Short answer
The risks around a working attachment fall into three groups and each travels in a different direction: a flying fragment goes horizontally, falling material goes vertically, and a buried service waits in the direction the attachment is advancing. So no single distance rule covers all three; the zone is set according to the direction of the risk. This guide gives no distance figures, because the right distance depends on the machine, the attachment, the material and local regulation. What it gives is the reasoning: knowing which risk lies in which direction also tells you where to draw the zone.
Flying fragments: horizontal and unpredictable
Fragments thrown by a working breaker do not fly at random; they follow the plane of the break. But because that plane is not known in advance, the outcome is unpredictable in practice. In hard brittle material the throw distance grows; concrete and natural stone deserve particular care.
Protecting the cab is a separate matter and belongs to machine equipment; front screen guards and cab protection structures exist for demolition work. But the zone protects the people outside the cab, not the one inside it.
Which is why the person most at risk is not the operator but whoever stands beside the attachment. The most common mistake on site is two workers working out of the machine’s field of view and close to the breaking face.
Falling material: vertical and delayed
In demolition a broken piece rarely falls at once; it breaks, shifts, and then falls. The interval can be several seconds, and by then the operator has usually moved to another point.
So the zone has to cover not only where the attachment is but the direction the broken structure will fall. In column cutting and floor removal that area is much larger than the attachment itself.
In urban demolition it concerns neighbouring plots as well; together with the vibration and noise side it is covered in its own guide and on the application page.
Buried services: the risk waiting ahead
This risk differs from the other two because it cannot be managed with a zone: if the location of the service is unknown, drawing a zone achieves nothing. It is managed by a services search before work, by marking out, and by hand digging where required.
- Electrical cable: cut by a breaker or ripper, it creates a direct electrical risk for the operator and everyone nearby.
- Gas main: the one with the gravest consequences. You do not put a breaker into the ground without a services search first.
- Water and sewer: less of a danger to life, but cutting one stops the job and makes the excavation unworkable.
- Telecoms and fibre: the hardest to notice; it can be cut without anyone realising and the liability surfaces later.
No distance figure is given here
A safe distance depends on the size of the machine, the type of attachment, the material, the height and local regulation. An invented figure here would be both wrong and dangerous. Take the distances that apply on your site from your machine’s manual, the attachment’s operating instructions and the client’s safety plan.
Do and don’t
Do
- Set the zone by the direction of the risk: fragments horizontal, falls vertical, services ahead.
- Have a services search done before excavation and breaking, and keep the marking visible on site.
- Agree a hand signal language between operator and ground crew in advance; nothing is heard while an attachment works.
- In demolition, bring the fall direction of the broken piece inside the zone.
- Stop the machine for attachment changes and maintenance; no work is done beside a running machine.
Don't
- Do not work beside the attachment and out of the operator’s field of view.
- Do not pass under a piece that has broken but not yet fallen.
- Do not go deep with a breaker or ripper on ground where no services search has been done.
- Do not drop the zone because "the job is short"; a fragment flies on the first blow too.
- Do not stand under or beside an attachment hanging in the air.
The link between operator and ground crew
Voice communication does not work while an attachment is running; the noise drowns both speech and radio. So an exclusion zone is as much a communication question as a distance question.
The arrangement that works is simple: whoever is about to enter the zone first makes eye contact with the operator, the operator stops the attachment and signals that visibly, and only then is entry made. When that order breaks down, the accident happens without any fault in the machine or the attachment.
The second rule is to accept that the operator’s field of view is limited. The bigger the attachment, the bigger the blind spot. The ground crew does not assume it has been seen; it confirms it.