Duress alarm

When a worker triggers a duress alarm, the device sends an alert to a set list of responders. Depending on the system, that alert can go to site first aiders, the site manager, the security gatehouse, a 24/7 monitoring centre or all of them at once. Most systems send the worker's identity and location so responders know who needs help and where to go.

On a construction site, duress alarms take a few common forms.

• Wearable duress buttons. A pendant, clip-on device or smartwatch with a duress button the worker can press without reaching for a phone.

• Fall and no-movement detection. Some wearables raise an alarm automatically if they detect a fall or no movement for a set time, often called man-down.

• Fixed call points. Emergency or first aid call points mounted at set locations on large sites, such as each floor of a building or along a civil corridor, so anyone can raise help quickly.

• Check-in timers. Apps or devices that alert a supervisor if a lone worker misses a scheduled check-in.

Under the model WHS Regulations, a person conducting a business or undertaking (PCBU) must manage the risks to a worker doing remote or isolated work. That means work that is isolated from the help of other people, including rescue, medical help and emergency services, because of the location, time or nature of the work. The PCBU must provide a system of work that includes effective communication with the worker.

On construction sites this covers more than people in the bush. A worker alone on an upper floor after hours, a security guard doing night patrols, a plant operator on a remote section of a linear project or a worker in a basement with no mobile reception can all be isolated. A duress alarm is one way to meet the communication requirement, alongside first aid arrangements and an emergency plan that the regulations also require.

Victoria has its own Occupational Health and Safety Act 2004 and regulations, but the general duty to provide a safe system of work still applies to lone workers.

A duress alarm only helps if someone responds. Plan the response before you choose the device.

• Who gets the alert. Name the first aiders, supervisors and backups for every shift, including after hours.

• How fast they get there. Large sites need call points or wearables close enough that help arrives in time.

• Coverage. Test mobile and radio coverage in basements, lift shafts, tunnels and remote areas. Some sites need repeaters or satellite devices.

• Location detail. GPS works outdoors but is weak indoors, so fixed call points or zone tags may be needed on multi-level builds.

• Testing and drills. Test devices regularly and run drills so responders know the process.

• Alerts that go to one person. If the only responder is off site or asleep, the alarm goes nowhere. Use an escalation list.

• No testing in dead zones. Devices that rely on mobile coverage can fail in the places lone workers are most likely to be.

• Treating the device as the whole control. A duress alarm supports, but does not replace, eliminating lone work where reasonably practicable.

• False alarm fatigue. Frequent accidental triggers lead responders to ignore alerts. Train workers and pick devices that suit gloved hands.