Construction Plant, Vehicles, Lifting and Energy Isolation

Introduction and Context

Construction projects depend on mobile plant, vehicles, cranes, hoists, powered tools, temporary electrical systems and numerous forms of stored energy. These systems improve productivity, but they also create severe hazards. Fatal incidents commonly arise when a worker is struck by a moving vehicle, caught between machine components, crushed by a suspended load, exposed to unexpected energization, or injured by defective tools and electrical installations.

Safety management in this area is therefore more than compliance with equipment rules. It requires a coordinated system of planning, competent operation, inspection, communication, physical separation, maintenance and energy control. The central principle is that work must be designed so that people are not unnecessarily exposed to moving equipment, suspended loads or uncontrolled energy.

This chapter presents the principles used to manage construction plant, vehicles, lifting operations, powered tools, machinery guarding, electrical systems and lockout/tagout. Specific legal requirements vary by jurisdiction; consequently, project teams must apply the relevant occupational safety legislation, electrical codes, lifting regulations, manufacturer instructions and approved standards in addition to the principles described here.

Learning Objectives

By the end of this chapter, students should be able to:

1. Identify struck-by, caught-between, lifting and energy-isolation hazards.
2. Select appropriate controls for mobile plant and construction vehicles.
3. Explain the duties of operators, supervisors, lifting teams and competent persons.
4. Interpret basic lifting information, including load mass, rated capacity and load radius.
5. Develop the main elements of a lifting plan.
6. Apply principles of tool safety, machinery guarding and temporary electrical safety.
7. Describe a reliable lockout/tagout procedure for hazardous energy.
8. Analyse a construction incident and recommend technically and organisationally sound controls.

1. Hazard Families and the Hierarchy of Control

Four hazard families are particularly important:

• Struck-by hazards: contact with a moving vehicle, plant component, flying object, falling object or suspended load.
• Caught-in or caught-between hazards: a person is trapped, compressed or drawn into machinery, excavations, collapsing materials or objects moving toward one another.
• Lifting hazards: uncontrolled movement, overturning, dropped loads, failed rigging, overload, electrical contact or poor communication.
• Energy hazards: electrical, mechanical, hydraulic, pneumatic, gravitational, thermal, chemical and pressure energy that can cause injury after equipment has apparently stopped.

The hierarchy of control should guide decisions. Elimination is preferred, followed by substitution, engineering controls, administrative controls and personal protective equipment (PPE). For example, eliminating the need for a worker to enter a plant movement zone is more reliable than relying only on a high-visibility vest. A physical barrier is generally stronger than a warning sign, although signs and PPE remain useful supplementary controls.

A useful planning sequence is:

1. Define the task and identify all energy sources.
2. Determine who and what can be exposed.
3. Eliminate or separate people from the hazard where possible.
4. Select equipment suitable for the task and environment.
5. Establish operating limits, communication and emergency arrangements.
6. Verify controls before work begins.
7. Monitor conditions and stop work when assumptions become invalid.

2. Mobile Plant and Construction Vehicles

2.1 Selection and suitability

Plant should be selected for the actual duty, ground conditions, access constraints, load characteristics, environmental conditions and operator competence. A machine that can perform a task is not necessarily a machine that can perform it safely. Selection should consider:

• rated capacity and attachments;
• dimensions, turning radius and visibility;
• ground bearing capacity and gradients;
• proximity to excavations, structures and overhead services;
• noise, vibration, emissions and weather exposure;
• maintenance support and availability of replacement parts;
• guarding, alarms, cameras and proximity-detection systems;
• compatibility between attachments and the host machine.

Attachments must be approved for the machine and used within the manufacturer’s limits. Improvised attachments, defective pins or unverified modifications can change stability and load capacity.

2.2 Traffic management

A construction traffic-management plan should establish vehicle routes, pedestrian routes, crossing points, speed limits, delivery areas, reversing controls, parking locations and emergency access. The preferred arrangement is physical separation. Where separation is impossible, the plan should use controlled crossings, barriers, trained signallers and clearly defined communication protocols.

Reversing is a high-risk activity because the operator’s field of view is restricted and workers may enter blind spots. Controls should follow this order:

1. Design the layout to avoid reversing.
2. Use drive-through routes or turning areas.
3. Provide physical segregation and pedestrian exclusion zones.
4. Use cameras, mirrors and other visibility aids.
5. Use a trained signaller when visual or physical controls do not adequately manage the risk.

