A zone plan is the first thing a responding firefighter looks at when the panel goes into alarm. It turns a flashing zone number into a place on a map - "Zone 3, first floor, east stairwell" - in the seconds that matter. This guide walks fire-alarm installers through building a clear, multi-floor zone plan on an iPhone: laying out the building, dropping fire symbols, colouring the zones, adding a title block and company branding, and showing detector coverage on the plan itself.
What a zone plan is for
Under BS 5839-1, a building with a fire-detection and alarm system carries a zone plan sited at the alarm panel (and often at each entrance). Its job is simple and non-negotiable: let anyone - a fire warden, an attending crew, an engineer on a service visit - translate a zone indicated on the panel into a physical area of the building, fast. A good zone plan is uncluttered, oriented the way you actually walk into the building, and consistent from floor to floor.
This guide is about producing that drawing cleanly and quickly. It is not compliance advice: the number, size, and boundaries of detection zones, the siting of the plan, and the symbols your authority expects are decisions for the system designer and the relevant standard. RoomPlot gives you the tools to draw it well - what goes in each zone is your call.
Step 1 - Build the building shell
Start with accurate geometry. If you are working in an occupied building with a recent iPhone or iPad Pro, scan each area: walk the perimeter and RoomPlot uses LiDAR to detect walls, doors, and windows automatically. Working from a drawing, or on a non-LiDAR device? Draw the walls by hand - snapping keeps corners square and walls aligned, so a freehand outline still comes out clean. Either way, the scan or sketch becomes a fully editable plan: move a wall, set an exact length, add an opening.
Because a zone plan almost always spans more than one storey, build each floor as its own floor in the same project. You can switch between floors, keep them aligned, and - where it helps the responder - combine the floors into a single 2D view so a stairwell or riser reads continuously top to bottom.
Keep the shell simple. A zone plan is not a survey drawing. Capture enough wall detail to make rooms recognisable, then stop - every extra line you leave in competes with the zone colours and symbols for a reader's attention.
Step 2 - Colour-code the zones
Zones are the whole point, so make them unmistakable. RoomPlot detects enclosed rooms automatically and lets you give each area its own name, colour, and label, so you can wash every space in a zone with one colour and drop a styled zone label on top. Keep a single colour per zone across every floor - if Zone 2 is amber on the ground floor, it should be amber on the first floor too - and the plan becomes readable at a glance.
- Fill each area with its zone colour and place a clear zone label (Zone 1, Zone 2, …).
- Re-use the same colour for the same zone on every floor for instant cross-floor recognition.
- Add a "You Are Here" marker so the plan reads correctly from where it is mounted.
- Use a colour key in the corner so the colours are self-explanatory.
Step 3 - Place fire symbols from the library
RoomPlot ships a dedicated fire-alarm symbol library alongside its general vector and furniture libraries, so you mark up the plan with the devices the system actually uses rather than improvising shapes. Drop a symbol, slide it into place, and rotate or resize it so the layout matches what was installed.
- Detection - smoke detectors, heat detectors, and other point devices.
- Manual call points and sounders where you need to record them on the plan.
- The control panel and any repeater positions, so the plan ties back to the indicator.
If your authority or your house style expects a glyph that is not in the stock set, the custom-symbol editor lets you build your own vector symbol once and re-use it across projects. Custom symbols sync with the rest of your work, so a glyph you draw on the iPhone is there when you continue on the iPad.
Step 4 - Show detector coverage on the plan
This is where RoomPlot does something most drawing tools cannot. Drop a smoke or heat detector and the app draws the area it covers directly on the plan - a detection-radius circle sized to the device. The nominal radii follow the figures installers already know: roughly 7.5 m for a smoke detector and 5.3 m for a heat detector under BS 5839 / NFPA 72. Coverage is enabled automatically when you place the device, and fire devices render in red so they read as a family.
Coverage circles are a fast visual sanity check while you lay out a plan - overlap them across a room and you can see at a glance where a zone is densely covered and where a corner sits outside every circle. You can hide or disable coverage for a clean print, and the same coverage information can be carried into a coverage report.
Coverage circles are a drawing aid, not a design certificate. The radii are nominal values for visualisation. Ceiling height, obstructions, and the specific device datasheet all affect real spacing - treat the circles as a way to see your layout, and let the system design and the standard set the actual device positions.
Step 5 - Add the title block and company branding
A zone plan is a controlled document, and it should look like one. Give the plan a clear title - building name, floor, and "Fire Alarm Zone Plan" - and stamp on your company branding: logo, address, and client details. A North marker, set once, keeps every floor and every export oriented the same way, which matters when a responder is matching the plan to the building. Use the layers panel to lock the shell and the title block so a stray drag during a later service visit cannot nudge them out of place.
| Plan element | Why it earns its place |
|---|---|
| Title + floor name | Tells the reader exactly which sheet and storey they are looking at. |
| Company logo & details | Identifies who maintains the system and who to call. |
| Colour key / legend | Makes the zone colours and symbols self-explanatory. |
| North marker | Orients the plan to the building, the same way on every floor. |
| "You are here" marker | Anchors the reader at the mounting point by the panel. |
Step 6 - Export and mount
When the plan is finished, RoomPlot produces the deliverables a fire-alarm job needs from the same project:
- Branded PDF - a print-ready zone plan, or a full report with legends, client and company details, and your branding, ready to frame at the panel.
- DXF - editable CAD geometry to hand to a consultant or feed into a wider drawing set.
- Image (PNG/JPG) - a crisp plan image for an O&M manual, an email, or a job sheet.
Because each floor lives in the same project, you can export the set as a consistent pack - same colours, same symbols, same orientation across every storey - rather than chasing a matching look across separate files.
A practical workflow
- Scan or draw each floor; keep the shell clean and switch units to metric if you work that way.
- Detect rooms, then fill and label each zone with a consistent colour across floors.
- Drop fire symbols - detectors, call points, sounders, the panel - and tidy their positions.
- Use detection-radius circles to eyeball coverage, then hide them for the final print.
- Add the title, branding, colour key, North marker, and "you are here"; lock the layers.
- Export a branded PDF for the panel and a DXF or image for the document set.
Common mistakes to avoid
- Inconsistent zone colours. If a zone changes colour between floors, the plan stops being readable at a glance - pick a colour per zone and hold it.
- An over-detailed shell. Survey-grade clutter fights the zones for attention. Keep walls recognisable and let colour do the work.
- No orientation. Without a North marker and a "you are here", a responder has to guess which way they are facing.
- Leaving coverage circles on the final print. They are a layout aid - turn them off before you export the mounted copy unless the reader needs them.
Frequently asked questions
Can I build a fire-alarm zone plan across several floors in one project?
Yes. Add each storey as its own floor, switch between them, and combine floors into a single 2D view where it helps a stairwell or riser read continuously.
Does RoomPlot draw detector coverage?
It does. Place a smoke or heat detector and the app draws a detection-radius circle on the plan - roughly 7.5 m for smoke and 5.3 m for heat as nominal BS 5839 / NFPA 72 radii. You can hide it for a clean print.
What if a symbol I need isn't in the library?
Use the custom-symbol editor to draw your own vector symbol once. It re-uses across projects and syncs to your other devices.
Which format should I mount at the panel?
A branded PDF - print-ready and consistent across floors. Send a DXF to a consultant who works in CAD, and use an image export for manuals or email.
Building your first zone plan on a job this week? Start by capturing the building shell - see how to create a floor plan and how to measure a room for the basics, or browse more guides. Then drop your zones, symbols, and coverage, and export a plan that earns its place beside the panel.