EN 1995-1-2:2004
(Main)Eurocode 5: Design of timber structures - Part 1-2: General - Structural fire design
Eurocode 5: Design of timber structures - Part 1-2: General - Structural fire design
Supplementary to Part 1-1. Additional and varied rules to be used for the design of timber structures which are required to avoid premature structural collapse and to limit the spread of fire in the accidental situation of exposure to fire.
Eurocode 5: Bemessung und Konstruktion von Holzbauten - Teil 1-2: Allgemeine Regeln - Tragwerksbemessung für den Brandfall
Eurocode 5: Conception et Calcul des structures en bois - Part 1-2: Généralités - Calcul des structures au feu
Evrokod 5: Projektiranje lesenih konstrukcij - 1-2. del: Splošna pravila - Projektiranje požarnovarnih konstrukcij
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Eurocode 5: Design of timber structures - Part 1-2: General - Structural fire designEvrokod 5: Projektiranje lesenih konstrukcij - 1-2. del: Splošna pravila - Projektiranje požarnovarnih konstrukcijEurocode 5: Conception et Calcul des structures en bois - Part 1-2: Généralités - Calcul des structures au feuEurocode 5: Bemessung und Konstruktion von Holzbauten - Teil 1-2: Allgemeine Regeln - Tragwerksbemessung für den BrandfallTa slovenski standard je istoveten z:EN 1995-1-2:2004SIST EN 1995-1-2:2005en91.080.20Lesene konstrukcijeTimber structures91.010.30Technical aspects13.220.50Požarna odpornost gradbenih materialov in elementovFire-resistance of building materials and elementsICS:SIST ENV 1995-1-2:20001DGRPHãþDSLOVENSKI
STANDARDSIST EN 1995-1-2:200501-maj-2005
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 1995-1-2
November 2004 ICS 91.010.30; 13.220.50; 91.080.20 Supersedes ENV 1995-1-2:1994 English version
Eurocode 5: Design of timber structures - Part 1-2: General - Structural fire design
Eurocode 5: Conception et Calcul des structures en bois - Part 1-2: Généralités - Calcul des structures au feu
Eurocode 5: Entwurf, Berechnung und Bemessung von Holzbauten - Teil 1-2: Allgemeine Regeln - Bemessung für den Brandfall This European Standard was approved by CEN on 16 April 2004.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36
B-1050 Brussels © 2004 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1995-1-2:2004: E
2 Contents
Foreword
4 Background of the Eurocode programme 4 Status and field of application of Eurocodes 5 National Standards implementing Eurocodes 5 Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for products 6 Additional information specific to EN 1995-1-2 6 National annex for EN 1995-1-2 7 Section 1
General 9 1.1
Scope 9 1.1.1 Scope of Eurocode 5 9 1.1.2 Scope of EN 1995-1-2 9 1.2
Normative references 10 1.3
Assumptions 10 1.4
Distinction between principles and application rules 10 1.5
Terms and definitions 11 1.6
Symbols 11 Section 2
Basis of design 14 2.1
Requirements 14 2.1.1 Basic requirements 14 2.1.2 Nominal fire exposure 14 2.1.3 Parametric fire exposure 14 2.2
Actions 15 2.3
Design values of material properties and resistances 15 2.4
Verification methods 16 2.4.1
General 16 2.4.2 Member analysis 17 2.4.3 Analysis of parts of the structure 18 2.4.4
Global structural analysis 19 Section 3
Material properties 20 3.1 General 20 3.2 Mechanical properties 20 3.3 Thermal properties 20 3.4 Charring depth 20 3.4.1
General 20 3.4.2
Surfaces unprotected throughout the time of fire exposure 21 3.4.3 Surfaces of beams and columns initially protected from fire exposure 23 3.4.3.1
General 23 3.4.3.2 Charring rates 26 3.4.3.3
Start of charring 27 3.4.3.4
Failure times of fire protective claddings 28 3.5
Adhesives 29 Section 4
Design procedures for mechanical resistance 30 4.1 General 30 4.2 Simplified rules for determining cross-sectional properties 30 4.2.1
General 30 4.2.2 Reduced cross-section method 30 4.2.3 Reduced properties method 31 4.3
Simplified rules for analysis of structural members and components 32 4.3.1 General 32 4.3.2
Beams 32 4.3.3
Columns 33 4.3.4
Mechanically jointed members 33 4.3.5
Bracings 34 4.4
Advanced calculation methods 34 Section 5
