NDT Methods — Family Index

Non-Destructive Testing (NDT) / Non-Destructive Examination (NDE) covers techniques that detect surface, subsurface, or volumetric discontinuities without rendering the part unusable. This family-index note catalogs the six classical methods plus modern variants, their standards, vendors, sensitivity bands, and selection heuristics.

1. At a glance

Per ASNT SNT-TC-1A categorization, the six classical NDT methods are:

Code	Method	Detects	Penetration
VT	Visual	Surface, geometry, finish	Surface only
PT	Liquid penetrant	Surface-breaking cracks	Surface only
MT	Magnetic particle	Surface + near-surface cracks (ferromagnetic)	<6 mm (0.24 in)
UT	Ultrasonic	Volumetric + planar flaws	Full thickness (<300 mm / 12 in typical)
RT	Radiographic	Volumetric flaws, density change	Full thickness
ET	Eddy current	Surface + near-surface, conductivity, thickness	<3 mm (0.12 in) typical

Modern + complementary variants:

• PAUT — Phased-Array Ultrasonic
• TOFD — Time-of-Flight Diffraction
• AE — Acoustic Emission
• IRT — Infrared Thermography
• LT — Leak Testing
• MFL — Magnetic Flux Leakage
• CT — X-ray Computed Tomography
• EMAT — Electro-Magnetic Acoustic Transducer
• NDT 4.0 — AI-augmented + IIoT-connected NDT

Standards landscape: ASTM E-series (E165 PT, E1444 MT, E114/E317/E2700 UT, E94/E2698 RT, E215/E309 ET), ISO 9712 (qualification), ISO 17636 (RT), ISO 17640 (UT), ASME BPVC Section V (pressure equipment), API 1104 (pipeline welds), AWS D1.1 (structural steel). ASNT certifications grade personnel Level I / II / III by method per SNT-TC-1A or the more prescriptive CP-189.

2. Visual testing (VT)

Direct visual (unaided eye, ≤610 mm / 24 in standoff, ≥30° angle, ≥500 lux per ASME) plus remote visual inspection (RVI).

Remote visual tools:

• Olympus IPLEX RX / IPLEX RT — articulating videoscopes, 4-/6-mm probes, 7.6 m (25 ft) insertion
• Karl Storz Techno Pack — rigid + fiberscope industrial
• GE / Waygate Mentor Visual iQ — videoscope with embedded analytics
• Borescopes for engine-blade + tube-bundle inspection

Weld inspection gauges:

• G.A.L. Gage WGA (Welding Gauge Automatic) — fillet leg, undercut, throat
• V-WAC (V-shaped Welding Gauge) — undercut + porosity sizing
• Bridge cam + skew T fillet gauges

Standards: AWS D1.1 Clause 6 (Visual Inspection), ISO 17637, ASME BPVC Section V Article 9, API 1104 §9.

Sensitivity: discontinuities ≥ 0.8 mm (0.030 in) typically; smaller with fluorescent eye-aided + 10× loupe.

Limit: surface only; operator-skill-dependent; lighting + cleanliness critical.

3. Penetrant testing (PT) / Dye-penetrant inspection (DPI)

Capillary action draws low-viscosity penetrant into surface-breaking discontinuities; developer pulls residual penetrant back out into a visible indication.

Penetrant types:

• Type I — Fluorescent (UV-A 365 nm illumination; highest sensitivity)
• Type II — Visible/color-contrast (red dye on white developer; field-friendly)

Removability methods:

• Method A — Water-washable (built-in emulsifier)
• Method B — Post-emulsifiable, lipophilic
• Method C — Solvent-removable (aerosol field kits)
• Method D — Post-emulsifiable, hydrophilic

Process: clean (degrease) → apply penetrant → 10-30 min dwell → remove excess → apply developer (dry, wet aqueous, or non-aqueous wet) → inspect 10-60 min → post-clean.

Sensitivity: Level 1/2/3/4 per ASTM E1417; ~0.025 mm (0.001 in) surface crack at Level 4.

Vendors: Magnaflux Spotcheck SKL-SP2 / Zyglo ZL-67B, Met-L-Chek E-series, Sherwin Babb Co DP-55.

