Dynamic Risk Assessment (UK)

A dynamic risk assessment is the on the spot judgement a worker makes when a job or a site changes in a way the written assessment did not foresee. It does not replace your paperwork. It is the thinking that keeps people safe in the moments between the planned assessment and the real conditions in front of them.

What it means in plain terms

Most risk assessments are written in advance, in the office, for a job as you expect it to be. A dynamic risk assessment is different. It is the continuous process of spotting, judging and acting on risk while the work is actually happening, when something on the ground is not what the written assessment assumed. A delivery blocks your access route, the weather turns, a wall you were about to drill into turns out to carry a live cable. Nobody can write all of that down beforehand, so the law expects a competent worker to reassess as they go.

Where it is used

Dynamic assessment matters most where conditions change quickly or cannot be fully predicted: lone workers, carers visiting homes, emergency services, security staff, and trades arriving on an unfamiliar site. It is widely taught in the fire and ambulance services and has spread into construction and facilities work for the same reason, that the person on site is often the only one who can see the hazard in time.

The law behind it

There is no regulation that uses the words dynamic risk assessment, but the duty is clear. The Management of Health and Safety at Work Regulations 1999 require assessments to be suitable and sufficient and to be reviewed when they are no longer valid or the work has changed significantly. Reassessing on the spot is how you meet that duty in real time. It sits on top of, and never instead of, the written assessment you did beforehand.

A simple way to do it on site

1. Observe. Before and during the task, look at what has actually changed from the plan: the environment, the people, the equipment, the time pressure.
2. Think. Judge whether the existing controls still hold. If the hazard is new or worse, decide what will reduce it.
3. Act. Put the control in place, stop the job, or get help. If you cannot make it safe, you stop and escalate. Stopping is always a valid outcome.

Do you have to record it?

By its nature much of a dynamic assessment happens in the moment and is not written down as it occurs. Good practice is to capture anything significant afterwards: what changed, what you decided, and any control you added, noted against the job. That record shows a client or an inspector that your people are trained to reassess, and it feeds back into updating the written assessment for next time.

Start from a solid written assessment

Dynamic assessment only works when it is backed by a proper written one that sets the baseline. Our guide to writing a risk assessment covers the five steps, and the editable risk assessment template gives you the format clients recognise, with space to note the on site reviews your team makes.