oSIST prEN 1999-1-2:2021

Eurocode 9 - Design of aluminium structures - Part 1-2: Structural fire design

1.1   Scope of EN 1999-1-2
(1)   EN 1999-1-2 deals with the design of aluminium structures for the accidental situation of fire exposure and is intended to be used in conjunction with EN 1999-1-1, EN 1999-1-2, EN 1999-1-3, EN 1999-1-4 and EN 1999-1-5. This document only identifies differences from, or supplements to, normal temperature design.
(2)   EN 1999-1-2 applies to aluminium structures required to fulfil a load bearing function.
(3)   EN 1999-1-2 gives principles and application rules for the design of structures for specified requirements in respect of the aforementioned function and the levels of performance.
(4)   EN 1999-1-2 applies to structures, or parts of structures, that are within the scope of EN 1999 1 1 and are designed accordingly.
(5)   The methods given in EN 1999-1-2 are applicable to the following aluminium alloys:
EN AW-3004 - H34   EN AW-5083 - O and H12   EN AW-6063 - T5 and T6
EN AW-5005  -  O and H34   EN AW-5454 - O and H34   EN AW-6082 - T4 and T6
EN AW-5052  - H34      EN AW-6061 - T6   
(6)   The methods given in EN 1999-1-2 are applicable also to other aluminium alloy/tempers of EN 1999 1-1, if reliable material properties at elevated temperatures are available or the simplified assumptions in 5.2.1 are applied.
1.2   Assumptions
(1)   In addition to the general assumptions of EN 1990, the following assumptions apply:
-   the choice of the relevant design fire scenario is made by appropriate qualified and experienced personnel, or is given by the relevant national regulation.
-   any active and passive fire protection systems taken into account in the design will be adequately maintained.
(2)   For the design of new structures, EN 1999 is intended to be used, for direct application, together with EN 1990, EN 1991, EN 1992, EN 1993, EN 1994, EN 1995, EN 1997, EN 1998 and EN 1999.
(3)   EN 1999 is intended to be used in conjunction with:
-   European Standards for construction products relevant for aluminium structures
-   EN 1090-1, Execution of steel structures and aluminium structures - Part 1: Requirements for conformity assessment of structural components
-   EN 1090-3, Execution of steel structures and aluminium structures - Part 3: Technical requirements for aluminium structures

Eurocode 9 - Bemessung und Konstruktion von Aluminiumtragwerken - Teil 1 2: Tragwerksbemessung für den Brandfall

1.1   Anwendungsbereich von EN 1999 1 2
(1) Dieses Dokument behandelt die Bemessung von Aluminiumkonstruktionen für den außergewöhnlichen Fall der Brandeinwirkung. Seine Anwendung gilt in Verbindung mit EN 1999 1 1, EN 1999 1 3, EN 1999 1 4 und EN 1999 1 5. Dieses Dokument beschränkt sich auf die Unterschiede oder Ergänzungen zur Bemessung bei normaler Temperatur.
(2) Dieses Dokument gilt für Tragwerke aus Aluminium, die eine lasttragende Funktion erfüllen müssen.
(3) Dieses Dokument liefert Grundsätze und Anwendungsregeln für die Bemessung von Tragwerken, für bestimmte Anforderungen im Hinblick auf die vorstehend genannte Funktion und die Leistungsstufen.
(4) Dieses Dokument gilt für Tragwerke oder Teile davon, die in den Anwendungsbereich von EN 1999 1 1 fallen und danach bemessen wurden.
(5) Die Verfahren nach EN 1999 1 2 gelten für die folgenden Aluminiumlegierungen:
EN AW 3004 – H34   EN AW 5083 – O und H12   EN AW 6063 – T5 und T6
EN AW 5005 – O und H34   EN AW 5454 – O und H34   EN AW 6082 – T4 und T6
EN AW 5052 – H34   EN AW 6061 – T6   
(6) Die in diesem Dokument angegebenen Verfahren sind auch für andere Aluminiumlegierungen nach EN 1999 1 1 anwendbar, wenn verlässliche Hochtemperatureigenschaften vorliegen oder vereinfachte Annahmen in 5.2.1 angegeben sind.
1.2   Annahmen
(1) Zusätzlich zu den allgemeinen Annahmen in EN 1990 gelten die folgenden Annahmen:
-   Die Wahl des maßgebenden Brandszenarios wird durch entsprechend qualifiziertes Personal getroffen oder wird durch die zuständigen nationalen Regeln festgelegt.
-   Jede berücksichtigte passive oder aktive Brandschutzmaßnahme wird angemessen gewartet.
(2) Bezüglich der Bemessung neuer Tragwerke ist EN 1999 zur direkten Anwendung in Verbindung mit EN 1990, EN 1991, EN 1992, EN 1993, EN 1994, EN 1995, EN 1997, EN 1998 und EN 1999 vorgesehen.
(3) EN 1999 gilt in Verbindung mit folgenden Regelwerken:
-   Europäische Normen für Bauprodukte, die für Tragwerke aus Aluminium Verwendung finden;
-   EN 1090 1, Ausführung von Stahltragwerken und Aluminiumtragwerken — Teil 1: Konformitäts-nachweisverfahren für tragende Bauteile;
-   EN 1090 3, Ausführung von Stahltragwerken und Aluminiumtragwerken — Teil 3: Technische Regeln für die Ausführung von Aluminiumtragwerken.