Standards: ASTM E165 (general), ASTM E1417 (aerospace), ISO 3452-1, ASME BPVC Section V Article 6.

Limit: surface-breaking discontinuities only; does not work on porous materials (powder-metal sintered parts, unsealed castings); requires good cleaning.

4. Magnetic particle testing (MT) / MPI

Magnetizes a ferromagnetic part; iron-particle indicator accumulates at flux-leakage points caused by surface + near-surface (<6 mm / 0.24 in) discontinuities. Works on steel, cast iron, nickel + cobalt alloys; not on austenitic stainless, aluminum, copper.

Particle media:

• Wet fluorescent (highest sensitivity, MIL-STD-1949 / AMS 3044 carriers)
• Wet visible
• Dry magnetic powder (field; gray/red/yellow contrast)

Magnetization methods:

• AC yoke (Magnaflux Y-7 / Y-8, Parker Research B-310S) — surface-only, portable
• DC half-wave (HWDC) — better near-surface penetration
• Prods + central conductor — circular field
• Coil shot — longitudinal field
• Multidirectional / multi-vector benches (Magnaflux H-Series, Circle Systems) — production OEM
• Demagnetization required after inspection

Sensitivity: ~0.13 mm (0.005 in) deep tight crack with wet fluorescent.

Standards: ASTM E1444 (aerospace), ASTM E709 (general), ISO 9934-1/2/3, ASME BPVC Section V Article 7, AMS 2641 (vehicle bath).

Vendors: Magnaflux Y-7 / Y-8 yokes, MAGNAFLO benches, Parker Research B-310S, Circle Systems, ITW Magnaflux.

5. Ultrasonic testing (UT)

High-frequency mechanical waves (1-15 MHz typical, up to 50 MHz for thin/precision) injected into material; echoes from interfaces + flaws return amplitude + time-of-flight data.

Modes:

• Pulse-echo (single transducer, most common)
• Through-transmission (two transducers; attenuation-based, composites)
• Immersion (water-bath couplant for production)
• Pitch-catch / TOFD (separated send + receive)

Wave types:

• Longitudinal (compression) — straight-beam
• Shear (transverse) — angle-beam (45°/60°/70° wedges)
• Lamb / plate waves — thin sheets
• Rayleigh / surface waves — near-surface

Display formats:

• A-scan — amplitude vs time (oscilloscope trace)
• B-scan — depth cross-section vs position
• C-scan — plan view (top-down map)
• D-scan — side view through volume

Standards: ASTM E114 (contact), E317 (calibration), E2700 (PAUT contact), ASME BPVC Section V Articles 4 + 5, API 6A (welds), ISO 17640.

Sensitivity: ~0.5 mm (0.020 in) flat-bottom-hole at 100 mm depth typical; better at lower depth.

Vendors (conventional UT): Olympus EPOCH 650 / EPOCH 6LT, Sonatest Masterscan D-70 / Sitescan D-50, GE / Waygate USM 36 / USM Go+, Sonotron NDT Isonic 2010, Krautkramer (GE) DMS Go (corrosion-mapping).

6. Phased Array UT (PAUT) + TOFD

Multi-element transducer array (16, 32, 64, 128, 256 elements typical) electronically steered + focused via per-element pulse-delay programming; faster, better coverage, and reproducible compared to single-element manual UT.

PAUT capabilities:

• Linear / sectorial / depth scans without moving probe
• Encoded mechanical raster — full weld coverage map
• Total Focusing Method (TFM) reconstruction
• Full Matrix Capture (FMC) → post-process beamforming

TOFD (Time-of-Flight Diffraction): pitch-catch pair straddling weld; diffracted tip-signals size cracks accurately. Standard partner for PAUT on critical welds.

