EN 1999-1-2:2023

SLOVENSKI STANDARD
SIST EN 1999-1-2:2023
01-september-2023
Nadomešča:
SIST EN 1999-1-2:2007
SIST EN 1999-1-2:2007/AC:2009
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: EN 1999-1-2:2023
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
SIST EN 1999-1-2:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SIST EN 1999-1-2:2023
SIST EN 1999-1-2:2023
EN 1999-1-2
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2023
EUROPÄISCHE NORM
ICS 13.220.50; 91.010.30; 91.080.17 Supersedes 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 European Standard was approved by CEN on 2 January 2023.

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 CEN-CENELEC Management Centre 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 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, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1999-1-2:2023 E
worldwide for CEN national Members.

SIST EN 1999-1-2:2023
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 .14
4.5 Design values of material properties .14
4.6 Verification methods .14
4.7 Member analysis .15
4.8 Analysis of part of the structure .15
4.9 Global structural analysis .15
5 Material properties .16
5.1 General .16
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 .31
8.1 General .31
SIST EN 1999-1-2:2023
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.3.1 Basis. 35
B.3.2 Conventions for dimensions . 35
B.3.3 Heat balance . 35
B.3.4 Overall configuration factors . 38
B.4 Column not engulfed in flame . 38
B.4.1 Radiative heat transfer . 38
B.4.2 Flame emissivity . 43
B.4.3 Flame temperature . 44
B.4.4 Flame absorptivity . 44
B.5 Beam not engulfed in flame . 44
B.5.1 Radiative heat transfer . 44
B.5.2 Flame emissivity . 46
B.5.3 Flame temperature . 47
B.5.4 Flame absorptivity . 48
B.6 Column engulfed in flame . 48

B.7 Beam fully or partially engulfed in flame . 50
B.7.1 Radiative heat transfer . 50
B.7.2 Flame emissivity . 54
B.7.3 Flame absorptivity . 54
Bibliography . 55

SIST EN 1999-1-2:2023
European foreword
This document (EN 1999-1-2:2023) 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 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 September 2027, and conflicting national standards shall
be withdrawn at the latest by March 2028.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes 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.
The main changes compared to the previous edition are listed below:
— Some reorganization of the text and its coherence with other Eurocodes;
— Improvement of figures;
— Update of symbols, alignment across the Eurocodes;
— Improved clarity and consistency.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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, Türkiye and the United
Kingdom.
SIST EN 1999-1-2:2023
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
• New parts are under development, e.g. Eurocode for design of structural glass
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 (all parts)
EN 1999 (all parts) 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 (all parts) 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 (all parts) 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.
Eurocode 9 is subdivided various parts:
— EN 1999-1-1 Design of Aluminium Structures — Part 1-1: General rules.
— EN 1999-1-2 Design of Aluminium Structures — Part 1-2: Structural fire design.
— EN 1999-1-3 Design of Aluminium Structures — Part 1-3: Structures susceptible to fatigue.
SIST EN 1999-1-2:2023
— EN 1999-1-4 Design of Aluminium Structures — Part 1-4: Cold-formed structural sheeting.
— EN 1999-1-5 Design of Aluminium Structures — Part 1-5: 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 EN 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) 7.2.1(1) 7.2.3(5) 7.2.4(4)
National choice is allowed in EN 1999-1-2 on the application of the following informative annexes:
Annex A Annex B
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.
SIST EN 1999-1-2:2023
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, provided that either all necessary information on 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 and EN 1998.
(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
SIST EN 1999-1-2:2023
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 design
prEN 1991-1-2:2021, Eurocode 1 — Actions on structures - Part 1-2: General actions - Actions on
structures exposed to fire
EN 1999-1-1:2023, Eurocode 9 — Design of aluminium structures - Part 1-1: General 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 prEN 1991-1-2:2021
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
Under preparation.
