Hole-Type IQI
A hole-type IQI is a thin plaque with three drilled holes of diameters 1T, 2T, and 4T (where T is the plaque thickness), used per ASTM/ASME standards to demonstrate radiographic sensitivity.
Definition
The hole IQI plaque has thickness T = 2% of the test piece thickness; the three holes (1T, 2T, 4T) provide the sensitivity reference. ASME Section V typically requires the 2T hole to be visible.
What it is
A hole-type image quality indicator: a plaque of radiographically similar material, thickness a set percentage of the part, with drilled holes of one, two and four times plaque thickness (1T/2T/4T). Seeing the required hole in the image demonstrates the technique's sensitivity.
Correct use
The designated hole visible on the required plaque proves contrast AND definition together — that is the point. Placement rules (source side by default, film side only with allowances and a lead letter F) exist because a film-side IQI flatters the technique.
Governing standards
ASTM E1025 defines them; ASME Section V Article 2 tables select plaque per thickness; wire IQIs per ASTM E747 are the common alternative.
The usual mistake
Reading IQI visibility as flaw detectability. A 2T hole proves the technique meets its sensitivity class — it does not promise a tight crack at an unfavourable angle will show. IQIs qualify technique, not outcomes.
Where Hole-Type IQI fits in an inspection programme
A term is only useful when it connects to a decision. Hole-Type IQI appears in written procedures, in technique sheets, and in the records an owner or accreditation body reviews afterwards — which means the way it is defined in your documentation has to match the way it is applied on site. Where the two drift apart, audits find it. Atlantis writes and reviews procedures against the governing codes, trains inspection personnel to apply them, and builds the record-keeping that makes the evidence retrievable years later. Procedure development and code consulting · NDT training and certification · Ask us about your programme.
Related terms
- Image Quality Indicator (IQI) — An image quality indicator (IQI), also called a penetrameter, is a device placed on the source side of a radiographic test piece to verify image sensitivity and resolution by displaying known features such as wires or holes.
- Wire IQI — A wire IQI is a set of parallel wires of progressively decreasing diameter encased in a clear plastic envelope, used per ISO/EN standards to verify radiographic sensitivity.
- ASME Section V — ASME Section V (Nondestructive Examination) is the chapter of the ASME Boiler and Pressure Vessel Code that defines NDT methods, procedures, and personnel qualification requirements for examinations referenced by other ASME construction and in-service codes.
More equipment terms
Calibration Block · Transducer · Dual-Element Probe · Angle-Beam Probe · Normal-Beam Probe · Couplant · Reference Reflector · Side-Drilled Hole · Flat-Bottom Hole · Notch Reference
Where this comes up in practice
Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.
Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.