S. S. Han

Atrium hot smoke tests in a big shopping complex

Hot smoke tests were carried out in the site of four atriums of heights over 32 m in a big shopping complex. The objective was to evaluate the performance of the mechanical smoke exhaust systems installed. This is required while inspecting the fire service installations as specified in the local codes. Testing procedures followed those in Australian Standard with slight modifications. A 2 MW methanol pool fire was agreed in the tests. It was set up with six trays in a test chamber for reducing the radiation effect to adjacent combustibles. The main testing criterion is to demonstrate that the smoke layer can be kept above 8 m upon operating the smoke exhaust system. Other testing criteria listed in the code such as that on roof air temperature were also assessed. Elevation of the smoke layer interface was observed visually through indication marks placed at height 8 m above the floor. Vertical temperature profile was also measured by a thermocouple tree placed a distance away from the fire source. Results of the hot smoke tests confirmed that operating the mechanical smoke exhaust system installed in the four atriums would keep space below 8 m free of smoke. Language: en

Smoke toxicity assessment of burning video compact disc boxes by a cone calorimeter

Video compact discs (VCD) are usually stored in plastic boxes for protection. Smoke toxicity of burning VCD boxes in a cone calorimeter will be assessed in this article. Samples of the materials commonly available in the market are burnt under different radiant heat fluxes from 10 kWm (sup)-2 to 70 kWm (sup)-2. Concentrations of carbon dioxide and carbon monoxide emitted are measured. The effects to human beings will be assessed based on the fractional exposure dose (FED) measured in the cone calorimeter. Smoke toxicity effects in real-scale fires will be estimated by some correlations. It is further confirmed that very different smoke toxicity effects will result from different scenarios of burning the VCD boxes.

Simulation of Atrium Smoke Filling by Computational Fluid Dynamics

Abstract Computational Fluid Dynamics (CFD) is evidently relevant to the study of fires, yet the intermediate chemistry has yet to be factored successfully into combustion models. Consequently, predicted airflow patterns, together with pressure and temperature contours, are mostly used in evaluating the performance of smoke control systems. But even using these assumptions, very few studies exist comparing predicted results from CFD with experimental findings. This leaves research with a paucity of data on how smoke is likely to spread, fill and be controlled in large halls. While hot smoke tests in a hall in Japan have yielded good’–quality experimental data for smoke layer interface heights, the dominant approach to hazard assessment on big projects in East Asia is to use a software Fire Dynamics Simulator (FDS) developed at the National Institute of Standards and Technology in the USA. In this paper, FDS predicted results for smoke filling and exhaust will be examined side’–by’–side with experimental data. Our technique is to compare recorded transient smoke layer interface heights with the results predicted by FDS. This work also responds to questions on how to determine smoke layer interface height. In addition to the default FDS method (FDS menu), two methods are proposed to determine heights from sharp changes in, respectively, vertical temperature profiles and particle tracking. Functional analysis is applied to justify predictions, with results suggesting that CFD offers fairly good predictions on smoke layer interface height.

On Assessing Flammability of Textiles

This study is to investigate the fire safety of textile and clothing materials. It also assesses the flammability for textiles in general. With the increase in big fires, accidental or non-accidental, people are worrying about the fire behaviour of combustibles. The flammability of textile and clothing materials is a great concern. Appropriate tests should be developed to assess textile and clothing materials to ensure they are safe in a fire. In fact, textile products should satisfy some fire safety criteria depending on their uses. There are specified flammability requirements on selected products, though whether these are good enough for assessing modern textile materials should be watched. Typical textile materials with and without fire retardants protection were selected for assessing the fire behaviour with a cone calorimeter. High radiative heat flux up to 70 kWm‒2 was applied to assess those selected textile materials. A cone calorimeter is suggested to be the minimum requirement, though some full...

Preliminary full-scale burning tests of electric cables

Full-scale burning tests on PVC electric cables at post-flashover stage were carried out. Real-scale room fires were considered and the heat release rates were measured. The results on the total heat release were compared with those measured from a cone calorimeter with different heat fluxes. Language: en