Applications:

• Pipe girth-weld inspection (API 1104 §11.4, ASME B31.3 Code Case 181, ASME B31.1 in lieu of RT)
• Nozzle weld + dissimilar-metal welds
• In-service refinery, petrochemical, nuclear (ASME Section XI)
• Wind-turbine blade root + bolts

Vendors:

• Olympus OmniScan X3 / X3 64 (32:128 / 64:128 / 32:64PR, 16:64M handheld)
• Eddyfi M2M Mantis / Gekko / Panther (TFM-capable)
• Sonatest Veo+ / Veo3 (encoded crawler for pipeline)
• Zetec TOPAZ16 / TOPAZ32 / TOPAZ64
• Waygate (GE) Mentor UT

Standards: ASME BPVC Section V Article 4, Mandatory Appendix III + IV; ASTM E2700, E2491; ISO 13588 (PAUT), ISO 10863 (TOFD); API RP 2X.

7. Radiographic testing (RT)

Penetrating ionizing radiation differentially attenuates through material; resulting image (film or digital) records density/thickness variation. Detects volumetric flaws (porosity, slag, inclusions, lack-of-fusion).

Sources:

• X-ray tubes — kV 50-450; constant-potential; variable mA; mainstays for thin/moderate steel
• Gamma — Ir-192 (HL 73.83 days, energies 296/308/468/604 keV; up to ~75 mm / 3 in steel)
• Gamma — Co-60 (HL 5.27 y, 1.17 / 1.33 MeV; up to ~200 mm / 8 in steel)
• Gamma — Se-75 (HL 119.8 days, 66/97/136/265/280 keV; lower energy for thin steel, less shielding)
• Yb-169 (HL 32 days, 63/110/130/177/198 keV; thin-section)
• Linatron / Linac (4-15 MeV) — heavy castings, rocket motors

Recording media:

• Film — Kodak Industrex M / D7 / AA400 / T200, Agfa Structurix D2 / D3 / D4 / D5 / D7 / D8, Fuji IX-FR / IX 80
• Computed Radiography (CR) — phosphor imaging plate scanned post-exposure (Carestream HPX-1, GE CRx Vision, Dürr NDT CR 35 NDT)
• Digital Radiography (DR) — direct flat-panel detector (GE DXR250C, Varex 2530HE, Yxlon Y.PXS)

Sensitivity: 2% of wall thickness via 2-T hole IQI (Image Quality Indicator) per ASTM E1025 / ISO 19232.

Standards: ASME BPVC Section V Article 2 (RT general) + Article 22 (DR), ISO 17636-1/2, ASTM E94/E1742/E2698 (DR), API 1104 §11.1 (pipeline).

Vendors:

• X-ray tubes / cabinets: GE Phoenix v|tome|x XL, Yxlon FF20 / FF35 CT, Comet ZX-series + MesoFocus, Yxlon Cougar EVO
• Gamma exposure devices: QSA Global Sentinel 880 Delta, Sentinel 880 Sigma; Industrial Nuclear Tech-Ops
• Cargo / Cargo CT: Agfa Cargo, Smiths Detection HCV-Mobile
• Pipeline crawlers: Jireh / OIS / Telewave Mark V crawler

Limit: radiation hazard requires shielding + qualified Radiation Safety Officer; orientation matters (planar flaws parallel to beam miss); resolution limited by film grain / pixel pitch.

8. Computed Tomography (CT)

X-ray CT for industrial NDT: rotation of part (or source) acquires hundreds of projections → reconstruction (filtered back-projection / iterative) into a 3D voxel volume. Detects porosity, inclusions, fiber orientation in composites, internal dimensional accuracy.

Industrial CT systems:

• Zeiss METROTOM 6 / METROTOM 800 / METROTOM 1500 — metrology-grade dimensional inspection, ±5 µm
• Nikon XT H 225 / XT H 320 / XT H 450 / VOXLS 30 / MCT225 — micro-CT
• Yxlon FF35-CT / FF20 CT / Cheetah / Cougar
• GE / Waygate phoenix v|tome|x M / S / L / XL
• Werth TomoScope HV Compact / HV 500 / XS
• North Star Imaging X5000 / X7000 / X-Cube
• Bruker SkyScan 1273 / 1275 / 2214 (industrial micro-CT)

Resolution: 1-100 µm voxel typical; sub-µm with nano-CT (Zeiss Xradia Versa).

