oSIST prEN 15080-13:2009
(Main)Extended application of results from fire resistance tests - Part 13: Load bearing columns
Extended application of results from fire resistance tests - Part 13: Load bearing columns
This Part of EN 15080 identifies the parameters and factors that affect the fire resistance of columns, when fully exposed to fire on all sides, and need to be taken into account when considering extended application of results of columns tested in accordance with EN 1365-4. It also gives the methodology to be used when preparing an extended application, including rules and calculation methods which can be applied to establish the resultant influence of a variation in one or more parameters and to determine the field of extended application.
Erweiterter Anwendungsbereich der Ergebnisse aus Feuerwiderstandsprüfungen - Teil 13: Tragende Stützen
Application étendue des résultats des essais de résistance au feu - Partie 13 : Poteaux porteurs
Razširjena uporaba rezultatov preskusov požarne odpornosti - 13. del: Nosilni stebri
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 15080-13:2009
01-september-2009
Razširjena uporaba rezultatov preskusov požarne odpornosti - 13. del: Nosilni
stebri
Extended application of results from fire resistance tests - Part 13: Load bearing columns
Erweiterter Anwendungsbereich der Ergebnisse aus Feuerwiderstandsprüfungen - Teil
13: Tragende Stützen
Application étendue des résultats des essais de résistance au feu - Partie 13 : Poteaux
porteurs
Ta slovenski standard je istoveten z: prEN 15080-13
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
oSIST prEN 15080-13:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 15080-13:2009
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oSIST prEN 15080-13:2009
EUROPEAN STANDARD
DRAFT
prEN 15080-13
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2009
ICS
English Version
Extended application of results from fire resistance tests - Part
13: Load bearing columns
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 127.
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 Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland 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
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15080-13:2009: E
worldwide for CEN national Members.
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oSIST prEN 15080-13:2009
prEN 15080-13:2009 (E)
Foreword
This document (prEN 15080-13:2009) has been prepared by Technical Committee CEN/TC 127 “Fire
safety in buildings”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association, and supports essential requirements of EC Directive(s).
For relationship with EC Directive(s), see informative Annex ZA, which is an integral part of this
document.
This document is based on the draft for beams (prEN 15080-8).
Sections 1 to 6 are almost identical to the final version of prEN 15080-8.
Annex A, GUIDELINES FOR MAKING ASSESSMENTS has been taken directly from prEN 15080-8
with ‘beam’ changed to ‘column’ and some of the examples changed
Some of the figures contain text and do not yet conform to CEN rules.
The document needs:
An example of EXAP on a steel column
An example of EXAP on a concrete column
An example of EXAP on a timber column – Is this practical? Is this required?
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Contents Page
Foreword . 2
1 Scope. 4
2 Normative references . 4
3 Terms and Definitions . 5
4 Basis and methodology of establishing the extended application . 6
4.1 General . 6
4.2 Basic principles . 6
4.2.1 General . 6
4.2.2 Basis of the extended application . 7
4.2.3 Mode of failure . 7
4.2.4 Methods of analysis . 7
4.3 Basic thermal analysis . 7
4.4 Basic structural analysis . 7
4.4.1 General . 7
4.4.2 Modelling factor . 8
4.4.3 Material properties . 9
4.5 Analysis of other features . 10
5 Critical parameters . 10
5.1 General. . 10
5.2 Common thermal parameters . 10
5.3 Common mechanical parameters . 10
5.4 Common constructional parameters . 10
5.5 Specific constructional parameters for columns without fire protection . 10
5.5.1 Concrete columns . 10
5.5.2 Steel columns . 11
5.5.3 Composite steel-concrete columns . 11
5.5.4 Timber columns . 12
5.5.5 Mechanically jointed timber columns . 12
5.5.6 Specific constructional parameters for columns with applied fire protection . 12
6 Report of the extended application analysis . 13
Annex A (informative) Guidelines for making assessment . 14
A.1 Mode of failure . 14
A.2 Effect of material strength . 15
A.3 Extrapolation of fire resistance . 15
A.4 Accuracy of predictions . 16
A.5 Prediction based on material laws . 17
A.6 Modifying predicted temperatures . 17
Annex B (informative) Background to the Scope . 19
Annex C (informative) Quantified extended application of composite steel concrete
columns . 21
C.1 Introduction . 21
C.2 Test Details . 22
C.3 Analysis of reference tests . 22
C.3.1 Thermal performance . 22
C.3.2 Structural performance . 24
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1 Scope
This Part of EN 15080 identifies the parameters and factors that affect the fire resistance of columns,
when fully exposed to fire on all sides, and need to be taken into account when considering extended
application of results of columns tested in accordance with EN 1365-4. It also gives the methodology
to be used when preparing an extended application, including rules and calculation methods which
can be applied to establish the resultant influence of a variation in one or more parameters and to
determine the field of extended application.