Eurocode 9 - Calcul des structures en aluminium - Partie 1-2: Calcul du comportement au feu

1.1   Domaine d'application de l'EN 1999-1-2
(1)   Le présent document traite du calcul de structures en aluminium pour la situation accidentelle d'exposition au feu. Elle est destinée à être utilisée conjointement avec l'EN 1999-1-1, l'EN 1999-1-3, l'EN 1999-1-4 et l'EN 1999-1-5. Le présent document identifie uniquement les différences avec le calcul à température normale, ou lui apporte des compléments.
(2)   Le présent document s'applique aux structures en aluminium devant remplir une fonction porteuse.
(3)   Le présent document donne les principes et les règles d'application relatifs au calcul des structures par rapport aux exigences spécifiées eu égard à la fonction mentionnée ci-dessus et aux niveaux de performances.
(4)   Le présent document s'applique aux structures, ou aux parties de structures, relevant du domaine d'application de l'EN 1999 1 1 et conçues en conséquence.
(5)   Les méthodes qui figurent dans le présent document sont applicables aux alliages d'aluminium suivants :
EN AW-3004 – H34   EN AW-5083 – O et H12   EN AW-6063 – T5 et T6
EN AW-5005 – O et H34   EN AW-5454 – O et H34   EN AW-6082 – T4 et T6
EN AW-5052 – H34   EN AW-6061 – T6   
(6)   Les méthodes qui figurent dans le présent document sont aussi applicables aux autres alliages d'aluminium de l'EN 1999 1-1 si des propriétés de matériaux fiables sont disponibles à des températures élevées ou si les hypothèses simplifiées du paragraphe 5.2.1 sont appliquées.
1.2   Hypothèses
(1)   Outre les hypothèses générales définies dans l'EN 1990, les hypothèses suivantes s'appliquent :
-   le choix du scénario d'incendie de calcul pertinent est fait par un personnel qualifié et expérimenté approprié, ou est indiqué par la réglementation nationale pertinente ;
-   les systèmes de protection active et passive contre l'incendie dont le calcul tient compte doivent faire l'objet d'un entretien approprié.
(2)   Pour le calcul des structures à construire, l'EN 1999 est destinée à être appliquée directement, de façon conjointe avec l'EN 1990, EN 1991, l'EN 1992, l'EN 1993, l'EN 1994, l'EN 1995, l'EN 1997, l'EN 1998 et l'EN 1999.
(3)   L'EN 1999 est destinée à être utilisée avec :
-   les Normes européennes pour les produits de construction appropriés aux structures en aluminium ;
-   l'EN 1090-1, Exécution des structures en acier et des structures en aluminium — Partie 1 : Exigences pour l'évaluation de la conformité des éléments structuraux ;
-   l'EN 1090-3, Exécution des structures en acier et des structures en aluminium — Partie 3 : Exigences techniques pour l'exécution des structures en aluminium.

