This paper addresses the present state-of-art of practical optical fibre sensors for process control. Results are presented for the first part of a major project to establish fibre optic instrumentation systems for process control on offshore oil rigs. The project, designed in three phases, has an aim to examine different instrumentation concepts, to laboratory test available components, to build and to hold tests of a fibre optic instrumentation system on an offshore installation. The aim of the first phase is: (i) Examining the feasibility of optical fibre instrumentation for process control on offshore oil platforms. (ii) Studying different architectures for a suitable instrumentation system. (iii) Surveying available sensors and components on a worldwide basis. (iv) Testing sensors and other transmission components. The work reported here was designed to investigate the working principles, performance and limitations of commercial sensors and to evaluate possible architectures of a complete instrumentation system.