What coverage discs show
A sprinkler head protects a set radius, a smoke detector senses within a set radius, and a luminaire lights one. When you have counted those devices, the question is whether the layout as drawn actually blankets the room or leaves gaps, and whether it is over-provisioned. Coverage view answers that by painting a translucent disc of a real-world radius around every marker in a Detection or Count group. Gaps in the shading are gaps in cover.
Coverage discs are a view, not a marker. They are not counted, priced or exported, and they disappear when you leave the mask.
Where the controls are
Coverage lives inside Mask view. The radius for each group is set in the mask bar's group picker, and two controls on the bar show or hide the discs: an eye per group in the picker and a Radii master switch on the bar itself.
Setting a radius
- 1
Enter the mask and open the group picker on the mask bar.
- 2
Tick the Detection or Count group whose devices you want to check (e.g.
Sprinkler head). - 3
A radius field appears on that row, blank and marked with m for metres. Type the radius (e.g.
2.5); the field steps in 0.5 m. - 4
Press Enter. Discs of that radius appear around every marker in the group. Esc reverts the field, and clearing it removes the radius.
Repeat for each group. The radius belongs to the group rather than to the bar, so a sprinkler group at 2.5 m and a detector group at 7.5 m can be checked side by side, and a group keeps its radius if you untick and re-tick it. A value of zero or less is refused.
Showing and hiding discs
| Control | Where | What it does |
|---|---|---|
| / eye | On each picker row, once that group has a radius | Hide discs / Show discs for that one group. Your choice is kept while the group stays in the mask, even if you untick and re-tick it. |
| Radii switch | On the mask bar | Shows or hides every group's discs at once. Greyed out with No coverage radius set on the selected groups until at least one masked group has a radius. |
Both must be on for a group's discs to draw. The Radii switch is a quick way to flip between the shaded view and the plain masked drawing without losing the radii you typed.
Reading the discs
- Each disc is filled in the group's colour at low opacity with a stronger ring at the edge, so an individual radius stays legible.
- Overlapping discs from one group read as a single continuous shaded area rather than stacking up darker. This is deliberate: on a dense sprinkler layout the shading would otherwise become a solid block and the gaps, the thing you are looking for, would vanish. Two groups in different colours shade independently.
- Discs are drawn to the drawing's scale. Change the scale or calibrate the drawing and the discs resize to match, so check the scale is right before trusting a coverage check. See Setting the scale and Calibrating a drawing.
- Discs are centred on each marker's box and ignore the marker's rotation.
- The drawing shows at most 3000 discs across all groups. Beyond that, further discs are not drawn, so on a very large layout check one group at a time.
Use the opacity slider on the mask bar to bring the floor plan back up behind the discs. Coverage gaps are much easier to judge against the walls and room outlines than against a blank sheet.
Typical uses
| Devices | What to check |
|---|---|
| Sprinkler heads | That every part of the floor plate is within throw of a head, and that heads are not doubled up in corridors. |
| Smoke and heat detectors | That detection radii overlap enough to leave no unprotected floor area, room by room. |
| Luminaires | That the lit area from a grid of fittings is continuous, and where a layout thins out towards the edges. |
| Wireless access points or sounders | Any device with a nominal range, where a quick visual check of overlap is enough to spot a missing unit. |
Coverage view is a visual aid rather than a design calculation: it draws a plain circle of the radius you give it and does not account for obstructions, mounting height or the shape of a device's pattern.
Common issues
The Radii switch is greyed out
None of the groups currently in the mask has a radius. Tick a Detection or Count group in the picker and type a radius on its row.
The radius field is not there
Only checked Detection and Count rows carry one. Linear and Area groups have no coverage radius, and the field appears only after the row is ticked.
The discs look far too big or too small
The discs are true to the drawing's scale. If a 2.5 m disc spans a whole room, the scale or calibration is wrong; fix that and the discs correct themselves.
Next steps
- Mask view — the picker and bar that coverage discs are built on.
- Setting the scale — the discs are only as accurate as the scale.
- Calibrating a drawing — correct a drawing that was not printed true to scale.
- Detect New Symbol — count the devices you want to check first.