Mobile cranes bring high-risk, high-change operations into busy worksites. The difference between a tidy lift and a near-miss is usually the quality of the exclusion zone: how it’s planned, who guards it, and how it copes with pressure from deliveries, pedestrians, and programme noise. Good zones aren’t just tape lines; they deal with slew, collapse potential, swing of the load, and the full travel path to the landing point. They are treated as live plant areas that flex with weather and sequencing, not a one-off setup left to fend for itself.
TL;DR
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– Map the crane’s footprint, collapse potential and the entire load path; zone for where the load could go if it swings or drops, not just where it should go.
– Use physical barriers that survive wind and crowding; tape alone is not an exclusion control.
– Brief every interface: slinger/signaller, lifting supervisor, traffic marshal, deliveries and adjacent trades; close crossings and set up alternatives.
– Control change: wind, re-rigging, extra deliveries and public interface trigger a pause and re-brief.
– Hold the line during the lift: one point of command, active marshals, and a clean, diversionary route for people and plant.
Staged controls for crane exclusion zones
# Plan the lift geometry and ground conditions
/> Start by fixing the basics on a drawing: crane position, outrigger spread, slew radius, jib length and the intended load path and landing area. Treat the ground as a temporary works issue: confirm bearing capacity, protection against soft spots and voids, and proximity of buried services with clear permits. Identify overhead power lines and adjacent structures that could be struck if the load deviates. The appointed person should set tolerances for wind, visibility and ground condition triggers that will pause the lift.
# Define the lines that keep people out
/> Create two zones. The primary zone wraps the crane’s footprint, outriggers and counterweight tail swing. The secondary zone follows the load path from pick-up to landing, including a buffer for potential swing, bounce and oversail. Where oversail crosses routes or workfaces, provide either physical segregation and controlled crossings or move the route. Near the public, extend the buffer and use solid barriers at open edges and footways.
# Install barriers and signage that survive the shift
/> Use robust barriers – Heras with ballast blocks, crowd control barriers or scaffold tubes – joined with no gaps, especially where the public or multiple trades pass nearby. Add lockable gates at slinger entry points rather than leaving removable sections. Sign clearly: “No entry – crane operations”, direction of alternative routes and named contact for the lifting supervisor. Use tape or paint only to supplement physical controls, never as the primary measure.
# Control people and plant interfaces
/> Set a single command channel: the lifting supervisor directs the lift, the slinger/signaller controls hooks, and the traffic marshal owns crossings and diversions. Keep plant out of the secondary zone unless it is part of the lift. When loads pass over or near routes, stop movements and clear people early; don’t rely on last-second whistles. If deliveries arrive mid-lift, hold them at a waiting area and bring them in only when the zone can be safely adjusted and re-briefed.
# Run the lift and hold the line
/> Before starting, carry out a face-to-face brief at the barrier line with everyone who could enter or pressure the zone. Monitor wind and visibility and record hold points, especially before slewing across interfaces. Keep housekeeping sharp inside the zone: no loose materials, no trip hazards, no spare operatives waiting around. PPE is only a last line; the real control is not having people beneath or beside a moving or suspended load.
# Adapt safely when conditions change and wrap-up
/> If the crane needs re-rigging, the load path shifts, or wind picks up, treat it as a change: stop, clear the zone, update barriers and re-brief. When the lift finishes, keep zones live until hooks are parked, outriggers are stowed and mats are either removed or made safe. Record lessons learned: which crossings worked, where people pressed barriers, and whether your alternative routes actually carried the footfall. Feed those notes into the next appointed person’s plan.
Scenario: tight truss lift on a housing plot
/> A 60-tonne mobile crane arrives at a cul-de-sac housing site on a breezy Thursday. The appointed person has plotted the crane by Plot 14 with outrigger mats signed off through temporary works, but the usual pedestrian route to the welfare block runs straight through the intended load path. The truss delivery lands late, clashing with the school run and a utilities team excavating near the site entrance. The lifting supervisor sets a primary zone around the crane and a secondary zone from the delivery wagon to the roof of Plot 15, with Heras and solid barriers at the footpath edge. A crowd barrier gate is installed at the slinger’s entry point; the traffic marshal diverts welfare access around the back of the plots. Mid-lift, wind gusts touch the agreed limit; the supervisor pauses the lift, clears the zone and waits ten minutes for steadier conditions. The job completes without crossing the zone, and the diverted welfare route stays in place for the rest of the day to avoid constant changes.
