Physical Security
Physical security covers the built and hardware measures that stop or slow an intruder - walls, doors, locks, safes, lighting and layout. The exam tests defence in depth, barrier principles and key/lock discipline.
Defence in depth
Security is arranged in concentric rings, each of which must be crossed:
- Perimeter - boundary wall, fence, gate.
- Building envelope - external walls, windows, doors, roof.
- Interior - corridors, zoning doors, reception control.
- Asset - strong room, safe, server rack, cash chest.
Each ring should add delay. The longer the intruder is delayed, the earlier the response arrives. A barrier that can be crossed in seconds with no detection has little value.
Barriers and openings
- Fences and walls must be high enough and free of climbing aids such as trees, drainpipes, stacked pallets.
- Doors: solid core or metal, good frame, hinge protection, minimum gap, and a lock that is not a simple latch.
- Windows and ventilators need grilles where the asset is valuable.
- Lighting should illuminate the intruder's approach without dazzling the guard or creating dark pools.
Locks, keys and safes
- A double-lock system means two different officers each hold one key; both must be present to open - this prevents one person acting alone.
- Keys are logged out and in; lost keys are reported and the lock is changed, not duplicated quietly.
- Safe combination or key custody is recorded, and the safe is opened only in the presence of the second custodian.
Worked example. A cash office has one key held by the accountant. Reasoning: a single-custodian key means the accountant could open the safe alone and later claim loss, and there is no witness. The correct solution is a dual-custody arrangement with the key register and a second officer present at opening and closing.
Traps
- Confusing locks (delay) with alarms (detection); one does not replace the other.
- Ignoring the roof, false ceiling or drainage openings as entry routes.
- Leaving trees and pallets against the boundary wall.