Eurocode 1: Actions on structures –

1. Eurocode 1: Actions on structures – Part 1–2: General actions – Actions on structures exposed to fire • Annex E (informative) • Fire load densities Part of the One Stop Shop program

2. Introduction • Fire load density evaluation • FLD used is a “design value” based on • Measurements or • Values given in national regulations • Determined by • Classification of occupancies and/or • Individual project analysis

3. Design value • The design value of the fire load: Fire activation risk factors for Characteristic fire load density per unit floor area Compartment size and Type of occupancy Fire-fighting measures risk factor Combustion factor

4. Determination of fire load densities • Fire load density needs to be determined taking into account • Type of building / occupancy • Protected fire loads • Calorific value of fuel • This process is used to determine the value of for previous equation

5. from occupancies • For a large number of buildings, e.g. offices, residencies, hotels, and the paper industry, In which case, Table E.4 may be used to determine the value of • Separate fire load densities within the building should be added to the tabular value if necessary

6. from basic principles • To obtain we must obtain a value for Compartment area Characteristic fire load Optional factor for protected loads Net calorific value Amount of combustible material

7. Combustion factor • Having determined a value for we next need a value for - the combustion factor • The value of 0.8 is taken for cases mainly consisting of cellulosic fuels • In other cases the combustion behaviour should be looked at as a function of occupancy and type of fire load

8. Fire activation risk factors • Due to size of compartment: • Due to type of occupancy: The factors vary from just under 1.0 to just over 2.0 – the particular value used is taken from Table E.1 included in the Annex

9. Fire-fighting measures risk factors • This factor is a function of active fire-fighting measures • Takes into account • Fire suppression systems • Automatic fire detection and alarm systems • Manual fire suppression systems • The values for the individual factors are given in Table E.2

10. Worked example • Work out the design fire load for a 6,500m2 office space, with no additional fuels present in the space. • The office is sprinkler protected • Heat detectors are the only source of A&D system within the space • No other special provisions are present apart from the normal fire-fighting measures

11. Worked example - workings • From Table E.4, we can see the value of can be taken as 420 MJ/m2 • This value may be taken because the value of is 1.0 (Table E.1) • The value of can be taken as 0.8 • The value of is 2.0, as it is between the 5,000 and 10,000m2 brackets (Table E.1)

12. Worked example - workings • The value of is therefore averaged from 0.61, 0.87, and 1.0 which results in having a value of 0.83

13. Worked example - answer • Putting these values back into the original equation gives us a design value of the fire load for our test case scenario highlighted in the worked example as: MJ/m2