Defined Situations of Hazard and Accident

Skjerve, A.B., Albrechtsen, E., and Tveiten, C.K. 2008. Defined Situations of Hazard and Accident related to Integrated Operations on the Norwegian Contmental Shelf. SINTEF report A9123, Trondheim. 

Defined situations of hazard and accident related to integrated operations on the Norwegian continental shelf... 

The hazards and risks associated with work activities need to be identified first. Hazards are defined as situations with the potential to cause harm or loss. Under the CDM Regulations it is both hazardous circumstances and hazardous activities that potentially threaten the health and safety of employees. So the identification of hazards and activities is an essential part of analysing the risks that these represent to health and safety in the workplace. Risk is a function of three factors the likelihood of actual harm resulting from a hazard, the potential severity of the consequence should it occur, and the number of people that might be exposed to the harm. There are a number of well established methods by which risks may be quantified and hazard indices developed, if reliable data is available. Risk is normally measured in terms of the probability of a worker being injured in any given year, while carrying out his or her work, by the severity of injury suffered. Accident frequency is often used as the prime indicator of risk overall. 

The frequency analysis step involves estimating the likelihood of occurrence of each of the undesired situations defined in the hazard identification step. Sometimes you can do this through direct comparison with experience or extrapolation from historical accident data. While this method may be of great assistance in determining accident frequencies, most accidents analyzed by QRA are so rare that the frequencies must be synthesized using frequency estimation methods and models. 

Risk assessments have been performed for a variety of topics, from accidents in the workplace, to lifestyle choices and natural catastrophes. This chapter will focus on evaluating human risk primarily from chemical and radiological exposure. Risk assessment as defined by the National Academy of Science is the use of the factual base to define the health effects of exposure of individuals or populations to hazardous materials and situations. Risk assessment determines if a chemical has a toxic effect, estimates the exposure to this chemical and identifies the adverse effects of the chemical. The combination of the toxicity influenced by the level of exposure estimates what the... 

Accident An unwanted transfer of energy or an environmental condition which, due to the absence or failure of barriers and/or controls, produces injury to persons, property, or process (SSDC) as defined in NHB 5300.41(lD-2), An unplanned event which results in an unsafe situation or operational mode (NSTS 22254) an unplanned and sometimes injurious or damaging event which interrupts the normal progress of an activity and is invariably preceded by an unsafe act or unsafe condition or some combination thereof. An accident may be seen as resulting from a failure to identify a hazard or from some inadequacy in an existing system of hazard controls (ASSE). 

Part One The accident situation and system have to be analysed for safety factors using the four aspects defined in the accident tetrahedron - exposure, assets, hazards and system response to the initiation of an accident. Evidence may be presented in tabular form or referenced to specific reports. The assessment and review methods should be recorded (including duration and participants), as it is likely that the evidence compiled in each aspect, may not be of equal volume. Every accident situation should have contributions in each area, any absence should be viewed as falling short of completeness. 

The word emergency is used in many different contexts and different areas of human activity. In Ret [4] emergency is defined in part as A nonroutine situation or event that necessitates prompt action primarily to mitigate a hazard or adverse consequences for human health and safety, quality of life, property or the environment . In IAEA safety assessment publications the following terms have been established for identification of different operational states and accident conditions of a nuclear power plant normal operation, anticipated operational occurrences (AOOs) (abnormal operation), design basis accidents (DBAs), beyond design basis accidents (BDBAs) and severe accidents. 

After evaluating the planned barriers as well as the influencing factors, then, the assessment of the occupational hazards within the defined susceptible hazards/risks exposed area need to be performed. The susceptible hazards/risks exposed area can be defined as per expert s judgement (opinions) and past experience. For example, a checklist analysis which is an experience based approach, can be used to identify known types of occupational hazards, potential accident situations, or design deficiencies (Neogy et al., 1996). Thereafter, the hazards needs to be classified as well as prioritise based on the standards, regulations and statutory requirements. 

Exposure is the time that a worker is at risk of having an accident. The exposure for each of 63 hazards has been determined by defining the activities/ situations—known as missions that can lead to these accidents and then conducting a nationwide survey in the Netherlands to establish the exposure to each mission (expressed as duration in hours). For example for Hazard 2 Struck by moving vehicle the mission is defined as ... 

While considering that the complexity of operational decision situations can lead to accidents occurring, Crowl and Jo (2007) point out that incidents may also provoke accidents. Many incidents are followed by a series of events that result in an accident. This may include explosions, leaks and fire. In this paper, hazard scenarios are defined for natural gas pipelines based on Brito et al. (2010), as presented (Fig. 2). 

When defining a hole in each coUision case hazardous situations which resulted in an accident because an unsafe act can be performed in a hazardous situation were considered. A hazardous situation is a circumstance in which people, property, or environments are exposed to one or more hazards defined by ISO/IEC GUIDE 51 1999. According to Honda (2008), when taking coUision avoidance action, a hard over turn is more effective than a crash astern stop maneuver and other maneuverings. For a local workplace, the research defined the situation of unacceptable risk in a coUision as the situation that two vessels approached within the maximum advance of a give-way vessel (Fukuoka 2015). 

The broad range of accidents/hazards (see Chapter 6), their associated risks, and the particular circumstances of each potential accident situation means that it may not be practicable to have one single set of criteria covering all contingencies. However, irrespective of which criteria are chosen, they must be substantiated and agreed by the relevant regulatory authority. To measure is to know, but first we need to define the measuring stick. Hence the production of the safety criteria report. The criteria should be formulated so as to provide effective safety measures, be readily understood in terms of both concept and application, and be flexible to provide scope for user contribution. 

On the other hand, voluntary incident reports are shown as not very useful in their current form for evidence-based modeling. They may only be useful in the way that they are currently used, as the alerts for possible hazards in the daily operation of shipping. In order to make the incident reports useful for accident modeling, first they need to be prepared in a more systematic way that can address the causality of the mishaps, and second a more consistent definition of near-miss situation needs to be defined to reliably assign occurred mishaps to a specific type of accident. 

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