way forward. The dates for meetings should be arranged to meet agreed deadlines in the work-item programmes, particularly published agreed Target Dates. CEN/TC 250 N250 F 28 December 2003 Page 11 of 77

12 4 CEN/TC250 Conversion programme and prioritisation 4.1 The Statement of Intent (1) At its meeting in October 1994 CEN/TC250 agreed a Statement of Intent setting out the initial priority documents for the conversion stage. These comprised EUROCODES necessary for the structural design of buildings and included Basis of Design, Loading and General Design Rules including those for Fire and Seismic Resistance. It also highlighted the requirement for early action on Bridge Parts. The Committee for the Structural EUROCODES declared it s determination to make rapid progress in the conversion of the whole suite of EUROCODES into the final EN documents which will be implemented by members in place of national design standards. 4.2 The mandate, schedule of works and prioritization programme (1) Subsequently, agreement was reached for the conversion stage of ENVs to ENs and the Commission issued Amendment No.3 to Mandate BC/CEN/11-89 on 31 March 1998 (See Annex B). The Schedule of Titles and Scopes of ENs, as agreed by TC 250, is appended as Annex C. (2) After extensive discussions a prioritization schedule was agreed and the first Order Voucher under Amendment No.3 was received in April 1998 to cover the First phase of conversions. (See Annex D). In accordance with the agreement with the Commission officers, similar Order Vouchers for phases two and three were received in March 1999 and February 2000 and the O.V. for phase four is expected in February Programme and target dates (1) The division into phases has been determined by taking account of the TC250 Statement of Intent, the availability of resources, inter-relationships between various Parts, and forecast dates of 2-year Enquiry results. Detailed programmes for each work item have been determined by relevant Sub-committees, and the overall coordinated programme agreed by TC250. The programme is subject to continuous monitoring and review by TC250. (See Annex E for latest update) 5. Setting up, briefing and managing project teams (1) In anticipation of the result of the 2-year Enquiry the appropriate Sub-committee should commence the procedure for the establishment of a Project Team of suitably qualified and experienced experts in order to commence conversion work as soon as possible after receipt of the Order Voucher (O.V.). Contracts for experts will be executed by the CEN/TC 250 Secretariat (BSI) in the established format immediately after the O.V. has been received and the Project Team agreed by Resolution. Each Sub-committee, through its Chairman and Secretariat, is responsible for briefing, managing and monitoring the activity and progress of its Project Teams. (See Annexes F and G) CEN/TC 250 N250 F 28 December 2003 Page 12 of 77

13 6. Conversion from ENV to EN 6.1 General (1) This section contains the information, which is specific to work on conversions. 6.2 CEN internal procedures (1) After 2 years of the 3-year life of the ENV the Central Secretariat (CEN/CS) will write to all Member Countries requesting a national reply within 6 months (The 2-year enquiry). The reply may be any of the following:- a) Conversion of existing ENV into an EN after formal vote. b) Continue with existing ENV as ENV for a further 2 years. c) Conversion into EN after formal vote based on updated ENV prepared by a technical body (i.e. TC or SC). d) Replace existing ENV by a revised ENV prepared by a technical body (TC or SC) e) Withdrawal of the existing ENV. (2) CEN/TC250 will decide the result of the Enquiry after receipt of replies and approve an appropriate resolution. (In addition, in the case of EUROCODES the wishes of the Commission and EFTA will inevitably be considered) (3) A decision to convert an ENV to EN immediately imposes Standstill. (See Annex H) 6.3 Sub-committee procedures (1) Sub-Committees should set up or adjust existing programmes of work so as to achieve the target dates in the Mandates/Order Vouchers. These will be monitored by CEN/TC250. (2) Sub-committee meeting dates shall be arranged to accord with the requirements of the agreed Works Programmes a) Whenever possible the conversion stages should run in parallel, in order to minimize the time to Formal Voting stage, e.g. early commencement of, translations and equivalence checks. b) By implementing the policy of minimum change an EN enquiry will not be necessary and the amended document should proceed directly to formal vote. Ongoing informal consultation, particularly with National Technical Contacts (see Annex G, para.5.4), is an essential part of this fast-track procedure. c) Contentious matters arising from the ENV enquiry should be identified early, and resolved during the early stages of EN preparation (including if necessary with TC250 action) before the documents reach EN voting stage. CEN/TC 250 N250 F 28 December 2003 Page 13 of 77