SIST EN 1999-1-2:2023
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 θ
i i
A exposed surface area of a member per unit length
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
p
A /V section factor for aluminium members insulated by fire protection material members
p
C protection coefficient of member face i
i
E modulus of elasticity of aluminium for normal temperature design
al
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
d
EN 1991-1–1
design effect of actions for the fire situation, determined in accordance with prEN 1991 1–
E,d,fi
2:2021, including the effects of thermal expansions and deformations
I radiative heat flux from an opening
f
I radiative heat flux from a flame to the beam face
z
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)
H
L length along axis between the opening and the relevant point
i
L flame height (from the upper part of the window)
L
Lx distance from the opening measured along the flame axis
M design buckling resistance moment for normal temperature design, according to EN 1999-1–
b,Rd
1:2023
M design moment for the fire situation
Ed,fi
M design buckling resistance moment in the fire situation at time t
b,Rd,fi,t
M design moment resistance in the fire situation at time t of a cross-section with a non-uniform
Rd,fi,t
temperature distribution
SIST EN 1999-1-2:2023
M design moment resistance of the cross-section for normal temperature design, either M or
Rd c,Rd
M
u,Rd
N design buckling resistance of a compressed member for normal temperature design
b,Rd
according to EN 1999-1–1:2023
N design axial force for the fire situation
Ed,fi
N design buckling resistance in the fire situation at time t of a compressed member
b,Rd,fi,t
N design resistance in the fire situation at time t of a tension member with a non-uniform
Rd,fi,t
temperature distribution across the cross-section
N design resistance of a tension member with a uniform temperature θ
Rd,fi,θ al
R design resistance in the fire situation at time t
d,fi,t
T temperature of fire
f
T temperature of the aluminium member
m
T flame temperature at the opening
o
T flame temperature at the flame tip
x
T flame temperature
z
T flame temperature from Annex B of prEN 1991-1–2:2021, at the bottom of a beam
z,1
T flame temperature from Annex B of prEN 1991-1–2:2021, at the top of a beam
z,2
V volume of a member per unit length
V design shear resistance of the net cross-section for normal temperature design, according to
Rd
EN 1999-1–1:2023.
V design shear force for the fire situation
Ed,fi
V design shear resistance in the fire situation at time t
Rd,fi,t
X characteristic value of a strength or deformation property (generally f or E ) for normal
k k k
temperature design to EN 1999-1–1:2023
SIST EN 1999-1-2:2023
Latin lower case letters:
a absorptivity of flames
z
c specific heat of aluminium
al
c specific heat of the fire protection material
p
d effective cross-sectional dimension
eq
d flame thickness
f
d cross-sectional dimension of member face i
i
d thickness of fire protection material
p
f effective 0,2 % proof strength at elevated temperature, θ
o,θ al
h equivalent height of the opening
eq
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
z
k relative value of a strength or deformation property of aluminium at elevated temperature θ
θ al
k strength reduction factor for the 0,2 % proof strength at the temperature θ
o,θ al
k reduction factor for the effective 0,2 % proof strength at the temperature θ in the elemental
o,θ,i i
area A .
i
k the strength reduction factor for 0,2 % proof strength at the maximum aluminium
o,θmax
temperature
k correction factor for the shadow effect
sh
l length at 20 °C; distance from an opening, measured along the flame axis
l buckling length of a column for the fire design situation
fi
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
t
z distance from the plastic neutral axis to the centroid of the elemental area A
i i
SIST EN 1999-1-2:2023
Greek lower-case letters
α heat transfer coefficient for convection
c
α heat transfer coefficient for radiation
r
γ partial safety factor for the relevant material property for the fire situation
M,fi
η reduction factor applied to E in order to obtain E
fi d fi,d
θ temperature in °C
θ aluminium temperature
al
θ ambient gas temperature at time t
(t)
θ aluminium temperature at time t
al(t)
θ maximum temperature of the cross section reached at time t
al,max(t)
ε emissivity of a flame; emissivity of an opening
f
ε surface emissivity of the component
m
ε emissivity of a flame
z
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
al
λ thermal conductivity of the fire protection material
p
μ degree of utilization at time t = 0
ρ density of aluminium
al
ρ the density of the fire protection material
p
−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
f
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
z
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
SIST EN 1999-1-2:2023
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
al
ρ the density of the fire protection material
p
4 Basis of design
4.1 General
(1) Where mechanical resistance in the case of fire is required, aluminium structures shall be designed
and constructed in such a way that they maintain their load bearing function during the relevant fire
exposure.
