Passive risk control

Passive hazard controls would not require continuous or even occasional actions from system users. Active controls would require operators and users to accomplish a task at some point during the operation to reduce risks and control hazards (Table 1.18). 

Risk acceptance can be a formal decision to accept the residual risk or it can be a passive decision in which residual risks are not specified. For some types of harms, even the best risk control might not entirely eliminate risk. In these circumstances it might be agreed that an appropriate quality risk management strategy has been applied and that quality risk is reduced to a specified (acceptable) level. This (specified) acceptable level will depend on many parameters and should be decided on a case-by-case basis. For in every case specific measures are created for diminishing the risks, for instance in-process controls may contribute significantly to decrease the risks of extemporaneous preparation, see Sect. 34.6. Examples of parameters... 

Simpson (1988) reviewed studies which considered individual differences in risk perception and the effects of these differences on behavior. A study by Verhaegen et al. (1985) looked at three groups of workers in wire mills. The first group comprised those who had been directly involved in events which led to the accident (the "active" group). The second group ("passive") were those who had only been involved indirectly ("innocent bystanders") and the third group were a control group who had not been involved in accidents at all. 

U.S. EPA defines MNA as the reliance on natural processes, within the context of a carefully controlled and monitored site cleanup approach, to achieve site-specific remediation objectives within a time frame that is reasonable compared to that offered by other more active methods. The natural processes include biodegradation, dispersion, dilution, sorption, volatilization, stabilization, and transformation. These processes reduce site risk by transforming contaminants to less toxic forms, reducing contaminant concentrations, and reducing contaminant mobility and bioavailability. Other terms for natural attenuation in the literature include intrinsic remediation, intrinsic bio-remediation, passive bioremediation natural recovery, and natural assimilation. 30... 

LOPA is a semi-quantitative tool for analyzing and assessing risk. This method includes simplified methods to characterize the consequences and estimate the frequencies. Various layers of protection are added to a process, for example, to lower the frequency of the undesired consequences. The protection layers may include inherently safer concepts the basic process control system safety instrumented functions passive devices, such as dikes or blast walls active devices, such as relief valves and human intervention. This concept of layers of protection is illustrated in Figure 11-16. The combined effects of the protection layers and the consequences are then compared against some risk tolerance criteria. 

Industrial fire protection and safety engineers attempt to eliminate hazards at their source or to reduce their intensity with protective systems. Hazard elimination may typically require the use of alternative and less toxic materials, changes in the process, spacing or guarding, improved ventilation or, spill control or inventory reduction measures, fire and explosion protective measures - both active and passive mechanisms, protective clothing, etc. The level or protection is dependent on the risk prevalent at the facility versus the cost to implement safety measures. 

Procedural controls, process controls, 98-99 Process controls, 96-100 active controls, 98 inherently safer approach, 97 mitigation techniques, 99 passive controls, 97-98 procedural controls, 98-99 safe operating limits, 99-100 Process definition, documentation, 102-104 Process design, documentation, 105 Process hazard analysis (PHA) risk assessment, 92-93 screening methods, 63 Process risk management decisions, documentation, 105-106... 

Bonita R, Duncan J, Truelsen T, et al. Passive smoking as well as active smoking increases the risk of acute stroke. Tob Control 1999 8(2) 156 60. 

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