Slinging and Signalling: The Seven Steps Every CPCS Operator Must Know

Slinging and Signalling: The Seven Steps Every CPCS Operator Must Know

The slinger signaller is one of the most critical members of any lifting team on a construction site. If you are preparing for your CPCS A40 Slinger Signaller assessment, renewing your card, or simply looking to sharpen your knowledge, understanding the fundamentals of safe slinging and signalling is essential. Getting it wrong does not just risk a failed test — it risks lives.

This guide breaks down the seven key steps of a safe lifting operation, covering everything from estimating load weights to storing your lifting accessories properly at the end of the job.

Step One: Checking the Weight of the Load

Before any lift can begin, you must know what the load weighs. Without this information, you cannot select the correct sling or confirm that the crane has sufficient capacity.

Until you know what the load weighs, you cannot continue with the lift.

Some loads will have the weight clearly marked. When they do not, you have several options:

• Check with the manufacturer for the published weight
• Ask an engineer to calculate the load weight
• Estimate the weight based on the size, shape, material, and whether the load is solid or hollow

If you are estimating, always increase your figure by at least 25 percent as a factor of safety. Then lift the load slowly so the crane operator can confirm the actual weight on the hook block. This is not guesswork — it is a disciplined process that keeps everyone on site safe.

Step Two: Choosing the Right Lifting Accessory

With the weight confirmed, the next step is selecting a suitable sling. The choice depends on several factors:

• How the sling will be attached — Does the load have built-in lifting points, or will the sling need to go around it?
• The sling material — Chain and wire slings can mark delicate surfaces, so man-made fibre slings may be more appropriate. Always use suitable packing material to protect against sharp edges.
• The number of legs — A single-leg sling is suitable for loads with a single lifting point such as motors, pumps, or concrete skips. For loads requiring balanced support, a multi-leg sling with two or more legs is necessary.
• The working load limit (WLL) — The WLL of the sling must exceed the weight of the load.

Understanding Sling Angles

The angle between sling legs — known as the included angle (or alpha angle) — directly affects the loading on each leg. The wider the angle, the greater the force in each sling leg.

• Maximum recommended included angle: 90 degrees
• Absolute maximum included angle: 120 degrees

Multi-leg slings are rated using either the uniform load method (which incorporates the newer European harmonised marking system using the beta angle from the vertical) or the older trigonometrical method. Both calculate the working load limit identically but express it differently. If a sling is not marked for use at a particular angle, or you have any doubts about its markings, do not use it. This is a commonly tested topic in CPCS renewal assessments, so make sure you understand it thoroughly.

Step Three: Fitting the Sling to the Load

Choosing the right slinging technique is just as important as selecting the right sling. The choke hitch is one of the safest and most efficient methods, particularly for bundled loads such as scaffolding poles. Double wrapping the sling legs increases the clamping force without battening down the hook, which is dangerous and can damage the sling.

Key considerations when fitting slings:

• Check the centre of gravity. The load’s centre of gravity will always position itself directly below the crane hook. Measure the load and place sling legs an equal distance either side of the centre.
• Ensure the hoist rope is vertical and the crane jib head is directly over the centre of the load.
• Carry out a trial lift by raising the load slightly to confirm it hangs level before continuing.
• Never drag slings along the floor. Dragging causes wear and can force grit into fibre slings, causing internal damage.

If a load has an offset centre of gravity requiring sling legs of different lengths and angles, do not attempt this unless you have been specifically trained. Seek the advice of a competent person.

Step Four: The Lift

Before signalling the crane operator to lift, confirm the following:

1. The area is clear of unauthorised persons
2. The route the load will take has been checked for proximity hazards
3. The method of communication has been agreed with the crane operator
4. A hand line (tagline) has been attached if needed, especially for long loads or those with a large sail area

The standard hand signals for crane operations are set out in BS 7121:1989, the code of practice for the safe use of cranes. Every member of the lifting team must understand and agree on these signals before the lift begins.

Always ensure that the hand line is not wrapped around the user’s hands or body.

Keep hands and fingers well away from the bite of the sling. Trapped hands and fingers are among the most common lifting accidents and can result in severe injury or amputation. Under the Health and Safety at Work Act 1974 and LOLER 1998, every member of the lifting team shares responsibility for maintaining safe working practices during a lift.

Step Five: Setting the Load Down

Once the load is in position, use the tagline to guide it during lowering. Before setting down:

• Confirm the ground is suitable to accept the weight
• Ensure suitable supports are in place
• Clear all unauthorised persons from the area
• Lower the load until it is just clear of the ground and stop
• Use the correct hand signal for lower slowly until the load is secure and stable

Watch your feet. It may sound obvious, but trapped feet during lowering are a surprisingly common injury among experienced slingers.

Step Six: Releasing the Slings Safely

Before removing slings, ensure the legs are not under tension. Using timber supports beneath the load makes removal far easier and prevents the crane from having to drag slings out — a practice that damages the slings and can pull the load over.

Once the slings are free, hook the legs back to the master ring. This prevents anyone from being struck by swinging legs. Signal the crane operator to hoist the slings up slowly and guide them clear of the load until they are above head height.

Step Seven: Storage and Maintenance

The final step is often overlooked, but it matters. All lifting accessories must be returned to proper storage — ideally hung on a rack off the floor where they are protected from deterioration, damage, and unauthorised use. A responsible person should be appointed to look after them.

Under LOLER 1998, every lifting accessory must carry a working load limit and unique identity number corresponding to a current six-monthly thorough examination report and a manufacturer’s test certificate. Before each use, inspect every item for obvious signs of damage regardless of its certification status. If damage is found, mark the item, lock it away, and do not allow it to be used until a competent person has carried out further examination.

Understanding your obligations around inspection and thorough examination is essential whether you are preparing for your initial CPCS assessment or approaching your renewal.

How CPCS CPD Mastery Fits Into This

Slinging and signalling covers a broad range of knowledge — from sling angle calculations and load estimation to hand signals and LOLER compliance. These are exactly the types of topics that appear in your CPCS theory test, and getting comfortable with them before test day makes all the difference.

CPCS CPD Mastery gives you access to over 4,000 practice questions across 43 plant categories, including dedicated content for the A40 Slinger Signaller category. The app features 5 plant calculators to help you practise load and sling angle calculations, 8 quick reference guides covering legislation and safe working practices, full mock tests that mirror the real assessment format, and detailed explanations for every answer so you understand the reasoning behind each correct response.

Whether you are working towards your Red Trained Operator card or renewing your Blue Competent Operator card, consistent revision with realistic questions is the most effective way to prepare. Download CPCS CPD Mastery today and start building the confidence you need to pass your assessment first time.