Eurocode 1: Actions on structures – Part 1–2: General actions – Actions on structures exposed to fire Annex C (informative) Localised Fires Part of the One Stop Shop program

Introduction Method of determining thermal action of a localised fire May also be used for multiple localised fires Of key importance is the relative height of the flame to the ceiling of the enclosure This Annex to be used in conjunction with Annex G (for configuration factor)

Small fires or open air fires The flame lengths of a localised fire is given by Flame axis RHR according to Annex E For fires not impinging on the ceiling, the temperature at a height along the flame axis can be given as: Where is the virtual origin of the axis given by:

Larger fires impacting on ceiling When a flame is impacting on the ceiling the heat flux (per unit area) received by the ceiling is given by For Flame axis For For

Equation components For For (Horizontal flame length) For Vertical position of virtual heat source (Non-dimensional RHR) This allows us to describe the heat flux to the ceiling, using only the parameters , , , and

Net heat flux to ceiling The net heat flux received by the fire exposed unit surface area at the level of the ceiling is given by Heat flux which has been described Stephan Boltzmann constant Configuration factor – see Annex G Surface temperature of member – see Section 3 of main Code Emissivity of fire, taken as 1.0 Coefficient of heat transfer – varies for different scenarios – see Section 3 of main Code Surface emissivity of the member – see Section 3 of main Code, taken as 0.8 unless specified otherwise in prEN 1992, 1996, 1999

Limitations and multiple fires The method described in this work is only valid under the following conditions: In the case of several localised fires, the expression derived for heat flux, may be used to get the individual heat fluxes These can then be used to build up a value of the total heat flux: metres MW [W/m2]