SPECIAL FOLLOW UP

Vehicle Loading and Load Stability'

Article contributed by SHARON GERBER – Auckland Cranes

Following the June 2019 issue of Lifting Matters on ‘Load Restraint’, we have taken a deep dive into New Zealand regulations to compile direct references sourced from the New Zealand Transport Agency Road Code as well as the Study Guide for Driver Requirements for Class 3 and Class 5, published by MITO New Zealand and reviewed by the NZ Transport Agency. To reiterate, the correct loading of heavy vehicles is vital in the prevention of injury to drivers and members of the public and the prevention of damage to materials and equipment. Vehicle loads must be sufficiently restrained to prevent movement which may be encountered by forces arising from:

The vehicle passing over ripples and furrows in the road (undulations);

Having to change direction;

Braking or accelerating.

We must always remember that it takes far more force to stop a load that has started moving than it does to prevent the load from moving in the first place. Hence, it is imperative that the load is restrained to prevent movement in any direction relative to the vehicle. The grip (friction) between the load and the vehicle deck cannot be relied on to keep a load in a secure place. The above-mentioned forces will certainly exceed the force of the grip (friction) resulting in the load to move. Therefore, additional restraint is required to prevent the load from moving. Restraints are normally provided by means of lashings secured to the vehicle chassis and load platform or by various baulking arrangements such as loading racks, headboards and chocks. Other methods of securing loads are acceptable, providing a certified engineer has approved the system and methodology. With that said, tests may need to be carried out to confirm that the security of the load meets the criteria of the designed system and methodology to be applied.

The Golden Rule: DO NOT move until the load has been restrained properly!

Arranging a load

Section C – Vehicle Loading and Load Stability of the Study Guide for Driver Requirements for Class 3 & Class 5 Driver Licences outlines good practices and essentials for placing a load on a vehicle:

Always stay within the legal weight and size limits applicable for the specific vehicle, unless you have an overdimension permit;

If a load sits ahead or behind the body of the vehicle by more than 1 metre, or over a side by more than 200mm, the load is overdimension;

The vehicle must be loaded to provide the correct axle weight distributions;

Place or spread the load so there is a legal weight distribution. This gives you the best vehicle handling and a low centre of gravity;

For stacked loads, larger and heavier items should be put on the bottom or base, and lighter items on the top;

Heavy solid items should be restrained and put in front of the lighter items;

The load may have to be redistributed each time part of the load is taken off or new items are picked up to keep it stable and secure at all times. Note: the general rules for placing a load on a vehicle may not apply the same way in all situations. Always refer to The official New Zealand truck loading code for specific information.

Securing a load

The Feature Article in the June 2019 issue covered the minimum amount of force a restraint system must be able to withstand, as outlined in The National [Australian] Transport Commission’s Load Restraint Guide 2018. The standard for 50% of the load weight in sideways and reverse directions, and 20% of the load weight in a vertical direction, is consistent with that stated in The official New Zealand truck loading code. However, the minimum amount of force a restraint system must be able to withstand in a forwards direction differs between countries, with Australian law stating 80% of the load weight and the New Zealand code stating the full weight of the load.

1.0W

100% of the weight of the load forwards (braking)

New Zealand

Australia

The official New Zealand truck loading code outlines the following do’s and don’ts when it comes to ensuring the correct loading of heavy vehicles: for the type and size of the load; points are adequate;

DON’T

Overload the vehicle or its individual axles;

Load the vehicle too high. Always ensure the load does not exceed the legal limit;

Use rope hooks to restrain heavy loads;

Forget that the size, nature and position of your load will affect the handling of the vehicle;

Forget to check the load: ɐ before departing your location, after travelling 25km and at set intervals thereafter, i.e. tyre checks should be made at regular intervals; ɐ every time items are removed or added to the load during your journey; ɐ after emergency braking; ɐ after an excessively sharp/ violent turn or manoeuvre;

Take risks. Always be patient (better late than never);

Move the vehicle if any part of the load is not secured, not even for short distances;

Leave loose items for example, wedges, lashings, chock and dunnage, etc lying on the vehicle deck once the load has been removed;

Leave the platform (deck) full of

DO

Make sure that your vehicle is suitable and in good condition

Ensure that the load anchorage dust or other fine particles.

