Api Rp 571 Pdf ^hot^ -

Then she saw the table she was looking for: Parameters that increase susceptibility. Her finger traced the words: Total Acid Number (TAN) > 0.5 mg KOH/g. Temperature range: 450°F to 750°F.

Marta opened the attached spreadsheet. It listed the usual suspects: thickness readings, hardness tests, and a few spot checks for creep in the heater tubes. She scrolled past the rows of standard checks, then paused. Her eyes landed on a small header: High-Temperature Naphthenic Acid Corrosion (NAP) — marked "Not Required." api rp 571 pdf

"Final NDE scope for the Crude Unit heater," he wrote. "Sign off by Friday." Then she saw the table she was looking

She knelt by the heater’s transfer line. There it was—barely visible under a layer of coke, a series of small, sharp-edged grooves. Not the wide, smooth wash of sulfide corrosion. These were scalloped , just like the photo in API RP 571. Marta opened the attached spreadsheet

She re-read the classic line: "High temperature naphthenic acid corrosion (NAP) is characterized by sharp, knife-edged pits or grooves with a scalloped appearance, often in high-velocity areas."