Oil & Gas Management

Risk Based Inspection Services

Introduction

Risk Based Inspection (RBI) is a systematic process for factoring risk into decisions concerning how, where and when to inspect a process plant. The intent of RBI is to focus inspection resources on critical equipment in ways which will prevent failures, particularly catastrophic ones. It is a tool that can help make process plants safer and more reliable in a cost effective way.

Key Benefits

Compared with a typical inspection program, the application of an effective RBI program can simultaneously reduce the risk in an operating unit as well as reduce the cost of the inspection effort.
Risk Based Inspection manages a shift of inspection and maintenance resources to provide a more significant effort concentrated on the high risk items and an appropriate level of effort directed toward the lower risk equipment.
In a process where the equipment is in clean, non-corrosive service, the inspection strategy for the equipment can be optimized to a minimum level with maximum intervals.
In corrosive services, the inspection strategy will focus on the anticipated mechanisms using the appropriate inspection methods, locations and intervals.
Non-intrusive inspection techniques can be utilized in place of more costly internal equipment inspections, when appropriate.

Details

Risk Based Inspection defines the risk of operating equipment using a Criticality Rating process which combines two separate factors: the likelihood and the consequence of failure. The OGM/Lloyd's Register Capstone semi-quantitative method for Criticality Rating has the appropriate balance between being simple to implement, requiring a minimum amount of data, and providing adequate discrimination between the items being evaluated. The OGM/Lloyd's Register Capstone Criticality Rating can be applied to all processes and categories of equipment. In an operating plant, a relatively large percentage of the risk is associated with a small percentage of the equipment items. The OGM/Lloyd's Register Capstone RBI program also includes a model to predict Corrosion Under Insulation (CUI).

The criticality analysis is a dynamic calculation, with the ability to take into account changes in the process or the results from an inspection. It allows optimum inspection methods and intervals to be selected, based on the deterioration rates of the failure mechanisms in the equipment. Since the analysis is time dependent, risk and inspection requirements can be projected for future dates. Scenarios such as extending the time between shutdowns and increased inspection intervals can be analyzed to identify critical equipment items and the impact on risk.