Cold rooms and freezers
A cold room door left ajar after a delivery warms the whole store. A held-open alert after a few minutes gives staff time to close it before the temperature climbs.
Door state monitoring tag
The ZARC door state tag reports the moment a door, gate, hatch or lid opens and closes, and warns when one is left open or ajar. Set the hours a door should be shut, and any opening outside them raises an alert in real time. It fits almost anything that opens, and it runs on its own battery.
01
What it reports
It reports every change of state as it happens: open, closed, and a door that has not shut fully. A door left ajar looks closed from across a room, and that is how a cold room warms overnight or a compound gate stands open until morning.
Each state is timed. The dashboard knows how long a door has been open, how long it stood ajar and how long it stayed closed, so an alert can fire on duration as well as on the event itself.
Schedules set when each door should and should not be open. An opening inside working hours can be logged quietly, while the same opening at 2am goes straight to the people you name.
02
Applications
If it opens and closes, the tag can report it. These are the requests we see most, and the tag is not limited to them.
Secure compounds and restricted rooms
Plant rooms, comms rooms, stores and compounds where every opening should be expected. An out-of-hours opening alerts at once, and the history sets every opening against the hours the door should have been shut.
Gates and site access
Site, yard and compound gates left open overnight, or opened when the site should be empty. A gate still open at the closing time you set raises its own alert.
Meter and valve chamber covers
The lid over a water meter or valve chamber is rarely checked. The tag reports when a chamber cover is lifted, so interference with a meter or valve is known the day it happens, long before the next read.
Street cabinets and electrical panels
Telecoms cabinets, kiosks and distribution panels on unmanned sites. A panel opened without a scheduled visit shows up in real time.
Roof hatches, risers and access panels
Hatches and risers give access to roofs, plant and service voids, and they are easy to leave open. Rain, heat loss and unauthorised access all start with a hatch nobody shut.
Drug, chemical and controlled stores
Medicine rooms, chemical stores and lockers where access has to be evidenced. Every opening is logged with its time and how long the door stayed open.
Fire doors that should stay shut
A fire door propped open does nothing in a fire. The tag reports how long each one stays open, as complementary monitoring alongside the building's fire strategy.
03
Where it can go
The contact comes in two small parts: a magnet on the moving side and a switch on the fixed side, cabled to the tag. That lets it fit almost anything that opens. Typical fittings:
Doors
Internal and external doors, cold room and freezer doors, fire doors and plant room doors.
Gates
Site, yard and compound gates, sliding or swinging, with the tag in an enclosure specified for the outdoors.
Hatches and covers
Roof hatches, loft hatches, floor access covers and meter or valve chamber lids.
Cabinets and panels
Street cabinets, electrical panels, server racks, lockers and equipment cases.
Windows and lids
Windows, skylights, container lids and chest freezers.
Surface or recessed
Surface-mounted as standard, or recessed into the door and frame where the fitting should not be seen.
04
In the dashboard
Every door has a live state and a full timeline of every opening and closing, with its time and duration. From that record the dashboard works out how often each door is used, how long it stays open, when it is busiest and which doors are left open most, per site or across an estate. Views and statistics are set to what you want to see, and every figure exports for reports, audits and insurers.
Alerts are pushed in real time: on opening, on a door left open or ajar past the time you set, on any opening outside its permitted hours, and on a door not closed by a set time. They go by email or SMS, and through an app where required, to the people you name, with escalation to further contacts.
- Live state of every door, gate and hatch, grouped by site
- Time open, time ajar and time closed for every door
- Openings per hour, day and week
- Longest, shortest and average time open
- Out-of-hours openings against each door's schedule
- Doors not closed by their set time
- Busiest doors and busiest times of day
- Site-by-site comparison across an estate
- Full event history, exportable
- A tag that misses its check-in is flagged
05
Industries
Anywhere an open door costs stock, security or evidence, including:
Defence and secure facilities
Out-of-hours openings on restricted rooms and compounds, reported the moment they happen.
Critical national infrastructure
Cabinets, kiosks and compounds on unmanned sites, where an unexpected opening is the first sign of a problem.
Energy and utilities
Meter and valve chambers, pumping stations and kiosks.
Facilities management and property operators
Plant rooms, risers and roof hatches across a managed portfolio, with one view of what was left open.
Healthcare
Drug rooms, medicine fridges and stores where access has to be evidenced.
Data centres and critical infrastructure
Cage, rack and suite doors, logged with the time and duration of every opening.
