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The transportation industry demands the flammability control in the safe transportation of any liquid mixtures. Here the flashpoint of a flammable solvent is controlled by adding an evaporative diluent into the mixture. The flashpoint of this binary mixture is predictable with the help of Method of Flammable Resistance. Here methanol and heptane were chosen as typical fuels to be tested while R141b and R1233zd were added to control the flashpoint. Experimental results show that the binary mixture demonstrated the predicted behavior with the help of a new modeling scheme for mixing and the activity models for non-ideal evaporation. This methodology has the potential for predicting the flashpoint of any combinations of solvents, though some kind of synergistic behavior may appear when small fraction of a diluent is involved.

Oxygen plays a duel role on mixture safety as a heat source and a heat sink. For the variable oxygen in a compartment (a type I problem), oxygen level in background air determines the upper limit of the fuel. For the oxygen in a fuel stream (a type II problem) in air, the oxygen will change the thermal properties of the fuel like a diluent or a fuel. Here both problems are solved with the thermal balance method. A new method, the flammable resistance method, can solve the type II problem more easily. It is equivalent with the thermal balance method, but with a perfect form like the Le Chatelier's Rule. Both methods are useful in assessing the danger of a flammable fuel stream containing oxygen.

The high-temperature and high-pressure methanol one-step oxidation has been the primary process for the mass production of dimethoxymethane. However, the risk of explosion for this process is still not properly defined. This paper presents new results from the experimental study on the explosion characteristics, including the explosion pressure and the explosion limits for methanol/air mixtures with a variable oxygen level, under an initial pressure between 0.3 MPa and 0.75 MPa and at the initial temperature of 423 K. The upper explosive limits were found to increase along with the initial pressure. If the limits for normal air are known, the oxygen effect on flammability is predictable from the thermal balance method. With a correlation for the pressure effect and a method for the oxygen effect, we can have the flammable range predictable.

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.

Starting from the flammability diagram, a thermal theory is proposed to scale various critical concentrations in combustion. By an analogy between ignition and suppression, the flammability limits are extrapolated to minimum extinguishing concentrations. Thus the suppressibility of a fuel will be evaluated from its flammability, while the suppression capability of an agent will be evaluated using the cup-burner (CB) value. By setting up the thermal balance at extinguishing, the synergistic effect can also be explained by an adjustable flame temperature factor. This thermal mechanism will guide the future work on selecting new combinations of binary agents.

Flammability limits are one of the most important characteristics to evaluate fire hazards associated with fuels. Currently, numerous correlations, based on either chemistry (stoichiometric oxygen number) or energy (heat of combustion), have been proposed to estimate flammability limits. In this study, a thermal model is proposed to incorporate the dual role (quenching and heating) of each component in a mixture. The energy term plays a vital role in Excess Heating Potential (EHP) and Quenching/Heating Ratio (QHR) and hence an association between flammability limits and energy terms can be established. In addition, oxygen calorimetry bridges chemistry formula with energy release of a certain fuel, thus all existing correlations are unified under the principle of energy conservation. Since this methodology is universal, it can be applied to estimate the flammability limits of any mixtures or guide future correlations with improved precision. Advantages and limitations for this methodology are also discussed.

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

Because it is difficult to treat the contributions of diluents explicitly using Le Chatelier's rule, a methodology based on thermal balance is proposed for estimating the flammability limits of a mixture. This method converts the flammability information of a mixture into a binary domain of heating/quenching potentials and, after some simple manipulations, converts them back into the flammability domain. The advantage of this conversion is the separation of the heating and quenching potential sums. The dual contribution (heating and quenching) of each species is stressed, while the simplicity of hand calculation is preserved. This method is equivalent to Le Chatelier's rule but has increased flexibility in dealing with various fuel/oxygen/diluents combinations. It will help safety engineers gain more confidence in the hazard analysis of flammable mixtures involving diluents.

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.

Data from two freeway locations show that absent lane changing, the relationships between congested speed and spacing are linear in most ranges of congested speed. The relationships are also found to be statistically indifferent across lanes, indicating that a single general model would suffice for all lanes. Moreover, speed-spacing relationships for different types of lane changers (discretionary versus mandatory due to merging and diverging) are also found to be statistically indifferent. Anticipation and relaxation periods, defined as durations of perturbed car-following behavior before and after a lane-change maneuver, were measured for lane changers and the vehicles immediately behind the followers. Lane changers exhibited anticipation and relaxation periods of 8 and 14 s, respectively. The followers in the initial lanes exhibited anticipation and relaxation periods of 4 and 8 s, which are smaller than the periods for the followers in the target lanes (12 and 16 s) as well as the periods for the lane changers. The findings suggest that car-following behavior on a freeway can be predicted according to Newell's simplified car-following theory, and a single model can be used without much loss of accuracy for different lanes. The findings also suggest that the anticipation and relaxation processes are independent of lane-changing types but are different for lane changers and followers.

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.

Within theoretical flammability diagrams, all dynamic processes to change the local concentration can be analytically demonstrated. Four flammability diagrams, standard diagram, reduced diagram, explosive triangle and ternary diagram will compared side-by-side for purge and dilution, or for total flooding and local application, or for solving type I and type II problems. The consistency in all four diagrams shows that all diagrams are equivalent and effective in solving dynamic problems. Their utility is most effectively demonstrated in the safe operations before filling and emptying a fuel tank.

Mainly based on the assumption on constant flame temperature, each non-reacting species has a non-dimensionalized heat-absorbing capability in critical flames. Applying the oxygen calorimetry, each fuel has a comparable thermal signature derived from their flammability information. Thermal balance method is manipulating these thermal terms in the energy domain, while all critical volumetric limits can be derived from these terms. Various flammability diagrams are derived from the principles in energy conservation and used to illustrate the mixing process. By grouping species in a mixture, this binary treatment can solve the flammable state in flexible ways.

Type II problems cover processes involving fuel streams releasing into a certain background (generally air) and emptying a fuel tank. Two types of flammability problems are covered here, clean combustion technologies and leaking of refrigerant mixtures. Operation parameters for clean combustion technologies are discussed, including diluent, oxygen, temperature, hydrogen and other fuels. The ignition danger of flammable leaking is typical of refrigerant safety. Both are dealing with the ignitability of the fuel rather than the explosibility of air.

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.