Applications:

• Metal additive (LPBF, EBM) part QC — porosity quantification + lack-of-fusion (per ASTM E3166, ISO/ASTM 52915)
• Aerospace composites — fiber-volume fraction, ply waviness, voids
• Castings — porosity, shrinkage, inclusion analysis (replaces 2D RT for complex geometry)
• MEMS, semiconductor, electronic assemblies
• Reverse engineering + dimensional metrology (CT-CMM)

Standards: ASTM E1441 / E1570 / E1672 / E1695, ISO 15708-1/2/3, VDI/VDE 2630 (metrology-grade CT).

9. Eddy current testing (ET / ECT)

AC-energized coil induces eddy currents in conductive material; defects/conductivity/thickness perturb the coil impedance, displayed on impedance plane.

Probe types:

• Surface / pencil probes — crack detection on aerospace skin
• Bobbin probes — internal tube inspection (heat exchangers)
• Rotating-probe / array (RPA) — fastener-hole bore scan
• Array probes — multi-element line scan
• Encircling coils — bar / rod / wire surface inspection

Variants:

• Pulsed Eddy Current (PEC) — measures through insulation/coating for corrosion-under-insulation (CUI); Eddyfi Lyft, GE PEC ART
• Remote-Field Eddy Current (RFEC) — ferromagnetic-tube ID + OD wall-loss (carbon-steel feedwater heaters)
• Array ECT — Olympus EcaArray, Eddyfi Sharck-T (topside weld), Sharck-H (subsea)
• Magnetic Flux Leakage (MFL) — see §13, often classed under eddy-current family

Applications:

• Heat-exchanger / condenser / steam-generator tube inspection
• Aircraft fastener-hole crack detection (eddy-current bolthole rotating scanner)
• Conductivity sorting (alloy verification, heat-treat condition)
• Coating-thickness gauging (non-conductive over conductive)

Vendors:

• Olympus Nortec 600D, OmniScan ECA / MX ECA / MX ECT, MultiScan MS5800
• Eddyfi Ectane2 / Reddy / Lyft (PEC) / Sharck-T / Sharck-H
• Zetec MIZ-21B / MIZ-200 / MIZ-21C
• Foerster MagnaTest / Defectomat (production sorting)
• Rohmann Elotest (production inline)

Standards: ASTM E215 (general), E309 (eddy current of seamless tubing), E243 (electromagnetic test of seamless tube), ISO 15549, ASME BPVC Section V Article 8 + Mandatory Appendix.

10. Acoustic emission (AE)

Passive monitoring: transient elastic waves emitted by growing crack / plastic deformation / leak detected by piezoelectric sensors mounted on structure during a load / proof test. Locates active flaws (whereas other NDT finds existing flaws).

Sensors: Mistras Group R15I (150 kHz resonant) / R6I (60 kHz) / WD wideband / Nano-30; PWAS (piezoelectric wafer active sensors).

Applications:

• ASME pressure-vessel proof test (Section V Article 12, ASTM E1067 for FRP tanks)
• Bridge cable + stay-cable monitoring (Pure Technologies SoundPrint)
• Storage-tank floor leak detection
• Composite stress monitoring
• Fatigue-crack growth research

Process: typical PV proof test = 1.10× to 1.50× design pressure with continuous AE listening; hits + amplitude + locations triangulated from multi-sensor TDOA.

Standards: ASTM E976 (sensor verification), ASTM E1067 (FRP tanks), ASTM E1316 (terminology), ASME BPVC Section V Article 12 (AE of metal vessels) + Article 13 (FRP), ISO 16148.

Vendors: Mistras Group / Physical Acoustics, Vallen Systeme AMSY-6, Mistras DiSP / Sensor Highway II.

11. Infrared thermography (IRT)

Detects surface temperature distribution via long-wave IR (LWIR 8-14 µm typical) or mid-wave (MWIR 3-5 µm) camera.

