Lone Working in Construction: Policy, Risk Assessment & Best Practice

Lone working on construction sites is more common than most people realise. Surveyors conducting pre-construction assessments. Security guards on night shift. Maintenance workers carrying out remedial repairs. Site managers doing weekend inspections. Every one of these scenarios involves a person working alone in an environment with significant hazards, and every one requires specific risk controls. This guide covers the legal framework, risk assessment process, and practical measures for managing lone workers safely on UK construction sites.

What Counts as Lone Working?

The HSE defines a lone worker as someone who works by themselves without close or direct supervision. On construction sites, this includes people who are the only person on site, people who work in an area of a site where they cannot be seen or heard by others, and people who work outside normal hours when the site is otherwise unoccupied.

It is important to understand that lone working is not automatically prohibited. There is no law that says a construction worker cannot work alone. The legal requirement is that the employer must assess the risks specific to lone working and implement appropriate controls. Some activities, however, should never be carried out by a lone worker. These include work in confined spaces, work at height where there is a risk of falling, work with high-voltage electrical systems, and work involving lifting operations.

Legal Requirements for Lone Working

Several pieces of UK legislation apply to lone working in construction:

• Health and Safety at Work Act 1974 -- employers must ensure, so far as is reasonably practicable, the health, safety and welfare of all employees, including those working alone (Section 2)
• Management of Health and Safety at Work Regulations 1999 -- requires employers to carry out risk assessments that specifically consider lone working scenarios (Regulation 3)
• CDM 2015 -- the principal contractor must plan, manage and monitor construction work to ensure it is carried out safely, which includes managing lone workers (Regulation 13)
• Corporate Manslaughter and Corporate Homicide Act 2007 -- an organisation can be found guilty of corporate manslaughter if a gross breach of duty of care leads to a death, including the death of a lone worker

The HSE publication INDG73 "Working alone: Health and safety guidance on the risks of lone working" provides specific guidance, though it is not construction-specific. For construction, the CITB and Build UK have published additional guidance on managing lone workers on sites.

Lone Worker Risk Assessment

A lone worker risk assessment follows the same five-step process as any risk assessment, but with additional considerations specific to working alone. The assessment must address the following questions:

Can the work be done safely by one person?

Some tasks are simply too dangerous for a lone worker. Moving heavy materials, working at height, operating certain plant, and electrical work on live systems all require at least two people. The risk assessment must identify which tasks on your site fall into this category.

What are the additional risks created by working alone?

The key additional risk is the inability to summon help in an emergency. If a lone worker suffers a fall, is struck by a falling object, or has a medical emergency, there may be no one to call for assistance. This delay in receiving help can turn a survivable injury into a fatal one.

Other lone-working-specific risks include violence from intruders (particularly on sites with valuable materials or plant), the psychological effects of isolation, the increased likelihood of taking shortcuts when unsupervised, and the difficulty of evacuating in an emergency.

What controls are needed?

Controls for lone working typically include:

• Check-in systems -- the lone worker must contact a designated person at agreed intervals. If contact is not made, an escalation procedure is triggered.
• Lone worker devices -- personal safety devices with GPS tracking, man-down detection (tilt sensors that trigger an alert if the wearer is horizontal for a set period), and panic buttons.
• Restricted activities -- a clear list of tasks that must not be carried out by a lone worker.
• Enhanced first aid provision -- lone workers should have personal first aid kits and training in self-administered first aid.
• Communication equipment -- reliable mobile phone signal or two-way radios. Do not assume mobile coverage exists everywhere on site.
• Site access controls -- if a lone worker is the only person on site, someone else must know they are there, when they expect to finish, and what to do if they do not check in.

Writing a Lone Worker Policy

Every construction company should have a lone worker policy. This is not a generic document downloaded from the internet. It should be a site-specific policy that reflects the actual lone working scenarios on your projects. The policy should cover:

1. Scope -- who does the policy apply to (employees, subcontractors, visitors)?
2. Prohibited activities -- which tasks must never be carried out by a lone worker
3. Authorisation -- who can authorise lone working and what checks they must carry out first
4. Communication requirements -- check-in intervals, communication methods, and escalation procedures
5. Emergency procedures -- what happens if a lone worker fails to check in, triggers a panic alarm, or is found injured
6. Monitoring -- how compliance with the policy is checked (site audits, spot checks, device data review)
7. Training -- what training lone workers receive before they are permitted to work alone
8. Review -- when and how the policy is reviewed (at least annually, and after any lone working incident)

The policy should be communicated to all workers during site induction. Subcontractors should be required to provide evidence that their lone working arrangements meet the principal contractor's requirements.

Lone Worker Monitoring Systems

Technology has significantly improved the options available for monitoring lone workers. The main options include:

Check-in Apps

Simple smartphone apps that require the lone worker to press a button at set intervals. If the check-in is missed, an alert is sent to a supervisor. These are cost-effective and easy to deploy, but they rely on the worker remembering to check in and having a charged phone with signal.

Dedicated Lone Worker Devices

Purpose-built devices with features specifically designed for lone workers: man-down detection (accelerometer-based), GPS tracking, panic buttons, two-way voice communication, and automatic alerts. Devices from providers like SoloProtect, Peoplesafe, and StaySafe are widely used in construction. They typically require a monthly subscription per device.

CCTV and Access Control

On sites with existing CCTV infrastructure, cameras can provide passive monitoring of lone workers. Access control systems can track who is on site and when they entered and left. This does not provide real-time safety monitoring, but it creates a record that can be used in investigations.

Digital Site Management Tools

Platforms like FORGE Command that digitise daily site management can incorporate lone worker check-in functionality alongside other site management tasks. This avoids the need for separate systems and ensures lone worker monitoring is integrated into the site's normal operating procedures.

Medical Fitness and Lone Working

Employers must consider whether a lone worker has any medical condition that could put them at increased risk. Conditions such as epilepsy, heart conditions, diabetes (particularly insulin-dependent), and severe asthma may require additional controls or may make lone working inappropriate for certain tasks.

This does not mean that people with medical conditions cannot work alone. It means the risk assessment must consider their condition and determine whether additional controls are needed. For example, a diabetic lone worker might need more frequent check-ins and access to glucose testing equipment.

Occupational health assessments should include a specific question about lone working capability. The assessment should be reviewed periodically and after any change in the worker's health status.

Managing Subcontractor Lone Workers

As a principal contractor, you have a duty under CDM 2015 to manage the work of all contractors on your site, including their lone workers. This means you need to know when subcontractors plan to have people working alone, ensure their lone working arrangements meet your site standards, include lone working requirements in your subcontractor management procedures, and audit subcontractor compliance with the lone working policy.

A common failure is assuming that because a subcontractor has their own lone working policy, the principal contractor has no further responsibility. This is incorrect. The principal contractor must satisfy themselves that the subcontractor's arrangements are adequate for the specific conditions on their site.

What to Do When Things Go Wrong

Your lone worker procedures must include a clear escalation protocol:

1. Missed check-in -- attempt to contact the lone worker by phone. If no response within 10 minutes, move to step 2.
2. Failed contact -- send someone to the lone worker's last known location. If the location is remote, call emergency services while sending someone to investigate.
3. Panic alarm / man-down alert -- treat as a genuine emergency. Call 999 immediately and dispatch someone to the location.
4. Post-incident -- record the incident, investigate root causes, and update the risk assessment and lone working procedures as needed.

Test your escalation procedure regularly. A procedure that has never been tested is a procedure that will fail when it matters. Run quarterly desktop exercises where you simulate a missed check-in and walk through the response.