What should be done with the IQI if using contact exposure on a pipe weld?

When using contact exposure on a pipe weld, the correct procedure regarding the Image Quality Indicator (IQI) is to reduce the IQI by one size. This is because contact exposure can produce a higher radiation dose, thereby enhancing the sensitivity of the radiographic film or digital detector. To maintain proper sensitivity and ensure that the radiographic image accurately reflects the weld quality without excessive contrast or saturation, it is necessary to adjust the IQI accordingly.

In this context, reducing the size of the IQI helps to ensure that the film or detector is detecting defects effectively without the image being overly influenced by the radiation intensity. This adjustment aids in achieving a balance between the exposure and the clarity required for an accurate assessment of the weld integrity.

This approach is rooted in the principles of radiographic testing, where ensuring the appropriate IQI size is crucial for assessing welds reliably.