Radiographic Testing: Safety Concerns and Alternative Methods
Radiographic testing (RT) has long been a widely accepted method of nondestructive testing (NDT) due to its ability to identify flaws such as cracks, thickness variations, corrosion, and material degradation with impressive precision. However, analysts must be wary of the safety concerns inherent in RT.
When dealing with radiographic NDT, a high degree of skill and experience are necessary. Additionally, analysts must be well-versed in radiographic testing safety procedures—both for the sake of their own well-being and in order to ensure compliance with federal standards. While radiographic testing is, in many ways, an effective NDT technique, it might not necessarily be the best available. Depending on the inspection application, other, modern methods such as eddy current testing (ECT) and ultrasonic testing (UT) can capture accurate data more efficiently—and more safely.
Potential Hazards of Radiography
The primary hazard of radiographic testing is the radiation, particularly ionized radiation. High radiation exposure can result in the following symptoms:
- Hair loss
- Nausea
- Vomiting
- Hair/skin loss
In fact, The National Center for Biotechnology Information (NCBI) evaluated an instance in Taiwan, where NDT analysts were exposed to industrial radiation during an inspection in 1999. Crew members suffered debilitating ailments in the form of tissue degradation and lowered blood cell counts. While cases of such extreme radiation exposure are thankfully rare, this cautionary tale highlights the potential severity of radiation poisoning.
Though the radiographic field has made vast headway in safety standards and technology since 1999, the NCBI warns that problems within this industry still exist. Ionized radiation is not only hazardous to personnel implementing the testing, but can also be harmful to others in the vicinity of the testing area.
Radiographic Testing Preparation
It should be noted that radiographic testing can be time-consuming and require careful interpretation. Beforehand, analysts might need the following gear to monitor and measure the radiation levels during testing:
- Dosimeter
- Geiger counter
Additionally, all personnel must adhere to central guidelines established by such organizations as The American Society of Mechanical Engineers and The American Society of Nondestructive Testing. The best way to mitigate accidents and radiation exposure is to follow protocols from beginning to end.
The analyst must also ensure that anyone who is not involved in the testing stage is kept away from the testing site. Most importantly, managers and analysts must make certain that personnel are fully trained to commence a radiographic test to minimize the possibility of a serious accident. A level 2 or 3 analyst is needed to not only prepare the test adequately, but skillfully assess anomalies within a structure or weld.
The Advantages of UT and ECT vs. Radiography
Ultrasonic testing and eddy current testing are two leading methods on the NDT market due to impeccable signal quality and flexible probing capabilities. And, perhaps most importantly, neither strategy requires radiation use or exposure to harsh chemicals.
Rather than radiation, UT relies on wave paths to probe through an object and detect any deviations within. With ECT, an electron current runs through the object being tested, generating magnetic fields and high conductivity that detects thickness deviations and other problems within structures.
Both ECT and UT (and particularly phased array ultrasonic testing) can be safer and less time-consuming than radiographic testing. Portable ultrasonic and eddy current instruments can also be more convenient in the field than radiographic equipment, which tends to be heavier and bulkier—not to mention, more complicated to operate.
The advanced software behind ECT and UT automates the testing process and provides straightforward, digestible data that can be more accessible to new or lower-level analysts. The software also produces impeccable image resolution, that can paint a full picture of the testing radius.
Radiographic Testing and Safety: Considering Alternatives
In the end, the powerful detection capabilities and increased safety of more advanced eddy current and ultrasound methods makes them ideal NDT technologies. More advanced ECT and UT techniques can spot additional defects while producing results faster—and both methods provide data that managers and inspectors can incorporate into regular maintenance schedules.
Of course, regardless of what specific NDT method is used, choosing the right equipment from an experienced NDT company is paramount. If using radiographic NDT, analysts should abide by radiographic testing safety measures, whether mandated or suggested. Failure to follow rules and regulations can result in long-term illnesses stemming from radiation sickness. If ECT equipment or UT instrumentation will be used instead, such extreme safety measures won’t be necessary. Instead, analysts’ focus will be where it should be: acquiring the highest quality data as efficiently as possible to ensure the health and safety of all.
Zetec is an experienced NDT company providing the latest UT and ECT instrumentation and software for all types of applications in a variety of industries. To learn more, contact Zetec today.