An exclusion zone keeps people out of contaminated or dangerous ground through three things done together: marking the boundary where people will meet it, making entry by mistake physically hard, and routing the few necessary entries through a logged gate with a decontamination point on the way out. A line on a map that nobody can see on the ground protects no one.
Part of Radiation Safety
An exclusion zone is ground closed to ordinary use because of radiation or contamination, with a defined edge and a controlled way in and out.
Choose A Boundary People Can Recognise
Set the edge on features visible from the approach, such as a road, a stream, a fence line or a wall, not on an abstract line. Place it with margin beyond the last evidence, since the data are poor. This guide supplies no standard distances for the margin; for facilities see Safe Distances. Zone colours and what each permits are in Zone Classification.
Mark It, Then Block It
- Signs and markers at every approach, in a symbol set that everyone has been taught; see Signage & Markings. Do not rely on writing alone, since children and visitors may not read it.
- Physical barriers such as ditches, fences and walls slow entry by mistake; the corpus’s barrier article states that none stops a determined intruder but all buy time and mark a boundary; see Physical Barriers.
- One gate watched and logged, like the access control described in Access Control. Everything else is closed.
Control The Few Who Must Enter
- A reason, a route and a time limit agreed before entry, and written down; see Record Keeping.
- Protective clothing per Personal Protection.
- An exit through a decontamination point where clothing is removed and bagged and people are washed; see Decontamination. Nothing leaves the zone without passing through it: not people, tools, carts, animals, or firewood.
- A sign-out check: the log shows who is still inside.
Why Enforcement Fails And How To Reduce That
Zones erode because the ground looks normal, someone needs the timber, the water or the shortcut, and the sign is faded. Counter this with explanations, not just rules: tell people what contamination does and why the line is where it is. Re-mark after weather. Offer an alternative for each use closed off. Review the zone when new evidence arrives, with data and dates in the register.
Common Mistakes
- Marking one side only. People approach from every direction.
- A gate with no decontamination point. The zone then leaks on boots and wheels.
- Tools and carts that go in and out. Keep zone tools in the zone.
- A sign that is the only barrier.
- Forgetting animals. Livestock graze across any unfenced line.
Safety
Never post sentries inside or on the edge for long periods
A guard’s time at the edge is dose time. Use fixed signs and fences instead of people wherever you can, rotate any watch and keep it short, and keep watch posts behind the line. Never let a person with an unexplained illness walk in or out unchecked.
What’s Next
- Learn next: Signage & Markings — the symbols to use
- Combine with: Safe Distances — how wide the margin should be