Area accidents

Accidents originating inside the plant but which affect the entire plant area are termed area accidents. In particular, these maybe fires and internal floods, typically started by breaks in the service water system. 

The physical separation of redundant sections of plant protection systems is usually one of the fundamental defences against the consequences of these events. 

Operational experience indicates the possibility of rather peculiar accidents of this kind. For example, the complete loss of external electric supplies caused 

An accurate examination of the risks relevant to each specific plant may reveal all the possible accidents and suggest pertinent prevention/mitiga-tion provisions. 

For fires, in particular, every regulatory system has issued guide criteria and requirements which, in general, necessitate the implementation of a complete fire protection program. This includes provisions for the separation of redundant safety systems, other prevention measures, anti-fire equipment and operating procedures. 

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Therefore, there are three main types accidents of tank area can trigger a domino effect fire, explosion, and fire—explosion occurred in both cases simultaneously cross. The first accident has devastating effects of thermal radiation, and other physical effects like overpressure effects may work on equipment close to the first unit, resulting in the close tank rupture, fire, explosion, that is the secondary accident. Under certain conditions, the secondary accident may lead to higher levels of three or more accident, causing extremely serious consequences of the accident. In simple terms is that two or more times of accidents caused by the initial Tank accident (mainly fire and explosion), and became a serious consequences phenomenon is called Tank domino effect. Figure 1 shows the mechanism of Domino effect in LPG tank area accidents. 

Figure 1. Mechanism of domino effect in LPG tank area accidents.

Vdrhelyi, A., Hjalmdahl, M., Hyden, C., and Draskdczy, M. 2004. Effects of an active accelerator pedal on driver behaviour and traffic safety after long-term use in urban areas. Accident Analysis and Prevention, 36(5), 729-732. 

Malenfant, J. E. L., R. Van Houten and B. Jonah (2002). A study to measure the incidence of driving under suspension in the Greater Moncton area. Accid, Anal Prev., 34, 439-447. 

Never store full cylinders and empties in the same area. Accidents and damage can occur if an empty cylinder is attached to a pressurized system. 

Consequently, a series of Acts was introduced to deal with the perceived safety problems. These Acts essentially governed safety for the following sixty years. The Acts dealt with five main areas accident reporting, specification of safety equipment, transportation of explosives, hours of work, and financial responsibility to injured employees and shippers whose freight was damaged. 

In the workplace, the impact of alcohol and drug abuse affects four major areas accidents, productivity, medical expenses, and employee morale. 

The range and dimensions of the problem area "accident" have, without doubt, been recognized before now. The fundamental work done by Greenwood Woods (1919), Newbold (1929), Marbe (1926) and many others was not the first serious and somewhat successful research on accident causes and prevention work of this type has existed since the early days of industrialization (compare Thiele Gottschalk, 1973). It has been regularly continued ever since, as every... 

Although team membership will vary according to the type of accident, a typical team investigating an operating area accident might include ... 

The next part of the procedure involves risk assessment. This includes a deterrnination of the accident probabiUty and the consequence of the accident and is done for each of the scenarios identified in the previous step. The probabiUty is deterrnined using a number of statistical models generally used to represent failures. The consequence is deterrnined using mostiy fundamentally based models, called source models, to describe how material is ejected from process equipment. These source models are coupled with a suitable dispersion model and/or an explosion model to estimate the area affected and predict the damage. The consequence is thus determined. 

Chernobyl. The most weU-known graphite-moderated reactor is the infamous Chemobyl-4, in Ukraine. It suffered a devastating accident in 1986 that spread radioactivity over a wide area of Europe. 

The accident at the Three Mile Island (TMI) plant in Pennsylvania in 1979 led to many safety and environmental improvements (4—6). No harm from radiation resulted to TMI workers, to the pubHc, or to the environment (7,8), although the accident caused the loss of a 2 x 10 investment. The accident at the Chernobyl plant in the Ukraine in 1986, on the other hand, caused the deaths of 31 workers from high doses of radiation, increased the chance of cancer later in life for thousands of people, and led to radioactive contamination of large areas. This latter accident was unique to Soviet-sponsored nuclear power. The Soviet-designed Chemobyl-type reactors did not have the intrinsic protection against a mnaway power excursion that is requited in the test of the world, not was there a containment building (9—11). 

Safety Showers. Safety showers and eyewash fountains or hoses should be installed where corrosive or toxic materials are handled. A large-volume, low velocity discharge from directly overhead should effect continuous drenching, ie, a minimum flow of 20 L/min (50 gal /min). Water to outside showers may be heated to a maximum temperature of 27°C by an electric heating cable. The valves for all safety showers should be at the same height and relative position to the shower head, and they should operate in the same way and direction. The shower station should be identified by paint of a bright, contrasting color. In areas where chemicals harmful to the eyes may be encountered, an eyewash fountain or spray should be available in case of splash accidents. 

Y. S. Sedunov, V. A. Borzilov, and N. V. Klepikova, Use of Mathematical Modeling to Estimate Formation of Contaminated Areas Resultingfrom Nuclear Accident, IAEA-SM-306/114, IAEA, Vienna, Austria, 1990. 

An important aspect of environmental, health, and safety laws and regulations is enforcement. Eederal, state, and local regulatory authorities usually have large enforcement sections. In the environmental area, compliance audits are usually conducted aimually. OSHA, both federal and state, usually audits based on a faciHty s accident/incident rate. 

Much of the damage and loss of life in chemical accidents results from the sudden release of material at high pressures which may or may not resiilt from fire. Chemical releases caused by fires and the failure of process equipment and pipelines can form toxic clouds that can be dangerous to people over large areas. 

The Center for Chemical Process Safety (CCPS) was established in 1985 by the American Institute of Chemical Engineers (AICliE) for the express purpose of assisting the Chemical and Hydrocarbon Process Industries in avoiding or mitigating catastrophic chemical accidents. To achieve this goal, CCPS has focused its work in four areas ... 

What are the rights and responsibilities regarding interviewing parties, requiring drug testing, medical review of people involved in the accident, as well as policies associated with these areas ... 

The chance of severely injuring someone because of detonation accidents in this area is D per year. 

Investigate the potential for unconfmed vapor cloud explosions resulting from accidents at the flammable storage tank area. 

In such emergencies, it is most important to know the local wind direchon at the accident site, so that the area that should be immediately evacuated can be determined. The next important factor is the wind speed, so that the travel hme to various areas can be determined, again primarily for evacuation purposes. Both of these can be estimated on-site by simple means such as watching the drift of cigarette smoke. It would be well to keep in mind that wind speeds are higher above ground and that wind direction is usually different. 

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