Evrokod 9 - Projektiranje konstrukcij iz aluminijevih zlitin - 1-2. del: Projektiranje požarnovarnih konstrukcij

General Information

• Status: Not Published
• Public Enquiry End Date: 19-May-2021
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• ICS: 91.010.30 - Technical aspects
• ICS: 91.080.17 - Aluminium structures
• Technical Committee: KON - Structures
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 17-Mar-2021
• Due Date: 04-Aug-2021
• Completion Date: 28-May-2021
• Mandate: M/515 - Mandate for amending existing Eurocodes and extending the scope of structural Eurocodes
• Ref Project: prEN 1999-1-2 - Eurocode 9 - Design of aluminium structures - Part 1-2: Structural fire design

RELATIONS

• Revised: SIST EN 1999-1-2:2007 - Eurocode 9 - Design of aluminium structures - Part 1-2: Structural fire design
• Effective Date: 01-May-2021

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 1999-1-2:2021
01-maj-2021

Evrokod 9 - Projektiranje konstrukcij iz aluminijevih zlitin - 1-2. del: Projektiranje

požarnovarnih konstrukcij
Eurocode 9 - Design of aluminium structures - Part 1-2: Structural fire design
Eurocode 9 - Bemessung und Konstruktion von Aluminiumtragwerken - Teil 1 2:
Tragwerksbemessung für den Brandfall

Eurocode 9 - Calcul des structures en aluminium - Partie 1-2: Calcul du comportement

au feu
Ta slovenski standard je istoveten z: prEN 1999-1-2
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
91.010.30 Tehnični vidiki Technical aspects
91.080.17 Aluminijaste konstrukcije Aluminium structures
oSIST prEN 1999-1-2:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 1999-1-2:2021
DRAFT
EUROPEAN STANDARD
prEN 1999-1-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2021
ICS 13.220.50; 91.010.30; 91.080.17 Will supersede EN 1999-1-2:2007
English Version
Eurocode 9 - Design of aluminium structures - Part 1-2:
Structural fire design

Eurocode 9 - Calcul des structures en aluminium - Eurocode 9 - Bemessung und Konstruktion von

Partie 1-2: Calcul du comportement au feu Aluminiumtragwerken - Teil 1 2:
Tragwerksbemessung für den Brandfall

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 250.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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 CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1999-1-2:2021 E

worldwide for CEN national Members.
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Contents Page

European foreword ............................................................................................................................................. 4

Introduction .......................................................................................................................................................... 5

1 Scope .......................................................................................................................................................... 7

1.1 Scope of EN 1999-1-2 ........................................................................................................................... 7

1.2 Assumptions ............................................................................................................................................ 7

2 Normative references .......................................................................................................................... 8

3 Terms, definitions and symbols ....................................................................................................... 8

3.1 Terms and definitions ......................................................................................................................... 8

3.2 Symbols and abbreviations ............................................................................................................... 9

4 Basis of design ......................................................................................................................................13

4.1 General ....................................................................................................................................................13

4.2 Nominal fire exposure .......................................................................................................................13

4.3 Physically based fire exposure .......................................................................................................13

4.4 Actions .....................................................................................................................................................13

4.5 Design values of material properties ...........................................................................................13

4.6 Verification methods .........................................................................................................................14

4.7 Structural analysis ..............................................................................................................................14

4.7.1 General ....................................................................................................................................................14

4.7.2 Member analysis .................................................................................................................................14

4.7.3 Analysis of part of the structure ....................................................................................................15

4.7.4 Global structural analysis ................................................................................................................15

5 Material properties ............................................................................................................................15

5.1 General ....................................................................................................................................................15

5.2 Thermal properties ............................................................................................................................16

5.2.1 Aluminium alloys ................................................................................................................................16