A signaller must stand in a safe, visible location and use agreed signals. The operator must stop if the signaller is lost from view or if instructions are unclear. Mobile phones and informal gestures should not replace an agreed communication system.

2.3 Operator competence and pre-use inspection

Operators must be trained, authorised and competent for the particular machine and attachment. Competence includes understanding controls, limitations, stability, emergency procedures, inspection requirements and site rules. A licence or certificate alone may not demonstrate competence for a specific machine or site condition.

A pre-use inspection should be proportionate to the equipment and include, where applicable:

• brakes, steering and controls;
• tyres, tracks, wheels and fasteners;
• hydraulic hoses, cylinders and leaks;
• guards, access steps and handrails;
• seat belts or restraint systems;
• lights, horns, alarms and cameras;
• fire extinguisher and emergency equipment;
• forks, buckets, hooks, pins and attachment locks;
• fluid levels and evidence of structural damage.

Defects affecting safe operation must be reported and the machine removed from service until repaired. Defeating an interlock, alarm or guard is unacceptable unless a controlled maintenance procedure specifically requires it and restores the device before operation.

2.4 Stability and ground conditions

Plant may overturn when its centre of gravity moves outside the area bounded by its support points, or when ground failure, slope, dynamic loading or an elevated load creates an overturning moment. Operators and supervisors must consider edge distances, underground voids, recently backfilled areas, wet ground and changing weather. Outriggers require adequately designed support mats or pads where ground pressure could cause settlement.

The simple relationship for a moment is:

where M is moment in newton-metres (N·m), F is force in newtons (N), and d is the perpendicular distance in metres (m) from the reference point. This equation is useful for understanding overturning tendencies, but it is not a substitute for the manufacturer’s load chart or a formal stability calculation. Actual stability also depends on geometry, counterweights, dynamic effects, ground deformation and machine configuration.

3. Lifting Operations and Crane Safety

3.1 Planning and responsibility

Every non-trivial lifting operation should be planned by a competent person. The plan should address the load, crane or lifting appliance, rigging, ground, weather, route, people, communication and emergency arrangements. It should identify who has authority to stop the lift.

Typical roles include:

• Lift planner: selects the method, equipment and controls.
• Crane supervisor or appointed person: coordinates the operation and verifies the plan.
• Operator: operates within the load chart and site instructions.
• Rigger or slinger: selects and attaches suitable lifting accessories.
• Signaller or banksman: communicates agreed movement signals.
• Site supervisor: controls interfaces with other work and maintains exclusion zones.

One person should have clear responsibility for directing the lift. Conflicting signals must result in an immediate stop.

3.2 Load information and capacity

The load mass should be established from reliable information such as drawings, manufacturer data, weighbridge records or a verified calculation. For a regularly shaped homogeneous object, mass may be estimated from density and volume:

where m is mass in kilograms (kg), ρ is density in kilograms per cubic metre (kg/m³), and V is volume in cubic metres (m³). This relationship assumes that density is known and the object’s volume has been correctly determined. Unknown contents, trapped liquids, attachments and packaging must be included.

The total lifted load is not merely the object’s mass. It may include lifting beams, shackles, slings, spreader bars, hooks and other accessories. The crane’s rated capacity depends on configuration and often decreases as load radius increases. The planned load, including relevant lifting accessories, must remain within the applicable capacity shown on the manufacturer’s load chart.

For a simple vertical lift, the gravitational force is:

where W is weight in newtons, m is mass in kilograms and g is gravitational acceleration, approximately 9.81 m/s² near Earth’s surface. Crane capacity is commonly stated as a mass rating, whereas rigging forces and structural forces may be analysed as forces. The units must not be mixed without conversion.

3.3 Sling angles and rigging forces

In a symmetrical two-leg sling arrangement, if the total load is W and each sling leg makes an angle θ with the vertical, the idealised tension in each leg is:

This assumes equal load sharing, a symmetric arrangement, a freely suspended load and θ measured from the vertical. It does not account for bending, friction, unequal leg lengths, impact, damaged equipment or dynamic effects. If the angle is measured from the horizontal, the corresponding trigonometric expression differs; therefore the angle convention must always be stated.

As θ increases, cos θ decreases and sling tension rises. This is why shallow sling angles can create very high forces even when the load mass is unchanged. Sling protection is needed where edges may cut or abrade the sling. Shackles, hooks and lifting points must be compatible, marked, inspected and used in the intended orientation.