(2) Deformation criteria shall be applied where the means of protection require consideration of the
deformation of the load bearing structure.
(3) Consideration of the deformation of the loadbearing structure may be omitted, when the efficiency
of the means of protection has been evaluated according to 5.2.2.
(4) Deformation criteria shall be applied where the design criteria for separating elements require
consideration of the deformation of the load bearing structure.
(5) Consideration of the deformation of the load bearing structure may be neglected when the separating
elements fulfil requirements of a nominal fire exposure, see 4.2.
4.2 Nominal fire exposure
(1) For standard fire exposure, elements shall comply with one of the following functions or
combinations of function defined in during the required time of fire exposure:
— loadbearing function: loadbearing capacity (R);
— separating function: integrity (E) and, when requested, insulation (I);
— separating and loadbearing functions: R, E and, when requested, I.
(2) The loadbearing function is assumed to be satisfied when loadbearing capacity is maintained.
(3) The separating function is assumed to be satisfied when integrity and, when requested, insulation is
maintained.
(4) Integrity is assumed to be maintained when a separating element of building construction, exposed
to fire on one side, prevents the passage through it of flames and hot gases and the occurrence of flames
on the unexposed side.
(5) Insulation is assumed to be maintained when the average temperature rise over the whole of the
unexposed surface is limited to 140 K, and the maximum temperature rise at any point of that surface
does not exceed 180 K.
(6) When the external fire exposure curve is used, the same function shall apply, with the reference to
this specific curve identified by the letters “ef”.
4.3 Physically based fire exposure
(1) The loadbearing function shall be maintained during the complete duration of the fire, including the
cooling phase, or during a required period of time according to 4.4 (4) of prEN 1991 1-2:2021.
SIST EN 1999-1-2:2023
4.4 Actions
(1) Thermal and mechanical actions shall be taken from EN 1991 1-2:2023.
4.5 Design values of material properties
(1) Design values of mechanical (strength and stiffness) material properties X should be determined
d,fi
from Formula (4.1):
X = k X /γ (4.1)
d,fi θ k M,fi
where
X is the characteristic value of a strength or stiffness property (generally f or E ) for
k k k
normal temperature design according to EN 1999-1–1:2023;
k is the temperature-dependent reduction factor for a strength or stiffness property
θ
(X /X );
k,θ k
γ is the partial factor for the relevant mechanical material property in the fire situation.
M,fi
NOTE The value of γ is 1,0 unless the National Annex gives a different value.
M,fi
(2) The design values of thermal material properties for the fire situation shall be taken equal to their
characteristic values.
NOTE The characteristic values of thermal material properties correspond to mean values.
4.6 Verification methods
(1) The model of the structural system adopted for design shall reflect the performance of the structure
in the fire situation.
(2) Mechanical resistance shall be verified for the required duration of fire exposure t according to
Formula (4.2):
≤ R (4.2)
Ed,fi d,fi,t
where
E is the design effect of actions for the fire situation, determined in accordance with 6.3 of
d,fi
prEN 1991-1–2:2021, including effects of thermal expansions and deformations;
R is the corresponding design resistance in the fire situation.
d,fi,t
(3) The structural analysis for the fire situation should be carried out according to EN 1990.
NOTE For verifying resistance requirements based on the standard fire curve, unless otherwise specified, a
member analysis is sufficient.
