NA to BS EN 1995-1-2:2004
UK National Annex to
Eurocode 5: Design of
timber structures –
Part 1-2: General – Structural fire
design
ICS 13.220.50; 91.010.30; 91.080.20
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NATIONAL ANNEX
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Publishing and copyright information
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© BSI 2006
ISBN 0 580 49350 4
The following BSI references relate to the work on this standard:
Committee reference B/525/5
Draft for comment 05/30134000
Publication history
First edition, October 2006
Amendments issued since publication
Amd. no.
Date
Text affected
NA to BS EN 1995-1-2:2004
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NA to BS EN 1995-1-2:2004
Contents
NA.1
NA.2
Nationally Determined Parameters 1
NA.3
Guidance on using informative annexes 2
NA.4
Reference to non-contradictory complementary
information 3
Summary of pages
This document comprises a front cover, an inside front cover,
pages i and ii, pages 1 to 4, an inside back cover and a back cover.
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1
NA to BS EN 1995-1-2:2004
National Annex NA (informative) to
BS EN 1995-1-2:2004, Eurocode 5: Design of
timber structures – Part 1-2: General –
Structural fire design
Introduction
This National Annex has been prepared by BSI Subcommittee, B/525/5,
Structural use of timber. In the UK it is to be used in conjunction with
BS EN 1995-1-2 for the structural fire design of timber structures,
together with BS EN 1995-1-1, BS EN 1990 and BS EN 1991 and their
National Annexes.
NA.1 Scope
This National Annex gives:
a) the UK decisions for the Nationally Determined Parameters
described in the following subclauses of BS EN 1995-1-2:2004:
•
2.1.3(2)
•
2.3(1)P
•
2.3(2)P
•
2.4.2(3)
•
4.2.1(1)
b) the UK decisions on the status of BS EN 1995-1-2:2004
informative annexes;
c) reference to non-contradictory complementary information.
NA.2 Nationally Determined Parameters
NA.2.1
Maximum temperature rise for separating
function in parametric fire exposure
[BS EN 1995-1-2:2004, 2.1.3(2)]
During the decay phase the temperature rise of the unexposed side of a
separating construction should be limited to the following:
a) average temperature rise (
Δ
Θ
1
) of 200 K;
b) maximum temperature rise (
Δ
Θ
2
) of 240 K.
NA.2.2
Partial factor for material properties in fire
[BS EN 1995-1-2:2004, 2.3(1)P]
The partial factor for material properties in fire,
γ
M,fi
, should be taken
as 1,0.
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NA.2.3
Partial factor for mechanical resistance of
connections in a fire situation
[BS EN 1995-1-2:2004, 2.3(2)P]
The partial factor for mechanical resistance of connections in a fire
situation,
γ
M,fi
, should be taken as 1,0.
NA.2.4
Reduction factor
η
fi
for combinations of actions
[BS EN 1995-1-2:2004, 2.4.2(3)]
The reduction factor for combinations of actions,
η
fi
, should be
evaluated using expression 2.9 of BS EN 1995-1-2, but is not permitted
to have a value less than 0,4.
NA.2.5
Procedure for determining cross-sectional
properties [BS EN 1995-1-2:2004, 4.2.1(1)]
The cross-sectional properties in fire should be determined using the
reduced cross-section method of 4.2.2.
NA.3 Guidance on using informative
annexes
NA.3.1
Parametric fire exposure [BS EN 1995-1-2:2004,
Annex A]
BS EN 1995-1-2:2004, Annex A should not be used.
NA.3.2
Advanced calculation methods
[BS EN 1995-1-2:2004, Annex B]
BS EN 1995-1-2:2004, Annex B should not be used.
NA.3.3
Load-bearing floor joists and wall studs in
assemblies whose cavities are completely
filled with insulation [BS EN 1995-1-2:2004,
Annex C]
BS EN 1995-1-2:2004, Annex C may be used.
NA.3.4
Charring of members in wall and floor
assemblies with void cavities
[BS EN 1995-1-2:2004, Annex D]
BS EN 1995-1-2:2004, Annex D should not be used.
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NA to BS EN 1995-1-2:2004
NA.3.5
Analysis of the separating function of wall and
floor assemblies [BS EN 1995-1-2:2004,
Annex E]
BS EN 1995-1-2:2004, Annex E should not be used.
NA.3.6
Guidance for users of EN 1995-1-2
[BS EN 1995-1-2:2004, Annex F]
BS EN 1995-1-2:2004, Annex F may be used.
NA.4 Reference to non-contradictory
complementary information
Material from BS 5268, Structural use of timber
PD 6693, Complementary information for use with Eurocode 5,
BSI, London. (Publication date to be announced.)
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Bibliography
Standards publications
For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
BS 5268, Structural use of timber
PD 6693, Complementary information for use with Eurocode 5
BS EN 1990:2002, Eurocode – Basis of structural design.
BS EN 1991 (all parts), Eurocode 1 – Actions on structures.
BS EN 1995-1-1:2004, Eurocode 5 – Design of timber structures –
Part 1-1: General – Common rules and rules for buildings.
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