EN 1999-1-2-2007 pdf download.Eurocode 9-Design of aluminium structures-Part 1-2 :Structural fire design.
4.2.1 General
(1)P The load-beanng function of an aluminium structure or structural member shall be assumed to be maintained after a time fin a given fire if
Ed Rd!
where
E,,d is the design effect of actions for the fire design situation, determined in accordance with EN 1991-1- 2. (the internal forces and moments Mf d. Ed’ Ed individually or In combination)
is the design resistance of the aluminium structure or structural member, for the fire design situation. at time t, (PA,, ,, N biRd. , ,.. V,,R individually or in combination)
(2) R, should be determined for the temperature distribution in the structural members at time I by modifying the design resistance for normal temperature design, determined from EN 1999-1-1. to take account of the mechanical properties of aluminium alloys at elevated temperature, see 3 21 and 32.2.
(3) The resistance of connections between members need not be checked provided that the thermal resistance (d I4) of the fire protection of the connection is not less than the minimum value of the thermal resistance (d0 14)u of the fire protection of any of the aluminium members joined by that connection
(4) For welded connections the reduced strength in the heat affected zones shall be taken into account. (5)lt may be assumed that the clauses in 4.2.2.2, 4.2.2.3 and 4.2.24 are satisfied if at time I the aluminium
temperature at all cross-sections is not more than 170 C.
4.2.2 Resistance
4.2.2.1 Classification of cross-sections
(1) In a fire design situation, cross-sections may be classified as for normal temperature design according to 6.1.4 in EN 1999-1-1
NOTE This rule as based on the same relative drop In the 0,2 % proof strength and modulus of elastiIy If the actual drop in modulus of elasticity is taken into account according to Figi.sre 2, the dassthcation of the section changes, and a larger capacity Va ue of the section can be calculated The National Annex may give povisions to take this into account
4.2.2.2 Tension members
(1)The design resistance !4 of a tension member with a non uniform temperature distribution over the cross section at time I may be determined from
4.23.4 External aluminium structures
(1)Ttie temperature in external aluminium structures should be determined taking into account.
— the radiative heat flux from the fire compartment;
— the radiative heat flux and the convection heat flux from flames emanating from openings;
— the radiative and convective heat loss from the aluminium structure to the ambient atmosphere:
– the sizes and locations of the structural members.
(2) Heat screens may be provided on one, two or three sides of an external aluminium member in order to protect it from radiative heat transfer
(3) Heat screens should be either:
directly attached to that side of the aluminium member which they are intended to protect, or;
— large enough to fully screen this side from the expected radiative heat flux.
(4) Heat screens should be non-combustible and have a fire resistance of at least El 30 according to EN ISO
13501-2.
NOTE Annex B gives lnfotmatlon
(5) The temperature in external aluminium structures protected by heat screens should be determined as specified In (1), assuming that there Is no radiative heat transfer to those skies which are protected by heat screens.
(6) Calculations may be based on steady state conditions resulting from a stationary heat balance. NOTE 1 Annex B gives recommendec methods
NOTE 2 Design using Annex B should be based on the model given In EN 1991-1-2 describing the compartment fire conditions and the flames emanating from openings, on which the calculation of the radiative and convective heal fluxes should be based
4.3 Advanced calculation models
(3) Advanced calculation methods should include calculation models for the determination of
— the development and distribution of the temperature within structural members (thermal response model):
the mechanical behaviour of the stwcture or of any part of it (mechanical response model) (4)Advanced calculation methods may be used in association with any heating curve, provided that the material properties are known for the relevant temperalure range
(5) Advanced calculation methods may be used with any type of ctoss-secbon
4.3.2 Thermal response
(1) Advanced calculation methods for thermal response should be based on the acknowledged principles and assumptions of the theory of heat transfer.
(2) The thermal response model should consider:
— the relevant thermal actions specified in EN 1991-1-2;
the variation of the thermal properties of the material with the temperature, see 3.3.
(3)The effects of non-uniform thermal exposure and of heat transfer to adjacent building components may be
Induded where appropriate
(4)The influence of any moisture content and of any migration of the moisture within the fire protection
matenal may conservatively be neglected
4.3.3 MechanIcal response
(1) Advanced calculation methods for mechanical response should be based on the acknowledged principles and assumptions of the theory of structural mechanics, taking into account the changes of mechanical properties with temperature.
(2) The effects of thermally induced strains and stresses both due to temperature rise and due to temperature differentials, should be considered
(3)The mechanical response of the model should also take account of:
the combined effects of mechanical actions, geometrical imperfections and thermal actions:
the temperature dependent mechanical properties of the material, see 32;
— geometrical non-linear effects;EN 1999-1-2-2007 pdf download.