(4) If not specified in the relevant clauses, the verification methods given in this part EN 1999-1-2 may
be applied for all types of fire exposure.
(5) The following design methods may be used in order to satisfy 4.6 (2):
— use of tabulated design data for specific types of members, see 6;
— use of simplified design methods for specific types of members, see 7;
SIST EN 1999-1-2:2023
— use of advanced design methods for the analysis of members, parts of the structure or the entire
structure, see 8.
(6) As an alternative to design by calculation, fire design may be based on the results of fire tests, or on
fire tests in combination with calculations.
4.7 Member analysis
(1) The design effect of actions should be determined for time t = 0 using combination factors according
to 6.3 of prEN 1991-1-2:2021.
(2) As a simplification, the value of η = 0,65 should be used, except for imposed loads according to
fi
category E as given in EN 1991-1-1 (areas susceptible to accumulation of goods, including access areas)
where the value should be η = 0,7.
fi
(3) The effects of thermal deformations resulting from thermal gradients across the cross-section shall
be considered. The effects of axial or in-plain thermal expansions may be neglected.
(4) The kinematic boundary conditions at supports and ends of a member, applicable at time t = 0, may
be assumed to remain unchanged throughout the fire exposure.
(5) Tabulated design data for simplified or advanced design methods given in Clauses 6, 7 and 8
respectively may be taken as suitable for verifying members under fire conditions.
4.8 Analysis of part of the structure
(1) The effect of actions should be determined for time t = 0 using combination factors according to 6.3
of prEN 1991-1-2:2021.
(2) Within the part of the structure to be analysed, the relevant failure mode in fire, the temperature-
dependent material properties and member stiffness, effects of thermal expansions and deformations
(indirect fire actions) shall be taken into account.
(3) The part of the structure to be analysed should be specified on the basis of the potential thermal
expansions and deformations such that their interaction with other parts of the structure can be
approximated by time-independent support and boundary conditions during fire exposure.
(4) As an alternative to 4.8(1), the reactions at supports and internal forces and moments at boundaries
of part of the structure may be obtained from structural analysis for normal temperature design as given
in 4.7.
4.9 Global structural analysis
(1) A global structural analysis for the fire situation shall take into account:
— the relevant failure mode in fire exposure;
— the temperature-dependent material properties and member stiffness;
— effects of thermal expansions and deformations (indirect fire actions).
SIST EN 1999-1-2:2023
5 Material properties
5.1 General
(1) Unless given as design values, the values of material properties given in Clause 5 shall be treated as
characteristic values.
(2) The mechanical properties of aluminium alloys at normal temperature 20 °C shall be taken as those
given in EN 1999-1-1 for normal temperature design.
5.2 Thermal properties
5.2.1 Aluminium alloys
5.2.1.1 Thermal elongation
(1) The relative thermal elongation (strain) of aluminium alloys, Δl/l, should be determined from
Formula (5.1):
for 0 °C < θ < 500 °C
al
−7 2 −6 −4
Δl/l = 0,1·10 θ + 22,5·10 θ – 4,5·10 (5.1)
al al
where
l is the length at 20 °C;
Δl is the temperature induced elongation.
NOTE The variation in the relative thermal elongation with temperature is illustrated in Figure 5.1.

Figure 5.1 — Relative thermal elongation of aluminium alloys as a function of the temperature
SIST EN 1999-1-2:2023
5.2.1.2 Specific heat
(1) The specific heat of aluminium, c , should be determined from Formula (5.2):
al
for 0 °C < θ < 500 °C
al
cal = 0,41θal + 903 (J/kg °C) (5.2)
NOTE The variation in specific heat is illustrated in Figure 5.2.

Figure 5.2 — Specific heat of aluminium alloys as a function of the temperature
5.2.1.3 Thermal conductivity
(1) The thermal conductivity of aluminium alloy, λal, for 0 °C < θal < 500 °C should be determined from
Formulae (5).3) and (5.4):
— for alloys in 3xxx and 6xxx series:
λ = 0,07θ + 190 (W/m°C) (5.3)
al al
— for alloys in 5xxx and 7xxx series:
λ = 0,1θ + 140 (W/m°C) (5.4)
al al
NOTE The variation of the thermal conductivity is illustrated in Figure 5.3.
