Mond fire, explosion, and toxicity index

The basic procedures for calculating the Mond indices are similar to those used for the Dow index. 

The process is first divided into a number of units which are assessed individually. The dominant material for each unit is then selected and its material factor determined. The material factor in the Mond index is a function of the energy content per unit weight (the heat of combustion). 

The material factor is then modified to allow for the effect of general and special process and material hazards the physical quantity of the material in the process step the plant layout and the toxicity of process materials. 

Separate fire and explosion indices are calculated. An aerial explosion index can also be estimated, to assess the potential hazard of aerial explosions. An equivalent Dow index can also be determined. 

The individual fire and explosion indexes are combined to give an overall index for the process unit. The overall index is the most important in assessing the potential hazard. 

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Lewis, D. J. (1979). The Mond Fire, Explosion and Toxicity Index Applied to Plant Layout and Spacing. i3th Annual Loss Prevention Symposium, April 2-5, 1979, Houston, TX, 20-26. Loss Prevention, No. 13. New York American Institute of Chemical Engineers. 

Lewis, D. J. (1919a) AIChE Loss Prevention Symposium, Houston, April. The Mond fire, explosion and toxicity index a development of the Dow index. 

Lewis DJ (1979) The Mond fire, explosion, and toxicity index—a development of the dow index. In A.I.Ch.E. Loss Prevention Symposium. Houston... 

The ICI-MOND Fire Explosion and Toxicity Index (ICI 1985) was derived from DOW one and it is yet appreciated in process industry in many countries, including Italy. In ICI-MOND index method there are some ninety elementary questions, nested in a three levels tree. For many issues there is also a forth level of nested questions. About two thirds of the questions are for penalties and one third for credits accounting. For the most of the questions a quantitative answer is required. The questions are organized in chapters for penalties section the subjects are related to materials and quantities, processes and equipment, layout, health for credits section instead the method deals with containment, control, safety culture, fire engineering and emergency preparedness. Every issue weighs differently in overall risk levels accounting. Results are presented in a structured way, discriminat-iug fire, toxic, confined and unconfined explosion. 

In the Mond Index the plant is divided into individual units on the basis of the feasibility of creating separating barriers. One of the factors taken into account in the index is therefore plant layout. The potential hazard is expressed in terms of the initial value of a set of indices for fire, explosion and toxicity. A hazard factor review is then carried out to see if design changes reduce the hazard, and intermediate values of the indices are determined. Offsetting factors for preventative and protective features are applied and the final values of the indices, or offset indices, are calculated. The elements of the Mond method are listed in Table 1. 

In addition to the chemical exposure, fire, and explosion, the various factors considered in the Mond Index are the material factor and its associated hazards, process hazard, quantity hazard, layout hazard, and toxicity hazard. The material factor relates to the type of materials, their flash point, explosive limits, etc., the nature of the process, and the process s inherent safety. The... 

The Dow index applies only to main process units and does not cover process auxiliaries. Also, only fire and explosion hazards are considered. Recently the index has been expanded to include business-interruption losses. The principles and general approach used in the Dow method of hazard evaluation have been further developed by Mond in the United Kingdom to include toxicity hazards. This revised Mond index is described in a paper by Lewis ... 

The Dow Fire and Explosion Index (FEI) (Dow, 1994 Van den Braken, 2002) and the Dow Chemical Exposure Index (CEI) have been developed and practiced hy Dow Chemicals for several decades. These tools measure process inherent safety characteristics, help to quantify the expected damage of potential fire and explosion incidents, and identify equipment that would likely contribute to the creation of the incident. The Mond Index was developed by ICI (UK) from the Dow Fire and Explosion Index. The Mond Index includes toxicity and covers a wider range of processes and storage installations than the FEI. The various aspects considered in the FEI are material factor (flammability and reactivity), general process hazards such as exothermic/endothermic reactions, and special process hazards such as toxic nature of the chemicals and dust explosion. For example. Table 8.6 shows the results of the FEI for various inventory levels of storage of ethyl acrylate. 

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