Fire Research

Wildfires in Portugal

2019-04-25T10:46:39+02:00

In 2017 Portugal was devastated by forest fires that destroyed more than 500 thousand hectares and claimed at least 112 lives. The country was plagued with a severe drought that raised the risk of fire and was caught by two prominent episodes of extreme conditions: one in mid-June and another in mid-October that caused the greatest damages.

Effect of radiation inside square hollow section under moderate non-symmetric fire

2019-04-25T10:46:34+02:00

The temperature calculation of hollow steel sections at elevated temperatures is a well-documented and standard procedure. Through this standard procedure, the temperature can be calculated by assuming a uniform gas temperature all around the section, which is called a symmetric fire in this paper. Embedding in surrounding structures or connecting to another steel member results in non-symmetric heat distribution in the member. This non-symmetricity of the surrounding temperature may cause surface- to-surface heat radiation inside the member, thus affecting the steel section temperature distribution. This effect is considered in this paper by adopting analytical and finite element method analysis.

Reliability on timber columns under fire situation

2019-04-25T10:46:37+02:00

Timber structures in fire situation are subject to intrinsic uncertainties from the material and the actions on the structure and their probabilistic behavior has not being studied exhaustively. In this paper, four limit state equations using the reduced cross-section method are developed for timber columns in fire situation. The security criteria taken into account in these equations are the compression, the lateral stability and the combined bending and compression, according to the NBR 7190:1997 standard. The structural reliability analysis of five simply supported timber columns with rectangular cross-section in fire situation and different base and height ratios where performed using the first order reliability method. The overall probability of failure of the column was obtained by associating the failure criteria in a series system. The reliability behavior of the different base to height ratios was evaluated, leading to different results for the distinct ratios and the criteria used. Also, a sensitivity analysis was performed indicating the timber charring rate as the most important random variable in the reliability analysis for these limit state equations.

Modelling the influence of crowd control railings on the Kiss nightclub evacuation

2019-04-25T10:46:36+02:00

Fires in crowded gathering places such as nightclubs generate imminent risks to people’s lives, as supported by historical facts. Building evacuation is defined as fundamental to prevent the occurrence of a tragedy. In the Kiss nightclub fire, many people could not reach the exit because of the controlling rails positioned in front of exit doors, as pointed-out by firefighters and survivors. This study aimed to evaluate the influence of these barriers in the escaping of Kiss nightclub, using computerassisted simulation. Four simulations were run, considering two types of capacity, each one with and without the rails. As preliminary analyses, the simulations presented a reduction of nearly 50% of the total time for the nightclub evacuation without the rails, confirming the barriers as a factor that considerably increased evacuation time of the nightclub occupants.

Natural fire tests in a dormitory with fire protected furniture

2019-04-25T10:46:31+02:00

This article presents a full-scale fire experiment carried out in a dormitory bedroom in the city of Recife, Pernambuco, Brazil. The experiment was recorded by thermal and conventional cameras, and temperatures were measured at 24 different points within the environment, making it possible to observe the dynamics and behavior of the fire in detail. Among the objects in the dormitory were two identical bedside tables, one of which was coated with intumescent paint. Particular attention was paid to the behavior of this piece of furniture, which, despite being in direct contact with the flames for more than 20 minutes, did not completely burn. Similar experiments are rare in Brazil and in Latin America as a whole, especially with the use of furniture and locally built structures. Understanding the dynamics of this fire, which very closely resembles many local cases, is therefore important to generate data on thermal behavior and overall understanding of the phenomenon. Regarding the specially-treated piece of furniture, its performance was found to be satisfactory, suggesting that such a protective process for furniture may help inhibit the spread of similar fires.

Graphical tool for assessing the critical temperatures of steel beams and columns in fire

2019-04-25T10:46:27+02:00

In a fire situation, the temperature in which the ultimate limit state of the structural element is reached is called critical temperature. It is very laborious to determine it. The aim of this work was to create a graphical tool to allow quick determination of the critical temperature of I shaped columns and beams without local buckling. The method used was based on the Brazilian standard and using AcoInc software developed by the authors. The result was a tool whose similarity was not found in the literature. The use of the tool developed in this study simplifies the use of the standardized design method. One conclusion to be highlighted is one in which constants values of the critical temperature, generally accepted in practice, may be unsafe.

Thermal and structural analysis of a fuel storage tank under an adjacent pool fire

2019-04-25T10:46:28+02:00

This work reports the modeling and computational implementation of heat transfer processes that take place from a source tank to a target tank in a tank farm, focusing on the thermal field that develops at the target tank. Pool fire with gasoline burning is modeled at the source, in which the flame is represented by a two-layer solid flame model. A rigorous heat transfer model is implemented together with a Computational Fluid Dynamics model for the fuel storage. This process yields the temperature field in the target tank. Such thermal fields are subsequently employed as input in a structural analysis of the target tank to compute displacements and stresses and to assess possible structural damage. For the case studied, the results show that a steady-state process is reached in less than an hour, with temperatures in the order of 400°C at elevations above the fuel level stored in the target tank, whereas much lower temperatures are computed on the zone in contact with fuel. Displacement jumps are seen to occur at the fuel level and at the junction between the cylinder and a fixed roof.