Components will appear differently on a radiograph as the denser and thicker materials are highlighted, whilst the lighter and thinner materials may not be shown. Therefore, the IEDD operator must analyse and interpret the radiograph to gain an understanding of the IED (if present) and its intended means of initiation. Beyond identifying individual components, the IEDD operator must analyse and interpret the nature and number of components present and the interaction between them.
ׁ WARNING. Important elements of an IED may NOT be visible on a radiograph. This is of particular concern with VOIEDs where detents holding a switch open, or fishing line connecting the switch to another item, are unlikely to be shown.
Images seen on a radiograph can be divided into three groups:
• Those which are not caused by radiation (e.g. marks from bad handling, poor procedures or dirty screens). These are referred to as artefacts and should be identified prior to analysis and interpretation;
• Those caused by the external features of IED components; and
• Those caused by internal features of IED components.
Information to accompany a radiograph
It is useful for certain information to accompany radiographs. This may be stipulated by the NMAA or MA organisation’s own SOPs and information management plans. The following information should be recorded with a radiograph:
• Task reference number
• Location
• Time and date
• X-ray generator control setting (e.g. number of pulses used) and distance from source
• Description of the item
• IEDD operator’s name
• Any other relevant information
4.12.4.CONSIDERATIONS WHEN PROCURING RADIOGRAPHY EQUIPMENT In addition to the usual considerations when procuring equipment, the MA organisation may find it useful to evaluate the following specifications of potential equipment models:
• Plate size
• Penetration capability of generator
• Ease of placing image capture plate
• Digital or analogue image capture plate
• Ease of developing an image
• Quality of image
• Ability to manipulate an image through software
• Wired or wireless
Typically, it will be a trade-off between the different attributes and the MA organisation must decide what will be most appropriate for them.
IEDD techniques and procedures
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