Worked Example: Two-leg sling

A 2,000 kg load is lifted with two equal sling legs, each at 30° from the vertical. Ignoring accessories and dynamic effects:

1. Weight: W = 2,000 × 9.81 = 19,620 N.
2. Tension in each leg: T = 19,620 ÷ (2 cos 30°).
3. Since cos 30° ≈ 0.866, T ≈ 11,329 N, or approximately 11.3 kN per leg.

This calculation is an idealised estimate, not a complete rigging approval. The competent person must also verify sling capacity, connection geometry, load stability, edge protection, crane capacity and the effect of accessories.

3.4 The lifting plan

A lifting plan should normally include:

• description, mass, dimensions and centre of gravity of the load;
• crane type, configuration, counterweight and applicable load chart;
• maximum radius, boom length and lift height;
• ground assessment, outrigger arrangement and bearing requirements;
• lifting accessories, working load limits and inspection status;
• travel path, landing location and exclusion zone;
• overhead lines, structures, excavations and other interfaces;
• weather limits, especially wind and lightning;
• communication method and agreed signals;
• trial lift, stop-work criteria and emergency plan.

The load should be raised only enough to verify balance and secure attachment before continuing. No person should stand under a suspended load. Tag lines may help control rotation, but they must not create entanglement or expose workers to the load path.

4. Struck-by and Caught-Between Prevention

Struck-by and caught-between events often result from normal work activities performed in poorly controlled spaces. Examples include a worker between a reversing truck and a wall, a hand caught in a rotating drill, a person crushed by a moving formwork panel, or a worker struck by material ejected from a saw.

Effective controls include:

• physical exclusion zones around moving plant and suspended loads;
• barriers that are strong enough and correctly positioned;
• designated maintenance positions and safe access routes;
• interlocked guards and emergency stops;
• securing of materials against rolling, tipping or falling;
• procedures for line breaking, stored pressure and suspended components;
• prohibition of work beneath unsupported loads;
• adequate lighting, housekeeping and visibility;
• verification that workers understand the machine’s danger zones.

Workers must not place themselves between a moving object and a fixed object unless the task is specifically designed, isolated and controlled. A machine must not be approached merely because its engine is off; residual hydraulic pressure, gravity, stored spring energy or electrical charge may remain.

5. Powered Tools and Machinery Guarding

Powered tools include portable electric tools, pneumatic tools, hydraulic tools, abrasive wheels, cutting equipment and fixed machinery. Selection should match the material, task and environment. A tool designed for dry indoor use may be unsuitable in wet or explosive atmospheres.

Before use, inspect the tool, cable, plug, guard, trigger, battery, hose and accessories. Discs, blades and bits must be compatible with the tool’s speed and intended material. Operators should maintain a stable stance, keep hands outside the line of cut, secure the workpiece and avoid defeating guards.

Guards should prevent access to points of operation, nip points, rotating shafts, gears, belts, pulleys, chains and ejected fragments. A guard must be robust, securely attached and designed so that it does not introduce a new hazard. Emergency stops are supplementary controls; they do not replace isolation and guarding.

Portable tools should be removed from service when damaged. Repairs must be carried out by authorised persons. Users should not tape over a damaged cable, bypass a trigger or continue using a tool because the defect appears minor.

6. Electrical Safety and Temporary Power

Construction electrical systems are exposed to moisture, mechanical damage, movement, dust, changing loads and unauthorised modification. Temporary installations should be designed, installed, inspected and maintained by competent electrical personnel in accordance with applicable electrical codes.

Important controls include:

• suitable supply capacity and overcurrent protection;
• effective earthing or grounding and bonding;
• residual-current protection where required;
• weather-resistant distribution equipment;
• protection of cables from vehicles, sharp edges, water and heat;
• elevated, buried or ramp-protected cable routes;
• lockable distribution boards and controlled access;
• identification of circuits and isolation points;
• periodic inspection and testing;
• prohibition of overloaded adapters and improvised connections.

A residual-current device (RCD), also called a ground-fault circuit interrupter in some jurisdictions, can disconnect a circuit when it detects an imbalance between outgoing and returning current. It reduces risk but does not make contact with live conductors safe, and it does not replace correct earthing, insulation, guarding or isolation.

Electrical work must be performed only by appropriately authorised persons. De-energisation must be verified using a properly rated test instrument. The instrument itself should be proven on a known source before and after testing, following the applicable safe-testing procedure. Testing for absence of voltage is not the same as assuming that a switch is off.

