3.5 – Understanding Load Restraint Equipment – Lashing of Lashings

The Load Restraint Guide defines lashings as:

Fastening devices (e.g. hooks, winches, etc.), chains, cables, ropes or webbing straps used to restrain loads. Webbing, chains and wire rope are the main types of lashings and there are several different types of tensioning devices used to tension these lashings to ensure they perform correctly.

When using any type of lashing it is important to understand that the number of lashings or rating of the lashings is NOT THE SAME AS THE MASS OF THE LOAD. This means that a 2,500 kg rated strap is not sufficient to tie down a 2,500 kg load. The ANGLES between the lashing and the direction of the force being restrained NEEDs TO BE TAKEN INTO ACCOUNT. This will be discussed in more detail in Lessons 4.1.1 and 4.1.2.

Webbing
Webbing is a lightweight restraint system that is widely used in the transport industry. It is typically used to tie down load such palletised goods, or goods that can settle such as bags and sacks (webbing has greater flexibility that chains or steel bands and is therefore more suitable for these loads)

Webbing is supplied as an assembly that included end fittings, tensioning devices and a rating tag showing the capacity of the lashing assembly measured using AS/NZS standard 4380 (Motor Vehicles Cargo Restraining Systems).

Using Webbing

There are a few key factors that need to be considered when using webbing:

• Webbing that is not rated to AS/NZS 4380 should not be used as it may have lower capacity.
• Webbing should not be used with Chemicals or high temperatures without referring to Manufacturer’s instructions.
• Avoid Knots: webbing that has knots in it should not be used and knots should not be used to attach webbing to rails or other structures.

• Webbing needs to be protected from damage caused by sharp edges, rough and high friction surfaces using corner protectors, sleeves or other packing material.

• Webbing should be checked regularly for wear (furry or cuts and abrasions) – See page 170 of the load restraint guide.

Tensioning the Webbing

Ensuring the webbing is adequately tensioned is absolutely critical. Tensioning is typically achieved by the use of In-Line Hand rachets which come in two different types which either add tension when pulled down or pushed up.

To achieve their rated capacity webbing needs to be tensioned according to Manufacturers specifications. The load restraint tables which will be discussed further in Lessons 4.1 and 4.4 make assumptions that the webbing has been tensioned to the required level of pre tension. (mouseover show this image.

If you do not achieve the required level of pre tension the webbing will not achieve its required capacity and you may need more lashings.

Calculating the required number of lashings

• It is important to ensure that the webbing assembly components have adequate capacity for the load.
• This may require the use of multiple lashings.
• The lashing capacity does not equal the pre-tensioning force (eg a typical lashing may have a 2000 kg rating but only 300Kg pretension).
• The number of webbing required for tying down a load is not equal to the rating of the lashing. It needs to take into account of the angle of the lashing and the coefficient of friction. The worked examples in pages 205-210 or the LRG illustrates how to calculate the required lashings using the tables on pages 271 -278 or the LTRG.

See Lesson 4.4 for more details

Transport Chain

Transport chain is typically used to restrain rigid load that are not easily damaged or where the product can be protected from damage due to contact with the chain.

Transport chain is highly durable and has low stretch characteristics. As a result it should not be used with loads that can crush or settle.

Transport chain should also not be used for lifting or loading as it is not designed for that purpose

The most common size is 8mm chain made from high tensile steel which has a capacity of 3,800-4,000 kg, however chain is also available in other sizes.

Chain used for load restraint should be compliant with AS/NZS 4344 which is marked with the rated capacity at least every 500mm.

Mention 2 types of inline tensioners push up and pull down illustrate their use – same for winches – mention triangle fittings illustrate points re one and a half and three turns and impact of tension as discussed on page 169.

Webbing is tensioned by in line Hand Ratchets attached to tie rails or by Trucks Winches that are clipped onto tie rails or slide into special tracks under the coming rails.

Using Chain

• Only use chain rated to AS 4344.
• Make sure the chain is free of knots and does not have joints using wire, bolts or joining links unless the joining link has been rated to the capacity of the chain assembly.
• Make sure the chain is attached to suitable anchor points using appropriate hooks (Do not use knots) see page 173 of the LRG for advice on hooks.
• Straighten out twists in chains before tensioning it.
• See page 171 and 172 of the load restraint guide for further advice on the use of transport chain
• Check chain for damaged links (see page 175 of the LRG)

Chain tensioners
Make video showing various types of chain tensioners and explain how to use them – see pages 174 And 175 ad 187- 189, 197 of LRG

Other Lashings
Another option for lashing some loads is to use wire ropes which have a higher stretch capacity than chains while still having high capacity see page 179-180 of t he LRG for tips on using wire ropes.

This video shows inspection of chains and a turnbuckle tensioner.

As is the case with webbing straps chains need to be pre tensioned to achieve the required level of restraining force.