digital radiography
Corrosion Under Insulation (CUI) Monitoring 

Thickness measurements of insulated pipelines in plant may be carried out by means of Ultrasounds (UT) or Radiography (RT).

Each of these methods presents advantages and limitations.

¨    UT   May be very accurate, but still have limited surface coverage, need removal of insulation and may need stop of plant.

 

¨    RT   has Long exposure times and the thickness measurements on film may be not very accurate.

Digital Radiography  is an economical way to inspect insulated pipes in Chemical and Petrochemical plants as it allows:

¨    ON-STREAM Inspection, both for hot and cold pipes.

 

¨    No stripping Inspection (no need for insulation to be removed)

Computed Radiography (CR) is a 3 steps process

 

1. Pipe is exposed to the radiation coming from the same kind of sources (X or gamma) used in traditional radiography. Energy is trapped in Phosphor screen plate.

     These plates are much faste than traditional films and have a wider latitude, allowing different sizes and thicknesses to be seen on a single shot.

 

2. Plate is scanned in a special laser scanner.

3.  The resulting digital image is transferred on a computer with a high definition screen.

     This image can then be processed by an appropriate software in order to provide quick and reliable thickness measurements.

 

Due to the digital nature of images, software tools may be employed in order to have a more meaningful, accurate and repeatable interpretation of data.

1.   Storage of images on mobile devices such as CD Rom or optical disks, thus minimizing the risk of loss and damage.

2.   Images may be transmitted by e-mail or internet for remote analysis and results sharing.

3.   Economical and efficient management of a big amount of images.

4.   Data and reports may be stored in a single place.

 

Computed Radiography is normally employed for profile measurements of pipes with very satisfactory results. In general, major advantages of this method are:

 

1.     Getting repeatable and comparable information for periodical monitoring surveys;

2.       Avoiding undesired shoot down; 

3.       Cost saving for insulation removal, installing and disposal; 

4.       Purchase planning only for materials required in case of maintenance needs, thus reducing storage; 

5.       Pre-assembling of items to be replaced with scheduling for replacement during turn-around;

6.       Avoiding sudden and undesired labour force rising during turn-around with unforeseen costs.

 

Link Brochure

 
Back to Advanced NDT