Understanding ASME Section V Scope
ASME Section V — "Nondestructive Examination" — is one of the most widely referenced codes in pressure vessel, piping, and structural fabrication. It defines the examination methods (not acceptance criteria — those are in Section I, VIII, IX, B31.1, B31.3, etc.) and the general requirements that NDT procedures must satisfy.
When your procedure states "examination shall be performed in accordance with ASME Section V," every element in the relevant Article becomes mandatory for your procedure. The most common mistake is referencing Section V without actually meeting all its Article-level requirements.
Scope Note: ASME Section V defines how to examine — not what is acceptable. Acceptance criteria always come from the referencing Code (Section VIII Div 1, B31.3, etc.). Your procedure must reference both — the examination method from Section V and the acceptance criteria from the construction code.
Article 1 — General Requirements (Mandatory for ALL Procedures)
Article 1 sets baseline requirements that apply regardless of method. Your procedure must address:
- T-120 Written Procedure: All examinations must be performed to a written procedure. Mandatory variables requiring procedure requalification must be listed
- T-150 Qualification of Personnel: Reference to qualification standard (SNT-TC-1A, CP-189, ISO 9712, etc.) and minimum level required
- T-170 Certification of NDE Personnel: Records of personnel certification must be maintained
- T-180 Documentation: Required content of examination reports
- T-191 Records Retention: Minimum retention period and responsible party
Critical: T-120 requires that when any essential variable changes, the procedure must be requalified (demonstrated). Your procedure must explicitly list all essential variables. Failure to do so is one of the most common Section V non-compliances.
Article 4 — Ultrasonic Examination (UT) — Mandatory Elements
Article 4 covers UT for welds, materials, and components. Every UT procedure under Section V must address these T-420 essential variables:
- T-421: Material specification (base metal type, product form, thickness range)
- T-422: Instrument type (pulse-echo, through-transmission) and manufacturer model
- T-423: Search unit characteristics (frequency, size, type, angle, element size)
- T-424: Couplant brand/type
- T-425: Reference standard description (block drawing, material, reflector sizes)
- T-426: Examination technique (straight beam, angle beam, immersion)
- T-427: Scan pattern, scan index, scan overlap percentage
- T-428: Reference level and calibration procedure (DAC construction method)
- T-429: Computer enhanced data acquisition details (if used)
- T-430: Recording criteria (threshold for recording indications)
- T-431: Acceptance/rejection criteria reference (to referencing Code)
Most Missed UT Element: T-427 scan overlap. Many procedures specify scan direction and index but omit the minimum scan overlap percentage. ASME typically requires a minimum 10% overlap between adjacent scans for full coverage.
Article 5 — Radiographic Examination (RT)
Article 5 essential variables your RT procedure must address:
- Radiation source type (X-ray, Ir-192, Co-60, Se-75) and energy/activity
- Film brand, speed class (D4, D5, D7 per ISO, or AA, A, B per ASTM E1742)
- Source-to-film distance (SFD) and geometric unsharpness calculation (Ug ≤ 0.020 in. or per Code)
- IQI type (hole-type, wire-type), material, and placement (source side preferred)
- Density requirements (2.0–4.0 for film RT per ASME T-282)
- Processing conditions (manual or automatic, chemicals, temperature, time)
- Viewing conditions (illuminator luminance, ambient light)
Article 7 — Magnetic Particle Examination (MT)
| Element | Requirement | Common Gap |
|---|---|---|
| Magnetisation technique | Must state: yoke, prod, coil, central conductor, or combination | Technique stated but not quantified (yoke lift weight not stated) |
| Field strength verification | AC yoke: 4.5 kg (10 lb) lift; DC yoke: 18 kg (40 lb) | Lift weight omitted |
| Particle type | Dry, wet (fluorescent or visible), colour contrast | No particle brand or colour specified |
| UV lamp intensity | Minimum 1000 μW/cm² at examination surface (fluorescent) | Ambient light limit (≤2 ft-candles) not stated |
| Surface condition | Cleanliness, maximum surface roughness | Often omitted entirely |
| Demagnetisation | Required when residual field exceeds 3 gauss | Not mentioned |
Article 9 — Liquid Penetrant Examination (PT)
PT seems simple but generates frequent non-compliances around timing. Your procedure must specify:
- Penetrant type and family (Type I fluorescent / Type II visible; Method A, B, C, or D)
- Surface temperature range (typically 10°C–52°C / 50°F–125°F)
- Pre-cleaning method and materials (solvent, detergent, blast)
- Dwell time (penetrant application dwell — often missed for specific materials or defect types)
- Penetrant removal technique matching penetrant family (water washable → water rinse; solvent removable → solvent wipe; post-emulsifiable → emulsifier dwell then rinse)
- Dry time after removal and before developer application
- Developer type (dry, aqueous, non-aqueous) and application method
- Developer dwell time (development time — minimum and maximum)
- Examination conditions (UV lamp intensity for fluorescent, ambient light for visible)
Most Cited PT Gap: Missing maximum dwell times. ASME T-672 requires both minimum and maximum penetrant dwell times. A procedure stating only "minimum 10 minutes" without a maximum is non-compliant.
Complete ASME Section V Procedure Compliance Checklist
- Article 1: Written procedure reference with all essential variables listed
- Article 1: Personnel qualification standard and minimum level stated
- Article 1: Documentation requirements and records retention period specified
- UT: All T-420 essential variables addressed (instrument, transducer, couplant, reference standard, technique)
- UT: DAC or TCG construction method specified
- UT: Scan overlap percentage stated
- UT: Recording threshold and reporting level defined
- RT: Source type, energy, SFD specified
- RT: IQI type, material, placement and required sensitivity stated
- RT: Film density range and viewing conditions specified
- MT: Magnetisation technique with quantified field strength verification
- MT: Particle type, UV intensity (if fluorescent), and ambient light limit
- MT: Demagnetisation requirement addressed
- PT: Penetrant type, method, and surface temperature range stated
- PT: Both minimum and maximum dwell times for penetrant AND developer
- PT: Developer type and application method specified
- All methods: Acceptance criteria reference specific referencing code clause
Check Your Procedure Against ASME Section V in Minutes
NDTVerify AI reviews your PDF against all ASME Section V articles simultaneously and shows exactly which elements are PASS, WARNING, FAIL, or MISSING — with the clause reference and required corrective action.
Upload Your Procedure — $20