Each layer of security may be comprised of different elements, including for example:
- Measures to assist in the detection of threat weapons, including for example explosives, knives, firearms, chemical/biological/radiological material etc.
- Measures to assist in the detection, tracking and monitoring of intruders and other threats, such as unmanned aerial vehicles
- Access control and locking systems
- Physical and active barriers to deny or delay the progress of adversaries
- Measures to protect people or assets from the effect of blast or ballistic attack
- Measures to protect against or limit the spread of chemical, biological or radiological material
- Measures to protect sensitive (e.g. classified) material or assets
- Command and control
- The response to an incident
- Security personnel (covered within the Personnel and People Security)
The above measures are interdependent and their effectiveness will be dictated by their ability to support one another. For this and a variety of other reasons, CPNI recommends that all security measures are developed following the Operational Requirements (OR) process.