API 570 flashcards
API 570 · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- API 570 scope
- Covers in-service metallic piping and components after construction: inspection, repair, alteration, and rerating; it does not cover new construction or pipeline systems.
- Piping system definition
- In API 570, the assembly of pipe, fittings, flanges, gaskets, bolting, valves, and supports that conveys fluid within defined battery limits.
- Inspector versus examiner
- An inspector holds a valid API 570 certification and directs inspection; an examiner performs specific NDE examinations and need not hold the API 570 certification.
- API 570 exclusions
- Excluded from API 570: pipelines under ASME B31.4 and B31.8, boiler and furnace tubes, instrument tubing, and nonmetallic piping.
- Owner/user responsibility
- The owner/user defines the piping to be covered, establishes inspection plans and intervals, ensures repairs are approved, and retains records for the piping's life.
- Rerating definition
- A change to the MAWP or temperature rating of existing piping, requiring engineering calculations and approval by an authorized engineer and the inspector.
- General corrosion
- Uniform metal loss over a broad area from electrochemical reaction with the environment; corrosion rate is expressed in mils per year (mpy) or mm/year.
- Chloride stress corrosion cracking
- Cracking of austenitic stainless steel exposed to chlorides and tensile stress, often under insulation in the 50–175 °C range; a common CUI mechanism.
- Microbiologically influenced corrosion
- Localized pitting or attack caused by bacteria in stagnant water, low-flow lines, and dead legs; often found in carbon steel and stainless steel water systems.
- Erosion-corrosion
- Accelerated metal loss where high-velocity or turbulent flow removes the protective oxide film, typically at elbows, tees, reducers, and downstream of control valves.
- Hydrogen blistering
- Damage in wet H2S or hydrogen-charging service where atomic hydrogen diffuses into steel and forms internal blisters or stepwise cracking.
- Creep
- Time-dependent deformation and stress rupture of metal at elevated temperature under sustained load, leading to bulging and cracking of piping.
- Corrosion under insulation
- External corrosion of carbon steel or chloride SCC of stainless steel beneath insulation and jacketing where water accumulates; hidden until insulation is removed.
- Remaining life formula
- Remaining life = (actual thickness − minimum required thickness) ÷ corrosion rate; the result sets the maximum inspection interval, which is half the remaining life.
- Corrosion rate calculation
- Corrosion rate = (previous thickness − current thickness) ÷ time between measurements; long-term rate uses initial thickness and short-term rate uses the last two readings.
- Inspection interval rule
- API 570 inspection interval is the lesser of half the remaining life or 10 years; if remaining life is under 10 years, the interval cannot exceed half the remaining life.
- Alteration definition
- A change in piping geometry, materials, or design conditions, or addition of a new component, that requires engineering design review and may require rerating.
- Repair definition
- Work that restores piping to a safe operating condition without changing its design, such as weld repair of localized metal loss or crack removal.
- Hydrostatic test pressure
- For ASME B31.3 piping, hydrostatic test pressure is normally 1.5 times the design pressure, adjusted for temperature; pneumatic testing uses lower ratios with extra precautions.
- Minimum required thickness
- Calculated from the applicable code (e.g., B31.3) using design pressure, diameter, allowable stress, weld joint factor, and corrosion allowance; used as t-min for rating.
- Ultrasonic thickness measurement
- The primary API 570 method for measuring remaining wall thickness at designated thickness measurement locations; readings are used to calculate corrosion rate and remaining life.
- Thickness measurement locations
- Pre-marked points on piping where UT readings are taken and compared over time; they are selected at likely thinning areas such as elbows and low points.
- ASME Section V
- The referenced code for nondestructive examination methods and qualification; API 570 inspections using RT, UT, MT, and PT follow its requirements.
- ASME Section IX
- The referenced code for welding procedure and performance qualifications; repair and alteration welds under API 570 must be made by welders qualified to it.
- API 574
- The companion inspection practices document referenced by API 570 for detailed guidance on inspecting piping components, flanges, valves, and supports.
- Visual acuity requirement
- API 570 inspectors must have corrected near vision of Jaeger 1 or equivalent at 12 inches, plus adequate color vision, verified periodically.
- Inspection report contents
- Records the inspection date, locations examined, methods, findings, remaining life, recommendations, and the next inspection date, signed by the inspector.
- Records retention period
- API 570 requires inspection, repair, and rerating records to be kept for the life of the piping system and made available to the inspector.
- Repair documentation
- Includes the repair description, materials, welding procedure and welder qualifications, NDE results, heat treatment, and pressure test records.
- Rerating documentation
- Retains the engineering calculations, design basis, approvals, and any new MAWP or temperature limit for the rerated piping.
- WPS and PQR
- Welding Procedure Specification and Procedure Qualification Record; both must be available for repair or alteration welding performed on API 570 piping.
- Thickness measurement records
- Chronological UT readings at each TML, with dates and locations, used to compute corrosion rates and remaining life and to set future intervals.