Communication, Signals, and Personnel Lifting

Introduction

Effective communication between the mobile crane operator and the rigger/signaller is a fundamental safety requirement and a skill thoroughly assessed on the Red Seal exam. Accident statistics demonstrate that communication failures cause a significant proportion of lifting incidents. This chapter covers standardized communication systems, official hand signals, personnel lifting procedures, and applicable Canadian regulatory requirements.

1. Roles and Responsibilities of Personnel

1.1 The Crane Operator

The operator is the last link in the safety chain. You must:

Fully understand all signals used on the job site before starting work.

Never obey an ambiguous or incomprehensible signal. When in doubt, stop all movement and ask for clarification.

Refuse to execute a signal that would endanger people or property, even if the signal is correctly given.

Know the crane's capacity and the limits of the load chart (capacity chart) for each configuration.

Maintain constant communication with the signaller, even when the load is not visible.

The operator has the final authority to stop any lift if conditions are judged unsafe. This authority cannot be overridden by the foreman or the rigger.

1.2 The Signaller (Signaller/Rigger)

The signaller is the designated person responsible for directing lifting operations. Their responsibilities include:

Being trained and competent in standardized signal methods (CSA Z150).

Positioning themselves to clearly see the load and the operator, or using an approved alternative communication system.

Knowing the weight of the load and the crane's limits.

Ensuring the lifting area is clear and that workers are outside the danger zone.

Giving clear, precise, and unambiguous signals.

The signaller must never give a signal until the rigging has been verified and secured. They must also wear high-visibility personal protective equipment (PPE).

1.3 The Rigger

The rigger is responsible for slinging and securing the load. Although sometimes the same person as the signaller, the rigger has distinct tasks:

Selecting appropriate slings and accessories based on the weight, shape, and centre of gravity of the load.

Inspecting all lifting equipment before use (slings, hooks, shackles, etc.).

Calculating sling angles and corresponding load factors.

Attaching the load securely and in a balanced manner.

Protecting slings from sharp edges with edge protectors.

2. Communication Methods

2.1 Radio Communication

Radio communication is the most common method on modern job sites. Key requirements include:

Using a dedicated radio channel, free from interference from other crews.

Performing a communication test before starting work.

Using clear, standardized language. The following terms are standardized:

"Hoist": raise the load.

"Lower": lower the load.

"Stop": cease all movement immediately.

"Emergency stop": cease immediately and do not resume without verbal confirmation.

"Swing right" / "Swing left": rotate the boom.

"Boom up" / "Boom down": change the boom angle.

"Extend boom" / "Retract boom": extension or retraction of the telescopic boom.

Golden Rule: The last word spoken is the command to be executed. The operator must repeat the signal to confirm understanding before acting. This verbal confirmation is mandatory in some jurisdictions and strongly recommended everywhere.

2.2 Hand Signal Communication

Hand signals are standardized in Canada according to CSA Z150-18 (Safety Code for Mobile Cranes) . These signals are mandatory when voice communication is not reliable (excessive noise, distance, etc.).

You must know the following signals perfectly:

Signal	Description of Gesture
Hoist	Forearm vertical, index finger pointing up, slow circular motion.
Lower	Forearm down, index finger pointing down, slow circular motion.
Stop	Arm horizontal, open palm facing down, sharp up-and-down motion.
Emergency stop	Both arms raised horizontally, fists clenched, rapid back-and-forth motion.
Swing	Arm horizontal, index finger pointing in the direction of desired rotation, circular motion.
Boom up	Arm horizontal, thumb up, fist clenched, pushing motion upward.
Boom down	Arm horizontal, thumb down, fist clenched, pulling motion downward.
Extend boom	Both hands at waist level, thumbs pointing outward, fists clenched.
Retract boom	Both hands at waist level, thumbs pointing inward, fists clenched.
Crane travel	Open palm facing forward, pushing motion in the direction of travel.
Slow down	One hand above the other, palms facing down, slow flapping motions.

Trap to Avoid: The "stop" signal and the "emergency stop" signal are often confused. The emergency stop (two clenched fists) means an immediate and total stop, used only in situations of imminent danger.

2.3 Rope (Tagline) Communication

In certain situations, communication by pulling on a guide rope may be used. A single pull = stop. Two pulls = hoist. Three pulls = lower. This method is rare and must be pre-defined before starting work.

3. Personnel Lifting

Lifting personnel with a mobile crane is a high-risk operation, strictly regulated. In Canada, the requirements are defined in CSA Z150-18 and in federal and provincial occupational health and safety regulations (which vary, but the Red Seal requires knowledge of general principles).