06
Technical specification
| Parameter | Specification |
|---|---|
| Function | Open, closed or not fully closed, for a door, gate, hatch or lid |
| Sensor | Magnetic contact: magnet on the moving part, switch on the frame |
| Mounting | Surface-mounted as standard; recessed where the fitting should not be seen |
| Inputs | Up to two contacts per tag |
| Reporting | Every change of state, sent as it happens |
| Timing | Time open, time ajar and time closed, recorded per door |
| Held-open alert | After a time you set, per door |
| Schedules | Hours each door should and should not be open, set per door |
| Closing-time alert | A door not closed by a set time raises an alert |
| Alert delivery | Dashboard, email or SMS; app where required |
| Recipients | Named people and groups, with escalation to further contacts |
| Check-in interval | Configurable; a silent tag is flagged |
| Gateway power loss | Raises its own platform alert |
| Statistics | Openings, durations and out-of-hours events per door, site or estate; configured to your requirement |
| Data | Full event history, exportable; UK-hosted or on servers on your own site |
| Power | Internal battery, up to five years depending on use and check-in interval |
| Radio | 433 MHz, one-way (transmit only) |
| Environment | Indoor or outdoor, enclosure specified to the location |
| Charges | No per-alert, per-user or licence charges |
| Manufacture | Made to order in the UK |
| Certification | CE marked |
07
From requirement to live alerts
Requirement
You tell us which doors, gates or covers matter, when each should be shut and who needs to know.
Configuration
We set the schedules, held-open times, alert routes and enclosure for each opening.
Fitting
The magnet goes on the moving part and the switch on the frame, cabled to a tag mounted nearby.
Commissioning
We open and close every monitored door and confirm each alert reaches every recipient before handover.
Ready to get started? Every deployment begins with a site survey.
Book a site survey08
How it reports
Every change of state goes over 433 MHz radio to a ZARC gateway, which passes it to the dashboard, where it is timestamped and checked against the schedules and timers you set. The tag transmits and never listens, so there is no receiver for anyone to reach or reprogramme over the air.
Related tags
Motion (crystal)
Reports when an extinguisher, defibrillator or item of equipment is lifted or moved.
Motion (PIR)
Reports movement inside a room once the door has opened.
Temperature
Pairs with door monitoring on cold rooms and freezers.
Dry contact
Reads the output of an existing door controller or access panel.
Questions we answer most.
Can it tell when a door is left ajar?
Yes. A door that has not shut fully reads as not closed, and the held-open timer raises an alert once it has stayed that way longer than you allow.
Can alerts depend on the time of day?
Yes. You set the hours each door should and should not be open. Openings inside those hours can be logged quietly, and openings outside them alert at once.
Will I know if a door is not closed by a set time?
Yes. A closing time can be set per door, and a door still open at that time raises an alert.
What can it be fitted to?
Anything that opens and closes: doors, gates, hatches, cabinets, panel doors, lids, windows and chamber covers.
How fast are the alerts?
Changes of state are sent as they happen and typically reach the dashboard within a second.
What statistics does the dashboard show?
Openings per door, time open, ajar and closed, longest and average durations, busiest times, out-of-hours events and comparisons between sites. Views are configured to what you want to see.
Can one tag cover two doors?
Yes. A tag takes up to two contacts.
Does it need mains power or wiring?
No. It runs on an internal battery for up to five years, depending on use and the check-in interval.
Is it a certified intruder alarm?
No. It is complementary monitoring that gives real-time visibility of every opening. It does not replace a certified intruder alarm or its monitoring.
Does it work outdoors?
Yes. Gates, cabinets and chamber covers take the tag in an enclosure specified for the location.
Do alerts or extra users cost more?
No. There are no per-alert, per-user or licence charges.
Looking for something else?
We work with any sensor for any application.
Most sensing needs are met by a tag we already build, configured for your equipment. If yours needs a sensor or interface we don't list, we have the engineering to build it. Tell us what you need to measure, and we will tell you how we would do it.
Discuss your requirementDiscuss a monitoring
or alerting solution
Tell us what is happening on site, what you need to see, and the event you need to hear about. We will come back with the system that answers it.
Direct contact
Location
Venator House, Unit 9, 15-17 St Stephen's Road, Bournemouth
Dorset, BH2 6LA · VAT GB 409644484
Products contact
Contact the engineering team
Direct to the team that designs and builds the range. Tell us the equipment and the event that matters.