14 d) The detailed procedures and timetable for the works are to be proposed by the Sub- Committee, for report to CEN/TC250 in accordance with these Guidelines and Procedures. e) The SC is responsible for establishing a Project Team for confirmation by CEN/TC250 (by resolution) to undertake the work of preparing the pren for Formal Voting. The SC is responsible for the work of the PT and shall keep an overview of its work and be responsible for ensuring the coordination of its technical work and progress with other related PTs within or outside the SC scope. (See Annex F) f) The PT is to be given clear terms of reference in terms of scope of work, procedures to be followed, target dates for defined stages and liaisons to be maintained. (See Annex G) g) The PT must make regular reports on progress and any difficulties to the SC (or the SC Chairman in urgency). h) The SC shall keep TC250 and its Coordination Group informed on progress and any difficulties. Any programme changes must be agreed by the TC who continue to be responsible for overall coordination of the whole EUROCODE programme 6.4 Conversion procedure - drafting and editing (1) The process of conversion from ENV to EN should commence as soon as practicable after the result of the '2- year Enquiry' is available. Initially this may be undertaken by an 'Ad hoc panel' for the SC in anticipation of the formal Order Voucher. The initial process will be the examination and categorization of National comments submitted under the Enquiry, together with any comments received from Members during the ENV period. (2) The Project Team for the conversion should be established by the SC in accordance with the agreed CEN/TC250 procedure (See Annex F) in order to commence the conversion work as soon as practicable after the Order Voucher is released. The PT must be given full terms of reference by the SC including clearly defined target dates and reporting requirements (See Annex G). (3) To speed up the process, the search for experts for inclusion in the PT should commence in advance of authority to proceed with the work. The PT Members will be required to enter a formal contract with BSI (acting on behalf of CEN). a) The conversion from ENV to EN is a simpler and more constrained process than the original drafting of the ENV. b) There should be no change to the title or scope (see annex C) without the prior approval of CEN/TC 250. c) The Project Teams for the conversions should ensure that draft EN text complies with the criteria in Section 7 of these Policy Guidelines. CEN/TC 250 N250 F 28 December 2003 Page 14 of 77

15 d) There should be no technical changes to the ENV text unless the national comments have identified a significant safety, usability or coordination problem. Potential changes should only be adopted after the Project Team has accepted the validity of the comments, having regard to these TC250 Policy Guidelines. e) The PT shall maintain a record of the action taken on each comment received and shall report accordingly to the SC. Ultimately all National Standards Bodies, and others, who have commented, should receive a note of the response to the comments they have submitted. f) Matters related to Basis of Design, Quality Assurance/Management, safety differentiation/classification of structures, and material-independent matters may be referred to TC250 if not already covered in these Guidelines. g) Lack of availability of supporting standards should not delay publication of the EN EUROCODES. (4) Each EUROCODE should make reference to the standards needed to make it operational. In the early stages, where the CEN standard is not yet available, other published and generally available documents may be referred to if they are agreed as appropriate by the SC. Otherwise references may be by Informative National Annexes (Annex J). 7 Guidance for project teams drafting ENs 7.1 The users (1) It should be assumed that the principal users of EUROCODES will be design engineers who are appropriately qualified and experienced in the particular field of work. However, other users may include; regulatory personnel, producers of structural components and materials, contract specifiers, building and civil engineering constructors/contractors, educators and trainers, drafters of related standards as well as authors of guides handbooks and computer programmers. 7.2 Level of technology (1) The EUROCODES shall be based on well accepted and of proven/established current practice ( State of the Art ). Input from expert bodies (for example FIB, ECCS) may make an important contribution. Research/testing or trial calculations may be helpful (and sometimes necessary) to harmonization different current practices. Only in exceptional circumstances, e.g. where significant safety issues are concerned, shall recent non-applied research results be taken into account. Novel/unproven methods shall not be included, and therefore no content shall be dependent on newly commissioned or future basic research. 7.3 Design economy (1) EUROCODES are to give the basis for the design of safe structures at acceptable cost. In order to achieve realistic and effective acceptance of the EUROCODES, structures designed using them should not cost significantly more, over their design life, than those designed to national standards, unless an important principle of acceptable safety has been identified and agreed e.g. a change in the level of reliability. CEN/TC 250 N250 F 28 December 2003 Page 15 of 77

