API RP 574

Covers — inspection practices for piping components (pipe, fittings, flanges, valves): planning, condition-monitoring location selection, thickness-measurement methods, and inspection of injection points, dead legs, small-bore connections, and supports, with evaluation and follow-up guidance.

Does NOT cover (exclusions) — the following are governed elsewhere:

• The inspection program requirements, intervals, and rerating → API 570.
• The damage mechanisms to anticipate → API RP 571.
• Material verification (PMI) → API RP 578; risk-based inspection → API RP 580.

RP 574 is the "how to inspect" practice; API 570 sets the "what and when."

RP 574 provides inspection practice guidance:

• Planning & CMLs — selecting condition-monitoring locations representative of the damage mechanism.
• Thickness Methods — ultrasonic and radiographic thickness techniques and their limitations.
• Focus Areas — injection/mix points, dead legs, small-bore, soil-to-air interfaces, and supports.
• Evaluation & Follow-up — recording, trending, and follow-up of findings feeding the API 570 program.

API RP 574 is the practical inspection-practices companion to the API 570 piping inspection code. Where 570 sets what to inspect and when, RP 574 shows how — the techniques and tools, where to place condition-monitoring locations, and the special attention needed at injection points, dead legs, small-bore connections, and soil-to-air interfaces.

Combined with RP 571 (the damage mechanisms to anticipate), it turns the inspection code's requirements into an effective field program. Thickness methods and their limitations are central, since remaining-life decisions rest on measured wall.

Engineering Note: Place condition-monitoring locations where the anticipated damage actually concentrates (per RP 571) — a thickness grid on a straight run can miss localized attack at an injection point or dead leg where corrosion is really occurring.