Facility risk acceptance

Facility Risk Acceptance. The following risk acceptability criteria are typical of those in MIL-STD-882B ... 

Risk insurance is the method chosen when the possible losses are financially too great to retain internally by risk acceptance and in some cases too expensive to prevent or avoid. However even the risk insurers will want to satisfy themselves that adequate precautions are being taken at facilities they are underwriting. Thus, they will look very carefully at risks they feel are above the industry norm or have high loss histories. 

The liquid and solid effluents are well characterized. As the ACW I Committee noted in its original and supplemental reports, the gaseous process emissions will have to be characterized for health risk assessments and environmental risk assessments required by EPA guidelines (NRC, 1999, 2000a). These results, along with the results of analyses of metals emissions (including chromium VI), can be used to assess the environmental impact of a facility through accepted risk-assessment methods (EPA, 1998). 

Most low-level waste, except high-activity, longer-lived waste that is anticipated to be produced in small volumes, is intended for disposal in a near-surface facility. The acceptability of near-surface disposal for most low-level waste is based primarily on assessments of the long-term performance of such facilities, which indicate that the health risks to the public, including future inadvertent intruders, should be acceptable. 

Provide reasoned arguments and judgments about the risk acceptance criteria including the rationale for their acceptance, references used, and details of the risk acceptance studies conducted into potential major accident events that may occur during the life of the facility. 

Those hazards that have a risk level above the facility s acceptable risk level generate a finding which will then become a recommendation. 

When we are communicating risk and risk acceptance criteria to the public, the figures as we present them in technical risk analyses and in e.g., Fig. 1 will often not be very informative. One way to visualise the actual risk for the activity (LNG facility) and the risk acceptance criteria is to plot known events in the risk... 

The facility system safety risk assessment process works such that if the initial risk assessment produces a RAC of 1 or 2, some type of control must be applied. After this control is applied, a second risk assessment or controlled RAC is determined. First, the control rating code is evaluated to ensure that the CRC rules have been met and then to ensure that the controlled RAC is 3 or 4. If the CRC rules are met and the controlled RAC is 3 or 4, the corrective action is taken and the risk has been reduced to an acceptable level. However, if the CRC rules have not been met and/or the RAC remains at 1 or 2, other controls must be applied and the reassessment cycle is repeated. If other controls are not available, then risk acceptance decisions must be made by the appropriate level of management, and risk acceptance decisions must be documented (Fig. 11-4). 

Figure 11-5 Residual risk acceptance form to be used for formal acceptance of residual risks. (Source US. Army Facility System Safety Manual. Draft.)...

Craig, D. K. et al. "Toxic Chemical Hazard Classification and Risk Acceptance Guidelines for Use in DOE "Facilities," WSRC-MS-92-206, Rev. 1 (April 1993 Recommendations of the Westinghouse M O Subcommittee on Nonradiologi il Risk Acceptance Guideline Development), Westinghouse Savannah River Company, Aiken, SC, April, 1993. 

The total faeility individual risk is then the sum of aU the event risks at a receptor point. Repeating the proeess at different receptor points wUl generate a risk curve, where risk generally deereases with increasing distance from the risk source. The units of this risk measure can be expressed as the annual chance that a person living near the hazardous facility might die due to potential accidents in that facility. (The MIACC risk acceptability guidelines are for a specific receptor location and not for a specific receptor that may spend some of his or her time away from that receptor location. Hence, the risk calculation should also assume continuous exposure of the receptor.)... 

This total risk cun/e can now be used for comparison against risk acceptability criteria for making decisions about the facility... 

Fire-safety objectives must be determined before a facility is designed. The architectural design and the building methods and materials used for a structure will often determine how a fire will be confined or will spread. At times, code comphance is not sufficient to meet the level of risk acceptable to a particular organization. 

The risk management techniques of the organization should be defined before any considerations of the philosophy of protection needs for a facility are identified. An organization that is capable of obtaining a high level of insurance coverage at very low expense, even though they may have risks, may opt to have a limited outlay for protection measures since it is not cost effective. In reality this would probably never occur, but serves to demonstrate influences in a corporate approach to protection levels and risk acceptance criteria. 

Another way of interpreting absolute risk estimates is through the use of benchmarks or goals. Consider a company that operates 50 chemical process facilities. It is determined (through other, purely qualitative means) that Plant A has exhibited acceptable safety performance over the years. A QRA is performed on Plant A, and the absolute estimates are established as calibration points, or benchmarks, for the rest of the firm s facilities. Over the years, QRAs are performed on other facilities to aid in making decisions about safety maintenance and improvement. As these studies are completed, the results are carefully scrutinized against the benchmark facility. The frequency/consequence estimates are not the only results compared—the lists of major risk contributors, the statistical risk importance of safety systems, and other types of QRA results are also compared. As more and more facility results are accumulated, resources are allocated to any plant areas that are out of line with respect to the benchmark facility. 

Evaluate whether it is acceptability with risk reduction measures, or move the facility to a recently refurbished LPG storage facility. 

Because the risks were not reduced by the risk-reduction measures to an acceptable level, relocation of the butane storage to the refurbished LPG facility is attractive. 

Accepted risk The risk is considered tolerable for a given activity by those responsible for managing or regulating the operation of a hazardous facility. The term acceptable risk has often been used, but this inevitably raises the question, Acceptable to whom Tweeddale... 

Managing Risk and Reliability of Process Plants, Gulf Professional, Houston, Tex, 2003, p. 70) suggests that accepted risk is a better term because it makes it clear that the risk has been accepted by those responsible for the decisions on how to build, operate, and regulate the facility. 

Potential future expansion should be assessed and space provided for known and unknown needs. Logical and orderly expansion can only be made if provision at the time of original facility installation. The master plan should be frozen and only altered if a risk analysis of the changes is acceptable. 

The first task in applying a spacing table to a facility is to ensure it corresponds to the philosophy of protection adopted by the company. Where limited space is available to provide the required spacing, an examination of the equivalent fire and explosive barriers or active fire suppression system should be confirmed. This analysis should be accepted by the company as part of the design risk analysis. 

The activation points should be located a minimum of 8 meters (25 ft.) away from a high process hazard location but not more than 5 minutes away from any location within the facility. 5 minutes is taken as the maximum allowable time since historical evidence indicates process vessel rupture may occur after this time period from flame impingement. If risk analysis calculations demonstrate longer vessel rupture periods are expected, longer time periods may be acceptable. 

However, (b) below need not be applied if the facility is used so infrequently that the probability that the pipeline fails while it is occupied is acceptably low. This can be determined by a risk assessment carried out per para. PL-3.5. 

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