Ensure that there are sufficient lashings and that they are in good condition and strong enough to secure the load;

Remember to tighten the restraining devices;

Ensure that the front of the load is abutted against the front rack or headboard, or other fixed restraint;

Ensure that the load cannot move, use wedges and chocks;

Make sure that no loose items can fall or be blown off the vehicle.

Restraints to combat forces

The total restraint required to combat the forces that may arise during transportation will likely be obtained from one or a combination of the following:

Baulking arrangements: load racks, headboards, stakes in pockets, transverse beams, shoring bars, chocks and dunnage, etc.,

Lashings secured to the vehicle's anchor points,

Friction between the load and the vehicle platform (deck).

Baulking

The Study Guide states if the load is not placed against the headboard, it can be baulked against the headboard to stop it from moving forward. As an example, an empty pallet could be used to baulk the load. When the load is baulked against the headboard, the combined rated strength of the restraint(s) must be at least the same as the weight of the load. This is the same as when a load is placed directly against the headboard. Note: the item used to baulk the load must also be individually secured to the load deck.

Lashing

The June 2019 Feature Article outlines a number of components that are utilised in direct and in-direct lashing design including: load/friction matting; load chain and binders; lashing pre-tension; and tie-down force. The Truck Loading Code states that the lashings or fastening devices, twitches and chains, cables, clamps, load binders, etc should be in a sound condition and must be capable of transmitting all the forces likely to be induced in them.

Baulk

Incorrect load position – weight is placed too far forward. This overloads the front axle and increases the risk of the rear axle locking up during braking. Correct load position with baulking against the headboard.

The following requirements should also be met:

The lashings or fastening devices must be properly tensioned at all times. They must be periodically checked during the journey to avoid the load moving on the vehicle platform, and to keep it firmly against the headboard or other obstacle referred to in the paragraph on baulking above. Over-tensioning should be avoided as this can overload the lashings or fastening device and weaken it.

The restraining system should be arranged so that the failure or slackening of a single component does not render the remainder of the system ineffective.

Lashings must not contact any sharp edges on the vehicle or load.

Incidents

Sadly we still see incidents of this nature happening on a regular basis. These two examples show what can happen when there has been insufficient, or a complete lack of, load restraint.

Incident 1

Figure 1: No Load Restraint

What happened?

The driver allegedly only wanted to drive up the road and park before restraining the load. The deck had insufficient rubber, resulting in the load being steel on steel. The driver went over an island and the load shifted forward causing damage.

Learning:

Always adhere to the golden rule: DO NOT move until the load has been properly restrained!

Incident 2

Figure 2: Insufficient Load Restraint

What happened?

A steel beam slammed into the back of a cab, pinning the driver, after he suddenly had to apply the brakes.

Learning:

Always ensure the load has been sufficiently restrained to prevent movement which may be encountered by forces such as sudden braking.

Always secure the load

Do not start your journey without first checking that your load is secure. It does not matter how far you are going to drive - the load must first be secured!

If it becomes difficult to control your vehicle as you drive, this can be an indication that your load is not secure and the centre of gravity has shifted. Reduce speed gradually and stop as soon as it is safe to do so. Exit your vehicle and inspect the load. Do not drive until the load is made secure again. Duly note that this article should not be read in isolation and should be read inconjuction with the New Zealand Transport Agency Road Code for Heavy Vehicle Drivers.

MITONew Zealand; Study Guide for Driver Requirements for Class 3 & Class 5 Driver Licences; Unit Standards 17575 & 17577; December 2016

NZ Transport Agency; Road Code for Heavy Vehicle Drivers; 16 July 2014.