Modes:

• Passive — observe steady-state temperature (facility scans, electrical hot spots)
• Active — apply thermal stimulus + observe response:
  • Pulsed thermography (flash → cool-down decay)
  • Lock-in thermography (LIT, sinusoidal stim, phase/amp image)
  • Vibrothermography / sonic IR (ultrasonic excitation → frictional heat at crack faces)
  • Step-heating, flying-spot, eddy-current-thermography (induction + IR)

Cameras:

• FLIR T540 / T865 / T1020 — handheld facility-scan
• FLIR Boson, FLIR Tau 2 — OEM microbolometer cores
• FLIR A6750sc / X6900sc — cooled MWIR research-grade
• Telops M-series, Optris PI-series, InfraTec VarioCAM HD

Active-IR systems:

• Thermal Wave Imaging EchoTherm
• Edevis OTvis / DisplayIMG (lock-in)
• Automation Technology IRBIS active

Applications:

• Composite delamination / impact damage (aerospace skin panels)
• Building envelope thermal-insulation surveys
• Electrical switchgear hot-spot (IEEE 1584 / NFPA 70B)
• PV solar panel cell-defect mapping
• Tribology + bearing-health monitoring

Standards: ASTM E1934 (electrical), ASTM E2582 (composite aerospace), ISO 18434 (condition-monitoring of machines), ISO 6781 (building envelope).

12. Leak testing (LT)

Detects through-thickness leaks; quantitative methods reach 10⁻⁹ mbar·L/s sensitivity with helium mass-spec.

Methods (by sensitivity, coarse → fine):

• Bubble (soapy water, Snoop, immersion) — ~10⁻³ to 10⁻⁴ mbar·L/s
• Pressure-decay / pressure-rise — sealed test, dP/dt over time
• Mass-flow / mass-fill — production high-throughput (Cincinnati Test Systems Sentinel)
• Tracer-gas sniffing — He or H₂ (~10⁻⁶ to 10⁻⁷)
• Tracer-gas accumulation — sealed enclosure → grow He concentration (~10⁻⁷)
• Tracer-gas vacuum / integral — vacuum chamber + mass spec (~10⁻⁹ to 10⁻¹¹ mbar·L/s)

Tracer gases:

• Helium (He-4, monoatomic, low background) — gold standard
• Hydrogen (5% H₂ in 95% N₂ “forming gas,” non-explosive mixture) — INFICON Sensistor, lower cost
• Refrigerant tracers (R-134a, R-1234yf detection for HVAC)

Helium mass spec vendors:

• INFICON Modul1000 / UL1000 Fab / UL3000 Fab / Sensistor ISH2000
• Pfeiffer Vacuum ASM 340 / ASM 380 / HiLT 670
• Agilent VS Series / HLD Trinos / VS C15 / VSPD3
• Leybold PHOENIX L300i / L500i

Applications:

• Aerospace pressurized fuselage + cryogenic propellant tanks
• HVAC/R systems (R-1234yf, R-32, R-744 CO₂ refrigerants)
• Nuclear primary loop + steam-generator U-tubes
• Semiconductor process chambers (vacuum integrity)
• Automotive fuel tanks (EVAP system per EPA)
• Medical device sealing (sterile barrier per ISO 11607)
• Battery cell + pack hermeticity

Standards: ASTM E432 (selection), E493 (mass-spec inboard), E498 (sniffer), ASME BPVC Section V Article 10 + Appendices I-IX, ISO 20485, MIL-STD-883 (hermetic semi).

13. Magnetic flux leakage (MFL)

Saturating magnetic field applied to ferromagnetic part; flux escapes (“leaks”) at metal-loss defects → Hall-effect or coil-array sensors detect. Primary tool for long-distance ferromagnetic pipeline + tank-floor inspection.

Applications:

• In-line inspection (“smart pig”) of oil + gas pipelines — Rosen RoCorr MFL-A / MFL-C / EMAT, NDT Global EVO (UC + MFL combo), Baker Hughes (formerly GE Oil & Gas) MagneScan HR / VECTRA
• Above-ground storage-tank floor scanning — Silverwing Floormap3D-i / RMS2 (Eddyfi), MFE Tankpac, Jireh Skoot
• Wire-rope inspection (mine hoist, elevator) — NDT Technologies LMA-250

Variants:

• High-field axial MFL — wall-loss
• Transverse / circumferential MFL — axial cracks
• Triaxial MFL — improved sizing
• EMAT — companion crack/SCC detection on ILI tools

Standards: API STD 1163 (ILI Systems Qualification), POF (Pipeline Operators Forum) Specifications + Requirements, NACE SP0102 (in-line inspection), API STD 653 (tank-floor inspection requirements).

