Document Title: API Recommended Practice 551 (Typically "Process Measurement" – latest edition: 3rd Ed., Dec 2016, Reaffirmed 2021) Subject: Best practices for the selection, installation, and application of pressure, temperature, level, and flow measurement instruments in refining and petrochemical services.
If you are writing a corporate engineering standard, you should cite API RP 551 pdf as follows: api rp 551 pdf
"All pressure, temperature, level, and flow instrumentation for hydrocarbon service shall conform to API RP 551, 2nd Edition (December 2016), Section 4 through 7. In case of conflict between this standard and API RP 551, the more stringent requirement shall apply." Technical Review: API RP 551 – Process Measurement
This phrasing gives your legal team a defensible position while allowing engineers on the ground to interpret the RP’s recommendations practically. This phrasing gives your legal team a defensible
API RP 551, “Management of Process Hazards Associated with Fires and Explosions,” is a Recommended Practice published by the American Petroleum Institute that provides guidance for assessing, preventing, and mitigating fire- and explosion-related hazards in petroleum and petrochemical facilities. It focuses on identifying potential ignition sources, evaluating scenario consequences, applying protective layers, and implementing risk-reduction measures.
A pressure tap installed in a Texas refinery should perform identically to one in a Singapore petrochemical plant. RP 551 provides uniform guidelines for impulse piping, transmitter mounting, and manifold arrangements.