Unacceptable risk, freedom from

This analysis might lead one to conclude that subjective views of risk are contaminants to its true and objective nature but this is not the complete picture. For activities which affect the public one could argue that people need to be assured to a level which is tolerable to society irrespective of whether the magnirnde of risk is based on scientific fact. If safety is freedom from unacceptable risk [8] (see Chap. 3) and what we consider to be acceptable is influenced by the values of society then one has to conclude that safety is itself at least partly defined by perception. 

Ultimately this is perhaps the most difQcult question to answer. This dilemma of risk acceptabiUty is more than just academic, in fact it goes to the very heart of our definition of safety safety is freedom from unacceptable risk [1], So how does one go about establishing to what extent risk is acceptable ... 

In Guide 51, this definition is given Safety—freedom from unacceptable risk (3.1). It is exchangeable with the definition I have used Safety is defined as that state for which the risks are judged to be acceptable. 

Safety is defined as freedom from unacceptable risk (3.1). 

The lEC 61508 standard defines safety as "freedom from unacceptable risk" (Ref. 1). Functional safety has been defined as "part of the overall safety relating to the process and the Basic Process Control System (BPCS) which depends on the correct functioning of the SIS and other protection layers." The phrase "correct functioning of the SIS" identifies the key concern. A high level of functional safety means that a safety... 

There is a lack of empirical surveys discussing how to increase safety and resilience in the oil and gas industry in a proactive manner. By safety we mean freedom from unacceptable risks resilience is defined as the ability of a system or an organization to react to and recover from disturbances at an early stage, with minimal effect on the dynamic stability , both from Hollnagel (2006). By proactive we mean acting in anticipation of future problems . 

Safety, in functional safety terms, is not defined as freedom from risk because no such state exists in the real world. Instead it is defined as freedom from unacceptable risk. Unacceptable is a community-derived yardstick, related to what may be tolerated by individuals and society as a whole. Safety standards improve with time and with the growing wealth of communities. The UK Health and Safety Executive provides a useful description of tolerable risk ... 

Activity performed by a competent senior engineer to determine if the safety system meets the specification and actually achieves functional safety (freedom from unacceptable risk). This assessment is an important part of reducing systematic failures. It must be performed at least after commissioning and validation but before the hazard is present. 

Safety is commonly defined as freedom from unacceptable risk of harm (or accident). One very useful view of safety, and of safety assessment, is the barrier model illustrated in Figure I using Air Traffic Management (ATM) as an example. 

The definition of safety in Guide 51 is Freedom from unacceptable risk (3.1). That definition is in concert with all previously cited definitions, other than for the dictionary definitions. It also implies an understanding of hazards and risks. 

Since 100% freedom from hazards and risk is not possible, safety is more effectively defined as freedom from unacceptable risk. (4)... 

In a Safety-I view, the focus is on adverse events. This can be as either the absolute number of adverse events or as the relative number. The focus on the absolute number is a corollary of the myth that all accidents are preventable, usually expressed as the goal or ideal of zero accidents, zero work site injuries, or even zero car accidents. (To be fair, this is presented as a virtually zero car accidents. ) The idea of zero accidents can be found in the mission statements of many large companies, as well as a service offered by numerous consultants. The focus on the relative number corresponds to a more probabilistic view, for instance that the probability of an accident must be below a certain value, or that there should be freedom from unacceptable risks. ... 

In the first case, the pursuit of absolute safety, the concern is for the value of the numerator N, where N represents the number of a certain type of events, for instance accidents, incidents, injuries, lost time injury, unplanned outages rejection rate, etc. The goal is to reduce N to as small a value as is practicable, preferably zero if that is possible. In the pursuit of absolute safety, there is no concern for the number of complementary events, i.e., the number of cases where N does not occur. For example, if N is the number of times per year a train passes a red signal (SPAD), then the number of complementary events is the number of times during the same time period that a train stops at a red signal. Having N=0 as the ideal in practice means that safety is defined as the freedom from risk rather than as the freedom from unacceptable (or unaffordable) risk. The difference is by no means unimportant. 

Safety - the freedom from unacceptable risk from harm. 

The definition of safety is freedom from unacceptable mishap risk. This definition implies that in order to know if a system is safe, all the hazards and their attached risk must be known, and then the risk must be communicated and controlled until it is deemed acceptable. This requires an established risk management process, which includes a risk acceptance step. 

Since 100% freedom from mishaps is not possible, safety is effectively freedom from conditions of unacceptable mishap risk. Safety is the... 

We often hear pundits pontificate the catch-phrase safety at all costs But what do we understandby the term safety Safety can be defined as freedom from unacceptable risk of harm (ISO/IEC Guide 2 1986 Definition 2.5). But how do we determine an acceptable risk of harm ... 

Disease surveillance is required to generate evidence that the country (or zone or compartment) has been able to maintain disease freedom. Appropriate biosecurity measures to maintain disease freedom need to be applied at the same level as the surveillance system. Under international agreements, disease freedom allows countries to restrict the introduction of animals (and products not considered safe) from areas of a lower disease status. A country may consider restrictions of trade not explicitly allowed for under international agreement, for instance, in the case where a proposed import of an aquatic animal product presents an unacceptable disease risk. In these circumstances, risk analysis has a clearly defined role within... 

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