Fire Safety Science 

About: Fire Safety Science is an academic journal. The journal publishes majorly in the area(s): Combustion & Fire protection. Over the lifetime, 2085 publications have been published receiving 18286 citations.

The size of flames from natural fires

Abstract: Uncontrolled fires produce flames where the initial momentum of the fuel is low compared with the momentum produced by buoyancy. The heights of such flames with wood as the fuel are examined and discussed in terms of both a dimensional analysis and the entrainment of air into the turbulent flame. They are then compared with other experiments on the flow of hot gases. Some recent experiments on the effects of wind on such flames are also reported.

Friction factors for pipe flow of xanthan-based concentrates of fire fighting foams

Abstract: In this paper we develop a friction factor correlation to predict the pressure drop during pumping and induction of concentrates of fire fighting foams containing around 1% of xanthan gum. Such concentrates are highly elastic, display small yield stress and exhibit significant thinning upon shearing. We demonstrate that in the turbulent regime, the Blasius equation normally used for Newtonian fluids seems to correlate well the friction factor with the Metzner-Reed Reynolds number. Our development provides an example of how the methodology used to develop the friction factor correlation can be applied to analyse a set of experimental data to verify its internal consistency. The friction factors developed in the paper can be applied to other foam concentrates that include a similar content of xanthan gum in their formulation, to predict pressure drop as a function of a flow rate and pipe diameter, provided that there exists an appropriate viscosity model. Subsequently, the paper presents experimental measurements of apparent viscosity for one foam concentrate and develops relevant viscosity models. We observe that the rheology of the concentrate is governed by the behaviour of xanthan gum. Although, the foam concentrate considered in the article is yield pseudo plastic (i.e., it follows the Herschel-Bulkley model), for the shear stresses normally encountered during pipe flow, the viscosity of the material can be described by a power law model. Over the temperature range of between 0 and 40 o C, the apparent viscosity displays only a weak dependence on temperature. Subsequent calculations of pressure drop with temperature demonstrate minor variation in pressure drop with temperature, but only in the turbulent flow regime. This suggests that induction systems intended to operate under widely varying temperature conditions should be designed to function in the turbulent flow regime.

To Prevent 'Panic' In An Underground Emergency: Why Not Tell People The Truth?

Abstract: The research study reported was carried out on behalf of Tyne and Wear Passenger Transport Executive (P,T.E) in Newcastle U.K., in order to assess the efficiency of their communication system in the event of an emergency evacuation. There were two stages in the research programme. Firstly, an evaluation of the day to day functioning of the sub-surface stations as an information system was carried out with particular reference to wayfinding. Secondly, an experiment involving five evacuations was conducted in the most spatially complex station. The information given to users in each of the five evacuations differed: 1. alarm bell only, 2. alarm bell with two staff members, 3. alarm bell and minimal non-directive public announcements, 4. alarm bell with two staffmembers and directive public announcements, 5. alarm bell with improved directive public announcements. Three measures were assessed: the time to start to move, the time to clear the station and the appropriate behaviour in the situation. The results show that evacuations 4 and 5 were completed rapidly and safely. The study highlights the importance of issuing prompt instructions to the public, explaining what is happening, what to do and why, if a successful evacuation is to be achieved.

Upward Turbulent Flame Spread

Abstract: Mechanisms and rates of upward spread of turbulent flames along thermally thick vertical sheets are considered for both noncharring and charring fuels. By addressing the time dependence of the rate of mass loss of the burning face of a charring fuel, a linear integral equation of the Volterra type is derived for the spread rate. Measurements of spread rates, of flame heights and of surface temperature histories are reported for polymethylmethacrylate and for Douglas-fir particle board for flames initiated and supported by a line-source gas burner, with various -rates of heat release, located at the base of the fuel face. Sustained spread occurs for the synthetic polymer and not for the wood. Comparisons of measurements with theory aid in estimating characteristic parameters for the fuels.

Fire Following Earthquake

Abstract: Prepared by the Technical Council on Lifeline Earthquake Engineering of ASCE. This TCLEE Monograph covers the entire range of fire following earthquake (FFE) issues, from historical fires to 20th-century fires in Kobe, San Francisco, Oakland, Berkeley, and Northridge. FFE has the potential of causing catastrophic losses in the United States, Japan, Canada, New Zealand, and other seismically active countries with wood houses. This comprehensive book on FFE and urban conflagrations provides state-of-the-practice insight on unique issues, such as large diameter flex hose applications by fire and water departments. Topics include: History of past fires; Computer modeling of fire spread in the post-earthquake urban environment; Concurrent damage and fire impacts for water, power gas, communication and transportation systems; Examples of reliable water systems built or designed in San Francisco, Vancouver, Berkeley, and Kyoto; Use of large diameter (5 in.) and ultra large diameter (12 in.) flex hose for fire fighting and water restoration; and Cost-effectiveness of various FFE mitigation strategies, with a detailed benefit-cost model. Water utility engineers, fire fighting professionals, and emergency response planners will benefit from reading this book.