SIST EN 1999-1-2:2023
Key
A 3xxx and 6xxx series
B 5xxx and 7xxx series
Figure 5.3 — Thermal conductivity of aluminium alloys as a function of the temperature
5.2.1.4 Emissivity coefficient
(1) In addition to prEN 1991-1-2:2021, the emissivity coefficient for the aluminium surface, ε , shall be
m
taken as 0,3 for clean uncovered surfaces and 0,7 for painted and covered (e.g. sooted) surfaces.
5.2.2 Fire protection materials
(1) The properties and performance of fire protection materials used in design should be assessed as to
verify that the fire protection remains coherent and cohesive to its support throughout the relevant fire
exposure.
NOTE The verification of the properties of protection materials is generally performed by tests. A European
standard for testing of such materials in connection with aluminium structures is being developed under the CEN
Work Item WI 00127357 Protection of aluminium systems.
5.3 Mechanical properties of aluminium alloys
5.3.1 Strength and deformation properties
(1) For thermal exposure up to 2 h, the 0,2 % proof strength at elevated temperature of the aluminium
alloys should be evaluated from Table 5.1 by using Formula (5.5):
f = k ·f (5.5)
o,θ o,θ o
where
f is the 0,2 % proof strength at elevated temperature;
o,θ
f is the 0,2 % proof strength at room temperature according to EN 1999-1–1:2023;
o
k is the reduction factor.
o,θ
(2) For intermediate values of aluminium temperature, Figure 5.4, Figure 5.5 or linear interpolation may
be used.
SIST EN 1999-1-2:2023
Table 5.1 — 0,2 % proof strength reduction factor, k , for aluminium alloys at elevated
o,θ
temperature for up to 2 h of thermal exposure
Aluminium alloy temperature °C
Alloy Temper
20 100 150 200 250 300 350 550
EN AW-3004 H34 1,00 1,00 0,98 0,57 0,31 0,19 0,13 0
EN AW-5005 O 1,00 1,00 1,00 1,00 0,82 0,58 0,39 0
a
EN AW-5005 H14 1,00 0,93 0,87 0,66 0,37 0,19 0,10 0
b
EN AW-5052 H34 1,00 1,00 0,92 0,52 0,29 0,20 0,12 0
EN AW-5083 O 1,00 1,00 0,98 0,90 0,75 0,40 0,22 0
c
EN AW-5083 H12 1,00 1,00 0,80 0,60 0,31 0,16 0,10 0
EN AW-5454 O 1,00 1,00 0,96 0,88 0,50 0,32 0,21 0
EN AW-5454 H34 1,00 1,00 0,85 0,58 0,34 0,24 0,15 0
EN AW-6061 T6 1,00 0,95 0,91 0,79 0,55 0,31 0,10 0
EN AW-6063 T5 1,00 0,92 0,87 0,76 0,49 0,29 0,14 0
d
EN AW-6063 T6 1,00 0,91 0,84 0,71 0,38 0,19 0,09 0
e
EN AW-6082 T4 1,00 1,00 0,84 0,77 0,77 0,34 0,19 0
EN AW-6082 T6 1,00 0,90 0,79 0,65 0,38 0,20 0,11 0
a
The values may be applied also for temper H24/H34/H12/H32.
b
The values may be applied also for temper H12/H22/H32.
c
The values may be applied also for temper H22/H32.
d
The values may be applied also for EN AW-6060 T6 and T66.
e
The values do not include an increase in strength due to aging effects. It is
recommended to ignore such effects.
(3) The 0,2 % proof strength of aluminium alloys at elevated temperature, not covered in Table 5.1, but
listed in Tables 5.3 and
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