2 Normative references
The following referenced documents are indispensable for the application 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.
EN 1363-1, Fire resistance tests — Part 1: General Requirements
EN 1363-2, Fire resistance tests — Part 2: Alternative and additional procedures
EN 1365-4, Fire resistance tests for load bearing elements — Part 3: Columns
EN 15080-1, Extended application of results from fire resistance tests — Part 1: General principles
EN 13502-2, Fire classification of construction products and building elements — Part 2: Classification
using data from fire resistance test (excluding products for use in ventilation systems)
EN 1992-1-2, Eurocode 2. Design of concrete structures — Part 1-2: General - Structural fire design
EN 1993-1-2, Eurocode 3. Design of steel structures — Part 1-2: General - Structural fire design
EN 1994-1-2, Eurocode 4. Design of composite steel and concrete structures — Part 1-2: General -
Structural fire design
EN 1995-1-1, Eurocode 5. Timber structures — Part 1-1: General — Common rules and rules for
buildings
EN 1995-1-2, Eurocode 5. Design of timber structures — Part 1-2: General — Structural fire design
EN 338, Structural timber — Strength classes
EN 1194, Glued laminated timber — Strength classes and determination of charactersitic values
EN 10025, Hot rolled products of non-alloy structural steels — Technical delivery conditions
EN 10080–1, Steel for the reinforcement of concrete — Weldable reinforcing steel — Part 1: General
requirements
EN 10138-1, Prestressing steels — Part 1: General requirements
ENV 13381-7, Contribution to fire resistance of structural members — Part 7: Timber elements
ISO 13943, Glossary of fire terms and definitions
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3 Terms and Definitions
The definitions given in ISO 13943, EN 1363-1 and EN 1365-4 together with the following apply:
3.1
Test result
outcome of a testing process and its associated procedures detailed within EN 1365-4 (which may
include some processing of the results from the testing of a number of specimens). A test result is
expressed in terms of one or more fire performance parameter(s)
3.2
direct field of application of test results
outcome of a process (involving the application of defined rules) whereby a test result is deemed to
be equally valid for variations in one or more of the product properties and/or intended end use
application(s)
NOTE The direct field of application of test results are presented in EN 1365-4.
3.3
extended field of application of test results
outcome of a process (involving the application of defined rules that may incorporate calculation
procedures) that predicts, for a variation of a product property and/or its intended end use
application(s), a test result on the basis of one or more test results to the same test standard, i.e. to
EN 1365-4
3.4
classification
process defined in EN 13501-2, whereby the fire performance parameters obtained from the results of
one test, or a set of tests, or from a process of extended application, are compared with limiting
values for those parameters that are set as criteria for achieving a certain classification
NOTE The relevant classes and related criteria for fire resistance are specified in Commission Decisions
(2000/367/EC, 2000/147/EC and 2001/671/EC).
3.5
reference test
fire resistance test according to EN 1365-4 on a column from which the test result is used for the
process of extended application
NOTE There may be more than one reference test.
3.6
parameter
aspect of the reference scenario that may vary in practice and may result in a change of the fire
resistance performance
NOTE Examples are the load level and the height.
