Application of the Hazard-Barrier-Target (HBT) Model for More Effective Design for Safety in a Computer-Based Technology Management Environment

摘要

This article discusses a computer-based tool integrating currently available methods (e.g., PSA, LOPA, Databases) into a distributed design environment. Rationale for development is to design more cost-effectively. Inadequate safety raises costs largely through down-time caused by incidents. But providing for safety also incurs costs through more complexity (i.e. maintenance, equipment and personnel). Approaching the safety limits often means more profit when producing commodities, while delay in marketing advanced products may ultimately result in total loss of investments. Hence, a design process that ineffectively takes safety into account raises costs. In this article we argue first that using a proactive life-cycle approach to the design of safety (including R&D) can significantly increase profitability. Second, we develop such an approach, called Design for Safety (DFS) and illustrate its use. DFS is built from two major components, a technology management environment (TME) that is computer teed and connects workers to one another, and a Safety Modelling Language (SML). The SML is object-oriented, defining so-called Hazard, Barrier and Target (HBT) objects and relations between these. It is also recursive; barriers can, in turn, be targets to other hazards. For example, mass transfer limitation prevents a runaway, thus serving as a Barrier; but this in turn may be vulnerable to contamination. The method developed thus makes explicit previously unrecognized barriers. HBT-objects include information, allowing for communication of intent, rationale and experience, as well as measuring performance, preventing wrong modifications and choosing between alternatives.