5.2.2 Fire protection materials .................................................................................................................18

5.3 Mechanical properties of aluminium alloys ..............................................................................18

5.3.1 Strength and deformation properties .........................................................................................18

5.3.2 Unit mass ................................................................................................................................................21

6 Tabulated design data .......................................................................................................................21

7 Simplified design methods ..............................................................................................................22

7.1 General ....................................................................................................................................................22

7.2 Resistance ..............................................................................................................................................23

7.2.1 Classification of cross-sections ......................................................................................................23

7.2.2 Tension members ...............................................................................................................................23

7.2.3 Beams ......................................................................................................................................................23

7.2.4 Columns ..................................................................................................................................................25

7.3 Aluminium temperature development .......................................................................................26

7.3.1 Unprotected interior aluminium members ...............................................................................26

7.3.2 Interior aluminium structures insulated by fire protection material .............................29

7.3.3 Interior aluminium structures in a void that is protected by heat screens ...................30

7.3.4 Exterior aluminium structures ......................................................................................................31

8 Advanced design methods ...............................................................................................................32

8.1 General ....................................................................................................................................................32

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8.2 Thermal analysis ................................................................................................................................ 32

8.3 Mechanical analysis ........................................................................................................................... 32

8.4 Validation of advanced design methods ..................................................................................... 33

Annex A (informative) Properties of aluminium alloys and/or tempers not listed in EN

1999-1-1 ................................................................................................................................................. 34

A.1 Use of this Informative Annex ........................................................................................................ 34

A.2 Scope and field of application ........................................................................................................ 34

Annex B (informative) Heat transfer to external structural aluminium members ................... 35

B.1 Use of this Informative Annex ........................................................................................................ 35

B.2 Scope and field of application ........................................................................................................ 35

B.3 General rules ........................................................................................................................................ 35

B.4 Column not engulfed in flame ........................................................................................................ 38

B.5 Beam not engulfed in flame ............................................................................................................ 44

B.6 Column engulfed in flame ................................................................................................................ 47

B.7 Beam fully or partially engulfed in flame .................................................................................. 49

Bibliography ....................................................................................................................................................... 53

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European foreword

This document (prEN 1999-1-2:2021) has been prepared by Technical Committee CEN/TC250

"Structural Eurocodes", the secretariat of which is held by BSI. CEN/TC 250 is responsible for all

Structural Eurocodes and has been assigned responsibility for structural and geotechnical design matters

by CEN.
This document will supersede EN 1999-1-2:2007.

The first generation of EN Eurocodes was published between 2002 and 2007. This document forms part

of the second generation of the Eurocodes, which have been prepared under Mandate M/515 issued to

CEN by the European Commission and the European Free Trade Association.

The Eurocodes have been drafted to be used in conjunction with relevant execution, material, product

and test standards, and to identify requirements for execution, materials, products and testing that are

relied upon by the Eurocodes.

The Eurocodes recognize the responsibility of each member State and have safeguarded their right to

determine values related to regulatory safety matters at national level through the use of National

Annexes.
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Introduction
0.1 Introduction to the Eurocodes

The Structural Eurocodes comprise the following standards generally consisting of a number of Parts:

• EN 1990 Eurocode: Basis of structural and geotechnical 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
• EN 1998 Eurocode 8: Design of structures for earthquake resistance
• EN 1999 Eurocode 9: Design of aluminium structures
•

The Eurocodes are intended for use by designers, clients, manufacturers, constructors, relevant

authorities (in exercising their duties in accordance with national or international regulations),

educators, software developers, and committees drafting standards for related product, testing and

execution standards.

NOTE Some aspects of design are most appropriately specified by relevant authorities or, where not specified,

can be agreed on a project-specific basis between relevant parties such as designers and clients. The Eurocodes

identify such aspects making explicit reference to relevant authorities and relevant parties.

0.2 Introduction to EN 1999 Eurocode 9

EN 1999 applies to the design of buildings and civil engineering and structural works made of aluminium.

