Medium-risk facilities

Medium Risk— Facilities whose transportation operations may pose a moderate level of risk to people from an accidental release of toxics or flammables and/or a significant environmental impact potential. 

Medium-risk facilities normally require at least a preliminary hazard analysis and some user involvement. 

FRI 2 (medium risk) There is a medium probability that hazards in this facUity can cause loss of life. Hazards may result in permanent disability to one or more persons, hospitalization (associated with illness or injury) of three or more persons, up to two lost-time injuries, loss of facility operational capability from 2 to 4 weeks, or damage to equipment or property from 250,000 to 500,000. 

However, there is a risk of reaeration when the medium is transferred to the dissolution vessels. A 275% increase in the level of oxygen has been reported after deaeration and dispensing of media into dissolution vessels.f An alternative approach to deaeration would be to sparge the medium in situ with helium. Dissolution testers with an on-line deaeration facility are available commercially. 

Based on these initial findings, qualitative operational-level reviews of facilities transporting any of the seven medium- or high-risk chemicals were directed from corporate. The goal of these risk analyses is to further understand XYZ Chemical s transportation risks and to identify where risk reduction options may need to be considered. This transition from a global to operational-level review will be the focus as the example continues to evolve in Chapters 4 and 5. 

Using the consequence and likelihood categories, risk matrix, and risk evaluation criteria, the team reviewed three release scenarios (small, medium, and large) for the segments identified for each of the chemical movements. The result of the semi-quantitative risk estimation for this facility s hazardous material transportation operation is detailed in Table 4.12. From this results table, the following are determined ... 

The risk of the proposed facility is initially categorized as Low, Medium, or High by evaluating such factors as energy sources (types and magnitudes), usage, occupancy, experience (historical data), location, and mission. 

In the design of many high-risk systems such as nuclear power facilities or weapon systems, there is often a strong tendency to rely solely on statistical analysis for hazard evaluations. Management finds such an approach somewhat easier to accept since it provides a convenient (if not entirely realistic) medium to express safety in terms to which they can relate. However, the unwary can be easily trapped in their failure to establish reasonable limits on the acceptability of a probability of risk occurrence. 

Risk avoidance involves eliminating the cause of the hazard. This is accomplished by changes in the inherent risk features of a process or facility, e.g., using noncombustible fluid as a heat transfer medium (i.e., hot oil system) instead of a combustible fluid (e.g., diesel oil). Risk reduction concerns the provision of prevention measures or protection features that will lessen the consequences of a particular incident. Some examples include firewalls, firewater sprays, emergency shutdown systems, etc. Most facilities include some aspect of risk reduction measures simply due to prescriptive or even performance based regulatory requirements. 

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