The API RP 551 PDF document is a comprehensive guide that covers various aspects of process measurement and control. Some of the key topics covered in this document include:

Whether you are designing a new hydrotreater or troubleshooting a sticky level transmitter on a crude unit, having the official recommended practice at your fingertips ensures you are not relying on memory or outdated forums. Buy the PDF from API, print the installation tables, and keep a copy in every instrument engineer’s digital library.

Accurate process measurement is the backbone of safe and efficient refinery operations.