3.1 Preconditions for Personnel Lifting

Personnel lifting is only permitted when the following conditions are met:

53.No other alternative method (aerial work platform, scaffolding, elevating platform) is reasonably available or feasible.

54.The crane is designed and equipped for personnel lifting, or has been modified according to manufacturer specifications.

55.A written lift plan is prepared and approved, including load calculations, angles, and emergency procedures.

56.The total load (platform + personnel + tools + materials) does not exceed 50% of the rated capacity of the crane in the configuration used (this rule is a requirement of CSA Z150).

57.The hoisting and lowering speed is limited to 0.3 m/s (18 m/min) maximum.

58.Personnel are trained in the use of the platform and emergency evacuation procedures.

3.2 Requirements for the Lifting Platform

The personnel lifting platform must:

Be designed by an engineer and manufactured according to recognized standards.

Have guardrails with a minimum height of 1.0 m (3.3 ft) with a toe board.

Have a slip-resistant floor.

Be equipped with anchor points for safety harnesses.

Have its capacity clearly indicated on a nameplate.

Be attached to the crane hook with a four-leg sling or a swivel attachment device, preventing rotation.

Be equipped with a tagline to control rotation, handled by a person on the ground.

3.3 Requirements for the Operator and Personnel

The operator must have minimum experience and be qualified for this type of operation.

Personnel in the platform must wear a safety harness attached to the platform's anchor point.

No one shall stand under the load or under the platform.

The platform must not be moved over workers on the ground.

Personnel must never enter or exit the platform while it is in motion.

A means of communication (radio or signals) must be maintained between the operator and personnel in the platform at all times.

3.4 Emergency Procedures

The lift plan must include specific emergency procedures:

Crane breakdown: procedure for manual or emergency lowering.

Evacuation: method for evacuating personnel if the crane cannot be operated.

Lost communication: the operator must stop all movement and stabilize the load until communication is restored.

4. Calculations and Load Factors

4.1 Calculating Total Load Weight

The total weight (W_total) is the sum of all elements:

W_total = W_load + W_platform + W_personnel + W_tools + W_slings + W_accessories

Example:

Load: 500 kg

Platform: 300 kg

Personnel (2 people × 100 kg): 200 kg

Tools and materials: 50 kg

Slings and accessories: 30 kg

W_total = 500 + 300 + 200 + 50 + 30 = 1080 kg

4.2 Capacity Limit for Personnel Lifting

CSA Z150 requires that the total load not exceed 50% of the crane's rated capacity in the configuration used.

Required rated capacity ≥ 2 × W_total

In the example above: Required capacity ≥ 2 × 1080 kg = 2160 kg.

If the crane has a rated capacity of 2000 kg at the required radius and height, the lift is prohibited.

4.3 Sling Angle Factor

When slings are used at an angle, the tension in each leg increases. The load factor (F) is calculated as follows:

F = 1 / cos(θ)

Where θ is the angle between the sling and the vertical.

Angle (θ)	Load Factor (F)	Tension per Leg (for 1000 kg load, 2 legs)
0°	1.00	500 kg
15°	1.04	520 kg
30°	1.16	580 kg
45°	1.41	705 kg
60°	2.00	1000 kg
75°	3.86	1930 kg

Rule of Thumb: The angle between two sling legs must never exceed 90° (i.e., 45° from the vertical). Beyond this, the tension becomes excessive and dangerous.

4.4 Calculating Height and Radius

You must verify that the crane can reach the required position with the load. The lifting height (H) and horizontal radius (R) determine the boom configuration. The manufacturer's load chart indicates the maximum capacity for each combination of boom length, angle, and radius.

Basic formula for boom tip height:

H = L × sin(α) + h_base

Where:

L = boom length

α = boom elevation angle

h_base = height of the boom pivot point

Horizontal radius:

R = L × cos(α)

These calculations are essential for verifying that the load can be placed in the desired position without exceeding the crane's limits.

5. Canadian Standards and Regulations

5.1 CSA Z150-18 — Safety Code for Mobile Cranes

This standard is the primary reference for mobile cranes in Canada. The relevant sections for communication and personnel lifting include:

Section 5: Requirements for the operator (training, certification, competence).

Section 7: Requirements for rigging and slings.

Section 8: Safe operating practices, including signals and communication.

Section 9: Personnel lifting (specific requirements detailed above).

Section 10: Inspection and testing.

5.2 Canada Labour Code — Occupational Health and Safety Regulations

The Canada Occupational Health and Safety Regulations (SOR/86-304) contain requirements for mobile cranes in workplaces under federal jurisdiction. Relevant sections include:

Section 14.5: Requirements for signallers.

