How to Perform a Dynamic Risk Assessment During Unplanned Work
Unplanned work is common across Australian process plants, mines, utilities, construction sites and energy facilities. A pump fails, a valve begins leaking, an electrical fault interrupts production or a delivery arrives with damaged equipment. The job may need to begin quickly, yet the conditions that made the original risk assessment valid may have changed within minutes.
A dynamic risk assessment is a structured check carried out while work is being planned or performed. It helps workers identify new hazards, assess changing exposure and choose controls that match the conditions in front of them. It does not replace a safe work method statement, job safety analysis, permit to work or formal risk assessment. It adds a practical layer of decision-making when the work differs from the plan.
Australian workplaces must account for the relevant state or territory work health and safety requirements, site rules and emergency arrangements. Model WHS laws apply in many jurisdictions, while Victoria operates under its own occupational health and safety legislation. A useful assessment therefore needs to be specific to the location, task, plant, workforce and level of supervision.
The strongest approach is calm and repeatable. Workers should know when to pause, who can authorise a change, how controls are recorded and what conditions require the task to stop. This is especially important during shutdowns in Gladstone, maintenance campaigns in the Hunter Valley, FIFO work in Western Australia and summer operations where heat, storms or bushfire conditions can change the risk quickly.
Recognise When The Plan Has Changed
Dynamic assessment starts when the actual job no longer matches the approved plan. The trigger may be obvious, such as a new leak or a failed isolation, or subtle, such as reduced visibility, unfamiliar equipment, a changed crew or a different access route. Treating these changes as routine can allow hazards to pass unnoticed.
Common triggers include:
- The scope, sequence or work location has changed
- Weather, lighting, noise or ground conditions have deteriorated
- The correct tools, parts, drawings or competent people are unavailable
- Another crew, vehicle or process has entered the work area
The worker in charge should pause the task and describe the change in plain language. “The line cannot be fully drained” is more useful than “conditions are different.” The team can then decide whether the job remains within the existing risk assessment or needs a revised method, additional controls or fresh authorisation.
A dynamic risk assessment should also be triggered by uncertainty. If the team cannot confirm the contents of a vessel, the status of an isolation, the condition of lifting gear or the competency needed for a step, work should not continue on assumption. In high-risk environments, an unanswered question is itself a reason to stop and verify.
Gather Information Before Choosing Controls
The next step is to collect reliable information from people, documents and the worksite. Speak with the person who reported the fault, the permit issuer, operations control room, supervisor and workers who know the equipment. Check drawings, isolation registers, manufacturer instructions, previous incident reports and emergency procedures where they are relevant.
Inspect the work area rather than relying only on a briefing. Look for stored energy, pressure, hazardous substances, moving machinery, electrical sources, confined spaces, work at height, dropped-object exposure, traffic interaction and simultaneous operations. Consider less visible hazards too, including fatigue, heat stress, poor communication, language barriers and rushed decision-making.
A useful assessment asks four practical questions:
- What can harm someone during this task?
- Who could be exposed, including contractors, visitors and the public?
- What controls are already in place, and can they be trusted right now?
- What additional control will reduce the risk before work resumes?
Controls should follow the hierarchy of control. Elimination is preferable, followed by substitution, isolation, engineering controls, administrative controls and personal protective equipment. For example, draining and isolating a process line is generally stronger than relying on a worker to wear chemical-resistant gloves near a live leak. PPE remains important, but it should not carry the whole control strategy.
Contractor management is part of this information-gathering process. Before a contractor enters an unfamiliar facility, the host organisation should verify capability, insurance, procedures, licences and relevant performance information. Clear prequalification information can help organisations establish whether a supplier is suitable before an urgent job begins.
Match The Assessment To The Level Of Risk
Not every change needs a lengthy form, but every change needs a proportionate response. A minor alteration to hand tools may require a brief team discussion and a supervisor’s confirmation. A change involving hazardous energy, toxic gas, confined space entry or process containment may require a new permit, isolation review, atmospheric testing and authorisation from several roles.
The difference between a planned and dynamic assessment should be clear to the team:
| Planned Risk Assessment | Dynamic Risk Assessment |
|---|---|
| Completed before the task or project begins | Completed when conditions change or information is uncertain |
| Based on the expected sequence and known work environment | Based on current conditions, new hazards and actual work progress |
| Usually prepared by a supervisor, engineer or safety professional | Often initiated by the worker or team closest to the change |
| May support a SWMS, JSA or permit | May confirm, modify, suspend or invalidate those controls |
| Reviewed at scheduled points or after significant changes | Repeated whenever conditions, people or scope change |
The assessment should identify the required authority. A worker may be able to stop work and request advice, while only an authorised isolating officer can alter an isolation or only an appointed person can approve a lift. Clear escalation paths prevent workers from feeling pressured to make decisions beyond their training.
