When radiographed with the source inside the piping, how many penetrameters must be used across the weld?

The requirement for using at least four penetrameters when radiographing a weld with the source inside the piping is based on ensuring comprehensive assessment of the weld quality. Penetrameters are used to measure the sensitivity of the radiographic film or digital detection method, assessing how well the radiograph can reveal defects within the weld.

When conducting an internal radiographic examination, using four penetrameters across the weld helps establish a more detailed evaluation of the weld's integrity, ensuring that any possible discontinuities are detectable. They provide a means of calibrating the radiographic exposure and ensure that the entire thickness of the weld is adequately represented and analyzed.

Utilizing a minimum of four penetrameters also aligns with industry best practices and standards stipulated in API 1104, which prioritizes the quality and reliability of the weld inspection process. The presence of multiple penetrameters ensures that variations in exposure and sensitivity are accounted for, leading to a more reliable overall assessment of the weld's condition.

In this context, employing fewer than four penetrameters could compromise the thoroughness of the inspection process, potentially overlooking critical defects that might be present. Thus, the requirement for at least four penetrameters is integral to maintaining high safety