Section 14.6: Communication of signals.

Section 14.7: Lifting of persons.

5.3 CSA B149.1 — Natural Gas and Propane Code

Although this code does not apply directly to mobile cranes, it is relevant when working near gas pipelines. You must know the minimum clearance distances and safe work procedures near this infrastructure. Work near electrical power lines is governed by other standards, including CSA C22.3 and provincial electrical safety regulations.

5.4 Minimum Distances from Power Lines

CSA Z150 and safety regulations require minimum distances between the crane (including the boom and load) and overhead power lines:

Line Voltage (kV)	Minimum Distance (m)
≤ 75 kV	3.0 m
75 kV to 250 kV	4.5 m
250 kV to 550 kV	6.0 m
> 550 kV	8.0 m (or more, as determined by an engineer)

These distances apply at all times, including during load swing. If the minimum distance cannot be maintained, you must contact the line owner to request a de-energization or protection.

6. Pre-Lift Procedures (Lift Briefing)

Before each lift, a pre-lift briefing must be conducted. This briefing includes:

134.Review of the lift plan: weight, dimensions, centre of gravity, attachment points.

135.Crane inspection: visual inspection, checking fluids, cables, brakes.

136.Check of environmental conditions: wind (typical maximum speed of 14 m/s or 50 km/h for most cranes), rain, snow, visibility.

137.Confirmation of signals: the operator and signaller review the signals that will be used.

138.Hazard identification: power lines, obstacles, danger zones, other workers.

139.Designation of roles: who gives the signals, who guides the load, who is responsible for safety.

The briefing must be documented and signed by all parties involved.

7. Managing Emergency Situations

7.1 Loss of Communication

If communication is lost during a lift:

You must stop all movement immediately.

Stabilize the load (if possible) in a safe position.

Do not resume operations until communication is restored and verbal confirmation is given.

7.2 Excessive Wind

Wind speed must be monitored continuously. Typical criteria:

Wind ≤ 14 m/s (50 km/h) : normal operations (according to the manufacturer).

Wind > 14 m/s : stop personnel lifting operations.

Wind > 20 m/s (72 km/h) : stop all lifting operations, place the boom in the rest position.

The crane manufacturer may specify more restrictive limits. These values always take precedence.

7.3 Contact with a Power Line

In the event of contact with a power line:

155.Do not leave the cab (unless there is an imminent fire).

156.Warn people nearby to stay at a distance.

157.Attempt to break contact by moving the crane if possible.

158.If the crane must be evacuated, jump (do not walk) keeping your feet together, then move away in small steps.

Summary

Communication is a complete system: roles, methods, signals, emergency procedures. Each element must be mastered.

Hand signals are standardized by CSA Z150-18. You must know them perfectly and never execute an ambiguous signal.

Personnel lifting is subject to strict requirements: load limited to 50% of rated capacity, maximum speed of 0.3 m/s, certified platform, mandatory harness, written lift plan.

Load calculations (total weight, angle factor, required capacity) are essential for safety and for the exam.

Minimum distances from power lines are absolute values that must never be compromised.

The pre-lift briefing is mandatory and documented before each operation.

In the event of loss of communication or a dangerous situation, you have the authority and the duty to stop immediately.

Traps to Avoid

168.Confusing "stop" and "emergency stop": the emergency stop (two clenched fists) is a distinct signal, reserved for situations of imminent danger.

169.Forgetting the angle factor: a sling at 60° from the vertical doubles the tension in each leg. This calculation is frequently tested.

170.Ignoring the 50% rule for personnel lifting: this is a CSA Z150 requirement, not just a recommendation.

171.Not repeating radio signals: verbal confirmation is an essential safety practice and a requirement in several jurisdictions.

172.Underestimating the weight of accessories: slings, shackles, platforms, and tools must be included in the total weight calculation.

173.Confusing power line distances: the values depend on the voltage. Memorize the table (3 m, 4.5 m, 6 m, 8 m).

174.Forgetting the tagline during personnel lifting: it is mandatory for controlling platform rotation.

175.Believing the signaller can be replaced by anyone: the signaller must be trained and competent, and their designation must be clear.

176.Not documenting the pre-lift briefing: documentation is a legal requirement and proof of due diligence.

177.Resuming operations after a loss of communication without confirmation: resumption must be explicitly confirmed by the signaller.

This chapter covers the essential knowledge for the Red Seal exam in mobile crane operation. Review CSA Z150-18 and the Canada Occupational Health and Safety Regulations to deepen your understanding. Mastering these concepts is not only necessary to pass the exam, but also to ensure the safety of all workers on the job site.

Communication, Signals, and Personnel Lifting