7. Hazardous Energy and Lockout/Tagout

7.1 The concept of zero-energy state

Lockout/tagout (LOTO) is a formal method for preventing unexpected energization, start-up or release of hazardous energy during servicing, maintenance, cleaning, adjustment and repair. Energy sources may include:

• electrical supply and capacitors;
• hydraulic and pneumatic pressure;
• mechanical rotation and flywheels;
• gravity and suspended parts;
• springs and tensioned components;
• thermal energy and steam;
• chemical reactions and stored pressure;
• fuel, batteries and remote control systems.

The goal is not merely to turn equipment off. The goal is to isolate every relevant energy source, secure the isolation, dissipate or restrain stored energy and verify that the equipment cannot operate.

7.2 A robust LOTO sequence

A typical sequence is:

1. Prepare: identify the machine, task, energy sources, isolation points and authorised workers.
2. Notify: inform operators, affected workers and other relevant parties.
3. Shut down: use the normal stopping procedure.
4. Isolate: open disconnects, close valves, block components or otherwise separate the equipment from energy sources.
5. Apply locks and tags: each authorised worker applies a personal lock where the procedure requires personal control.
6. Release or restrain stored energy: discharge capacitors, bleed pressure, lower or block elevated parts, secure springs and allow hot components to cool.
7. Verify isolation: attempt a start from the normal control station and test for absence of energy using an appropriate instrument. Return controls to the off position after the test.
8. Perform work: maintain the isolation and control changes in conditions.
9. Restore safely: inspect the work, replace guards, remove tools, account for personnel, remove locks by their owners, notify affected people and re-energise in a controlled manner.

Verification is the critical step. A lock on one disconnect does not prove that another supply, back-feed, stored pressure or gravity hazard has been controlled.

7.3 Group lockout and shift changes

For group work, a group lockbox or equivalent system can allow each worker to apply a personal lock while the primary isolation remains controlled. The system must clearly identify the responsible coordinator, isolation points, authorised workers and handover arrangements. During shift changes, protection must be continuous; an incoming worker must apply their lock before the outgoing worker removes theirs, or an approved equivalent process must be used.

Tags communicate danger but do not provide the physical restraint of a lock. Procedures for removing another person’s lock must be exceptional, documented, authorised and based on verification that the person is absent and informed before returning to work.

8. Integrated Risk Management and Human Factors

Equipment incidents are rarely caused by a single technical defect. Contributing factors may include production pressure, inadequate planning, unclear authority, poor housekeeping, fatigue, weak supervision, unfamiliar equipment and ineffective maintenance. A mature safety system therefore examines both immediate causes and organisational conditions.

Pre-task briefings should identify the equipment, work zone, energy sources, communication method, exclusion zone and stop-work triggers. Dynamic risk assessment is necessary when weather changes, another contractor enters the area, the ground deteriorates or the load differs from the plan.

Safety-critical communication should use closed-loop communication: the instruction is given, repeated by the receiver and confirmed by the sender. This is particularly valuable for crane signals, electrical switching and plant movements.

9. Technology and Contemporary Practice

Cameras, radar, proximity-warning systems, telematics, digital inspection records and electronic permit-to-work systems can improve hazard detection and accountability. Building information models and three-dimensional site planning can help identify crane envelopes, vehicle routes and interfaces with temporary works.

However, technology has limitations. Cameras may be obscured, sensors may not detect every person, alarms may be ignored, and digital records may create false confidence. Artificial intelligence may assist with video-based detection of people in exclusion zones or unsafe equipment behaviour, but it should be treated as a supplementary control. The employer remains responsible for verifying performance, protecting personal data, managing false alarms and ensuring that workers understand system limitations.

10. Illustrative Case Study: Reversing Vehicle and Temporary Power Interface

Background

A commercial building project used a telehandler to move materials near a temporary distribution board. Pedestrians and delivery vehicles shared a narrow access route. The telehandler had a reversing alarm and camera, but the camera was frequently obscured by dust.

Problem

During a delivery, a worker walked behind the telehandler while the operator reversed toward a storage area. The worker narrowly avoided being trapped between the machine and the distribution-board enclosure. Investigation found that the traffic plan did not define a pedestrian crossing, the signaller role was informal, and the temporary cable route reduced the available clearance.

Analysis

The immediate hazard was the reversing machine. Deeper causes included inadequate layout design, poor separation, reliance on an alarm, lack of a formal reversing procedure and failure to review the temporary electrical installation when site logistics changed. The event also demonstrated an interface hazard: traffic controls and electrical controls had been planned independently, although both occupied the same constrained area.

