Dynamic Risk Assessment on Irish Construction Sites: When and How to Update Your Assessments
A risk assessment prepared before work begins may not reflect conditions as they change on site.
# Dynamic Risk Assessment on Irish Construction Sites: When and How to Update Your Assessments Risk assessments are a legal requirement on Irish construction sites. Most contractors understand this and have risk assessments in place for their standard work activities. What many do not fully appreciate is that a risk assessment is not a one-time exercise. Conditions on construction sites change constantly, and a risk assessment that was accurate when it was prepared may no longer reflect the actual risks on site. This is where dynamic risk assessment comes in. ## What Is Dynamic Risk Assessment? Dynamic risk assessment is the continuous process of identifying and managing hazards as they arise during the course of work. It is the mental process that every experienced worker carries out instinctively when they arrive on site and assess whether conditions are as expected. The difference between informal hazard awareness and a proper dynamic risk assessment is that the latter is structured, documented, and acted upon. Dynamic risk assessment does not replace the formal risk assessment that must be prepared before work begins. Rather, it supplements it. The formal risk assessment identifies the foreseeable hazards and the planned control measures. Dynamic risk assessment identifies changes to those hazards and triggers a review of the control measures when circumstances change. ## The Legal Basis The Safety, Health and Welfare at Work Act 2005 requires employers to assess the risks to the safety, health and welfare of their employees and to implement appropriate control measures. Critically, Section 19 of the Act requires the risk assessment to be reviewed when there is reason to believe that it is no longer valid or when there has been a significant change in the matters to which it relates. This review obligation is the legal basis for dynamic risk assessment. If conditions on site change in a way that affects the validity of the existing risk assessment, the employer must review and update the assessment. Failure to do so, and failure to implement appropriate control measures in response to changed conditions, is a breach of the Act. The Construction Regulations 2013 reinforce this by requiring contractors to provide the PSCS with relevant information about the risks their work creates. If those risks change during the course of the work, the contractor must update the information they have provided. ## When Should a Risk Assessment Be Reviewed? The formal risk assessment should be reviewed in the following circumstances. **After an accident or near miss.** Any accident or near miss is evidence that the existing risk assessment may not have adequately identified or controlled the risks. The risk assessment must be reviewed to determine whether the accident or near miss was foreseeable and whether the control measures were adequate. **When conditions change.** Construction sites are dynamic environments. Ground conditions can change as excavation progresses. Weather conditions can deteriorate. Adjacent structures can become unstable. New contractors can introduce new hazards. Any significant change in conditions should trigger a review of the relevant risk assessments. **When the scope of work changes.** If the work changes in a way that introduces new hazards or changes the level of risk, the risk assessment must be updated before the new work begins. This is particularly important when additional work is added to a contract after the original risk assessments have been prepared. **When new information becomes available.** If new information becomes available about a hazard, for example if a survey reveals the presence of asbestos that was not previously known, the risk assessment must be updated to reflect this. **At regular intervals.** Even if none of the above triggers apply, risk assessments should be reviewed at regular intervals to ensure they remain current. On a long construction project, a review every three to six months is good practice. ## The Dynamic Risk Assessment Process Dynamic risk assessment on a construction site involves the following steps. **Observe.** Before starting work each day, and throughout the working day, workers and supervisors should observe the site conditions and compare them with the conditions assumed in the risk assessment. Are the access routes clear? Is the ground stable? Are the weather conditions as expected? Are there any new hazards that were not present when the risk assessment was prepared? **Assess.** If conditions have changed, assess the significance of the change. Has the level of risk increased? Are the existing control measures still adequate? Is it safe to proceed? **Act.** If the existing control measures are no longer adequate, implement additional controls before proceeding. This might mean stopping work, installing additional edge protection, changing the sequence of work, or briefing workers on a new hazard. **Record.** Document the change in conditions, the assessment of the risk, and the action taken. This does not need to be a lengthy document. A brief note in the site diary, a completed dynamic risk assessment form, or an update to the existing risk assessment is sufficient. **Communicate.** Ensure that all workers affected by the change are informed. A brief toolbox talk is an effective way to communicate changes in risk and control measures to the workforce. ## Practical Examples on Construction Sites Understanding dynamic risk assessment in the abstract is one thing. Seeing how it applies in practice is more useful. Here are some common scenarios on Irish construction sites where dynamic risk assessment is required. **Deteriorating weather.** A team is working on a scaffold in fine conditions. During the morning, the wind picks up significantly. The supervisor must assess whether the wind speed has reached the level at which work on the scaffold should stop. If it has, work must stop and workers must descend safely. The decision must be made before the conditions become dangerous, not after a worker has been blown off the scaffold. **Unexpected ground conditions.** An excavation is progressing according to plan when the excavator operator notices that the ground is softer and wetter than expected. The supervisor must assess whether the existing shoring is adequate for the changed ground conditions. If it is not, work must stop and the shoring must be upgraded before excavation continues. **Adjacent work creating new hazards.** A sub-contractor starts overhead work in an area where another trade is working below. The supervisor must assess whether the overhead work creates a risk of falling objects for the workers below. If it does, the area below must be cleared, or overhead protection must be installed, before the overhead work continues. **Discovery of an uncharted service.** An excavator strikes an uncharted underground cable. Work must stop immediately. The area must be made safe. The cable must be identified and isolated before excavation resumes. The risk assessment for the excavation must be updated to reflect the presence of the cable. **Change in the number of workers.** A task that was assessed for two workers is now being carried out by four workers in the same space. The supervisor must assess whether the increased number of workers creates additional risks, for example through increased congestion in a confined space or increased manual handling loads. ## Toolbox Talks as a Dynamic Risk Assessment Tool Toolbox talks are an effective way to communicate the results of dynamic risk assessments to the workforce. A brief toolbox talk at the start of the working day, covering any changes in conditions or new hazards identified since the previous day, ensures that all workers are aware of the current risk picture before they start work. Toolbox talks should be documented. Record the date, the topic covered, and the names of the workers who attended. This documentation demonstrates that you are actively managing safety and communicating risk information to your workforce. ## The Difference Between Dynamic Risk Assessment and Stopping Work Dynamic risk assessment is not a reason to stop work at the first sign of any change in conditions. It is a process for assessing whether changed conditions require a change in control measures. In many cases, the assessment will conclude that the existing control measures are still adequate and work can continue safely. The key is to make the assessment consciously and to document it. A supervisor who observes a change in conditions, assesses that the existing controls are still adequate, and continues work has carried out a dynamic risk assessment even if they did not use that term. The problem arises when changes in conditions are not noticed, or when they are noticed but not assessed, and work continues without any consideration of whether the existing controls are still adequate. ## Building Dynamic Risk Assessment into Site Culture The most effective way to implement dynamic risk assessment on a construction site is to build it into the site culture. This means training supervisors and workers to observe, assess, and act on changes in conditions as a matter of routine. It means creating an environment where workers feel comfortable raising concerns about changed conditions without fear of being dismissed or pressured to continue working. Morning briefings, end-of-day debriefs, and regular toolbox talks all contribute to a culture of continuous risk awareness. When workers understand why dynamic risk assessment matters and how to carry it out, it becomes part of how they work rather than an additional administrative burden. If you need support with risk assessment training, site safety management, or PSCS services for your construction project in Leinster, Safety Check can help. Contact us to discuss your requirements.