Dow Fire and Explosion

Methods for performing hazard analysis and risk assessment include safety review, checkhsts, Dow Fire and Explosion Index, what-if analysis, hazard and operabihty analysis (HAZOP), failure modes and effects analysis (FMEA), fault tree analysis, and event tree analysis. Other methods are also available, but those given are used most often. 

Dow Fire and Explosion Index. The Dow Eire and Explosion Index (3) is a procedure usehil for determining the relative degree of hazard related to flammable and explosive materials. This Index form works essentially the same way as an income tax form. Penalties are provided for inventory, extended temperatures and pressures, reactivity, etc, and credits are appHed for fire protection systems, process control (qv), and material isolation. The complete procedure is capable of estimating a doUar amount for the maximum probable property damage and the business intermptionloss based on an empirical correlation provided with the Index. 

Quantitative Fire and Explosion Index (FExplosion Index Hazard Classification Guide, 1994 Lees, 1980, pp. 149-160). The F EI is used to rate the potential of hazard from fires and explosions. Its purpose is to quantify damage from an incident. It identifies equipment that could contribute to an incident and ways to mitigate possible incidents. It is a way to communicate to management the quantitative hazard potential. 

Relative Ranking (DOW Fire and Explosion and Chemical Exposure Index) to evaluate siting/layout considerations... 

Dow Fire and Explosion Index (F EI) A method (developed by Dow Chemieal Company) for ranking the relative fire and explosion risk assoeiated with a proeess. Analysts ealeulate various hazard and explosion indexes using material eharaeteristies and proeess data. 

Tools are available to assist in comparing the risk associated with two or more different processes. For example, the first sheet of the Dow Fire and Explosion Index (FEI) (Dow, 1994b) ranks the safety characteristics of the process from a fire/explosion standpoint, without taking credit for protective and mitigation features. The Dow Chemical Exposure Index (CEI) (Dow, 1994a) and Id s Mond Index (ICI, 1985 Tyler, 1985) are other ranking tools. 

The approach to developing metrics for process safety is analogous to those that might be used to assess Occupational Exposure risk. One can cite as well several indices that have been developed as metrics for estimating and ranking the safety of a given process or chemical reaction, such as the DOW fire and explosion index,the Stoessel index ° for hazard assessment and classification of chemical reactions, the Inherent Safety Index, the Prototype Index for Inherent Safety, amongst others. ... 

Other techniques that take into account some site-specific conditions, such as the Dow Fire and Explosion Index (Ref. 34) and the Mond Index (Ref. 39), have been used to prioritize buildings for evaluation. The results of these indices should be used in conjunction with consideration of other factors, rather than as stand-alone criteria. These other factors might include an evaluation of the effects of confinement and/or congestion-induced turbulence on the potential for blast. 

Figure 9.2. Dow Fire and Explosion Index calculation form.

More detailed check lists are given by Carson and Mumford (1988) and Wells (1980). Balemans (1974) gives a comprehensive list of guidelines for the safe design of chemical plant, drawn up in the form of a check list. A loss prevention check list is included in the Dow Fire and Explosion Index Hazard Classification Guide, Dow (1987). 

A hazards survey can be as simple as an inventory of hazardous materials in a facility or as complicated as a rigorous procedure such as the Dow Fire and Explosion Index (F EI)2 and the... 

Figure 10-3 Form used in the Dow Fire and Explosion Index. The figures and tables referenced in the form are provided in the index booklet. Source Dow s Fire and Explosion Index Hazard Classification Guide, 7th ed., (1994). Reproduced by permission of the American Institute of Chemical Engineers.

Table 10-1 Selected Data for the Dow Fire and Explosion Index1...

This problem requires student access to the Dow Fire and Explosion Index manual.) In a devolatilizer, a solvent (60% cyclohexane and 40% pentane) is removed from a... 

Process industry has used the Dow Fire and Explosion Hazard Index (DOW, 1987) and the Mond Index (ICI, 1985) for many years. These indices deal with fire and explosion hazard rating of process plants. Dow and Mond Indices are rapid hazard-assessment methods for use on chemical plant, during process and plant development, and in the design of plant layout. They are best suited to later design stages when process equipment, chemical substances and process conditions are known. 

The Dow Fire and Explosion Hazard Index, the Mond Index, Hazop and PIIS are discussed here in more detail. The methods and their elements are also presented in Table 1. 

The purpose of the Dow Fire and Explosion Hazard Index (Dow, 1987) is to 1) quantify the expected damage of potential fire and explosion incidents in realistic terms, 2) identify equipment that would be likely to contribute to the creation or escalation of an incident and 3) communicate the fire and explosion risk potential to management. The Dow Index is the product of the Unit Hazard Factor and the Material Factor (Table 1). 

Also indices such as the Dow Fire and Explosion Hazard Index and the Mond Index have been suggested to measure the degree of inherent SHE of a process. Rushton et al. (1994) pointed out that these indices can be used for the assessment of existing plants or at the detailed design stages. They require detailed plant specifications such as the plot plan, equipment sizes, material inventories and flows. Checklists, interaction matrices, Hazop and other hazard identification tools are also usable for the evaluation, because all hazards must be identified and their potential consequences must be understood. E.g. Hazop can be used in different stages of process design but in restricted mode. A complete Hazop-study requires final process plans with flow sheets and PIDs. 

The Finnish legislation (Pyotsia, 1994) classifies the flammability of chemical substances on the basis of their flash and boiling points. This is similar to the European Union Directives concerning hazardous substances. Also the Dow Fire and Explosion Index (1987) and Edwards Lawrence (1993) have been used similar approaches. 

Also Dow Fire and Explosion Index (1987) considers corrosion risks, but the penalties are given through unacceptable corrosion rates. Design standards also include advice of acceptable corrosion rates (Uhlig and Reviev, 1985). 

Several qualitative approaches can be used to identify hazardous reaction scenarios, including process hazard analysis, checklists, chemical interaction matrices, and an experience-based review. CCPS (1995a p. 176) describes nine hazard evaluation procedures that can be used to identify hazardous reaction scenarios-checklists, Dow fire and explosion indices, preliminary hazard analysis, what-if analysis, failure modes and effects analysis (FMEA), HAZOP study, fault tree analysis, human error analysis, and quantitative risk analysis. 

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