It complies with the principles and requirements for the safety and serviceability of structures, the basis

of their design and verification that are given in EN 1990 – Basis of structural design.

EN 1999 is only concerned with requirements for resistance, serviceability, durability and fire resistance

of aluminium structures. Other requirements, e.g. concerning thermal or sound insulation, are not

considered.

EN 1999 does not cover the special requirements of seismic design. Provisions related to such

requirements are given in EN 1998, which complements, and is consistent with EN 1999.

EN 1999 is subdivided in five parts:
— EN 1999-1-1 Design of Aluminium Structures: General structural rules.
— EN 1999-1-2 Design of Aluminium Structures: Structural fire design.
— EN 1999-1-3 Design of Aluminium Structures: Structures susceptible to fatigue.
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— EN 1999-1-4 Design of Aluminium Structures: Cold-formed structural sheeting.
— EN 1999-1-5 Design of Aluminium Structures: Shell structures.
0.3 Introduction to EN 1999-1-2

This document describes the principles, requirements and rules for the structural design of aluminium

buildings exposed to fire. The focus in EN 1999-1-2 is on design methods and design rules for individual

members (beams, columns, beam-columns), joints and skeletal structures (frames) regarding resistance

and stability under fire conditions.
0.4 Verbal forms used in the Eurocodes

The verb “shall" expresses a requirement strictly to be followed and from which no deviation is permitted

in order to comply with the Eurocodes.

The verb “should” expresses a highly recommended choice or course of action. Subject to national

regulation and/or any relevant contractual provisions, alternative approaches could be used/adopted

where technically justified.

The verb “may" expresses a course of action permissible within the limits of the Eurocodes.

The verb “can" expresses possibility and capability; it is used for statements of fact and clarification of

concepts.
0.5 National annex for prEN 1999-1-2

National choice is allowed in this standard where explicitly stated within notes. National choice includes

the selection of values for Nationally Determined Parameters (NDPs).

The national standard implementing EN 1999-1-2 can have a National Annex containing all national

choices to be used for the design of buildings and civil engineering works to be constructed in the relevant

country.

When no national choice is given, the default choice given in this standard is to be used.

When no national choice is made and no default is given in this standard, the choice can be specified by a

relevant authority or, where not specified, agreed for a specific project by appropriate parties.

National choice is allowed in EN 1999-1-2 through the following clauses:
4.5(1) NOTE
4.7(1) NOTE
7.2.1 (1) NOTE
7.2.3 (5) NOTE
7.2.4 (4) NOTE

National choice is allowed in EN 1999-1-2 on the application of the following informative annexes:

Annex A (informative) Properties of aluminium alloys and/or tempers not listed in EN 1999-1-1

Annex B (informative) Heat transfer to external structural aluminium members

The National Annex can contain, directly or by reference, non-contradictory complementary information

for ease of implementation, provided it does not alter any provisions of the Eurocodes.

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1 Scope
1.1 Scope of EN 1999-1-2

(1) This document deals with the design of aluminium structures for the accidental situation of fire

exposure and is intended to be used in conjunction with EN 1999-1-1, EN 1999-1-3, EN 1999-1-4 and

EN 1999-1-5. This document only identifies differences from, or supplements to, normal temperature

design.

(2) This document applies to aluminium structures required to fulfil a load bearing function.

(3) This document gives principles and application rules for the design of structures for specified

requirements in respect of the aforementioned function and the levels of performance.

(4) This document applies to structures, or parts of structures, that are within the scope of EN 1999-1-1

and are designed accordingly.

(5) The methods given in this document are applicable to the following aluminium alloys:

EN AW-3004 – H34 EN AW-5083 – O and H12 EN AW-6063 – T5 and T6
EN AW-5005 – O and H34 EN AW-5454 – O and H34 EN AW-6082 – T4 and T6
EN AW-5052 – H34 EN AW-6061 – T6

(6) The methods given in this document are applicable also to other aluminium alloy/tempers of

EN 1999-1-1, if reliable material properties at elevated temperatures are available or the simplified

assumptions in 5.2.1 are applied.
1.2 Assumptions

(1) In addition to the general assumptions of EN 1990, the following assumptions apply:

— the choice of the relevant design fire scenario is made by appropriate qualified and experienced

personnel, or is given by the relevant national regulation.