16 7.4 User-friendliness (1) Every EUROCODE part should be organized and drafted to make it understandable and logically applicable by the anticipated user (see 7.1) in everyday use. In this regard, the views of the National Technical Contacts (NTCs - see 6.2d and Annex G para. 5.4), and the national responses from the trial use of the ENV documents must be respected, and only set aside when other extremely strong reasons are accepted by the SC. 7.5 Comprehensiveness of scope and text (1) The Scope Clause of each EUROCODE part shall be precisely detailed and make specific reference to any exclusions and limitations. (2) Each EUROCODE part is to be comprehensive in its coverage of the PRINCIPLES in its particular subject area. The APPLICATION RULES should embrace at least 90% of construction in its field. Exotic, novel, or extremely unusual forms of construction or design conditions will not be covered, or will be stated to require additional consideration by the designer. Although the documents may be lengthy (for example, when treatment of alternative forms of members, with alternative design methods, are included), it should be appreciated that design aids, in the form of manuals/handbooks/ computer programs, etc. will be produced, often by others, and will be an important part of the application of the EUROCODES. Background material, worked examples, very specialized applications and non-essential informative narrative material should be removed and possibly included in such support items. (3) The user should be assisted to use the EUROCODES effectively. Therefore any helpful guidance should be provided where possible as to which parts of the text will be relevant to various forms of construction, types of structure, or level of precision in the calculations. 7.6 Organization of EUROCODE parts (1) All the material-related structural EUROCODES (Eurocodes 2, 3, 4, 5, 6 and 9) are organized on the following basis: - Part 1 deals with General Rules, including structural fire design rules, which apply to all structures unless specifically omitted or amended in supplementary parts for specific structures - Parts 2, 3, 4, etc. are supplementary to Part 1 and contain additional and varied rules for specific applications, e.g. particular types of structure (e.g. buildings, bridges, silos.) NOTE in some EUROCODES Part 1 also deals with rules for buildings. (2) EUROCODE: Basis of Structural Design (pr EN 1990) covers the general design philosophy, basis of design, common non material-related aspects and common terminology and symbols. (3) EUROCODE 1: Actions on structures covers general actions (loading) applicable to all structures in Part 1 and additional loadings for specific structures (bridges, silos and tanks and loads from machinery) in further Parts. CEN/TC 250 N250 F 28 December 2003 Page 16 of 77

