Radiography

The ability of radiation to pass through materials, and reveal their internal condition and contents, has been utilised in many fields throughout the decades. Whilst many new inspection technologies have entered the field since Radiography’s introduction, Radiography holds popularity due to its wide range of applications, reliability and familiarity.

Industrial Radiography is a common non-destructive technique that uses ionising radiation to reveal flaws in assets and structures which are otherwise not visible. Industrial Radiography is typically used to detect:

• The presence of material flaws, including cracks, weld defects and voids;
• Loss of material, due to corrosion or erosion, in piping; and,
• The presence of internal blockages, such as in pipework.

Radiography uses a variety of different radioactive sources depending on the requirements of the inspection and the materials being examined. Strict procedures for transportation and handling of the sources are paramount for the safety of operators and the general public.

The ALS Approach

ALS remains an industry leader in the implementation of sophisticated analysis tools and techniques for radiographic imaging and in the use of safe radiation sources.

Our investment in this area means that our clients can be confident:

• That high-quality outcomes from radiation work will be produced.
• Their teams can work safely alongside ALS staff whilst Radiography is performed.

With new developments in the field of Radiography there are various means by which the inspections can be delivered. These developments are explored below.

Film Radiography

By utilising film, ALS performs Radiography typically using x-ray and gamma radiation sources. Radiography performed using film is highly sensitive, flexible and well-tailored to both compliance and investigative testing.

Applications

• Examination of a wide variety of materials and components, where internal flaws may occur.
• Code compliant inspection of welds and fabricated items.

Advantages

• Permanent images and auditable results.
• Relatively low setup times and equipment costs.

Computed & Digital Radiography

Digital image capture technology produces an image of the internal condition of the component under examination. These digital images can provide superior interpretation outcomes and greater ability to manage complex geometries.

Computed Radiography (CR) uses flexible image plates which require laser scanning to extract the digital data. Digital Radiography (DR) captures the image on solid plates which produces almost instantaneous images. Given this, DR is a high productivity Radiography solution.

Applications

• Examination of a wide variety of materials and components, where internal flaws may occur.
• Particular demand for this service seen in Profile Radiography which examines for internal pipe erosion or corrosion.

Advantages

• Often greater efficiency in high production inspection scenarios.
• Better ability to interpret radiographic results in many geometries.

Real-Time/ Movable Radiometry

Rather than taking discreet location images as per Film and Digital Radiography, Real-Time/ Movable Radiometry involves a live scan at the job site using mobile equipment. This process allows inspection to pass items through the scanner, or more commonly to walk along a long item whilst scanning the areas of interest.

As a result, this technology has strong applications for examining pipelines for blockages and for examining wall loss in piping, particularly through insulation.

Applications

• Pipework inspection when looking for blockages or material loss.

Advantages

• Movable Radiometry at the job site allows more rapid inspection of piping and small diameter vessels.

Small Controlled Area Radiography (SCAR)

This method is also referred to as Closed Proximity Radiography and uses specialist isotopes and equipment to reduce the size of the exclusion zone when performing Radiography inspections.

The low energy isotopes are housed in specialised containers and high efficiency shielding materials are used. This means that Radiography testing can be completed in such a way that minimizes disruption on-site by safely reducing the size of the exclusion zone.

Applications

• Examination of a wide variety of materials and components, where internal flaws may occur.
• Code compliant inspection of welds and fabricated items.
• Particular demand for this service is seen in Profile Radiography, which examines for internal pipe erosion or corrosion.

Advantages

• Reduced exclusion zones allow greater capacity for simultaneous tasks to be completed near the radiographic inspection, leading to overall site productivity improvements.