Implementing Safety Lifecycle and Functional Safety with an Existing Organic Rankin Cycle Unit

Abstract

Changes to health and safety regulations in New Zealand now require that operators of many large industrial facilities prove to the health and safety regulator that their plant is safe to operate. To do this, operations, maintenance, engineering and health and safety personnel have to work together to identify and correct gaps in business processes, equipment and operations that could lead to large-scale industrial accidents. Contact Energy decided to implement a safety lifecycle approach as defined by International Electrotechnical Commission (IEC) standard 61508 (Functional safety of electrical/electronic/programmable electronic safety-related systems) and sub-standard IEC 61511 (Functional safety – Safety instrumented systems for the process industry sector) as a way of demonstrating adequate reduction of risks. To the owner’s knowledge, this is the first time this standard has been fully applied to an existing Organic Rankine Cycle plant. This paper presents a case study of some of the challenges and solutions, both technical and managerial, encountered in this process. The paper also outlines the assessment methodology and some key aspects of the decision making process.