ASNT Level III IR case studies
ASNT Level III IR · Put your knowledge to work in context.
The ASNT NDT Level III certification is a professional credential in nondestructive testing, with Infrared Testing (IR) as one of the method-specific endorsements a Level III candidate can pursue. Level III personnel are typically the people who write and approve NDT procedures, interpret codes and specifications, select techniques and equipment, evaluate and sign off on results, and supervise or qualify Level I and Level II staff - so the IR exam is aimed at experienced infrared thermographers moving into that technical-leadership and program-ownership role rather than at entry-level operators. The ASNT Level III IR case studies are 5 cases and about 2,527 words.
1Roof Moisture Survey: Emissivity Correction vs. Solar Loading
A thermographer surveys a low-slope EPDM roof (emissivity about 0.90) at 0600 after a clear, calm night with a 14 K drop below the previous day's high. Ambient is 8 °C, sky is clear, wind under 1 m/s.
514 words, about 3 min2Switchgear Survey Through an IR Window: Apparent vs. True Temperature
An electrician asks you to survey energized 480 V switchgear through installed IR-transparent windows (stated transmission 0.80, spectral range 8–14 µm). The imager is a 320×240 microbolometer, 8–14 µm, with a 24° lens and a stated accuracy of ±2 °C.
515 words, about 3 min3Detector Sizing and NETD for a Small Target at Distance
You must detect a 20 mm overheated terminal on a 400 V panel from 8 m away. Candidate imager A: 160×120 microbolometer, 8–14 µm, 25° FOV, NETD 80 mK, IFOV computed from a 160-pixel horizontal array.
491 words, about 2 min4Qualitative vs. Quantitative Reporting and the Standard Being Applied
A client's specification cites 'infrared inspection of electrical distribution equipment per the applicable ASTM standard' and requires 'temperature rise limits per the standard.' You perform a survey of 480 V motor control centers. Loads vary from 20% to 90% of rated.
514 words, about 3 min5Personnel Certification and the Limits of the Level III's Role
A Level III IR thermographer is asked by a client to (a) certify two Level I candidates by administering the client's in-house written exam and practical, (b) sign the inspection report as the 'certifying authority' for a survey performed by a Level I thermographer, and (c) approve a written practice that omits any requirement for near-vision acuity or annual vision exams. The Level III holds a certification from a recognized certification body.
493 words, about 2 min