Experiments and Numerical Simulations of Pressure Effects in Apartment Fires

R Kallada Janardhan,S Hostikka

doi:10.1007/s10694-016-0641-z

Abstract

The fire induced pressure and its influence on ventilation flows within a compartment have not been studied in detail previously. In this research work, we have investigated the development of gas pressure and the resulting flows in compartment fires first experimentally, by burning a series of heptane pool and polyurethane mattress fires inside a real, 58.6 m^2 by 2.57 m high, apartment and then by carrying out numerical simulations of the experiments with the FDS code. The experiments were conducted with three different ventilation duct configurations to simulate three different airtightness conditions. The peak heat release rates were less than 1 MW and the burning times were about 180 s. The experimental results indicate that the gas pressure in relatively closed apartment can become high enough to revert the flows of the ventilation system, prevent escape through inwards-opening doors, and even break some structures. The peak gas temperatures under the ceiling of the burn room were about 300°C. The pool fires remained well-ventilated. The pressure ranges encountered in the experiments were between 100 Pa to 1650 Pa and the pressure occured within 50 s of ignition. We also report the FDS validation for this type of simulations and discuss the process of modelling the ventilation system and leakages.

Highlights

In early 2014, a group of professional fire fighters from the Southwest Finland Emergency Services, city of Turku, was rehearsing a situation where they ignited a fire inside an apartment of an abandoned building, closed the door and tried to attack the fire after a moment to suppress it
A set of fire experiments was conducted in an apartment building under different ventilation conditions to understand the pressure rise in compartments and its effects on the ventilation flows
The main finding was that the heptane pool and polyurethane foam fires in relatively closed compartments can lead to very high over- and under-pressures

Summary

Introduction

In early 2014, a group of professional fire fighters from the Southwest Finland Emergency Services, city of Turku, was rehearsing a situation where they ignited a fire inside an apartment of an abandoned building, closed the door and tried to attack the fire after a moment to suppress it. To their surprise, two firemen could not open the inner door of the apartment (many Finnish apartments have double doors to the corridor) due to the high pressure inside the apartment.

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Conclusion