Fire Safety Journal 

About: Fire Safety Journal is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Poison control & Fire test. It has an ISSN identifier of 0379-7112. Over the lifetime, 3024 publications have been published receiving 84541 citations.

Comments on calculation of temperature in fire-exposed bare steel structures in prEN 1993-1-2: Eurocode 3—design of steel structures—Part 1–2: general rules—structural fire design

Abstract: Comments on calculation of temperature in fire exposed bare steel structures in prEN 1993-1-2 : Eurocode 3-design of steel structures-Part 1-2

Heat release rate: The single most important variable in fire hazard☆

Abstract: Heat release rate measurements are sometimes seen by manufacturers and product users as just another piece of data to gather. It is the purpose of this paper to explain why heat release rate is, in fact, the single most important variable in characterizing the ‘flammability’ of products and their consequent fire hazard. Examples of typical fire histories are given which illustrate that even though fire deaths are primarily caused by toxic gases, the heat release rate is the best predictor of fire hazard. Conversely, the relative toxicity of the combustion gases plays a smaller role. The delays in ignition time, as measured by various Bunsen burner type tests, also have only a minor effect on the development of fire hazard.

Effects of elevated temperatures on properties of concrete

Abstract: Concrete material in structures is likely exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. This paper presents the effects of elevated temperatures on the physical and mechanical properties of various concrete mixtures prepared by ordinary Portland cement, crushed limestone, and river gravel. Test samples were subjected to elevated temperatures ranging from 200 to 1200 °C. After exposure, weight losses were determined and then compressive strength test was conducted. Test results indicated that weight of the specimen significantly reduced with an increase in temperature. This reduction was very sharp beyond 800 °C. The effects of water/cement (w/c) ratio and type of aggregate on losses in weight were not found to be significant. The results also revealed that the relative strength of concrete decreased as the exposure temperature increased. The effect of high temperatures on the strength of concrete was more pronounced for concrete mixtures produced by river gravel aggregate. The results of the physical and mechanical tests were also combined with those obtained from differential thermal analysis, and colour image analysis.

Control of smoke flow in tunnel fires using longitudinal ventilation systems - a study of the critical velocity

Abstract: The “critical velocity” is the minimum air velocity required to suppress the smoke spreading against the longitudinal ventilation flow during tunnel fire situations. The current techniques for prediction of the values of the critical velocity for various tunnels were mainly based on semi-empirical equations obtained from the Froude number preservation combining with some experimental data. There are a few uncertainties in the current methods of prediction of the critical ventilation velocity. The first is the influence of the fire power on the critical ventilation velocity. The second is the effect of the tunnel geometry on the critical velocity. Both problems lead to the issues of the scaling techniques in tunnel fires. This study addressed these problems by carrying out a series of experimental tests in five model tunnels having the same height but different cross-sectional geometry. Detailed temperature and velocity distributions in the tunnels have been carried out. The experimental results showed that the critical velocity did vary with the tunnel cross-sectional geometry. It was also shown clearly that there are two regimes of variation of critical velocity against fire heat release rate. At low rates of heat release the critical velocity varies as the one-third power of the heat release rate, however at higher rates of heat release, the critical velocity becomes independent of fire heat release rate. Analysis of the distribution of temperature within the fire plumes showed that there were two fire plume distributions at the critical ventilation conditions. The change of the fire plume distribution coincided with the change of the regime in the curves of the critical velocity against fire heat release rate. The study used dimensionless velocity and dimensionless heat release rate with the tunnel hydraulic height (tunnel mean hydraulic diameter) as the characteristic length in the experimental data analysis. It was shown that the experimental data for the five tunnels can be correlated into simple formulae which can be used for scaling. The new scaling techniques are examined by applying the scaling techniques to the present experimental results and three large-scale experimental results available in the public literature. A good agreement has been obtained. This suggests that the scaling techniques can be used with confidence to predict the critical ventilation velocity for larger-scale tunnels in any cross-sectional geometry. Comprehensive CFD simulations have been carried out to examine the flow behaviour inside the tunnels. Validation against the experimental results showed that the CFD gave slightly lower but satisfactory prediction of the flow velocity. However the temperature prediction in the fire region was too high. The findings from the CFD simulations supported the ones from experimental tests.

Entrainment in fire plumes.

Abstract: A new technique for measurement of mass flow rates in buoyant fire plumes is described. The characteristics of 10 - 200 k W methane diffusion flames stabilized on porous-bed-burners of 0.10 - 0.50 m dia. are described. A transition in the dependence of flame height on heat input and burner size was observed when the flame height was about four times the burner diameter. The mass flow rates in the buoyant plumes produced by the fires were measured for a range of elevations starting just below the time-averaged top of the flame and extending to six times this flame height. The mass flow rates in this region of the plume were correlated by the use of a simple plume model. Atmospheric and forced disturbances in the air being entrained increased the entrainment rate of the plume.