3.7
modelling factor
factor determined for a considered relevant structural failure mode on basis of the assessment of the
reference test(s), which takes into account the differences between the test results and calculated
results, and which is used to adjust the results of the extended application
3.8
Calculated structural resistance
resistance to axial compression of a column in a fire test calculated at the end of the test
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3.9
effective structural resistance
predicted resistance to axial compression of a column for use in an extended application
3.10
relative resistance
ratio of the compressive resistance of a column in a fire resistance test to the resistance at normal
temperatures calculated with all safety factors taken as unity
3.11
target classification
fire resistance that the extended application is required to achieve
4 Basis and methodology of establishing the extended application
4.1 General
An extended application analysis is required when the application of a column is not covered by the
field of direct application given in the classification document of the product.
The situation of (a) fire test(s) carried out according to EN 1365-4 will be referred to as the “reference
test” and “reference scenario”. The result of a test, i.e. the fire resistance with respect to the load
bearing capacity, will be referred as “t ”.
ref,fi
If more then one reference test is available, normally they will not be identical due to differences in
design or differences between test conditions (for example load level or restraint conditions). In that
case it is possible that in the classification report all reference columns are classified with the same
classification “R ” although the actual test results (t ) given in the test reports may differ.
ref ref,fi
4.2 Basic principles
4.2.1 General
It is assumed that extended application is made by appropriately qualified and experienced persons in
the field of structural fire design.
The reference test(s) shall be well documented, i.e. an insight into the performance of the test
specimen(s) and the mode of failure, leading to R , are available.
ref
Three analyses (described in 4.3, 4.4 and 4.5) should be carried out, where appropriate. It shall be
decided whether:
the field of application can be extended, maintaining the classification R or changing the
ref
classification and if so, by how much;
extension is not possible (new tests are required).
Any predicted increase in fire resistance shall not exceed the lesser of 15 minutes and 20 % of the
target classification.
NOTE This is illustrated in A.1.
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4.2.2 Basis of the extended application
An adequate understanding of the structural and thermal performance, as well as an understanding of
other relevant features, shall be achieved based on the scope of the required extended application.
For minor or obvious extensions to the reference test, the depth of analysis required may be reduced.
4.2.3 Mode of failure
Any assessment shall consider the possibility that the mode or cause of failure, such as structural
collapse or failure of a fire protection system, might change and that the mode or cause of failure in a
fire test may no longer be critical if one or more parameters are changed.
If a change of failure mode is expected, then extended application is not possible unless additional
information is available.
NOTE For additional information see A.1.
4.2.4 Methods of analysis
When analysing the reference test(s) the rules given in the Eurocodes shall be used if applicable.
Additional rules are given in this standard; these are also applicable in cases where the Eurocodes do
not fully cover the construction to be assessed. Other calculation models, as well as empirical rules,
shall be validated on the basis of similar tests as the reference test(s). Historic data and ad hoc tests
may be used to supplement to the information of the reference test(s).
4.3 Basic thermal analysis
If the extended application is intended to be for a cross section of a size or shape different from the
reference test(s) or for a different resistance time or another nominal fire curve, then a thermal
assessment shall be made. The analysis should lead to an understanding of the temperature
distribution and material strength variation throughout the column.
The analysis may take the form of a finite element or finite difference thermal analysis. In limited
circumstances, when a dimension is changed, it may be possible to show, using a simple calculation,
that the temperature distribution measured in the test can be conservatively used for the modified
cross section.
For timber columns, it may be sufficient to analyse the charring depth instead of carrying out a
complete thermal analysis. Where a thermal analysis is carried out, the position of the char-line shall
be taken as the position of the 300 °C isotherm.
4.4 Basic structural analysis
4.4.1 General
The structural behaviour of the reference test(s) and of the situation to be assessed shall be analysed.
