4.6.5. SELECTION OF THE APPROPRIATE SHAPED CHARGE FOR THE INTENDED ROLE There are several factors to consider when selecting the appropriate shaped charge to achieve the desired effect. These include:
• The distance the shaped charge will travel and through what mediums / barriers;
• The type of material and thickness of the IED main charge’s casing;
• The type and condition of the IED explosive filling;
• The desired effect – high order detonation or deflagration.
The MA IEDD operator must draw on their training, published documentation, trials and experience when selecting the shaped charge which will give the highest probability of success. There are several variables to consider, however some of these will be fixed by what is available:
• Type of shaped charge to use.
• Size of shaped charge.
• Liner material and thickness.
• Type and quantity of explosive fill for the shaped charge.
• Minimum stand-off distance required.
Section 4.7 of this sub-section gives a basic overview of shaped charge effects.
LINER SELECTION
When considering the liner of a shaped charge there are three main considerations:
• Shape. The shape of the liner will give the effect and will normally be either: ◦ Jet forming cone (JFC) (Munroe effect) producing an extremely high velocity plasma jet capable of penetrating thick steel plate. ◦ Explosively formed projectile (EFP) (Misznay-Schardin effect) projecting a high velocity slug of compact metal. • Size. The size of the liner, particularly its diameter (often referred to as ‘charge / cone diameter’) effects the penetration depth for JFCs and the range for EFPs (assuming the liner’s angles are correct and suitable explosives are used). • Material. The construction material of the liner affects its performance. For EOD applications the use of certain materials like magnesium will assist in igniting a burn. 4.6.6.COMMERCIAL OR LOCALLY MANUFACTURED User filled shaped charges are commercially available. They come in a variety of sizes with different liner options, and the user is able to select the quantity of explosives to use and the means of initiation. Some have fixed liners whilst others are modular, allowing the user to select the desired liner.
Locally produced shaped charges are a potential option (local laws permitting) and can be very effective. The materials and tools required are easily accessible in most parts of the world.
Whether commercially available or locally developed by an MA organisation, the type of shaped charge should be designed, trialled, tested and evaluated in accordance with IMAS 03.10 Guide to the procurement of mine action equipment and IMAS 03.40 Test and evaluation of mine action equipment. It is good practice to conduct trials, especially with locally produced shaped charges, to provide confidence
IEDD techniques and procedures
380
Powered by FlippingBook