RBI Case Study from the 1990's

I thought this may be of interest. It is a small section from my new book "Asset Resource Planning" which I am expecting to be published within the next few months. It looks briefly at some of the benefits gained from the implementation of RBI into the Altona plant in Victoria Australia.

The remarkeble thing about this case study is it occurred at the same time that the American Petroleum Institute was also developing the API580 and 581 standards for RBI.

In 1995 the Boiler and Pressure Vessel Regulations, which mandated inspection of pressure equipment at set intervals by a government inspector, were repealed, and the performance-based Plant Safety regulations were introduced under the existing Occupational Health and Safety Act. This presented an opportunity to optimize the inspection turnaround program.
The new regulations required owners, manufacturers and designers to identify hazards, assess risk and mitigate risk where required. Inspection intervals are no longer mandated.

Coincidentally, the American Petroleum Institute (API) initiated a sponsored program in 1993 to develop a risk-based inspection process. The Altona project, in Victoria Australia, was developed entirely separately from the API program. The two processes contain a number of similarities, but in key areas are quite different.

After taking a decision to focus solely on vessels during the initial stages of the project, an approach was used to identify failure modes with a “wear out” characteristic based on ASME CRTD-Vol.20-1.

The semi-quantitative approach that was finally agreed upon and the failure distributions were plotted and the frequencies calculated. Inspection plans were then optimized using cost analysis techniques.

In the project documentation there was an admission that the process was not useful for managing those failures that were known to have no relation to time, or random failure modes. Refractory spalling in process heaters, for example, were delegated to methodologies such as RCM which are better at managing such issues.
Key results from the project are as follows:

• The project provides a valid methodology for directly relating risk reduction to inspection interval.

• Increase in inspection intervals on all processing units, resulting in less turnarounds.

• Reduction in turnaround scopes (measured in number of vessels opened) by 30-50% over previous statutory requirements

• Reduction in the costs of turnaround maintenance and lost production by approximately AUD 2.5MM/year (US$1.8MM/yr.)

• The process improves the understanding of risks associated with vulnerabilities and therefore better targets inspections.

The processes increases focus on on-stream monitoring and inspection in order to decrease the uncertainty in time to failure and reduce turnaround scope.

The Victorian regulatory authority has accepted the process as a valid method of identifying hazards, assessing risk and managing those risks in accordance with the Plant Safety regulations.

This is a very comprehensive case study that shows the ability of to or more methodologies to be applied together. It also lists a range of tangible and non-tangible benefits, which hen taken together provide a sound basis for this approach to ARP.

This particular application of Risk based Inspection shows a strong blend of developing effective maintenance and inspection regimes through the application of risk, and then optimizing this to produce the most efficient means of executing the strategy.