API 581-2000 pdf free download
API 581-2000 pdf free download.Risk-Based Inspection Base| Resource Document .
The American Petroleum Institute (API) Risk Based Inspection Project was initiated in May 1993 by an industry sponsored group to develop practical methods for Risk Based Inspection. This sponsor group was organized and adminis- tered by the API and included the following members: Amoco; ARCO; Ashland; BP; Chevron; CITGO; Conoco; Dow Chemical; DNO Heather, DSM Services; Equistar Exon; Fina; Koch; Marathon; Mobil; Petro-Canada; Phil- lips; Saudi Aramco; Shell; Sun; Texaco; and UNOCAL. The Base Resource Document (BRD) clearly states there are limitations to the methods presented within it, and lists some of those limitations. The BRD states“to accurately por- tray the risk in a facilty… a more rigorous analysis may be necessary, such as the traditional risk analysis described..” According to the proposal for the API sponsor group project, the BRD, and the methods in it were“to be aimed at an inspec- tion and engineering function audience.” The BRD is specif- cally not intended to“become a comprehensive reference on the technology of Quantitative Risk Assessment (QRA).” For failure rate estimations, the proposal promised“meth- odologies to modify generic equipment item failure rates” via “modifcation factors.” In addition, the proposal specified that for this activity,“the contractor would seck to involve special- ized expertise by drawing upon API Comittee on Refinery Equipment member resources for this task.” This was done in the project by the formation of working groups of sponsor members who directed the development of the modification factors, with assistance by the contractor. For consequence calculations, safety, monetary loss, and environmental impact were all to be included. For safety eval- uations, the proposal noted that existing algorithms in AIChE CPQRA guidelines are“complex and are best suited for use in a computerized form.”
The purposes of the Risk-Based Inspection Program are summarized as follows: a. Screen operating units within a plant to identify areas of high risk. b. Estimate a risk value associated with the operation of each equipment item in a refinery or chemical process plant based on a consistent methodology. C. Prioritize the equipment based on the measured risk. d. Design an appropriate inspection program. e. Systematically manage the risk of equipment failures. The RBI method defines the risk of operating equipment as the combination of two separate terms: the consequence of failure and the likelihood of failure. The Base Resource Document includes a qualitative analy- sis that allows operating units to be quickly prioritized for further risk analysis. The result of the qualitative analysis positions the unit within a five-by-five risk matrix, which rates it from lower to higher risk. 0.2.2 The likelihood analysis is based on a generic data- base of failure frequencies by equipment types which are modified by two factors that reflect identifiable differences from“generic” to the equipment item being studied. The Equipment Modification Factor reflects the specific operating conditions of each item, and the Management Modification Factor is based on an evaluation of the facility’s management practices that afect the mechanical integrity of the equip- ment. The management systems evaluation tool is based on API guidelines and is included as a workbook of audit ques- tions in the Base Resource Document.
Guidelines are provided to develop and modify an inspec- tion program so it will appropriately manage the risks that have been identified in the risk calculation and prioritization steps. A simple method is presented for categorizing inspec- tion effectiveness and estimating the probability that the inspection plan will identify the true damage state in a piece of equipment. The effects of altemate inspection plans, and an approach to devcloping an inspection program, are presented. Worked examples of actual plant equipment are provided to demonstrate the methodology. A Risk-Based Inspection study, sponsored by the full comitee, has been performed al a Shell facility. This stuady will serve as a pilot program for the group. Future work might include development of an industry fail- ure database, software to support Risk Based Inspection, and expanding the program to fit into other industry initiatives, including Reliability Centered Maintenance (RCM).
