PetroStreet

When considering installation of corrosion Coupons, what are the cases where those are mandatory to be installed? What are the guidelines to follow, and how to maintain, inspect, and apply their installation. Please share with me the applicable references to be applied in petrochemical industries.

There is no single universal “mandatory” clause in one code like API 570, but in practice (and per AMPP/NACE philosophy) they become mandatory-by-risk like in systems with expected internal corrosion including wet hydrocarbon systems (water + CO₂/H₂S), sour service / amine / sour water strippers, cooling water & overhead systems in crude units.

That is something you do when validating the corrosion control program as well including:
Corrosion inhibitor injection systems
Filming amines / neutralizers
Oxygen scavengers

Coupons are required to confirm before injection (worst case) and after injection (effectiveness).

That then is used in multiphase flow also like stratified flow systems including oil + water pipelines, condensing vaopr systems as the corrosion remains localized, and the coupon is to be installed at 6 o'clock clock for water wet and 12 o'clock for clock for condensation.
With reference to the location, coupons must be installed where corrosion actually happens like bottom of line (water accumulation), stagnant zones, high turbulence / impingement points. For condensing zones, it has to be at the top of the line.

Very useful inputs guys, thanks.