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In order to utilize the low-calorific value gases, oxy-combustion technology is generally used to burn the diluted fuel mixture more efficiently, cleanly and safely. Here the thermal balance method is tailored to check the fuel mixture flammability with the help of theoretical flammability diagrams and non-dimensional HQR diagrams. Specifically, the contributions of diluent/oxidant/temperature are checked. Even with limited experimental data, they are found to be a powerful tool to understand the mixture flammability, since they are based on simple principles of energy conservation. This approach provides the foundation for fine-tuning safe operation parameters related to oxy-combustion technologies.

One of the challenges in controlling an underground coal mine fire is that it is fully sealed with limited information available through gas sampling. Most of previous works look at the fuel content of the mixture, or the explosibility. Here we are proposing a progress variable to check both fuel and oxygen for diagnosing what is the status of fire after sealing, and when the sealed atmosphere is explosive if a leaking is allowed. In essence, the flammability problem of mine gases is a mixture problem of multiple fuels, with carbon dioxide as the diluent, in an oxygen-modified air [1]. In order to determine the status of a sealed fire, a progress variable, heating/quenching ratio, is proposed as the completion between heating and quenching, whereas heating can be oxygen-based or fuel-based.

A generic method is proposed to use the flammability diagram to determine the flammable state of a mixture and the dilution requirements. All graphs are derived from theory, without any empirical constants. This method is comprehensive and consistent with a same treatment for fuel(s)/oxidizer(s)/diluent(s). The theoretical LFL lines are generally lower than the experimental lines due to the assumption on constant flame temperature. So, the prediction is usually conservative, which is good for estimation purposes. © 2013 American Institute of Chemical Engineers Process Saf Prog 33: 70–76, 2014

Out of the thermal balance method, a method of presenting mine fire data is proposed in this work. By grouping fuels into a pseudo fuel, grouping nitrogen and oxygen into a pseudo air, and using carbon dioxide as the diluent, a diluted flammability diagram is reconstructed for this oxygen-modified environment. The flammability envelop is controlled by oxygen availability, while the operation point is controlled by fuel/diluent availability. The relative position between the envelop and the operation point shows the flammable state of this mixture. Coward’s explosive triangle is also applied using the limiting oxygen concentration derived from the diagram. Both are most useful in guiding the suppression operation for an underground coal mine fire.

Recently, a thermal method was proposed to recheck the concept of flammability by manipulating the competition between heating and quenching. This method is further explored here to reconstruct flammability diagrams, explaining the contribution of each component toward flammability change for a mixture. Based on the assumption that a diluent will not change the flame temperature at the flammability limits, these isothermal processes lead to a conservative estimation of the flammable zone. Although rough near the inertion point, the theoretical flammability envelop has the potential to guide future purging and diluting operations. It will be a powerful tool for both educational purposes and practical utilities. © 2012 American Institute of Chemical Engineers Process Saf Prog 32: 42–48, 2013

The Incident Command System (ICS) is a standardized approach typically structured into five functional areas: command, operations, planning, logistics, and finance. The system allows for the integration of personnel, facilities, equipment, procedures, and communications within an organizational structure. It is a mature system and has been used by industries for a long time to aid in the proper mitigation of industrial incidents. The course named “Hazardous Materials Incident Management” is taught in the Department of Fire Protection & Safety at Oklahoma State University, which is designed to prepare students to manage hazardous materials emergencies through extensive hands-on trainings. This article shows three design scenarios and how the ICS procedures are applied by student teams during the field trainings. Emergency response can be safely and effectively accomplished only when procedures are established and standardized through appropriate training. The discussion will help the academia and industry to well prepare/train the next generation of both public and private sector emergencyresponse personnel. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

Flammable liquid fuel spills on flooring including carpets and other porous materials have long been a subject of interest to the fire investigation community. Early understanding in this community about the indicators of a liquid fuel fire, such as holes in flooring material or heavy burning in this area, have been shown to be incomplete. Research from the past two decades have enabled fire investigators to identify burn patterns from liquid fuel pours, estimate the evaporation and mass burning rates of the liquid fuel on the carpet, and be able to test the carpet forensically to determine if the fuel was present during the fire or was introduced by post-fire contamination. These science-based tools have enabled fire investigators to tackle a seemingly simple fire problem and have aided in fire origin and cause determination. The authors believe that the type of work that has been undertaken on liquid fuels on carpet and flooring should be conducted for many other problems in fire investigation to give fire investigators as many scientific tools as possible. These tools should be taught in the framework of education instead of as simple rule of thumb training. As this is done, the fire investigation industry will advance as a whole.

Within theoretical flammability diagrams, two types of flammability problems can be solved. Type I problems cover flexible oxygen levels in a closed domain, while type II problems deal with fuel streams in a fixed background. For chemical engineering, purge and dilution are conventional approaches for mixture safety. For suppression engineering, total flooding and local application are corresponding solutions for hazard control. By identifying the critical points within a flammability diagram, two parameters (MMR and MMF), are identified to be more important than others in reconstructing any flammability diagram. All static problems on flammable state can be solved with the help of a theoretical flammability diagram.

Sir Humphrey Davy pioneered the research on combustion safety of gases and vapors. A brief review of his experimental work shows that the principle of flammability measurement is still not finalized. There is some inconsistency of concepts between various platforms. Over two centuries, different groups have developed different interests on flammability. This work is built upon various historical interests on combustion safety.

Type I problems cover the explosive (premixed) burning in a confined space, including underground coal mine fires and backdrafts in a compartment fire. Treating multiple fuels and diluents consistently using the thermal balance between heating and quenching, coal mine fire is a typical mixture safety problem to be solved within a theoretical flammability diagram. The energy terms are also demonstrating the progress of a growing fire. A similar scenario happened in a compartment fire, where eruptive burning, backdraft and blow-torch effect can be better represented by the energy balance inside. They are all solvable within theoretical flammability diagrams.

Research paper published in the journal Fire Technology 2004 The occurrence of a liquid fuel burning on carpet has been involved in many incendiary and accidental fires. While the research on a liquid fuel fire on carpet is still limited, much work on porous media has been performed using sand or glass beads soaked with liquid fuel. In this study, a heat and mass transfer theory was first developed to analyze the burning process of liquid on carpet, and then several small-scale tests were performed to validate the theory. This analysis is valid for pool fires intermediate in size (5-20 cm. in diameter). The experimental apparatus consisted of a circular pan (105mm) and a load cell. Varying amounts of fuels (heptane, kerosene and methanol) were spilled onto the carpet, which was allowed to burn in a quiescent environment. It was found that due to the different controlling mechanisms, the liquid burning rate could be less or more than that of a similarly spilled free-burning pool fire. For the worst-case scenario in fires, the maximum enhancement of the burning rate due to the porous media is predictable through the physical properties of the fuel. This analysis is valid for both combustion and evaporation. Several similar results in the scientific literature are analyzed to further describe the trend. This work explains the role of carpet in liquid pool fires and also helps to explain special risks related to the presence of carpet involved in arsons and will be useful in reconstruction of the early development of an incendiary or accidental fire.