14. Hardness testing

Debatably NDT (leaves a small indent), included here as standard mechanical-property field check.

Bench/static methods:

• Rockwell — HRA / HRB / HRC / HRN scales, diamond cone or steel ball indenter, major load 60/100/150 kgf (ASTM E18)
• Brinell — 10 mm ball, 3000/1500/500 kgf load → HBW (ASTM E10)
• Vickers — diamond pyramid, HV0.1 to HV100 (ASTM E92, E384 micro)
• Knoop — elongated pyramid, thin coatings + brittle ceramics (ASTM E384)

Portable / field methods:

• Leeb rebound (UCI, Equotip Bambino 2 + Equotip 550 — Proceq/Screening Eagle, Krautkramer MIC 20)
• UCI Ultrasonic Contact Impedance — small indent, smooth surfaces
• TIV / Through-Indenter Viewing (Krautkramer MIC 10)
• Portable Brinell (King Tester)

Bench vendors:

• Struers DuraScan / Duramin (automated micro-Vickers)
• Wilson / Buehler Rockwell + Vickers
• Mitutoyo HM / HV
• Innovatest NEMESIS / NEXUS / FALCON
• Zwick/Roell ZHV / ZHN

Standards: ASTM E18 (Rockwell), E10 (Brinell), E92 / E384 (Vickers + Knoop), ISO 6508 / 6506 / 6507, ISO 16859 (Leeb).

15. Modern + NDT 4.0 trends

AI-augmented defect detection:

• CNN/UNet image classifiers on RT + UT B-scan + IR imagery (auto-defect-recognition ADR)
• Olympus AI-NDT for OmniScan PAUT data, Eddyfi M2M Capture AI
• Vendor + research: Carl Zeiss INSPECT (CT defect ADR), Volume Graphics VGSTUDIO MAX (CT auto-porosity), Waygate (GE) Mentor Visual iQ Real3D + InspectionWorks
• ISO/IEC TR 24028 + ASTM E07.10 standards in progress for NDE AI/ML

Industrial IoT + remote monitoring:

• Continuous ultrasonic thickness probes (Permasense / Emerson Rosemount Wireless WT100, Sensorlink Ultramonit) — corrosion-rate trending in refineries
• Acoustic-emission permanent monitoring (Mistras PIM, Vallen ASIP)
• Fiber-optic distributed sensing (Silixa, OptaSense) — pipeline + cable integrity

Drone / robotic inspection:

• Flyability Elios 3 — collision-tolerant indoor flyer; LiDAR + thermal + UT thickness payload (Cygnus Mini)
• Skydio X10 + Sundance AeroVision — outdoor stack/tower
• Magnetic-wheel crawlers (Silverwing Crawler, Jireh Navic2 / Skoot) for tank shell + ship hull
• ROV underwater inspection of offshore platforms + ship hulls

Augmented reality + digital twin:

• Microsoft HoloLens 2 + Trimble Connect / ServiceLayer / PTC Vuforia for AR-guided inspection workflows
• Bentley iTwin, AspenTech Mtell, Siemens MindSphere — asset digital twin platforms ingesting NDE data
• ASME V&V 40 + ISO 23247 (digital-twin manufacturing) frameworks

Other emerging:

• Guided-wave UT (long-range UT, LRUT) — Plant Integrity Teletest Focus+, Eddyfi Teletest, Guided Ultrasonics Wavemaker; screens long pipe runs from one access point
• Air-coupled UT — non-contact composite scan
• Microwave / mm-wave NDT — composite + non-metallic
• Terahertz imaging — paint/coating thickness, foam insulation, security/aerospace

16. Certification + standards landscape

Personnel qualification (USA):