Supervisor walk-round checklist for crane exclusion zones
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– Barriers continuous, stable and ballasted, with no informal “shortcuts” or gaps at corners and edges.
– Outrigger mats laid as per the temporary works brief; no spoil heaps, trenches or soft ground encroaching under pads.
– Alternative pedestrian route signed and obvious, with lighting if early or late lifts run in low light.
– Slinger entry gate lockable and controlled; no other site personnel inside the zone unless they are part of the lift.
– Radios tested with a spare set available; air horns or hand signals confirmed as fallbacks.
– Deliveries held at the waiting area with the traffic marshal; no wagons called to the crane unless sequenced in the plan.
Common mistakes to eliminate
# Marking only the slew radius and ignoring the load path
/> The danger often sits under the travelling load, not just around the crane. Zone the full path with a buffer for swing and oversail.
# Relying on barrier tape in windy conditions
/> Tape disappears and invites crossings. Use weighted barriers that can’t be nudged aside by boots or bumpers.
# Letting briefings drift across subcontractors
/> Assuming “word will get round” guarantees gaps. Conduct short, direct briefs at the barrier line for any crew working adjacent.
# Leaving a gap for ‘quick crossings’
/> Any hole becomes the busiest route on site. Provide a controlled, staffed crossing or close it completely and sign a proper alternative.
Short-term push: be lift-ready
# Actions before the next lift slot
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– Map the collapse potential on the lift drawing and carry that line onto the ground with physical barriers, not just paint.
– Ringfence a delivery holding bay outside both zones so late arrivals don’t pressure the barrier line.
– Brief the welfare route change at the morning start-up and position clear directional signage well before the diversion.
– Stagger adjacent noisy or high-movement tasks (e.g. scaffold moves, concrete pours) so they don’t peak during the lift window.
– Audit the communications chain: confirm the lifting supervisor’s authority is understood by traffic, security and gate staff.
Practical bottom line
/> Exclusion zones for mobile cranes succeed when they are treated as live plant areas, not decoration. Draw them from the load’s worst-case behaviour, build them with robust kit, and keep people out through active supervision and credible alternative routes. The pressure points are deliveries, welfare movements and wind; arrange your controls to absorb those without improvisation. Expect closer scrutiny on plant–pedestrian separation and change management where mobile cranes operate near the public realm. Ask at your next briefing: Does our zone follow the load? Where will people go instead? Who has the clout to say stop?
FAQ
# How big should a crane exclusion zone be?
/> There’s no one-size answer because it depends on crane type, jib length, ground, oversail and the nature of the load. As good practice, set a primary zone that covers the crane footprint and tail swing, then a secondary zone that follows the full load path with buffer space for swing and deviation. If the public are nearby, increase your buffer and use solid barriers. Record the rationale on the lift plan or sketch.
# Do we need a permit to set up an exclusion zone for a crane?
/> Most sites control lifting operations through a permit or a specific lift authorisation. The point is to make sure the appointed person’s plan, temporary works for mats, and traffic arrangements are aligned and communicated. Treat the permit as a coordination tool rather than paperwork; if conditions change, pause and update it.
# What barriers are acceptable around a crane?
/> Use barriers that won’t sag or blow over: Heras with ballast, crowd barriers fixed together, or scaffold tube rails. Barrier tape alone is poor practice, especially in wind or where the public might be present. At slinger access points, install a lockable gate so it can’t be casually opened by others. Keep barriers tight to the intended lines to avoid creeping encroachment.
# How do we manage welfare and pedestrian routes during a lift?
/> Plan an alternative route that is shorter or at least no slower than the original, with clear arrows and, if needed, lighting. Announce the change at the start-of-shift briefing and position a marshal initially to guide foot traffic. Never allow ad-hoc crossings through the secondary zone; if a controlled crossing is essential, staff it and stop the lift before letting anyone through.
# What should trigger stopping a lift once it’s started?
/> Common triggers include wind picking up beyond the agreed limit, ground movement under mats, communications failure, people breaching the barrier, or changes to the load path. Build these triggers into the briefing so everyone knows when to call a stop. A short, calm pause to reset the zone is always better than trying to muscle through changing conditions.