— any active and passive fire protection systems taken into account in the design will be adequately

maintained.

(2) For the design of new structures, EN 1999 is intended to be used, for direct application, together with

EN 1990, EN 1991, EN 1992, EN 1993, EN 1994, EN 1995, EN 1997, EN 1998 and EN 1999.

(3) EN 1999 is intended to be used in conjunction with:
— European Standards for construction products relevant for aluminium structures

— EN 1090-1, Execution of steel structures and aluminium structures - Part 1: Requirements for

conformity assessment of structural components

— EN 1090-3, Execution of steel structures and aluminium structures - Part 3: Technical requirements for

aluminium structures
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2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

NOTE See the Bibliography for a list of other documents cited that are not normative references, including

those referenced as recommendations (i.e. through ‘should’ clauses) and permissions (i.e. through ‘may’ clauses).

EN 1990, Eurocode - Basis of structural and geotechnical design

EN 1991-1-2, Eurocode 1: Actions on structures - Part 1-2: General actions - Actions on structures exposed

to fire

EN 1999-1-1, Eurocode 9: Design of aluminium structures - Part 1-1: General structural rules

3 Terms, definitions and symbols
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1990 and EN 1991-1-2 and the

following apply.
3.1.1
part of structure
isolated part of a structure with appropriate support and boundary conditions
3.1.2
fire protection material

any material or combination of materials applied to a structural member for the purpose of increasing its

fire resistance
3.1.3
section factor

ratio of the exposed surface area to the volume of aluminium or, in case of enclosed members, of the

exposed encasement to the volume of aluminium
3.1.4
box value of section factor

ratio of the exposed surface area of a notional bounding box to the section and the volume of aluminium

3.1.5
critical temperature of a structural aluminium member

for a given load level, the temperature at which failure is expected to occur in a structural aluminium

element assuming a uniform temperature distribution
3.1.6
effective 0,2 % proof strength

for a given temperature, the stress level at which the stress-strain relationship of aluminium gives a 0,2 %

permanent strain
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3.2 Symbols and abbreviations
For the purpose of this document, the following symbols apply.
Latin upper case letters:
A an elemental area of the cross-section with a temperature θi
A exposed surface area of a member per unit length [m /m]
A /V section factor of unprotected aluminium members [m ];

A area of the inner surface of the fire protection material per unit length of the member

A /V section factor for aluminium members insulated by fire protection material members [m ]

C protection coefficient of member face i
E modulus of elasticity of aluminium for normal temperature design
E modulus of elasticity for aluminium at elevated temperature, θ
al,θ al

E design effect of actions at normal temperature, determined in accordance with EN 1990 and

EN 1991-1-1

E design effect of actions for the fire situation, determined in accordance with EN 1991-1-2,

fi,d
including the effects of thermal expansions and deformations
I radiative heat flux from an opening
I radiative heat flux from a flame to the beam face
I radiative heat flux from a flame to a column face
z,i
L system length of a column in the relevant storey
L horizontal projection of the flame (from the facade)
L length along axis between the opening and the relevant point
L flame height (from the upper part of the window)
Lx distance from the opening measured along the flame axis

M design buckling resistance moment for normal temperature design, according to EN 1999-1-1

b,Rd
M design moment for the fire situation
fi,Ed
M design buckling resistance moment in the fire situation at time t
b,fi,t,Rd

M design moment resistance in the fire situation at time t of a cross-section with a non-uniform

fi,t,Rd
temperature distribution

M is the moment resistance of the cross-section for normal temperature design, either M or

