In today's competitive market, every EPC company aims at building client's trust through each project it executes. One of the best ways to develop this trust is by putting yourself in client's shoe while working on revamp/ brown field projects, where the main intent of client is to safely use the existing facility, instruments, and installation as much as possible in order to reduce capital expenditure. This gives rise to the subject of adequacy check of inline/offline instrument, i.e evaluating if the existing inline/offline instrument shall work under new process conditions or not. This paper describes various steps involved for checking adequacy of existing orifice plates for Revamp / Brownfield projects. Since every project has a significant number of orifice plates, adequacy check of existing orifice is quite essential and can save a huge amount to client in terms of effort hours and installation cost, if existing plate is reused.