1. 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

2. 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)

3. 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:

4. 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

5. 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

6. 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

7. 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]