Design procedures for wall and floor assemblies 35
3 5.1
General 35 5.2
Analysis of load-bearing function 35 5.3
Analysis of separating function 35 Section 6
Connections 36 6.1 General 36 6.2 Connections with side members of wood 36 6.2.1 Simplified rules 36 6.2.1.1 Unprotected connections 36 6.2.1.2 Protected connections 37 6.2.1.3 Additional rules for connections with internal steel plates 38 6.2.2 Reduced load method 39 6.2.2.1 Unprotected connections 39 6.2.2.2 Protected connections 41 6.3 Connections with external steel plates 41 6.3.1 Unprotected connections 41 6.3.2 Protected connections 41 6.4 Simplified rules for axially loaded screws 41 Section 7
Detailing 43 7.1 Walls and floors 43 7.1.1
Dimensions and spacings 43 7.1.2
Detailing of panel connections 43 7.1.3
Insulation 43 7.2 Other elements 43 Annex A (Informative) Parametric fire exposure 45 A1
General 45 A2
Charring rates and charring depths 45 A3
Mechanical resistance of members in edgewise bending 47 Annex B (informative) Advanced calculation methods 48 B1 General 48 B2
Thermal properties 48 B3
Mechanical properties 50 Annex C (Informative) Load-bearing floor joists and wall studs in assemblies whose cavities are completely filled with insulation 52 C1 General 52 C2
Residual cross-section 52 C2.1 Charring rates 52 C2.2 Start of charring 54 C2.3 Failure times of panels 54 C3
Reduction of strength and stiffness parameters 56 Annex D (informative) Charring of members in wall and floor assemblies with void cavities 58 D1 General 58 D2 Charring rates 58 D3 Start of charring 58 D4 Failure times of panels 58 Annex E (informative) Analysis of the separating function of wall and floor assemblies 60 E1
General 60 E2 Simplified method for the analysis of insulation 60 E2.1 General 60 E2.2 Basic insulation values 61 E2.3 Position coefficients 62 E2.4 Effect of joints 62 Annex F (informative) Guidance for users of this Eurocode Part 68
Foreword
This European Standard EN 1995-1-2 has been prepared by Technical Committee CEN/TC250 “Structural Eurocodes”, the Secretariat of which is held by BSI.
This European Standard shall be given the status of a National Standard, either by publication of an identical text or by endorsement, at the latest by May 2005, and conflicting national standards shall be withdrawn at the latest by March 2010.
This European Standard supersedes ENV 1995-1-2:1994.
CEN/TC250 is responsible for all Structural Eurocodes.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxemburg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Background of the Eurocode programme
In 1975, the Commission of the European Community decided on an action programme in the field of construction, based on article 95 of the Treaty. The objective of the programme was the elimination of technical obstacles to trade and the harmonisation of technical specifications.
Within this action programme, the Commission took the initiative to establish a set of harmonised technical rules for the design of construction works which, in a first stage, would serve as an alternative to the national rules in force in the Member States and, ultimately, would replace them.
For fifteen years, the Commission, with the help of a Steering Committee with Representatives of Member States, conducted the development of the Eurocodes programme, which led to the first generation of European codes in the 1980’s.
In 1989, the Commission and the Member States of the EU and EFTA decided, on the basis of an agreement1 between the Commission and CEN, to transfer the preparation and the publication of the Eurocodes to the CEN through a series of Mandates, in order to provide them with a future status of European Standard (EN). This links de facto the Eurocodes with the provisions of all the Council’s Directives and/or Commission’s Decisions dealing with European standards (e.g. the Council Directive 89/106/EEC on construction products - CPD - and Council Directives 93/37/EEC, 92/50/EEC and 89/440/EEC on public works and services and equivalent EFTA Directives initiated in pursuit of setting up the internal market).