• ASNT SNT-TC-1A — recommended practice, employer-administered, Level I / II / III by method
• ASNT CP-189 — prescriptive standard for employer programs (referenced by ASME)
• ASNT CP-105 — topical outlines for training
• ASNT ACCP — central certification across employers
• NAS 410 / EN 4179 — aerospace NDT personnel (FAA + EASA acceptance)

Personnel qualification (international):

• ISO 9712 — international harmonized scheme (Level I / II / III)
• EN ISO 9712 — European adoption via national bodies (PCN UK, COFREND France, DGZfP Germany, CICPND Italy)
• FAA AC 65-31B — aerospace inspector guidance
• CAN/CGSB-48.9712 — Canadian
• AS 3998 / ISO 9712 — Australian

Method/industry standards:

• ASME BPVC Section V — pressure equipment NDE (Articles 1-30)
• API 1104 — pipeline welding + NDE
• API 510 / 570 / 653 — in-service inspection of vessels / piping / tanks
• AWS D1.1 / D1.5 / D1.6 — structural-steel welding NDE
• ISO 17636 (RT), 17640 (UT), 13588 (PAUT), 17638 (MT), 3452 (PT), 15549 (ET)
• AS 4359 — Australian welding inspection
• DNV-OS-F101, DNV-CG-0051 — offshore pipeline NDE

17. Standards quick-reference matrix

Method	ASME Section V Article	ISO	ASTM	Typical use
VT	Art. 9	17637	E165 / E1932	Always-first surface check
PT	Art. 6	3452-1	E165 / E1417	Non-ferrous + ferrous surface cracks
MT	Art. 7	9934-1	E1444 / E709	Ferromagnetic surface + near-surface
UT (conv.)	Art. 4 / 5	17640 / 22825	E114 / E317	Volumetric, weld inspection
PAUT	Art. 4 App. III / IV	13588	E2700	Critical welds, pipe girth
TOFD	Art. 4 App. III / V	10863	E2373	Crack sizing in weld
RT	Art. 2	17636-1/2	E94 / E1742 / E2698	Volumetric defect imaging
DR / CR	Art. 2 + 22	17636-2	E2698 / E2597	Digital RT
CT	—	15708 / VDI 2630	E1441 / E1570	3D internal inspection
ET	Art. 8 + App.	15549	E215 / E309 / E243	Conductive surface + tubes
AE	Art. 12 / 13	16148	E1067 / E1316	Active flaw growth, proof test
IRT	—	18434 / 6781	E1934 / E2582	Composite delam, thermal
LT	Art. 10	20485	E432 / E493 / E498	Pressure / vacuum integrity
MFL	—	API 1163	E570	Pipeline + tank-floor metal loss

18. Selection heuristics

• Surface crack in steel weld → MT first (cheap, fast), PT if non-ferro, VT always.
• Volumetric defect in casting → RT (best at picking up porosity + inclusions), UT for thick sections >75 mm (3 in).
• Pipeline girth-weld in service → PAUT or PAUT + TOFD with field crawler (Sonatest Veo+, Olympus OmniScan, ScanRoller crawler).
• Heat-exchanger tube-bundle → ET (eddy current bobbin probe) for non-ferromagnetic, RFEC for carbon-steel feedwater, IRIS (Internal Rotary Inspection System UT) for wall-loss sizing.
• Composite delamination → IR pulse thermography (Thermal Wave Imaging EchoTherm) or PAUT + air-coupled UT.
• AM part internal porosity → X-ray CT (Zeiss METROTOM, Nikon XT H series).
• In-service refinery vessel — creep + crack → PAUT for sizing + AE during hydrotest for growth detection.
• In-line pipeline integrity (long distance) → MFL ILI tool (Rosen, NDT Global, Baker Hughes) + EMAT for axial cracks.
• Corrosion under insulation (CUI) → pulsed eddy current (Eddyfi Lyft, GE PEC) or guided-wave UT (Plant Integrity Teletest, Guided Ultrasonics Wavemaker).
• Aerospace fastener-hole crack → eddy-current bolthole rotating probe (Olympus Nortec 600D + rotating scanner).
• Bond integrity in adhesive joints → through-transmission UT or air-coupled UT.
• High-voltage cable cathodic protection → ACVG / CIPS / DCVG holiday surveys (separate non-NDT corrosion-survey discipline, but adjacent).
• Hermeticity of MEMS / hermetic IC package → He mass-spec fine leak (MIL-STD-883 Method 1014).