The depth of structural analysis will depend on the complexity of the column and the extent of the
proposed extended application. For any assessment, as appropriate, the following limit states should
be considered:
Compression failure;
Flexural buckling;
Torsional buckling;
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Local instability.
NOTE It is normally not necessary to consider vertical contraction (negative elongation) as specified in
EN 1365-4.
The assessment shall also include:
Connections, either mechanical of glued, between parts of the construction;
Boundary conditions;
Material properties.
4.4.2 Modelling factor
Any assessment shall take into account the accuracy of the structural model used. Models which
over estimate the load resistance of the reference test(s), shall have a modelling factor applied when
used to make an assessment for extended application.
In making any assessment the effective structural resistance shall be determined as follows:
R = R × k
eff mf
where:
R is the effective structural resistance
eff
R is the calculated structural resistance
k is the modelling factor
mf
For a single reference test, the modelling factor is defined as:
F
k = but not greater than 1,0
mf
R
Where:
F is the applied load or moment in the reference test
For more than one reference test:
1 F
i
k = but not greater than 1,0
mf ∑
n R
i
where:
F is the applied load or moment in the reference test i
i
R is the calculated structural resistance of test i calculated using the measured
i
temperature distribution.
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n is the number of tests
and with each individual value:
(F / R ) ≤ 1,3
i i
If the value of (F / R ) exceeds 1,3 then that test should not be used as part of the assessment of
i i
extended application.
NOTE 1 If the measured temperature distribution is not sufficiently comprehensive to allow the structural
resistance to be adequately predicted then it may be supplemented with computed temperatures.
NOTE 2 If the value of (F / R) exceeds 1.3 there may be something wrong with the test data or the some
i i
aspect of the engineering model being used so use the particular test may be considered unreliable.
The above does not mention the temperature distribution across the section. If the temperature
distribution is predicted then the predicted structural resistance should be computed using the
predicted temperatures. Temperature was not mentioned in the EXAP for beams.
4.4.3 Material properties
The reference test(s) should be assessed using measured material strength. If the actual material
strength is not available then the strength should be taken from Table 1.
In making any assessment of extended application, mean material properties shall be assumed. If the
actual mean value is unknown, then values for the mean strength should be taken from Table 1.
NOTE The values in table are conservative values for the mean strength
For additional information see A.1.
Table 1 — Conservative values for mean strength
(a)
Material Mean strength
2
Concrete compressive strength f + 8 N/mm
ck
Reinforcement steel to EN 10080 for concrete
f × 1,1
sk
Prestressing steel to EN 10138-1 for concrete f × 1,1
pk
Hot rolled structural steel to EN 10025
f × 1,1
y
Timber
- Structural timber, strength classes C14 to
f × 1,5
k
C40 to EN 338
- glued laminated timber, all strength
f × 1,3
k
classes to EN 1194
- LVL f × 1,25
k
Other materials to be estimated
(a) f and f are the characteristic strength values (5 % fractile)
i k y
Table 1 is taken from the latest EXAP for beams
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4.5 Analysis of other features
Where relevant phenomena not assessed in 4.3 and 4.4 shall be taken into account.
NOTE These may include such things as the stickability of fire protection materials and spalling of concrete.
For spalling of concrete reference should be made to the recommendations of EN 1992-1-2, clauses 4.5 and 6.2.
The stickability of fire protection materials should be either:
assessed using the methods given in ENV 13381,
Or
be based on clear evidence of the performance of the material and fixing system in at least two fire tests.
5 Critical parameters
5.1 General.
The parameters listed in 5.2 to 5.5 may affect the fire performance, i.e. the value of Rref, and shall be
taken into account when preparing an extended application. The specific constructional parameters
vary depending upon the nature of the column being considered.
NOTE The list in this section is not definitive; in special cases other parameters may also be appropriate.
5.2 Common thermal parameters
1) Nominal gas temperature time curves.
5.3 Common mechanical parameters
1) Load level.
2) Eccentricity of loading (value and direction).
3) End support conditions axial or rotational restraint.
5.4 Common constructional parameters
1) System height.