Approach and solution

The project team:

1. relocated the distribution board and protected the cable route;
2. established a one-way vehicle route and a separate pedestrian route;
3. created a physical barrier and controlled crossing point;
4. prohibited reversing in the area except under a documented arrangement;
5. appointed trained signallers for unavoidable reversing;
6. repaired and cleaned the camera and introduced daily checks;
7. briefed all contractors and audited compliance;
8. reviewed the arrangement after each major change in site logistics.

Outcome

The revised layout eliminated most reversing and separated pedestrians from vehicles. The remaining reversing movements had a defined exclusion zone and a named signaller. The project also incorporated temporary services into its logistics review rather than treating electrical safety as a separate issue.

Learning points

The case illustrates that engineering separation is stronger than warnings, that temporary works and traffic routes must be coordinated, and that alarms and cameras are not substitutes for a safe layout. It also shows why near misses should be investigated before a serious injury occurs.

11. Professional, Ethical and Regulatory Responsibilities

Employers and principal contractors have a duty to provide safe systems of work, competent supervision, suitable equipment and information. Supervisors must not pressure operators to continue when conditions fall outside the plan. Operators and workers must follow procedures, report defects and exercise stop-work authority when an immediate danger exists.

Records commonly include training and authorisation, pre-use inspections, maintenance, lifting plans, equipment examinations, electrical test results, permits, LOTO registers and incident investigations. Records support assurance but cannot compensate for defective equipment or unsafe behaviour.

Ethically, production targets cannot justify exposing workers or the public to foreseeable serious harm. Procurement decisions should consider lifecycle safety, maintainability, spare parts, emissions, noise and operator ergonomics rather than initial price alone. Regulatory compliance is the minimum standard; professional practice seeks reasonably practicable risk reduction beyond minimum compliance when significant hazards remain.

Challenges and Limitations

Several challenges complicate control of construction plant and energy:

• rapidly changing work areas and temporary routes;
• multiple contractors with different procedures;
• incomplete information about buried services or load mass;
• pressure to maintain production;
• variable ground and weather conditions;
• ageing or hired equipment with uncertain history;
• language and communication barriers;
• overreliance on alarms, paperwork or digital systems.

No single control is universally effective. A lifting plan may become invalid when the crane radius changes; a traffic barrier may be moved for access; and a LOTO procedure may fail if an energy source is omitted. Continuous verification and competent supervision are therefore essential.

Chapter Summary

Safe management of construction plant, vehicles, lifting equipment and energy systems depends on planning, competent people, suitable equipment and effective physical controls. Struck-by and caught-between hazards are best controlled through elimination, separation, guarding and clearly managed interfaces. Vehicle routes should minimise reversing and physically separate pedestrians wherever possible.

Lifting operations require verified load information, suitable equipment, competent roles, load-chart compliance, inspected rigging, controlled communication and exclusion zones. Basic relationships such as m = ρV, W = mg and M = F × d help students understand load and stability principles, but they do not replace manufacturer data or a competent engineering assessment.

Powered tools require inspection, correct accessories and effective guarding. Temporary electrical systems need competent design, protection, inspection and protection from mechanical and environmental damage. Lockout/tagout must control every hazardous energy source, including stored and gravitational energy, and must include verification before work begins. Technology can strengthen controls but cannot replace sound layout, supervision and worker authority to stop unsafe work.

Key Terms

Hazardous energy: Energy that can cause injury through unexpected release or movement.

Struck-by hazard: Risk of being hit by a moving, falling or ejected object.

Caught-between hazard: Risk of being crushed, trapped or drawn between objects or machine parts.

Mobile plant: Self-propelled or towable machinery used for construction activities.

Competent person: A person with appropriate knowledge, training, experience and authority for the task.

Rated capacity: Maximum permitted load under specified equipment and operating conditions.

Load radius: Horizontal distance from the crane’s reference axis to the load centre or lifting point, as defined by the manufacturer.

Lifting plan: Documented method for safely organising a lifting operation.

Sling angle: Angle of a sling leg measured from a stated reference, commonly the vertical or horizontal.

Working load limit: Maximum permitted working load for a lifting accessory in specified conditions.

Exclusion zone: Area from which unauthorised people are kept away from a hazard.

Signaller: Competent person who directs plant or lifting movements using agreed communication.

Guard: Physical protective device that prevents access to dangerous machine parts.

Interlock: Device that prevents or interrupts operation when a guard or condition is unsafe.

Temporary power: Electrical supply and distribution installed for construction activities.

Residual-current device: Protective device that disconnects a circuit when current imbalance indicates leakage.