17 (4) EUROCODE 7: Geotechnical design deals in Part 1 with general rules Geotechnical design for structures and in Parts 2 and 3 with geotechnical field tests and laboratory tests to assist design. (5) EUROCODE 8: Design for earthquake resistance, is organized on a similar basis to the material-related EUROCODES. 7.7 Consistency and interdependency (1) All EUROCODE Parts have interdependency with other Parts and are not intended to be self-sufficient. Each EUROCODE Part must be fully consistent with other parts of the same EUROCODE and with related parts of other EUROCODES, as well as with EN 1990 "Eurocode: Basis of Structural Design" in terms of technology, terminology and symbols. (2) Repetition of clauses must be avoided; instead use precise unambiguous cross-references quoting the full clause/sub-clause number. (3) To facilitate consistency between Parts, liaison between Project Teams will be essential when clauses dealing with similar or related subjects are being considered, e.g. serviceability criteria. 7.8 Principles and application rules (1) The PRINCIPLES given in a EUROCODE Part shall only comprise: - general statements and definitions for which there is no alternative throughout the scope of the Part - as well as requirements and analytical models for which no alternative is permitted unless specifically stated. They should therefore be brief statements of all-embracing fundamentals. The PRINCIPLES are to be identified in EUROCODES by use of (P) after the paragraph number. (2) The APPLICATION RULES given in a EUROCODE Part are generally recognized rules, which are recommended methods of achieving the PRINCIPLES and satisfy their requirements for the whole or a specific field within the scope of the Part. In the case of a specific field the limitations shall be clearly given. (3) It is permissible to use alternative design rules different from the APPLICATION RULES given in the EUROCODE Part, provided that it is shown that the alternative rules accord with the relevant PRINCIPLES and are at least equivalent with regard to the structural safety, serviceability and durability which would be expected when using the EUROCODE. CEN/TC 250 N250 F 28 December 2003 Page 17 of 77

18 NOTE 1 If an alternative design rule is substituted for an application rule, the resulting design cannot be claimed to be wholly in accordance with the Eurocode, although the design will remain in accordance with its Principles. When the Eurocode is used in respect of a property listed in an Annex Z of a product standard or an ETAG, the use of an alternative design may not be acceptable for CE marking. NOTE 2 The Coordination Group has an ongoing role in reviewing consistency of implementation of this arrangement particularly in conversions from ENV to EN. 7.9 Innovative and alternative design (1) It is particularly important to ensure that the European construction industry maintains or improves its share of the European and worldwide market in design services and structural products and materials. The objective of the EUROCODES is to provide common structural design rules for everyday use for whole structures and for design of component products. (2) Manufacturers have expressed the importance of encouraging the design of innovative products and of ensuring that the EUROCODES do not inhibit such development. Project Teams should therefore ensure that the design of innovative products is covered and facilitated in the EUROCODES, which should allow alternative designs rules (see 7.8) Format of text - standard sequence of sections (1) CEN/TC250 has agreed that the EUROCODE Parts will adopt the following standard sequence of sections unless it is agreed that this will not be appropriate:- Foreword (Informative) Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 General Basis of Design (material specific) Materials Durability Basis of Structural Analysis Ultimate Limit States Serviceability Limit States * Section? Details/Connections * Section? Special Considerations * Section? Execution * Section? Design Assisted by Testing * Annexes (Normative) * Annexes (Informative) NOTE Sub-committees are required to advise TC250 or CG when Sections marked * are used, giving number, title and brief scope. H G Fire will determine sequence of sections for Fire Parts Format of text - foreword, standard clauses CEN/TC 250 N250 F 28 December 2003 Page 18 of 77

19 (1) CEN/TC 250 has agreed the standard clauses, which should form the beginning of the Foreword to all Parts of all EUROCODES. These are set out in Annex K together with background notes and extracts from the rules. Any additional informative, helpful clauses specific to the particular Part should be inserted before the final standard paragraph which should be followed by an invitation to submit constructive comments to the NSB Format of text - harmonized editorial style (1) CEN/250 has agreed a harmonized editorial style which is based on the CEN PNE rules (with agreed derogation), and on the experience of drafting and coordinating the ENV documents. This is to be adopted in every EUROCODE Part, unless TC250 agrees otherwise for exceptional circumstances. (See Annex L) 7.13 Editing committees (1) For the duration of the conversion to EN stages each SC should establish an Editing committee comprising a member of the SC Secretariat (as convenor) and 3 technical representatives whose mother tongues are English, French and German respectively. The Editing committee will monitor draft texts to ensure compliance with PNE rules as modified by ISO Regulations, TC250 derogation, agreed TC250 format and Harmonized Editorial Style. They should also check drafts for technical equivalence of the 3 language versions (2) The Comité de Lecture (CDL) within CEN, comprising one AFNOR, one DIN and one BSI representative (usually a staff editor) and the TC/SC Secretary shall receive copies of the 3 language versions as prepared for EN Formal Vote. When the CDL works on a document, it generally works only by correspondence and sends comments to the Secretary before the Formal Vote deadline. This action does not detract from the responsibilities of the TC/SC Editing Committee. The CDL generally only examines a small random selection of final documents Translations from the working language (1) The working language of CEN/TC250 is English, however, translations into French and German will be required before the final version is submitted for Formal Vote as an EN. (See Annex M) Translation into any other European language is a matter for the Country concerned and shall be prepared from the definitive texts as circulated by CEN/CS following the Formal Vote Relationship with National Regulations (1) The role of national regulations has not changed. The method of specifying the standard(s) which may (or must) be used for particular situations differs between Member States. In some (for instance UK) there is a very 'permissive' regime, which gives flexibility of choice of design method but also identifies certain standard(s) which are 'deemed to satisfy' the regulations - these have usually been established national codes or standards, and will become progressively the EUROCODES (even at ENV stage in one or two cases). (2) At the other extreme, some Member States (for example Italy and Spain) have the relevant CEN/TC 250 N250 F 28 December 2003 Page 19 of 77

