Crushing Hazard in Construction & Demolition

A crushing hazard arises wherever high forces act in a confined space and body parts can become trapped between moving and fixed components. In the practice of concrete demolition, interior demolition, rock excavation, tunnel construction and natural stone extraction, hydraulically operated tools and attachment equipment are central work resources. These include, among others, concrete demolition shear as well as Rock Splitters, complemented by hydraulic power pack, hydraulic demolition shear, rock wedge splitter cylinders, Multi Cutters, steel shear and tank cutters. The specific combination of material (concrete, natural stone, steel), energy source (hydraulic pressure) and work environment (construction site, industrial hall, underground tunneling) makes the systematic control of the crushing hazard a core task of occupational safety – from planning through operation to maintenance.

Definition: What is meant by a crushing hazard

A crushing hazard is the risk of body parts being crushed between fixed and/or moving parts. Typical crushing points are gripping, cutting and pressing zones, shear points, infeed and clamping points, but also transfer points where workpieces rest, are shifted or held. In applications with hydraulic demolition and splitting tools, these hazards arise in particular at the jaw areas of the concrete demolition shear, at splitting wedges and cylinders of rock and concrete splitter devices, at joints, bolts, hinges, as well as between the workpiece and the ground. Crush injuries can be triggered by intended movements (opening, closing, splitting) or by uncontrolled events (secondary breakage, slippage, rebound, follow-on movement due to residual pressure).

Causes and typical scenarios

Crushing risks arise from the interaction of tool motion, material behavior and human intervention. With a concrete demolition shear, the danger lies in the gripping and cutting area, when re-positioning on edges and when holding components by hand. With rock and concrete splitter devices, expansion in boreholes, the formation and propagation of cracks, and the sudden release of stresses play a role. Additional triggers include restricted visibility, time pressure, tight spaces, slippery surfaces, inadequate support and residual energies in the hydraulic system that can cause unexpected movements.

Hazard analysis and systematically identifying sources of risk

A robust hazard analysis links the characteristics of the tool with the behavior of the material and the specific work environment. Crushing points are identified, directions and speeds of movement are assessed, energies and load paths are analyzed, and safe operating positions are defined.

Steps of the assessment

Describe the task and workflow: tool, material, carrier/handheld, location, weather, spatial constraints, visibility.
Locate crushing, clamping and shear points: jaw areas, splitting zones, joints, bearing and holding points, transfer points.
Record energy sources and residual energies: hydraulic pressure, gravitational loads, spring and clamping forces, potential secondary breakage.
Assess material behavior: crack paths, influence of reinforcement, layers, joints, concealed inserts.
Plan load and movement paths: shoring, cribbing, keep zones clear, define safe escape and retreat routes.
Regulate communication: unambiguous hand signals, clear roles, releases, stop signals.
Set limits: operating pressure, feed, opening and closing speed, approach distances.

The risk profiles differ: A concrete demolition shear generates dynamic gripping and shear movements, whereas rock and concrete splitter devices trigger controlled but powerful expansion in the borehole that propagates through the component. Both require reliable shoring, stable positioning and consistent exclusion zones.

Safety measures and technical protection principles

An effective approach is a layered concept of technical, organizational and person-related measures, adapted to the tool, application area and team.

Technical measures

Guarding and distance: spatially separate crushing points, guard where possible; define minimum distances.
Control movements: gentle start and closing movements, demand-driven pressure and speed limiting.
Shore and crib: secure workpieces, prevent tipping and sliding movements, relieve load paths.
Isolate energy safely: before maintenance and setup, release hydraulic pressure, lock out to prevent restart.
Check connections: inspect couplings, hydraulic hose lines and bolts before use; use leak-free, correctly locked connections.

Organizational measures

Define exclusion zones: only operating personnel in the work area, keep others away.
Clarify roles: operator, signaler, supervisor – no dual roles during critical phases.
Use clearances: start, re-positioning, change of position only after explicit feedback.
Standardize workflows: sequence for gripping, separating, setting down; emergency stop rules.

Person-related measures

Operator training: tool principle, crushing points, safe hand and foot positions.
Personal protective equipment: hand protection with suitable grip, safety footwear, hard hat, eye and hearing protection – according to the hazard analysis.
Observe ergonomics: keep the body out of swing and shear areas, stable stance, no hand guidance within crushing zones.

Special notes on concrete demolition shear

Concrete demolition shear combines gripping, crushing and shearing movements. The risk is not only between the jaws, but also at flanks, joints, and at the interface between component and ground. Reinforcement can suddenly give way after cutting or become tensioned.

Practical aspects

Never help position within the gripping area; do not align components by hand while the tool is moving or under pressure.
When re-seating on edges, expect uncontrolled secondary breakage; add shoring in good time.
Factor in reinforcement bundles and concealed inserts; residual stresses can shift components unexpectedly.
Select gripping and set-down points so that the load is stable and no finger/foot areas are endangered.

Special notes on rock and concrete splitter devices

Rock and concrete splitter devices as well as rock wedge splitter cylinders create controlled cracks by expansion in boreholes. Crush injuries occur at wedge and bearing zones and due to the sudden release of stresses in the workpiece.