2) Buckling length.
3) Dimensions cross section.
4) Shape of cross section.
5) Position and size of holes.
5.5 Specific constructional parameters for columns without fire protection
5.5.1 Concrete columns
The following specific parameters can be distinguished:
1) Concrete specification.
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NOTE This will normally include:
a) Type of concrete, i.e. normal weight or lightweight concrete.
b) Type of concrete aggregate, i.e. siliceous, calcareous or lightweight.
c) Strength of concrete.
2) Specification of reinforcement.
NOTE This will normally include:
i) Type of reinforcement, i.e. reinforcing steel, prestressing bars, wires or strands.
ii) Characteristic strength of the reinforcing or prestessing steel.
iii) Is the steel hot rolled or cold worked or quenched and tempered ?
iv) The ductility characteristics of the reinforcing steel.
3) Degree of any prestressing.
4) Bond and anchorage properties of the reinforcing or prestessing steel: i.e.: ribbed or plain
surface.
5) Bonded versus unbonded tendons (post tensioned columns).
6) Amount of the main reinforcement and position of the main reinforcement in the cross
section.
7) Concrete cover to reinforcement.
8) Amount and position of the shear reinforcement.
9) Minimum dimensions, the level of compressive stresses, moisture content and other
parameters possible relevant for spalling.
10) Other parameters which may effect spalling.
5.5.2 Steel columns
The following specific parameters can be distinguished:
1) Properties of the steel (grade and actual yield strength, heat treatments).
2) Section factor.
5.5.3 Composite steel-concrete columns
In addition to 5.5.1 and 5.5.2 the following parameters may apply:
1) Shear connection details (degree of shear connection, number and type of shear
connectors).
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5.5.4 Timber columns
The following parameters apply, where relevant, to timber columns made of solid timber, glued
laminated timber and LVL (laminated veneer lumber) or other engineered wood products:
1) Timber specification.
NOTE This will normally include:
a) Material (timber or wood based materials).
b) Species of timber.
c) Strength class of solid or glued laminated timber (including characteristic values of strength and
stiffness parameters and density).
d) Strength.
e) Stiffness.
f) Density.
g) Charing rate.
2) Type of adhesive.
The above parameters may also apply to columns composed of several parts connected by gluing,
such as thin-webbed I-sections with solid timber flanges, thin-flanged columns with solid timber webs
and I-sections with solid or glued laminated timber flanges and webs. For these columns, in addition
to the above, the following parameter may also be applicable:
1) Materials of flange(s) and web(s).
5.5.5 Mechanically jointed timber columns
The parameters presented in 5.5.4(1) and 5.5.4(2) apply where relevant also to columns of box-, I- or
T-shape, composed of several parts connected by mechanical fasteners with flanges and/or webs
made of solid or glued laminated timber, wood-based panels and LVL or other engineered wood
products. In addition the following parameters may apply:
1) Type of fastener.
2) Spacing of fasteners.
3) Edge distances of fasteners.
5.5.6 Specific constructional parameters for columns with applied fire protection
In addition to the parameters given in 5.5 the following parameters may apply:
1) Surface treatment of the column (i.e. grit blasted, primer).
2) Type of protection material (generic or proprietary).
3) Thermal characteristics of the protection (thermal conductivity and specific heat).
4) Density of the protection.
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5) Thickness of the protection.
6) Number of layers of the applied fire protection.
7) Position and geometry of joints in the applied fire protection.
8) All details of method of fixing of the fire protection (type of fasteners, spacing and edge
distances; including reinforcement where relevant).
9) Surface treatment of the fire protection.
10) Position of the fire protection (vertical, horizontal sides; one or more sides may be
unprotected).
6 Report of the extended application analysis
The Extended Application report shall be used in conjunction with the classification document as
specified in EN 13501-2 and shall contain the following:
1) The name of the sponsor.
2) The name of the expert body which has performed the extended application.
3) The type of the tested columns. This shall include a general description and any trade
names of al
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