20 standard enshrined in the law, so that the introduction of the EUROCODES will need a change in the national law. The steps to be taken to adopt or recognize the EUROCODES will vary according to the national situation because the harmonization of national regulations is not in prospect and is outside the scope of the National and European Standards bodies. It is expected that, in accordance with CEN rules and agreements, the EUROCODE texts approved by CEN will be published by the NSBs, without variation from one Member State to another. This is the objective of 'harmonization', and this is the means of achieving the removal of barriers to trade (in services or products.) 7.16 Removal of boxed values (1) The boxed values in the ENVs were adopted as an interim expedient with a view to total removal prior to publication of ENs. Total removal and replacement by common agreed values to be used in all Member States is not fully achievable until there is a harmonization of national safety regulations. The European Commission has published Guidance Paper L on Application and Use of Eurocodes. It provides for the use of a Nationally Determined Parameter (NDP) where a national choice is left open in a EN-Eurocode about values (where symbols are given in the EN- Eurocodes), a set of classes or alternative procedures permitted within the EN-Eurocodes. CEN/TC 250 has agreed that Project Teams will take the following action to remove all boxed values :- - "Boxed values" which do not relate to safety levels and differences should, in the EN- Eurocodes, be replaced by fixed values or methods. - "Boxed values" which relate to safety levels and differences should be replaced, in the EN- Eurocodes, by symbols, sets of classes or sets of alternative methods (i.e. Nationally Determined Parameters). Where relevant, the range of possible national choice should be given for information. Boxed values which have an influence on the level of serviceability or durability should be handled in the same way. (2) The types of information that may be included in a National Annex are given in the common Foreword for EN-Eurocodes, see EN Examples of the use of NDPs and the National Annex are given in Annex P. The wording to be used to refer, in Notes, to National Annexes is given in Annex L Safety classification/reliability differentiation (1) It is clear that these issues are important to the design process in some Countries as the National requirement for safety on construction works is based on such practices. This is reflected in some National Application Documents to ENVs. As no generally accepted approach has been developed for the first phase of conversion to EN, such concepts may be adopted by individual Member States under the arrangements set out in Quality Assurance, control and management (1) The achievement of predicable and adequate levels of quality in construction is an objective, which is receiving increasing attention in Europe. As there is no generally accepted framework at present it is difficult to produce sensibly detailed content. It is not the role of CEN/TC250 (or EUROCODES) to define such levels, nevertheless, where relevant, simple statements of assumptions made in this context must be included. (2) EUROCODE Parts are permitted to refer to QA policies in the construction process as a whole bearing in mind that they could become part of a general QA/Quality Management System. CEN/TC 250 N250 F 28 December 2003 Page 20 of 77