Rd c,Rd
u,Rd
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N buckling resistance of a compressed member for normal temperature design according to

b,Rd
EN 1999-1-1
N design axial force for the fire situation
fi,Ed

N design buckling resistance in the fire situation at time t of a compressed member

b,fi,t,Rd

N design resistance in the fire situation at time t of a tension member with a non-uniform

fi,t,Rd
temperature distribution across the cross-section
N design resistance of a tension member with a uniform temperature θ
fi,q,Rd al
R design resistance in the fire situation at time t
fi,d,t
T temperature of fire [K]
T temperature of the aluminium member [K]
T flame temperature at the opening [K]
T flame temperature at the flame tip [813 K]
T flame temperature [K]

T flame temperature [K] from Annex B of prEN 1991-1-2:20XX, at the bottom of a beam

z,1

T flame temperature [K] from Annex B of prEN 1991-1-2:20XX, at the top of a beam

z,2
V volume of a member per unit length

V shear resistance of the net cross-section for normal temperature design, according to

EN 1999-1-1.
V design shear force for the fire situation
fi,Ed
V design shear resistance in the fire situation at time t
fi,t,Rd

X characteristic value of a strength or deformation property (generally fk or Ek) for normal

temperature design to EN 1999-1-1
Latin lower case letters:
a absorptivity of flames
c specific heat of aluminium
c specific heat of the fire protection material
d effective cross-sectional dimension
d flame thickness
d cross-sectional dimension of member face i
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oSIST prEN 1999-1-2:2021
prEN 1999-1-2:2021 (E)
d thickness of fire protection material
f effective 0,2 % proof strength at elevated temperature, θ
o,θ al
h equivalent height of the opening
h design value of the net heat flux per unit area
net,d
h height of the top of the flame above the bottom of the beam

k relative value of a strength or deformation property of aluminium at elevated temperature θa

k strength reduction factor for the 0,2 proof strength at at temperature θ
o,θ al

k is the reduction factor for the effective 0,2 % proof strength at the temperature θ in the

o,θ,i i
elemental area A .

k the strength reduction factor for the 0,2 proof strength at the maximum aluminium

o,θmax
temperature
k correction factor for the shadow effect
l length at 20 °C; a distance from an opening, measured along the flame axis
l buckling length of a column for the fire design situation
m number of openings on side m
n number of openings on side n

s horizontal distance from the centreline of a column to a wall of a fire compartment

t time in fire exposure
w width of an opening
z distance from the plastic neutral axis to the centroid of the elemental area A
i i
Greek lower-case letters
α heat transfer coefficient for convection [kW/m K]
α heat transfer coefficient for radiation [kW/m K]

γ partial safety factor for the relevant material property for the fire situation

M,fi
η reduction factor applied to Ed in order to obtain Efi,d
θ temperature in °C
θ aluminium temperature
θ ambient gas temperature at time t (°C)
(t)
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oSIST prEN 1999-1-2:2021
prEN 1999-1-2:2021 (E)
θ aluminium temperature at time t (°C)
al(t)
θ maximum temperature of the cross section reached at time t
al,max
ε emissivity of a flame; the emissivity of an opening
ε surface emissivity of the component
ε emissivity of a flame
ε total emissivity of the flames on side m
z,m
ε total emissivity of the flames on side n
z,n
κ adaptation factor
λ thermal conductivity of aluminium
λ thermal conductivity of the fire protection material
μ degree of utilization at time t = 0
ρ density of aluminium
ρ the density of the fire protection material
-12 2 4
σ Stefan Boltzmann constant [56,7 × 10 kW/(m K )]

ϕ overall configuration factor of the member for radiative heat transfer from the opening

ϕ configuration factor of member face i for an opening
f,i

ϕ overall configuration factor of the member for radiative heat transfer from the flame

ϕ configuration factor of member face i for a flame
z,i
ϕ overall configuration factor of the column for heat from flames on side m
z,m
ϕ overall configuration factor of the column for heat from flames on side n
z,n
μ degree of utilization at time t = 0
ρ density of aluminium
ρ the density of the fire protection material
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oSIST prEN 1999-1-2:2021
prEN 1999-1-2:2021 (E)
4 Basis of design
4.1 General

(1) Where mechanical resistance in the case of fire is required, aluminium structures shall be designed

...