What a man down alarm is
A man down alarm is a safety feature that raises an alert automatically when a worker may have been incapacitated. The idea is simple but important: if someone has fallen, collapsed or been knocked unconscious, they may be unable to press an SOS button, so the system needs to recognise the situation and call for help on their behalf.
Man down capability is usually part of a wider lone worker solution rather than a standalone gadget. It typically sits alongside a manual SOS, check-in and GPS location, so a worker can raise the alarm deliberately or have it raised for them.
The feature is most valuable in roles where a sudden collapse or fall would leave someone alone and unable to react, such as working at height, in remote areas, around machinery or in physically demanding environments.
How detection works
Man down detection relies on motion sensors, chiefly an accelerometer and often a gyroscope, in a device or smartphone. The software watches for patterns that suggest an incident, such as a sudden impact consistent with a fall, or a period of no movement when the worker would normally be active.
Common triggers include fall detection, where a rapid change in acceleration is recognised, and no-motion or no-movement detection, where the alarm activates if the device stays still for a set time. Tilt or orientation detection can also alert when a device, and by implication its wearer, remains lying horizontal for too long.
Most systems combine these signals and give a short pre-alarm countdown with a sound or vibration. This lets a worker who is simply resting or bent over cancel the alert before it escalates, which is central to keeping detection both sensitive and practical.
Device-based versus app-based
A dedicated device is a purpose-built unit, often a fob, pendant or rugged handset, designed for man down detection and durability. Its sensors and battery are tuned for the task, which can make detection consistent and battery life predictable, at the cost of extra hardware to buy, carry and manage.
An app-based approach uses the sensors already in a worker's smartphone, so there is nothing extra to carry and updates arrive over the air. It suits organisations whose staff already use phones for work and want lower hardware overheads, provided the phone is carried correctly and kept charged.
Neither is universally better. The right choice depends on the environment, how staff already work, and how tolerant the setting is of a phone being in a pocket or bag rather than mounted where its sensors can read movement accurately.
Handling false alarms
False alarms are the main practical challenge with automatic detection. Set the sensitivity too high and normal activity such as bending, sitting or driving over rough ground can trigger alerts. Set it too low and a genuine incident might be missed. Good systems let you tune thresholds to the role.
The pre-alarm countdown is the first line of defence, giving the worker a few seconds to cancel before an alert is sent. Clear feedback through sound and vibration helps workers respond, and sensible defaults reduce nuisance activations without dulling real detection.
A robust escalation process handles the false alarms that do slip through. When a monitoring centre or responder can quickly assess an alert, confirm the worker is fine and stand down, occasional false positives become a manageable inconvenience rather than a reason to distrust the system.
ARC monitoring and BS 8484
An alarm receiving centre, or ARC, is a professionally staffed facility that receives alerts around the clock and follows agreed procedures, including contacting the worker, escalating to nominated contacts and, where appropriate, requesting an emergency response. Monitoring turns an alarm into a dependable response rather than a message that might be missed.
BS 8484 is the British Standard for lone worker device services. It sets requirements across the service, from the app or device and the monitoring centre to the way alerts are handled, and is closely linked to arrangements for a properly graded police response to verified alarms.
For higher-risk roles, choosing a solution aligned to BS 8484 and backed by a monitored ARC gives assurance that alerts will be handled consistently and taken seriously. It also helps demonstrate that your safety arrangements meet a recognised benchmark.
Choosing a man down alarm
Start from the risk. Identify where a fall or collapse would leave a worker alone and unable to react, and let those scenarios drive your requirements for detection type, sensitivity and monitoring. A quiet office worker and a lone forestry operative need very different levels of cover.
Then weigh the practicalities: battery life, signal coverage where staff actually work, how the device or phone is carried, ease of use, and whether alerts route to a monitored ARC or a reliable internal process. The best specification is worthless if workers find it awkward and stop carrying it.
Finally, look for a solution that combines man down with SOS, check-in and GPS in one place. Platforms such as Vygard bring these together, so a single system covers deliberate alerts, automatic detection and the response behind them.
Frequently asked questions
- What is a man down alarm?
- A man down alarm is a lone worker safety feature that automatically raises an alert when a worker may be incapacitated, for example after a fall or collapse. It is designed to summon help when the person is unable to press an SOS button themselves, usually alongside manual alerts, check-in and GPS location.
- How does man down detection work?
- It uses motion sensors, mainly an accelerometer, in a device or smartphone to spot patterns that suggest an incident. Typical triggers are a sudden impact consistent with a fall, a period of no movement, or the device staying tilted horizontal too long, usually with a short countdown so the worker can cancel.
- How do you reduce false man down alarms?
- Tune the detection sensitivity to the role, use the pre-alarm countdown so workers can cancel accidental triggers, and rely on clear sound and vibration feedback. A strong escalation process, ideally through a monitoring centre, then handles any false alerts that do get through by quickly confirming the worker is safe.
- What is BS 8484 for lone worker devices?
- BS 8484 is the British Standard for lone worker device services in the UK. It sets requirements across the app or device, the alarm receiving centre and how alerts are handled, and underpins arrangements for a graded police response to verified alarms. It is a recognised benchmark for higher-risk lone working.
- Should a man down alarm be monitored by an ARC?
- For most higher-risk roles, yes. An alarm receiving centre receives alerts around the clock and follows agreed procedures to contact the worker, escalate to nominated people and request an emergency response where needed. Monitoring ensures alerts are acted on consistently rather than sitting unseen on a colleague's phone.
Last updated 2026-07