21 EUROCODES are directly concerned with the design phase of construction, so at this stage they should not venture into detailed treatment of the subject. Statements of the level of workmanship and supervision assumed for the purposes of design must, of course, be included Liaison/compatibility with other standards (1) CEN/TC250 has the responsibility to ensure that adequate and effective liaisons are maintained with other CEN Technical Committees, and these liaisons are normally carried out by the relevant SC. The objective is to mutually achieve compatibility with other relevant and related standards and to obtain essential information for EUROCODES. (2) The Structural EUROCODES provide a consistent set of design rules for all forms of building and civil engineering works using the full range of materials in common use. They deal with the design of whole structures comprising interconnected elements of structure thus providing consistency of resistance, reliability and integrity throughout. EUROCODES are equally appropriate for design of single products (structural elements) which are manufactured to be permanently incorporated into building and civil engineering works and for individual load-bearing products. (3) CEN/TC250 and its sub-committees are required to establish active liaison (or 'Modes of Cooperation') with other TCs responsible for performance standards for products under the CPD (harmonized standards) and with those dealing with material specifications and characteristics. Liaison is also necessary with others (not necessarily within scope of CPD) where verification of reliability is required by calculation. Monitoring and reporting liaison activities are essential activities of all sub-committees and the TC itself. (4) In summary, product and material TCs relate to Structural EUROCODES: - as a means of verifying compliance of individual products (elements of structure), - to achieve consistency of reliability etc, of inter-related products to be used in a single structure, - to mutually agree consistent material property descriptions, characteristics and values, - to demonstrate consistency of reliability to procurers and regulators under safety and durability requirements, - to improve functioning of the single markets and remove barriers inherent in having a variety of different national design codes. (4) Annex N, sets out a schedule of TCs (in CEN and ECISS), which have relationships with CEN/TC250 for the above purposes. The levels of coordination vary by need and cover joint working, full exchange of documents and drafts, common membership, consultation as required, exchange of correspondence, etc., as appropriate. CEN/TC 250 N250 F 28 December 2003 Page 21 of 77

22 ANNEX A Responsibilities of the Chairman of a Technical Committee or Sub-committee Drafted by CEN Central Secretariat Directorate Standards Programme - Training Tools and Support Unit CEN/TC 250 N250 F 28 December 2003 Page 22 of 77

23 Contents 1 Definition and objective Applicable rules 24 3 Associated process(es) Management of a Technical Committee Management of meeting Administrative responsibilities Policy guidance 26 CEN/TC 250 N250 F 28 December 2003 Page 23 of 77

24 1 Definition and objectives (1) The Technical Committee is in charge of the programming and planning of technical work in the form of a Business Plan, for the monitoring and the execution of the work in accordance with the agreed Business Plan and for the management of the standards making process, including the respect of CEN's policies (e.g. PNE-Rules, Editing Committee, availability and coherence of the three language versions) and the consensus building amongst all interested parties represented through the CEN members. (2) The Chairman of a Technical Committee is responsible for the total management of the activities of the Technical Committee. (3) Specifically the Chairman - is appointed by the Technical Committee on the proposal of the Secretariat for a period not exceeding six years, but with the possibility of a three year extension; - is accountable to the Technical Board (BT); - must act impartially, divesting himself of a national point of view; - has no voting rights. 2 Applicable rules (1) CEN/CENELEC Internal Regulations - Part 2: Common rules for standards work - subclause 2.3.3: Appointment and responsibilities of Chairman. (2) CEN Technical Board standing resolution(s) - resolution CEN/BT 79/1996: CEN Optimizing - Endorsement of procedures by BT. 3 Associated process(es) (1) Technical Committee s Business Plan (PROGR/BP/TC). 4 Management of a Technical Committee (1) The Chairman shall - support the Technical Committee Secretariat in preparation and maintenance of Business Plan and be in a position to explain to the "Strategic Review Panel" the Business Plan and be in a position to explain to the "Strategic Review Panel" the rationale put forward by the Technical Committee in the context of the Business Plan. - manage, with the support of the Technical Committee Secretariat, the activities of the CEN/TC 250 N250 F 28 December 2003 Page 24 of 77