The Structural Eurocode programme comprises the following standards generally consisting of a number of Parts:
EN 1990 Eurocode : Basis of Structural Design
EN 1991 Eurocode 1: Actions on structures EN 1992 Eurocode 2: Design of concrete structures EN 1993 Eurocode 3: Design of steel structures EN 1994 Eurocode 4: Design of composite steel and concrete structures EN 1995 Eurocode 5: Design of timber structures EN 1996 Eurocode 6: Design of masonry structures EN 1997 Eurocode 7: Geotechnical design
1 Agreement between the Commission of the European Communities and the European Committee for Standardisation (CEN) concerning the work on EUROCODES for the design of building and civil engineering works (BC/CEN/03/89).
5 EN 1998 Eurocode 8: Design of structures for earthquake resistance EN 1999 Eurocode 9: Design of aluminium structures
Eurocode standards recognise the responsibility of regulatory authorities in each Member State and have safeguarded their right to determine values related to regulatory safety matters at national level where these continue to vary from State to State.
Status and field of application of Eurocodes
The Member States of the EU and EFTA recognise that EUROCODES serve as reference documents for the following purposes: − as a means to prove compliance of building and civil engineering works with the essential requirements of Council Directive 89/106/EEC, particularly Essential Requirement N°1 – Mechanical resistance and stability – and Essential Requirement N°2 – Safety in case of fire; − as a basis for specifying contracts for construction works and related engineering services; − as a framework for drawing up harmonised technical specifications for construction products (ENs and ETAs).
The Eurocodes, as far as they concern the construction works themselves, have a direct relationship with the Interpretative Documents2 referred to in Article 12 of the CPD, although they are of a different nature from harmonised product standards3. Therefore, technical aspects arising from the Eurocodes work need to be adequately considered by CEN Technical Committees and/or EOTA Working Groups working on product standards with a view to achieving full compatibility of these technical specifications with the Eurocodes.
The Eurocode standards provide common structural design rules for everyday use for the design of whole structures and component products of both a traditional and an innovative nature. Unusual forms of construction or design conditions are not specifically covered and additional expert consideration will be required by the designer in such cases.
National Standards implementing Eurocodes
The National Standards implementing Eurocodes will comprise the full text of the Eurocode (including any annexes), as published by CEN, which may be preceded by a National title page and National Foreword, and may be followed by a National Annex.
The National annex may only contain information on those parameters which are left open in the Eurocode for national choice, known as Nationally Determined Parameters, to be used for the design of buildings and civil engineering works to be constructed in the country concerned, i.e.: – values and/or classes where alternatives are given in the Eurocode, – values to be used where a symbol only is given in the Eurocode, – country specific data (geographical, climatic, etc.), e.g. snow map, – the procedure to be used where alternative procedures are given in the Eurocode. It may also contain
2 According to Art. 3.3 of the CPD, the essential requirements (ERs) shall be given concrete form in interpretative documents for the creation of the necessary links between the essential requirements and the mandates for harmonised ENs and ETAGs/ETAs. 3 According to Art. 12 of the CPD the interpretative documents shall: give concrete form to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each requirement where necessary; indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical rules for project design, etc.; serve as a reference for the establishment of harmonised standards and guidelines for European technical approvals. The Eurocodes, de facto, play a similar role in the field of the ER 1 and a part of ER 2.
6 – decisions on the application of informative annexes, – references to non-contradictory complementary information to assist the user to apply the Eurocode.
Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for products
There is a need for consistency between the harmonised technical specifications for construction products and the technical rules for works4. Furthermore, all the information accompanying the CE Marking of the construction products which refer to Eurocodes shall clearly mention which Nationally Determined Parameters have been taken into account.
Additional information specific to EN 1995-1-2
EN 1995-1-2 describes the principles, requirements and rules for the structural design of buildings exposed to fire, including the following aspects.
Safety requirements
EN 1995-1-2 is intended for clients (e.g. for the formulation of their specific requirements), designers, contractors and relevant authorities.
The general objectives of fire protection are to limit risks with respect to the individual, society, neighbouring property, and where required, directly exposed property, in the case of fire.
Construction Products Directive 89/106/EEC gives the following essential requirement for the limitation of fire risks: "The construction works must be designed and built in such a way, that in the event of an outbreak of fire − the load-bearing resistance of the construction can be assumed for a specified period of time; − the generation and spread of fire and smoke within the works is limited; −
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