Practical aspects

Keep hands and body out of the crack line; assess probable chip direction and separation faces in advance.
Shore and hold down the workpiece so the crack propagates in the planned direction.
Only pressurize wedges and cylinders once they are seated correctly; no re-gripping under load.
Expect secondary breakage: the crack can continue after pressure release; maintain the exclusion zone.

Areas of application: crushing risks in context

Concrete demolition and special demolition

Components are under restraint; reinforcement holds elements together and can trigger sudden movements. This is typical in concrete demolition and deconstruction contexts.
Crushing points exist between tool and component, but also when setting down on supports or during repositioning.

Interior demolition and cutting

Confined spaces, varying materials, concealed inserts: increased risk due to restricted escape routes.
Do not hand-guide small, seemingly light parts during cutting and separating.

Rock excavation and tunnel construction

Layering, joints and water ingress influence crack paths; plan for secondary breakage and block movements.
Crushing points during positioning in niches and pre-cuts, especially for overhead or wall work.

Natural stone extraction

Large blocks and uneven ground create rolling and tipping hazards; plan cribbing and wedging carefully.
Do not place splitting tools between block and foundation until secure shoring is in place.

Special operation

Unclear material conditions and special situations require conservative parameters, expanded exclusion zones and additional communication.

Hydraulic power pack, lines and pressure: controlling movements safely

Hydraulic power units provide the energy for tools such as concrete demolition shear and rock and concrete splitter devices. Pressure fluctuations, residual pressure and leaks can promote unexpected movements and activate crushing points.

Completely release pressure before conversion and maintenance work; use locks, secure against restart.
Route hoses without kinks or abrasion; avoid tripping and infeed points.
Connect and disconnect couplings without tension; after coupling, briefly check depressurized, then apply load.
After start-up, begin at low speed and control tool movement before applying load.

Work equipment inspection, maintenance and servicing

The condition of the work equipment directly influences the crushing hazard. Play in joints, worn jaws, deformed wedges or leaks change movement sequences and force transmission.

Before use: visual inspection of jaws/cutting edges, wedges, bolts, shoring elements, hose lines, couplings.
Function test without load: observe opening/closing, pressure build-up, holding capacity.
Observe wear limits: service tools in good time or replace components.
After exceptional events (jamming, overload, impact) document an additional inspection.

Positioning, hand grips and material handling

Hand position and stance often decide between safety and crush injury. Keep hands out of crushing and shear areas at all times; do not hand-guide workpieces while the tool is applied or moving.

Define safe gripping points and supports; place wedges/cribbing so that no re-gripping in danger zones is required.
Keep the retreat path clear; stand laterally offset from the main direction of movement.
Position small parts with suitable aids (tongs, grippers, distance holders) instead of by hand.

Communication, instruction and teamwork

Clear communication can significantly reduce crushing hazards. Signaler and operator need unambiguous signals, clear roles and stop rules. Instructions should cover tool principles, specific crushing points, safe distances, shoring techniques and emergency procedures. New team members are briefed on site specifics; language barriers are bridged with simple hand signals and read-back confirmations.

Documentation and organizational framework

Requirements for occupational safety, operating instructions and applicable regulations form the basis for planning and execution. Documented hazard analyses, training records and inspection protocols create binding force and facilitate effectiveness control. Information and notes from Darda GmbH on products must be taken into account in planning, operation and maintenance. Legal requirements may vary by country and application environment; implementation is carried out generally and with sound judgment for the specific case.

Identify typical crushing points

Tool-side crushing points

Gripping and cutting areas of concrete demolition shear, hydraulic demolition shear, Multi Cutters, steel shear, tank cutters.
Splitting wedges, wedge slides and cylinders on rock and concrete splitter devices and rock wedge splitter cylinders.
Joints, bolts, hinges; parallel surfaces that approach each other.

Workpiece and environmental influences

Bearing points between component and ground, setting down on cribbing and supports.
Secondary breakage lines, crack extensions, spalling edges and the interaction with reinforcement.
Tight niches, proximity to walls and ceilings, overhead work with limited retreat options.

Weather, visibility and environmental conditions

Moisture, dirt, dust, darkness and noise impair perception and surefootedness. Lighting, slip-resistant pads and clean footholds improve control over tool and workpiece. In cold and heat, glove grip changes; appropriate selection and replacement are a simple but effective contribution to prevention.

Planning the work sequence: from initial approach to setting down

Select approach points: stable zones, clear load paths, free crack lines.
Shore and crib: prevent tipping, rolling and sliding.
Reduce exposure time: approach, grip/split, step back – each step with clearance.
Re-position only after clearance: announce movements, visual contact or confirmed signals.
Set down in a controlled and flat manner: do not place finger or foot areas under load.

Emergency preparedness for crushing incidents

Despite caution, crush injuries can occur. Before starting work, clarify alerting, first-aid procedures, access routes for emergency services and aids (e.g., suitable lifting and cribbing aids). Measures are carried out carefully and with attention to self-protection; protecting additional persons has priority.