Elsevier

Fire Safety Journal

Volume 57, April 2013, Pages 3-10
Fire Safety Journal

Smoke and heat control for fires in large car parks: Lessons learnt from research?

https://doi.org/10.1016/j.firesaf.2012.05.001Get rights and content

Abstract

This paper focuses on car park fire safety, more particularly on fire and smoke (and heat) dynamics. The first part deals with the choice of design fire, based on recent full-scale car fire experiments with modern cars and different set-ups. Different aspects of smoke and heat control (SHC) systems are then discussed from the perspective of smoke (and heat) dynamics. The focus is mainly on the effect of horizontal mechanical ventilation, a popular technique, on the smoke and heat generated by the fire source. Some fundamental differences from (longitudinal) mechanical ventilation in tunnels are described. Possible effects of water (sprinklers, water mist or from a fire brigade intervention), as well as some possible routes for further research, are briefly commented.

Highlight

► Review on fire and smoke dynamics for car park fire safety. ► Design fires for car park fire safety. ► Full-scale car fire experiments with modern cars and different set-ups. ► Impact of smoke and heat control (SHC) systems on car park fire smoke movement. ► Fundamental differences between flow dynamics in large car parks and tunnels.

Introduction

In densely populated regions, underground car parks are increasingly popular. Obviously, fire and explosion safety are important issues. With respect to fire safety, two large research projects have recently been executed in Europe [1], [2]. The papers in the present special issue report on the research results of [2], discussed in the light of state-of-the-art knowledge on car park fire and explosion safety. Obviously, not all aspects can be covered. Detection, human behaviour, fire service intervention and operational issues of smoke and heat control (SHC) systems are examples of topics that, though all interesting, are not addressed.

In the present paper the focus is on fire safety, more particularly on fire and smoke (and heat) dynamics in the case of car park fires. The first part deals with the choice of design fire. This is largely based on a recent extensive full-scale experimental campaign with modern cars, in different set-ups [1]. However, fire development in car parks has been the subject of a number of experimental programmes over recent years [3], [4], [5], [6], [7], [8]. These various experiments have examined the heat release rates and temperatures of individual modern cars and small numbers of cars parked in typical car park arrangements, some in test rigs intended to represent a car park. As source of heat and smoke, the design fire is beyond any doubt crucial in the process of smoke and heat control (SHC) system design. Indeed, the fire source, in terms of heat release rate (HRR) and smoke production rate primarily, determines which problem the SHC system is supposed to tackle.

Next, different aspects of SHC systems are discussed from the perspective of smoke (and heat) dynamics. In many relatively small car parks (say, less than 800 m2 floor area), such as car parks underneath private buildings (e.g., apartment blocks), no SHC system is in place. In larger car parks, in particular public car parks or car parks underneath office blocks, a SHC system is typically installed. Different types of systems exist. One option is the use of ductwork to ‘trap’ the smoke and remove it through the ductwork. Heat is removed along with the smoke, reducing the risk for fire spread, compared to the situation where no heat is removed. Another option is natural vertical venting, aiming at a guaranteed smoke-free height. Due to the typically low ceiling height in car parks, this system is not very common, though. Horizontal mechanical ventilation, on the other hand, is a rather popular technique. The interaction between the fire source and the flow as generated by the SHC system can become quite complex. The second part of this paper focuses on smoke and heat control by means of horizontal mechanical ventilation. An overview is provided first of different existing rules or guidelines. Next, some fundamental differences from (longitudinal) mechanical ventilation in tunnels are described. This discussion is supported by full-scale car park fire experiments [9], numerical Computational Fluid Dynamics (CFD) simulations [10] and reduced-scale experiments [11]. The reader is referred to the references mentioned for more details on these campaigns.

The final part of the paper briefly comments on the possible effects of water, be it in the form of sprinklers, water mist or from a fire brigade intervention. These comments must be handled with care, as more research is needed in this area.

After discussing some possible routes for further research, the paper ends with a few concluding remarks.

Section snippets

Fire source: Source for smoke and heat

There has been increasing concern about the consequences of fires in car parks associated with modern car design (e.g., plastic fuel tanks) and how these fires may spread to other vehicles parked adjacently and nearby. This concern has been heightened by the entry into the market place of cars powered by alternative fuels such as LPG (Liquefied Petroleum Gas).

Although there have been few deaths or injuries recorded to date (if UK statistics are typical), there are concerns regarding new and

Variety in existing rules and guidelines

In many countries, design calculation rules for SHC systems for car parks are already in place, in terms of standards or guidelines. It is not the intention to provide here an exhaustive list of these rules worldwide. Yet, the variety in the existing rules is interesting to discuss briefly, as this is partly the motivation for large-scale research on this topic. It must be stressed that the comparison of different guidelines cannot be done without consideration of the strategy behind the

Effect of water

The primary effect of water is a cooling effect, resulting in a reduction in fire heat release rate and smoke production rate. Indeed, water is a very efficient heat absorber, in particular when the phase change from liquid to vapour takes place. Water is also a very efficient radiation attenuator, both in the liquid and the vapour phases. Consequently, the risk of fire spread to neighbouring cars by radiation is substantially reduced. This has been confirmed in [1]: the effect of activated

Discussion—Further research

As mentioned in the introduction, not all issues can be tackled within a limited number of research projects. In this section, we argue that further research is required for a number of aspects. This list is by no means exhaustive, but the authors feel that the issues mentioned here deserve to be investigated in the near future.

Concluding remarks

The results have been summarised of two extensive research campaigns [1], [2], [9] on car park fire safety, more particularly on fire and smoke (and heat) dynamics in case of car fires.

First, statistics and time dependent heat release rate measurements from recent full-scale car fire experiments with modern cars and different set-ups have been discussed. The statistical survey revealed that fires in car parks, statistically, are not of major concern, since there are very few deaths or injuries,

Acknowledgements

The results presented have been obtained through the SBO project 080010, funded by IWT (Flanders, Belgium), and ‘Fire spread in car parks’, project BD2552, Department for Communities and Local Government, (UK).

References (20)

  • N. Tilley et al.

    CFD study of relation between ventilation velocity and smoke backlayering distance in large closed car parks

    Fire Saf. J.

    (2012)
  • M. Shipp et al., ‘Fire Spread in Car Parks’, BD2552, Department for Communities and Local Government, December 2010...
  • B. Merci, L. Taerwe, P. Vandevelde, E. Van den Bulck, F. Van den Schoor, J. van Beeck, J. Vantomme, Fundamental Design...
  • D. Joyeux, “Natural Fires in Closed Car Parks: Car Fire Tests”, CTICM, INC-96/294d-DJ/NB...
  • D. Joyeux et al.

    Demonstrations of real fire tests in car parks and buildings

    Steel Struct.

    (2001)
  • J. Mangs, O. Keski-Rahkonen, Characterisation of the Fire behaviour of a Burning Passenger Car. Part I: Car Fire...
  • J. Mangs, O. Keski-Rahkonen, Characterisation of the Fire behaviour of a Burning Passenger Car. Part II:...
  • B. Zhao et al.

    Structural behaviour of an open car park under real fire scenarios

    Fire Mater.

    (2004)
  • M. Shipp et al.

    Measurements of the severity of fires involving private motor vehicles

    Fire Mater.

    (1995)
  • X. Deckers, S. Haga, B. Sette, B. Merci, “Smoke Control in Case of Fire in a Large Car Park: Full-Scale Experiments”,...
There are more references available in the full text version of this article.

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