Conducting multistage HFE validations:Constructing systems usability case

This paper describes how independent stepwise Human Factors Engineering (HFE) validations have been conducted in Fortum Lovisa power plant control room modernization project. We discuss the challenges of HFE verification and validation in a project which is realized in multiple phases, stretches over several years in time, and is in tight coupling with automation modernization. These challenges eventually lead to the need of developing a new approach to control HFE validation; conducting validations in a stepwise manner. In our sub-system validation approach a particular sub-system of the control room are always the main focus of testing but simultaneously we also analyse the overall operational concept and its possible development need