# Zones & bands

Source: https://meptools.com/tools/ceiling-coordination-studio/docs/zones-and-bands/

![Ceiling Coordination Studio workspace with the default void and zone layout](./_assets/ccs-workspace-overview.png)

## The five zones

| Zone                                     | Holds                                                                                               | Notes                                                     |
| ---------------------------------------- | --------------------------------------------------------------------------------------------------- | --------------------------------------------------------- |
| **Zone D — Condensation-Risk Ducts**     | Standard HVAC ducts                                                                                 | A standard duct is flagged if it sits over Zone A's width |
| **Zone E — Low-Condensation-Risk Ducts** | Ducts flagged **Low Condensation Risk Duct**                                                        | May pass over Zone A                                      |
| **Zone A — Electrical Services**         | Cable trays                                                                                         |                                                           |
| **Zone B — Access & Maintenance**        | Kept clear — this is the **access corridor** a technician stands in to reach the services around it |                                                           |
| **Zone C — Piped Services**              | Pipes                                                                                               |                                                           |

Two further bands appear in the section but aren't zones you place services in directly:
the **Structural Beam Band** at the top of the void, and the **Ceiling Device Drops Band**
at the bottom, reserved for vertical drops to fittings below the ceiling.

## Turning a zone off

Each zone has an **Enabled** checkbox in its properties. Turning a zone off drops it from
the drawing and from the coordination checks — but a zone that still holds services can't be
disabled until you remove or move them out first.

## Linked zones

**Linked zones** (on by default for a new document) keeps the zones attached edge to edge
and filling the void: resizing one zone moves its neighbours so there's never a gap or an
overlap. Turn it off in **Project Settings** to position each zone independently.

## The access corridor (Zone B)

Zone B has to stay wide enough to work in, and it has to sit next to Zone A so the trays in
it are reachable:

- Below the **Zone B minimum width** threshold (Tool Default: 600 mm), the corridor is
  flagged as too narrow to work in. At exactly the minimum it's flagged as a warning instead
  — there's no margin left for a later change to narrow it further.
- If Zone B doesn't share an edge with Zone A, every tray in Zone A is flagged as
  unreachable.
- A cable tray whose centreline sits further than the **Arm's reach limit** (Tool Default:
  900 mm) from the nearest Zone B edge is flagged — it can only be reached by leaning into
  the void.

These thresholds are project-editable — see [Rule set](/tools/ceiling-coordination-studio/docs/rule-set).
The checks themselves are covered in full on
[Compliance checks](/tools/ceiling-coordination-studio/docs/compliance-rules).

## Low Condensation Risk ducts

A duct flagged **Low Condensation Risk Duct** goes into Zone E instead of Zone D and is
allowed to pass over Zone A's width — a standard duct is not, because it can shed
condensate onto whatever sits below it. See
[Ducts, trays & pipes](/tools/ceiling-coordination-studio/docs/services).