Chemical fire/ explosion

The hazard assessment must include a determination of the type of hazard(s) present in the workplace such as exposure to fire or explosion hazards and the hazard classification, e.g., chemical, fire, explosion, etc., of the work area [Section 4.2.3 and A.4.2.3] ... 

There are many other kinds of hazards that safety engineering must recognize, evaluate, and control. Included are electrical, low and high pressure, thermal, chemical, fire, explosion, waste, vibration, noise, ionizing and non-ionizing radiation, visual, biological, materials handling, transportation, and others. Many of these are addressed elsewhere in this book. 

AH gas-fired power plants require oxygen analy2ers to ensure that air has not been drawn into the piping system. Oxygen intake can lead to the presence of an explosive mixture in the pipeline before the fuel reaches the burner or combustor 2one. When gas-fired units are located in an enclosed area, multiple ultraviolet flame detectors are used to shut down equipment and flood the area with CO2 or a chemical fire suppressant whenever a spark or flame is detected. 

Process Safety A discipline that focuses on the prevention and mitigation of fires, explosions, and accidental chemical releases at process facilities. Excludes classic worker health and safety issues involving working surfaces, ladders, protective equipment, etc. 

Have there been fires, explosions or chemical release incidents If yes, request the incident investigation data, including actions taken to prevent a reoccurrence. 

Have there been fires, explosions or chemical release incidents If yes, explain. 

Emergency response plan A written plan which addresses actions to take in case of plant fire, explosion or accidental chemical release. 

Hydroprocesses Hydrogen is chemically stable and relatively unreactive at ordinary temperatures most processes utilizing it require a catalyst. Above 500°C it reacts readily with oxygen and confined flammable mixtures explode violently if ignited Main hazards fire, explosion, metallurgical problems arising from hydrogen attack... 

Chemical incompatibility can manifest itself in many ways however, discussions will be limited to those combinations resulting in fires, explosions, extreme heat, evolution of gas (both toxic and nontoxic), and polymerization. 

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. 

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. 

In addition, responses to releases of hazardous substances where there is no potential health or safety hazard (i.e., fire, explosion, or chemical exposure) are not considered to be emergency responses. Keep in mind that qualified personnel who are trained to clean up incidental... 

Safety issues are not covered here. These are dealt with in Systems and Equipment book, and some fundamental issues will be taken up in the second edition of the Fundamentals book. The following aspects should be taken into account in system design fan safety AHU fire protection issues safety measures in mines, tunnels, underground car parks, etc. transportation of chemical and explosives. 

The Phillips 66 Company Houston Chemical Complex Explosion and Fire, U.S. Dept, of Labor, Washington, D.C., Apr. 1990. 

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

Physical properties are important considerations in any study of accidents and emergencies. A substance may exhibit certain characteristics under one set of conditions of temperature, pressure, and composition. However, if the conditions are clianged, a once-safe operation may become a liazard by virtue of vulnerability to fire, explosion, or mpturing. To promote a better understanding of these effects, many of which are covered in Chapter 7, a brief rc iew of some key physical and chemical properties is provided in tliis and the next section. 

The first step in minimizing accidents in a chemical phuit is to evaluate the facility for potential fires, explosions, and vulnerability to other liazards, particularly those of a chemical miture. This calls for a detailed study of plant site and layout, materials, processes, operations, equipment, and training, plus an effective loss prevention program. The technical nature of industry requires detailed data and a broad range of experience. Tliis complex task, today becoming the most important in plant design, is facilitated by the safety codes, standiu ds, and practice information available. The technical approach to evaluating die consequences of hazards is discussed later in tliis cliapter and in Part V (Chapters 20 and 21). 

The equipment and systems of the processing phuit are designed to contain tlie chemicals mider processing conditions and to provide tlie controlled environment required for production. This equipment is designed to function under both specific process conditions and upset conditions. Upset conditions tliat are considered in design include fire, explosions, and accidental chemical releases. 

The rapid growth and expansion of the chemical industry has been accompanied by a spontaneous rise in human, material, and property losses because of fires, explosions, hazardous and toxic spills, equipment failures, other accidents, and business interruptions. Concern over the potential consequences of catastrophic accidents, particularly at chemical and petrochemical plants, has sparked interest at both the industrial and regulatory levels in obtaining a better understanding of the subject of this book Health, Safety, and Accident Management (HS AM). The writing of this book was undertaken, in part, as a result of this growing concern. 

Stull, D. R., Fundamentals of Fire Explosion, Monograph Series, No. 10, Vol 73, The Dow Chemical Co., published Amer. Inst. Chem. Engrs., 1977. 

Prevent accidents. Chemical substances and processes should minimize the potential for fires, explosions, or other accidents. 

On release, vapours heavier than air tend to spread (i.e. to slump ) at low level and will accumulate in pits, sumps, depressions in ground etc. This may promote a fire/ explosion hazard, or a toxic hazard, or cause an oxygen-deficient atmosphere to form, depending on the chemical. 

As discussed in Chapter 4, chemicals can be a nuisance or pose health risks if they become airborne as a result of inadequate process control, operation and maintenance malpractice, inadequate maintenance, incomplete understanding of the process etc. Hazards may arise if the oxygen concentration in the air fluctuates beyond its normal level of 21% by volume, and fire/explosion dangers may arise from the presence of flammable gases, vapours or dusts in the atmosphere. Thus air quality tests may be required for a variety of purposes such as ... 

American Institute of Chemical Engineers. Dow s Fire Explosion Index Hazard Classification Guide. New York, NY. 

In addition to the toxicological risk, high concentrations of metal carbonyls pose a significant fire/explosion hazard that may prevent safe entry even wearing the appropriate chemical protective apparel. 

The three most common chemical plant accidents are fires, explosions, and toxic releases, in that order (see chapter 1). Organic solvents are the most common source of fires and explosions in the chemical industry. 

With the various system available for the suppression high energy chemical fires, there is, in most cases a configuration suitable for almost any explosives, pyrotechnic or munitions facility. 

---