Plan against three sizes of human threat, thieves and scavengers of 1-5 people, raiders of 5-20 and organised groups of 20 or more, and test each design against the time it gives you. A group walking at 1.4 m/s covers 380 m in the 270 seconds a settlement may need to alarm everyone and reach its refuge, so detection must reach beyond a 300 m outer zone, and against the largest group no wall substitutes for alliances or leaving.
Part of Defensive Architecture
Threat categories and likely scenarios are the sorted kinds of attacker a settlement may face and the way each is expected to behave, used to test whether a defensive design gives enough warning and time.
Each Size Of Group Asks A Different Question Of The Design
The defensive-architecture guide gives three tiers and a design target. Individuals or small groups of 1-5 are opportunistic thieves and desperate scavengers; strong doors, alert dogs and a night watch deter them. Armed groups of 5-20, bandits and raiders, are deterred by visible community strength, controlled access and hardened refuge points. Organised groups of 20 or more are a military-style threat that will take a settlement unless it has equivalent force; fortification buys time and cannot substitute for diplomacy, alliances or relocation. The target is the middle tier.
The household threat guide notes that early signs of scouting and coordination show whether an organised group is cooperative or predatory (Organised Groups), and the layered-defense guide says an intruder tests the weakest side, so the weakest side matters more than the strongest (Layered Defense Principles).
| Tier | Likely behaviour | What it tests | Response |
|---|---|---|---|
| 1-5 | Night theft, scavenging, probing for an unwatched store | Alert, dogs, doors | Watch, dogs, locks (Animal Sentinels) |
| 5-20 | Approach by day or night, a demand, a raid on stores | Warning time, controlled access, refuge | Layers, one watched gate, hardened refuge |
| 20 or more | Siege, demand or seizure | Whole settlement | Alliances, negotiation from strength (Negotiation From Strength), relocation |
Worked Example: Does The Warning Outlast The Muster?
The outer-zone guide gives a walker 3.6 minutes to cross a 300 m outer zone on a path and 6 minutes through brush (Outer Detection Zone). The trigger guide gives the rule D = speed × time needed (Trigger Criteria). Inputs: approach at 1.4 m/s; time to sound the alarm, about 30 s (assumed); time to bring everyone into the refuge 240 s, borrowed as an illustration from the top of the evacuation article’s range of 148 to 239 s for a hall emptying and a 100 m walk; measure your own (Evacuation Routes & Assembly).
- Time needed: 30 + 240 = 270 s.
- Distance covered by the approach in that time: 1.4 × 270 = 378 m, about 380 m.
- Warning from a sighting at the edge of a 300 m zone on a path: 300 ÷ 1.4 = 214 s. That is 270 − 214 = 56 s short.
- Through brush at 6 minutes for 300 m (0.83 m/s): 360 s, which is 90 s to spare, so cover and terrain change the answer.
So the carrier’s detection layer of 100-500 m only works if the sighting is made well out, by a lookout, a dog or a line of noise makers, not at the edge of the buildings. Time bought by delay features (ditches, hedges, one watched gate) adds to the 214 s.
What You Need
- A map of approaches, with distances paced out
- The measured muster time from a drill, not the estimate above
- A lookout post that sees 380 m or more along the likely routes (Observation Posts)
- A watch rota (Watch and Patrol Scheduling)
Method: Test The Design Against A Scenario
Step 1: Pick the tier and the approach route.
Step 2: Work out the warning time from the detection distance and the approach speed.
Step 3: Compare with the muster time, and with the time to close the gate and reach the refuge.
Step 4: Close the gap by detecting farther out, shortening the muster, or adding delay in the middle zone.
Step 5: Run the scenario as a drill, at night once.
Common Mistakes
- Preparing only for the tier that frightens you most. The likely threat is the small one.
- Counting detection at the walls. The warning ends where the sighting is made.
- Assuming the attacker comes up the strong side. They test the weak one.
- Ignoring dogs and animals as detectors.
Safety
A refuge that cannot be left is a trap
A refuge that needs a bar or a key to leave, or is reached only through one door, fails the settlement in a fire, which is likelier than an attack. Any room that can hold a crowd exits outward by pushing, with nothing to work first. Plan the muster to a place that is safe from fire as well as from raiders.
What’s Next
- Learn next: Layers of Defense Concept — building the warning and the delay
- Combine with: Safe Rooms & Refuge Points — where the muster goes