Without a doubt, knowing about design notes of a fired heater, which is the heart of a petrochemical or gas processing plants would be tremendous advantage for process engineers in their career. Here we have provided principles and mechanical-process design notes for fired heaters. To help process engineers these design notes stick to their minds, we have used our previous projects fired heaters pictures from different angles and views in a way that you as process or mechanical engineer can imagine a clear picture in your mind.