Passive engineered controls

Some passive controls will live outside the user interface and may not be apparent to day-to-day operators. For example, HIT systems typically need to exhibit resiliency in their architecture whether brought about through redundancy or other systematic means. These design features represent active engineered controls. However it is common for this to be supported by other more passive controls which require some degree of human intervention. The platforms on which systems reside can often be monitored for availability and performance. In some cases systems may be specifically instrumented to provide metrics on the execution of specific functions or the success of database transactions. Similarly systems may log errors or failed messages which are then made available for inspection by service management personnel. 

Unfortunately passive controls have a number of shortcomings perhaps the most significant being that they can simply be ignored and this fundamentally constrains their effectiveness. The more passive the control, the less likely it is to be attended to. 

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Percentage of recommendations for administrative controls, active engineered controls, passive engineered controls, and inherently safer alternatives X ... 

The topics for this checklist have been taken from CCPS (1993b) and Bollinger et al. (1996). Every effort was made to ensure that this checklist is comprehensive therefore, there may be some redundancy or overlap in questions among the different sections. It should be noted that some of the items in this checklist employ a very broad concept of inherent safety, as presented by Bollinger et al. (1996). As such, they may address inherent aspects of passive, engineered or even administrative controls, rather than the narrower inherent safety conception of reducing the underlying process hazards that must be contained and controlled to safely operate a facility. 

Are adequate and appropriate controls for chemical hazards identified through the hazard analysis Are adequate controls identified for all chemical hazards Are engineered controls preferred over administrative controls Are administrative controls preferred over personal protective equipment Are passive controls preferred over active controls ... 

The primary philosophy is to follow the principles of inherent safety. This implies a systematic effort to apply the principles of hazard elimination, minimization/ intensification, hazard substitution, moderation/attenuation, and simplification. However, additional controls will still be required to control a hazardous situation, prevent escalation, and mitigate the risk to people, to the environment, asset, and reputation. Preferably, these safeguards will be passive- or active-engineered controls rather than administrative controls (i.e., dependent on direct human intervention). 

Although many engineers provide only the minimum adequate vessel design to minimize costs, it is inherently safer to minimize the use of safety interlocks and administrative controls by designing robust equipment. Passive hardware devices can be substituted for active control systems. For example, if the design pressure of the vessel system is higher than the maximum expected pressure, an interlock to trip the system on high pressure or temperatures may be unnecessary. 

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. 

Most of the drugs shown in Table 7.1 are administered passively in the now familiar skin patches. These devices are carefully engineered in order to ensure that the drug is released at a predetermined rate, often with the use of rate-controlling... 

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