Safety advantages, inherent process

In many cases, the inherent safety advantages of one process are clear when compared with alternatives. One or more hazards may be significantly reduced, while others are unaffected or only marginally increased. For example, aqueous latex paints are clearly inherently safer than solvent based paints, although there are applications where the increased performance of solvent based paints justifies their use, with the appropriate layers of protection. 

Deciding among a number of process options having inherent safety advantages and disadvantages with respect to different hazards can be quite difficult. The first step is to understand thoroughly all hazards associated with the process options. Process hazard analysis and evaluation techniques are appropriate tools (CCPS, 1992). These include ... 

One of the main advantages of the continuous process is increased safety. There are certain design requirements in the continuous process which have resulted in an inherently safe operation. (1) To reduce the hazard created by handling dry nitrocellulose or powder, all operations up to the final dry processing (75% of the handling) are carried out under water. 

Although there are many advantages of applying process intensification, there are some aspects that will invariably need to be managed. Some of these issues to be managed are a potential for decreased inherent safety as there will be less incentive to ehminate hazardous materials, given that the inventories are minimized a potential for reaction runaway if heat transfer is not sufficient, given a reduction of solvent used a potential for... 

If we consider human error to be a process of variation akin to the genetic variability inherent in mutation, it is possible to see that some error may well be advantageous to performance and therefore adaptive in nature. We already know that some error is deleterious to performance and safety, whereas a significant proportion of error is neutral. The next logical step is to accept that, indeed, some error must have adaptive benefits. To this end, in systems that attempt to standardize and constrain performance to eliminate error, are we simply interfering with natural processes designed to optimize performance ... 

Simplification of process and safety systems by taking advantage of particular inherent small reactor characteristics. For example, natural circulation in some BWR concepts (not practical in large-size units because of pressure vessel size limitations) taking advantage of the high heat sink capacity/capability of small gas-cooled reactor cores. 

It is estimated that 43% of today s high-production-volume chemicals do not have complete toxicity data—and 7% of these chemicals have no data at all. Inherent safety implies that the process is inherently safe and that it is not kept safe with the help of several safety checks and alarms. Several available hazard analysis techniques can be used at various stages of the process development. Developing inherently safe process is more advantageous than... 

Power Supply. An energize-to-trip (ETT) design means that power is required for the SIF to achieve the safe state. ETT was predominantly implemented in the past to overcome poor reliability of the main power supply system. When de-energize-to-trip is used with no alternate power source (e.g., uninterruptible power supply), a dip in power results in the process going to the safe state. This causes major financial loss and potential safety concerns that normally accompany a process trip and restart. To overcome poor power supply reliability, some facilities chose to implement ETT in order to maintain process reliability. These circuits have the inherent advantage that a loss of power does not result in a spurious trip, hence improved process uptime can be achieved. The disadvantage is that power is required to safely shutdown the process, so loss of power presents the potential for a failure to trip on demand situation. 

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