What percentage of the thickness of the object being radiographed is typically used for a hole type image quality indicator?

The appropriate percentage of the thickness of the object being radiographed that is typically used for a hole-type image quality indicator is 2% to 4%. This range effectively ensures that the indicator provides a representative assessment of the radiographic quality achieved.

The hole-type image quality indicator, often referred to as an image quality indicator (IQI), is designed to evaluate the interaction of radiation with the material being inspected. By utilizing a percentage of the material's thickness, the IQI can simulate or quantify the ability of the radiographic technique to detect variations in density due to flaws, such as pores or voids.

Using a thickness percentage that falls within this range ensures adequate sensitivity to variations in image quality required to meet industry standards for weld and material integrity assessments. Choosing a lesser percentage, like 1% to 2%, may not adequately represent the resolution needed in thicker materials, while higher percentages beyond 4% might produce indicators that are too large and do not accurately reflect the necessary detail for assessment in typical radiographic inspections. Thus, 2% to 4% strikes a suitable balance for quality assurance in radiographic examinations.