A lone worker device is a personal alarm, worn or carried on the body, that connects the wearer to a 24/7 alarm receiving centre when they raise an alert. Devices supplied as part of a service audited against BS 8484:2022 qualify for an escalated police response through the unique reference number (URN) scheme.
How lone worker devices work
The device does one job. When the wearer needs help, it opens a live audio connection to an alarm receiving centre (ARC), where a trained operator listens, speaks to the wearer if that is safe, and escalates. The alert carries the wearer's identity and location, so the operator knows who needs help and where before a word is spoken.
Most services distinguish two kinds of alert. A red alert is the emergency: the wearer presses the SOS button and the device calls the ARC. An amber alert is preventative. Before a higher-risk task, the worker records a short voice message on the device (the address, who they are meeting, what the job is) and sets a timer. If the timer expires without a check-in, the ARC treats it as an incident and has the context recording ready when it does.
Escalation depends on what the operator hears. That might mean calling the worker's manager or a nominated contact. In a confirmed emergency, an ARC operating under the standards described below can request a police response directly rather than dialling 999.
Types of lone worker device
ID badge devices
Worn behind or in place of a staff pass, badge devices are built for public-facing roles. The alarm button sits on the back of the badge, so a housing officer or community nurse can raise an alert mid-conversation without reaching for anything. Reaching for a phone can escalate a confrontation; pressing the back of a badge goes unnoticed.
Key fob and pendant devices
Small units that clip to a belt, keyring or lanyard. They suit roles where a badge is impractical, such as trades, engineering and site work, and they tend to have larger buttons that work through gloves.
Devices with fall detection
Often sold as man down devices, these carry motion sensors that raise the alarm automatically after a hard fall, a sudden impact or a set period without movement. No button press is needed. They are the right choice where the main risk is incapacitation rather than confrontation: working at height, working alone with machinery, or environments with slip and trip hazards.
Satellite devices
Standard devices use multi-network mobile SIMs that connect to whichever network has signal. Where there is no mobile coverage at all, on remote agricultural, forestry or energy sites, satellite units send alerts and location over a satellite link instead. They cost more and are bulkier, so they are usually reserved for genuinely off-network work.
What BS 8484:2022 requires
BS 8484 is a code of practice for the whole lone worker service, and that framing matters when comparing products. The standard is not a badge on a piece of hardware. It audits the company supplying the service, the device or app raising the alert, and the monitoring arrangements behind it. The 2022 edition took effect on 31 March 2022 and superseded the 2011 and 2016 editions.
| Area | What is checked |
|---|---|
| Supplier organisation | The company behind the service, including financial standing and staff screening to BS 7858 |
| Device or app | How alerts are raised and delivered, including over data connections as well as voice calls |
| Monitoring | A 24/7 alarm receiving centre operating to BS 9518, the standard for ARCs handling police-response alarms |
| Scope of protection | Lone workers, and since 2022 also pairs, small groups and home workers |
Two changes in the 2022 edition catch people out. Alerts may now travel as data calls, not only as traditional voice calls, which is what lets modern devices and apps qualify. And the detailed ARC requirements moved out of BS 8484 itself into BS 9518, so a compliant service now points at two standards where older guides mention one. Summaries written against the 2016 edition are out of date on both points.
How the standard decides police response
This is the practical reason the standard matters when choosing a device. An ARC that meets the standards above holds unique reference numbers (URNs) issued by police forces under national policing guidance [VERIFY: current NPCC guidance title and date]. When an operator confirms a genuine emergency, they contact the force control room directly, quoting the URN, and request a Level 1 response, the highest priority. The alert never joins the public 999 queue.
A service without the audit has no URN. Its monitoring centre, or the worker themselves, dials 999 and waits like any other caller. The hardware might be identical; the response is not.
Note: BS 8484 is voluntary. Nothing stops an employer buying an unaudited alarm. But police forces only offer the escalated response to alerts raised through an audited service, which is why most UK buyers treat the standard as a requirement rather than a preference.
Devices or apps
A smartphone app can deliver the same service, connect to the same ARC and carry the same audit. The choice between them is practical rather than technical. A dedicated device earns its keep when the phone is locked away or in a bag, when PPE or gloves make a screen awkward, when shifts outlast a phone battery, or when the risk involves confrontation and raising an alarm needs to be invisible. Where staff already carry a work phone all day and the risk profile is lower, an app is cheaper to roll out and one less thing to charge. The lone worker apps page covers that side in full.
What lone worker devices cost
Almost every accredited supplier prices the device as a monthly subscription per worker rather than a hardware purchase, because the product is the service: the SIM connectivity, the ARC monitoring and the audit sit behind the monthly fee. Hardware is usually bundled into that price or supplied for a modest upfront charge. Satellite units and their airtime cost noticeably more than cellular devices.
When comparing quotes, check what the monthly figure includes. The points that vary between suppliers are whether the ARC monitoring is included or an add-on, whether there is a minimum contract term, who pays if a device is lost or damaged, and whether training and escalation-list changes carry extra charges.
Choosing a device
Start from the risks your lone working risk assessment has actually identified, not from a product list. The device is a control measure; the assessment tells you which risks it needs to control, and it sits alongside the procedures and training covered in our best practices guide. Employers' duties around all of this are set out in the legal responsibilities guide.
The questions that separate the options:
- Is there reliable mobile signal everywhere your people work, or do some sites need satellite cover?
- Could a worker be incapacitated without warning? If so, fall detection is the feature that matters most.
- Is the risk public-facing? Discretion favours a badge device.
- How long is a shift, and will charging discipline realistically hold? Device battery life spans days; a phone running a tracking app does not.
- Who answers the alert? An audited ARC brings the URN police response. Self-monitoring by managers is cheaper and carries no such access.
Suppliers audited against the standard, and what each is accredited to provide, are listed in the accredited companies directory.