19. Cost / throughput comparison

Indicative order-of-magnitude pricing (2025 USD, North America, qualified contractor + consumables; not including capital depreciation):

Method	Setup cost	Per-weld / per-joint / per-unit
VT	Low (gauges + light)	trivial; bundled into welder/inspector hourly
PT	$50-200 per kit	$0.50-$2 per meter of weld
MT	$200-2,000 per yoke	$0.50-$2 per meter of weld
UT (manual)	$5k-25k instrument	$1-$5 per meter of weld (operator-time-driven)
PAUT	$40k-120k instrument	$5-$10 per meter of weld; encoded scan
RT (film)	$30k-100k source + darkroom	$20-$50 per pipe joint with film + processing
CR / DR	$50k-200k system	$10-$30 per joint, electronic record + faster cycle
ET (tubes)	$30k-80k instrument	$50-$200 per tube (HX bundle)
Leak test (He sniffing)	$40k-120k mass spec	$200-$2,000 per system
CT (industrial)	$300k-2M+	$200-$5,000 per scan depending on size
AE proof test	$30k-80k system	$5k-30k per vessel test event
MFL ILI run	$500k-3M tool	per-km run pricing, $300-$1,500 per km of pipeline

Caveats: RT requires radiation-shielding + qualified RSO; CT throughput is the bottleneck (minutes to hours per scan); PAUT requires more skill investment than conventional UT but throughput offsets it on long welds.

20. Cross-references

• welding-processes — weld NDE drives most PT/MT/UT/PAUT/RT volume
• casting-processes — RT + CT for porosity + inclusions
• additive-manufacturing-taxonomy — CT for AM porosity + lack-of-fusion
• pipe-fittings — pipeline girth-weld RT + PAUT + AUT
• seals-taxonomy — leak test for sealing systems
• standards-bodies — ASNT, ASTM, ISO, ASME, API governance
• engineering-codes — ASME BPVC + API 1104 + AWS D1.1 NDE clauses
• composites-taxonomy — IR thermography + air-coupled UT for composites
• heat-transfer-correlations — adjacent to IR-thermography fundamentals

21. Citations

• ASME BPVC Section V (2023 Edition): Nondestructive Examination
• ASNT NDT Handbook, 3rd ed., 10 volumes (2010-2020): Vol 1 Leak Testing, Vol 2 Liquid Penetrant, Vol 3 Infrared & Thermal, Vol 4 Radiographic, Vol 5 Electromagnetic, Vol 6 Acoustic Emission, Vol 7 Ultrasonic, Vol 8 Magnetic, Vol 9 Visual, Vol 10 Overview
• ISO 17636-1 / -2:2022 — Radiographic testing of welds
• ISO 17640:2018 — Ultrasonic testing of welds
• ISO 13588:2019 — PAUT of welds
• ISO 9712:2021 — Qualification + certification of NDT personnel
• API 1104:2021 — Welding of pipelines + related facilities
• AWS D1.1/D1.1M:2020 — Structural Welding Code — Steel
• ASTM E165 / E1417 — Liquid Penetrant Testing
• ASTM E1444 / E709 — Magnetic Particle Testing
• ASTM E114 / E317 / E2700 — Ultrasonic Testing
• ASTM E94 / E1742 / E2698 — Radiographic Testing
• ASTM E215 / E309 / E243 — Eddy Current Testing
• ASTM E1067 / E1316 / E976 — Acoustic Emission
• ASTM E1934 / E2582 — Infrared Thermography
• ASTM E432 / E493 / E498 — Leak Testing
• ASTM E1441 / E1570 / E1695 — Computed Tomography
• ASNT SNT-TC-1A:2020, CP-189:2020, CP-105:2020 — NDT personnel programs
• NAS 410 Rev. 5:2020 — NAS Certification & Qualification of NDT Personnel (aerospace)
• API STD 510, 570, 653, 1163 — in-service inspection + ILI qualification