Australian sites often have layers of control involving the principal contractor, asset owner, specialist contractor and operations team. On a major shutdown near Brisbane or Newcastle, multiple crews may work within the same boundary while production systems are being reconfigured. The dynamic assessment needs to consider interfaces between teams, not just the hazards of one activity.
If the revised risk is not tolerable, the correct decision is to stop, make the area safe and escalate. Production pressure, a delayed spare part or a narrow outage window cannot justify bypassing a critical control. A short delay is easier to manage than an injury, release, fire or uncontrolled plant event.
Communicate And Record The Decision
A dynamic assessment only works when the people exposed to the risk understand the decision. Hold a focused pre-start or point-of-work discussion covering the changed condition, hazards, controls, individual responsibilities and stop-work triggers. Use site terminology that everyone understands, especially where teams include labour hire workers, international contractors or people with different levels of English proficiency.
The person leading the discussion should invite challenge. Workers often notice practical problems that are missed in formal planning: an access gate that will not open, a radio dead zone, a drain that cannot handle wash-down water or a lifting path blocked by temporary materials. Listening to these observations is a control in itself.
Record the decision in the site’s approved system. Depending on the task, this may involve updating the JSA, SWMS, permit, isolation certificate, shift log, digital field form or toolbox talk record. The record should show what changed, what controls were added, who was consulted and who authorised the work. It should be concise enough to use at the job location.
Good records support handover between shifts. This matters in 24-hour operations, remote mining camps and extended maintenance outages. A night crew should not have to reconstruct why a temporary barrier, gas monitor or exclusion zone was introduced. If the control is temporary, identify who will remove it and what must be checked first.
Use Stop-Work Triggers And Review Controls
Workers need clear authority to stop work without fear of blame. A stop-work trigger may include an unexpected odour, alarm, pressure change, loss of communication, failed gas test, unauthorised person entering the exclusion zone, lightning nearby or a control that cannot be maintained. The team should know whether to withdraw to a muster point, isolate equipment, contact control or wait for a supervisor.
A practical dynamic assessment can use this sequence:
- Stop and move to a safe position
- Describe the change and identify exposed people
- Recheck isolations, permits, equipment and environmental conditions
- Select controls, communicate them and obtain required approval
Review is required after the task as well as during it. Ask whether the controls worked, whether the original assessment missed anything and whether the event reveals a wider plant or system issue. A near miss involving an unexpected residual pressure, for example, may require changes to isolation standards, training, drawings or maintenance planning.
Training should include realistic scenarios rather than relying only on classroom definitions. A live-process-plant environment allows trainees and apprentices to practise identifying changing conditions, communicating with a control room, applying permits and making a safe stop. Industrial training providers such as HCF CATCH use practical environments to connect safety theory with the decisions workers face around process, energy, engineering and electrical systems.
Organisations can also use facility tours, incident reviews and emergency exercises to build familiarity before an unplanned event occurs. This is valuable for employers bringing new contractors onto a site or preparing teams for seasonal conditions. In Australia, heatwaves, tropical storms in northern regions, dust at remote sites and sudden changes in bushfire risk may all require controls to be reviewed during a shift.
Build Dynamic Thinking Into Everyday Work
Dynamic risk assessment is most effective when it becomes normal work practice rather than an emergency form completed after a problem appears. Supervisors should reinforce that pausing is a professional decision, and managers should measure the quality of hazard controls rather than rewarding teams simply for finishing quickly.
Employers can strengthen the process by making sure workers have access to current procedures, reliable communications, suitable monitoring equipment and competent supervision. They should also check that contractors understand local permit systems, isolation standards, emergency arrangements and stop-work expectations before beginning work.
For trainees, apprentices and experienced tradespeople alike, the core skill is recognising when the original plan is no longer reliable. A changed condition requires fresh attention, not automatic continuation. Practical exercises, coaching during maintenance and short post-task reviews help turn that principle into dependable behaviour.
HCF CATCH supports industrial employers and workers through hands-on training in a realistic operational setting. Organisations seeking to improve how teams respond to changing conditions can explore relevant courses, arrange practical development or discuss training needs with the centre. Build the confidence to identify hazards early, pause safely and control unplanned work before it becomes an incident.