With the increasing threat of bombs and the use of IEDs becoming a regular feature both at the national and international level, it has become necessary for major installations and security organisations to take adequate measures against such threats. For the safety of installations against bomb attacks, preventive measures by way of denial of access, opportunity, time and place to the prospective attackers assumes utmost importance. Preventive security measures can be classified as perimeter security, internal security and vital area protection

Any important installation if unguarded is likely to become a target for a terrorist bomb attack. It is, therefore, essential that the perimeter of all vulnerable installations be kept under surveillance by physical presence and instrument deployment. The best perimeter fencing is a boundary wall of such height that it is beyond negotiation by human beings. In the next category comes the open wire or steel mesh fencing of adequate height. Such enclosures and boundaries need to be well illuminated and kept under electronic and human surveillance. The area within the enclosure has to be kept clear of garbage, foliage, wastes and heaps so that it easily lends itself to proper visual check and surveillance. Flowerpots, fountains, water channels etc. should not provide any hiding opportunities for improvised explosive devices. All doors, windows and ventilators should be strong and well secured and covered by strong iron rods and wire mesh. All wall openings need to be well guarded. For monitoring of approaches and vulnerable areas, closed circuit television (CCTV) monitors are very useful. An effective access control system is the most important precautionary measure against explosive attack. It should be well structured to detect any attempt to carry explosives into any installations or building in hand packages, vehicles, cargo mail, etc.

The identity of visitors and their purpose of visit should be carefully checked. Movements of all visitors should be monitored and a proper record of all details should be maintained.

A temporary pass system for visitors and its authentication, as also escorting of visitors to sensitive areas and protected persons must be ensured.

All packages should be thoroughly screened and checked. Vehicles should be carefully searched as also the occupants and the load. Inaccessible parts of the vehicle-body like the bottom sheet and inner side of the wheels need to be checked with instruments such as long-handle mirrors. Suitable methods of screening at entry points are : (a) physical frisking, (b) use of mobile metal detectors, (c) screening of persons through door frame metal detectors, (d) use of gas chromatography detectors, (e) screening of luggage through X-ray monitors and (f) use of trained explosive detection dogs.

In buildings, improvised explosive devices (IEDs) can be concealed anywhere. Such vulnerable places should be carefully searched periodically and people responsible for ensuring protection of the area should be carefully nominated. Some of the suggested methods are (a) false ceilings, elevator shafts, air conditioning or heating ducts and other cavities should be effectively sealed and checked periodically by security patrols, (b) blue prints of distribution lines and services connections should be inaccessible to unauthorized persons, (c) public areas should be patrolled round-the-clock, (d) adequate burglar alarms should be installed and maintained and (e) CCTV should be installed in conjunction with physical guards.

Vital and vulnerable areas need to be protected by strict "Key Holder" control, body and luggage search, electronic sweeps etc. All vital areas should be equipped with alarms and CCTV cameras should be installed. While developing or planning security, these areas should be identified and provided comparative security.

Public areas need to be frequently checked by security patrols as these serve as ideal spots for planting of explosive devices. Cinema halls, stadia, convention halls etc., should be regularly checked for explosive devices. Regular observations by security patrols of TV monitors provide the most efficient watch system.

All the security personnel should be trained to respond to telephonic and other bomb threats. Response to bomb threats should be carried out in a pre-determined manner and without panic. Anti-bomb drills, cooperation between various security agencies and inculcation of security awareness in one and all are vital. In short, protection against explosive damage can be achieved by evaluating the risks and developing an appropriate security programme. Preventive and emergency response plans should be devised and rehearsed so that all concerned can react quickly to any emergent situation.