Qualitative Risk Assessment of a Commercial Refrigeration System

Introduction

This case study presents; the methods that were used to calculate qualitative risk for a critical refrigeration system, and the results of the assessment. This case study is intended to demonstrate how a Qualitative Risk Assessment can be a cost-effective and resource-efficient means to prioritize equipment which is often “under the radar”.

• This assessment was performed to scope a capital reliability investment by focusing the inspections, improvements, and repairs to ensure reliable future operation.
• Probability was assessed using simple hoop stress, historical and expected corrosion rates, and to account for a unique damage mechanism (Ice Damage). 
• Consequence was tabulated using Safety, Environmental and Operational factors based on Site SME review and assignment. 
• A non-standard risk matrix was developed based on the needs of the site.

Background

Commercial Refrigeration System Description

The subject was a 14-year-old commercial refrigeration system which supported four cold rooms, in total: two storage rooms, one working room, and one packaging room. Redundancy was required to meet the required temperature tolerance of +/- 5°C. Only one train was required to meet the demands of the system. Mechanical, Electrical and Instrumentation equipment were not part of the scope of this project as these assets were included in the site reliability program. Table 1 lists the equipment which was in the scope of this project.