Lockout/tagout: Procedure for isolating and securing hazardous energy before servicing or maintenance.

Stored energy: Energy remaining after normal shutdown, including pressure, gravity, springs and capacitors.

Zero-energy state: Condition in which hazardous energy has been isolated, released or restrained and verified.

Review Questions

5 Short Answer Questions

1. What is the difference between a struck-by hazard and a caught-between hazard?
2. Why is physical separation preferred in construction traffic management?
3. Name four items that should be checked during a mobile-plant pre-use inspection.
4. Why does sling tension increase as the sling angle becomes shallower?
5. What is the purpose of verifying isolation during lockout/tagout?

5 Long Answer Questions

1. Explain how the hierarchy of control can be applied to reversing vehicles on a congested construction site.
2. Describe the responsibilities of the lift planner, crane operator, rigger and signaller during a lifting operation.
3. Discuss the main design and maintenance requirements for temporary construction power.
4. Explain why machinery guarding and emergency stops are complementary rather than interchangeable controls.
5. Describe a complete lockout/tagout procedure, including stored-energy control and restoration to service.

3 Analytical / Application Questions

1. A 1,500 kg load is lifted using two equal sling legs at 45° from the vertical. Calculate the idealised tension in each leg using T = W ÷ (2 cos θ), and identify at least four additional checks required before approving the lift.
2. A site has frequent near misses involving dump trucks, pedestrians and temporary cable ramps. Analyse the likely systemic causes and propose an integrated redesign of the traffic and power arrangements.
3. During maintenance, a machine is switched off and electrically isolated, but its hydraulic ram supports an elevated component. Explain why the equipment is not yet safe and develop the additional isolation and verification steps required.

Multiple Choice Questions with Answers

Question 1

Which control is generally most reliable for preventing pedestrians from entering a vehicle operating zone?

A. A warning sign alone

B. A high-visibility vest

C. Physical separation with controlled access

D. An instruction to be careful

Correct Answer: C. Physical separation with controlled access

Question 2

In the idealised two-leg sling relationship T = W ÷ (2 cos θ), θ is measured from which reference in this chapter?

A. The horizontal plane

B. The vertical

C. The crane boom

D. The ground support mat

Correct Answer: B. The vertical

Question 3

A 1,000 kg load has a weight of approximately what value near Earth’s surface, ignoring accessories?

A. 98.1 N

B. 981 N

C. 9,810 N

D. 98,100 N

Correct Answer: C. 9,810 N

Question 4

What should an operator do if a signaller disappears from view during a reversing movement?

A. Continue at reduced speed

B. Stop until communication is restored

C. Follow the last signal received indefinitely

D. Sound the horn and continue

Correct Answer: B. Stop until communication is restored

Question 5

Which statement about an RCD is correct?

A. It makes contact with live conductors safe

B. It replaces the need for earthing and insulation

C. It can disconnect a circuit when it detects current imbalance

D. It permits overloaded temporary wiring

Correct Answer: C. It can disconnect a circuit when it detects current imbalance

Question 6

Which action is part of verifying lockout/tagout?

A. Assuming the isolation is effective because the switch is labelled

B. Attempting a start and testing for absence of energy using an appropriate instrument

C. Removing all machine guards before isolation

D. Applying a warning sign without isolating the supply

Correct Answer: B. Attempting a start and testing for absence of energy using an appropriate instrument

Question 7

Why must a lifting plan consider load radius?

A. Crane capacity can depend on the distance of the load from the crane’s reference axis

B. Radius determines the colour of the crane

C. Radius eliminates the need to know load mass

D. Radius applies only to hand tools

Correct Answer: A. Crane capacity can depend on the distance of the load from the crane’s reference axis

Question 8

Which is an example of stored energy?

A. A completed inspection record

B. A discharged and verified capacitor

C. Pressure remaining in a hydraulic system

D. A painted machine guard

Correct Answer: C. Pressure remaining in a hydraulic system

Question 9

What is the primary purpose of a machinery guard?

A. To increase production speed

B. To prevent access to dangerous moving parts

C. To replace operator training

D. To identify the machine owner

Correct Answer: B. To prevent access to dangerous moving parts

Question 10

If a machine’s attachment is changed, what is the most appropriate safety action?

A. Assume the original inspection remains sufficient

B. Use the attachment if it physically fits

C. Verify compatibility, capacity and secure attachment before operation

D. Remove all warning labels

Correct Answer: C. Verify compatibility, capacity and secure attachment before operation