��� ��� PART 1 THERMAL & MECHANICAL ACTIONS ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 0 / 50
Background of the RFCS Project DIFISEK+ Background of the RFCS Project DIFISEK+ This project is funded by the European Commission in the frame of the “Research Fund for Coal and Steel” The aim of DIFISEK+ is to promote different projects of the last decades that dealt with fire engineering and, which results have been implemented in the EN 1991-1-2. This objective will be reached trough seminars held in different European countries. The partnership of the project is as follows: University of Hannover Institute for Steel Construction ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 1 / 50
Treated Topics Treated Topics Part 1: Thermal & Mechanical Actions Part 2: Thermal Response Part 3: Mechanical Response of Structures in Fire Part 4: Software for Fire Design Part 5a: Worked Examples Part 5b: Illustration of Completed Projects ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 2 / 50
Resistance to Fire - Chain of Events Resistance to Fire - Chain of Events Loads Θ Θ Θ Θ Steel columns time 1: Ignition 2: Thermal action 3: Mechanical actions R time 6: Possible 4: Thermal 5: Mechanical collapse response response ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 3 / 50
Thermal action on structure Thermal action on structure Composite Slab Column 1 side exposed 4 sides exposed ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 4 / 50
Heat transfer at surface Heat transfer at surface of building elements of building elements + & & & = h h h net net,c net r , Net Radiative Heat Flux Net Convective Heat Flux Total net Heat Flux � Exposed side � Non-exposed side ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 5 / 50
Structural Fire Safety Engineering Structural Fire Safety Engineering vs. Classification vs. Classification Prescriptive Performance based standard fire natural fire classification fire safety eng . fire safety eng. fire safety eng. ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 6 / 50
Actions on Structures Exposed to Fire Actions on Structures Exposed to Fire EN 1991-1-2 - Prescriptive Rules EN 1991-1-2 - Prescriptive Rules Design Procedures Prescriptive Rules Performance-Based Code ( Thermal Actions given ( Physically based Thermal Actions) by Nominal Fire) ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 7 / 50
Nominal Temperature-Time Curve Nominal Temperature-Time Curve *) Nominal temperature-time curve Standard temperature-, External fire - & No data needed Hydrocarbon fire curve *) Simplified Fire Models Localised Fire Fully Engulfed Compartment - HESKESTADT Rate of heat release - Parametric Fire - HASEMI Fire surface θ θ (t) uniform θ θ θ (x, y, z, t) θ θ θ in the compartment Boundary properties Opening area Ceiling height *) Advanced Fire Models + - Two-Zone Model - One-Zone Model Exact geometry - Combined Two-Zones and One-Zone fire - CFD ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 8 / 50
Prescriptive Fire Regulations Defining Prescriptive Fire Regulations Defining ISO Curve Requirements ISO Curve Requirements ISO-834 Curve (EN1364 -1) T = 20 + 345 log (8 t + 1) θ θ [° θ θ C] 1200 1110 1049 1006 The ISO curve 1000 945 * Has to be considered in the WHOLE 842 compartment, even if the compartment 800 is huge ISO ISO ISO ISO 600 ISO ISO ISO ISO 400 Time [min] * Never goes DOWN * does not consider the PRE-FLASHOVER PHASE 200 * Does not depend on FIRE LOAD and VENTILATION CONDITIONS 0 0 30 60 90 120 180 ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 9 / 50
Stages of a Natural Fire and the Stages of a Natural Fire and the Standard Fire Curve Standard Fire Curve Temperature Post- Flashover Pre- Flashover 1000-1200° C Flashover Natural fire curve ISO834 standard fire curve Time Ignition - Smouldering Heating Cooling …. ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 10 / 50
Sprayed Protection Sprayed Protection ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 11 / 50
Partially Encased Beams & Columns Partially Encased Beams & Columns ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 12 / 50
Actions on Structures Exposed to Fire Actions on Structures Exposed to Fire EN 1991-1-2 - Performance Based Code EN 1991-1-2 - Performance Based Code Design Procedures Prescriptive Rules Performance-Based Code (Physically based Thermal Actions) ( Thermal Actions given by Nominal Fire) ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 13 / 50
Natural Fire Safety Concept Natural Fire Safety Concept e u r v c S O I θ [°C] θ θ θ 1200 1000 800 600 400 200 0 0 30 60 90 120 180 Time [min] Implemented in: • EN 1991-1-2 • Some National Fire Regulations include now alternative requirements based on Natural Fire ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 14 / 50
NFSC Valorisation Project NFSC Valorisation Project ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 15 / 50
Natural Fire Model Natural Fire Model *) Nominal temperature-time curve Standard temperature-, External fire - & No data needed Hydrocarbon fire curve *) Simplified Fire Models Localised Fire Fully Engulfed Compartment - HESKESTADT Rate of heat release - Parametric Fire - HASEMI Fire surface θ θ (t) uniform θ θ θ (x, y, z, t) θ θ θ in the compartment Boundary properties Opening area Ceiling height *) Advanced Fire Models + - Two-Zone Model - One-Zone Model Exact geometry - Combined Two-Zones and One-Zone fire - CFD ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 16 / 50
List of needed Physical Parameters for List of needed Physical Parameters for Natural Fire Model Natural Fire Model � Boundary properties � Ceiling height Geometry � Opening Area � Fire surface Fire � Rate of heat release ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 17 / 50
Characteristics of the Fire Compartment Characteristics of the Fire Compartment Fire resistant enclosures defining the fire compartment according to the national regulations Material properties of enclosures: c , ρ, λ , ρ, λ , ρ, λ , ρ, λ Definition of Openings ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 18 / 50
Characteristic of the Fire for Different Buildings Characteristic of the Fire for Different Buildings RHR Fire Load q Fire Growth Occupancy f f,k Rate 80% fractile [kW/m²] [MJ/m²] Dwelling Medium 250 948 Hospital (room) Medium 250 280 Hotel (room) Medium 250 377 Library Fast 500 1824 Office Medium 250 511 School Medium 250 347 Shopping Centre Fast 250 730 Theatre (movie/cinema) Fast 500 365 Transport (public space) Slow 250 122 ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 19 / 50
Fire Load Density Fire Load Density Examples Danger of Danger of Compartment Fire Activation Fire Activation of floor area A f [m²] δ q2 δ δ δ δ q1 δ δ δ Occupancies Art gallery, museum, 25 1,10 0,78 swimming pool 250 1,00 Residence, hotel, office 1,50 Manufactory for machinery 1,22 2500 1,90 & engines Chemical laboratory, 1,44 5000 2,00 Painting workshop Manufactory of fireworks 2,13 1,66 10000 or paints ∏ = δ δ δ q m q . . . . δ δ δ δ ni Function of Active Fire Safety Measures f , d q 1 q 2 ni f , k Automatic Fire Suppression Automatic Fire Detection Manual Fire Suppression Automatic fire Automatic Automatic Independent Work Off Site Safe Fire Smoke Alarm Detection Water Water Fire Fire Access Fighting Exhaust Transmission & Alarm Supplies Extinguishing Brigade Brigade Routes Devices System to by by System Fire Brigade 0 1 2 Heat Smoke δ n1 δ δ δ δ δ n6 δ δ n7 δ n8 δ δ n9 δ δ δ n10 δ δ δ δ δ δ n2 δ δ n5 δ δ δ δ δ δ δ δ δ δ δ n3 δ δ δ δ δ n4 δ δ 0,9 or 1 1,0 1,0 0,61 or 0,78 0,61 1,0 0,87 0,7 0,87 or 0,73 0,87 1,5 1,5 1,5 ��� ��� ��� ��� Part 1: Thermal & Mechanical Actions 20 / 50
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