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Inferior stitching on load strap webbing - it tears open under actual load conditions, ditches the hook and introduces the cargo to other road users. Home stitching of safety critical load straps is an example of cost-saving that compromises quality and protection of goods in transit. |
How many times do we listen to traffic reports telling of load spills causing traffic jams? How many times do we see cargo shifting on a truck load-deck as we travel the 'freeways'? Too often, writes
FleetWatch technical correspondent Dave Scott who contends that this is not surprising seeing that inferior load straps are being sold into our market. These straps are fitted with mild steel hooks that open like petals under strain while the webbing is stitched so badly around a securing hook that it tears open when stretched to only 50% of rated limits. It's a safety critical item that operators should be more aware of.
Training drivers and crews to properly secure goods in transit comes to nought if the very straps they use are the cheapest inferior quality items one can buy.
FleetWatch addressed this issue in April 1994 in an article titled Lethal Loads and again in May 1997 under an article titled
'Safety in Transport: Load Securement a Sorry Mess'.
It's now four years on and the problem is still there. In fact, the sight of load spills and cargo shifting on our roads is worse than ever.
South Africans love a discounted price. The problem here is that quality and safety fall out the bus when price is all that counts. We are such poor judges of quality when it comes to safety-critical components that we fail to spot a weak link that can lead to horrendous public liability suits. On this point, load-straps are yet another item I will add to my list of safety-critical trucking items, along with king pins, brakes, tow hitches, tyres, fifth wheels and others.
Load-strap failure has just got to be a reportable incident, regardless of cargo spills or accidents. An inquisition must follow load strap replacement and questions such as the following must be asked:
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Why did the strap fail?
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What cascade of events preceded the failure?
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Where did it fail?
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Was this anticipated?
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What are our load-strap replacement policies?
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What are our specifications?
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Can this type of failure be prevented?
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What training must be conducted?
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Is this just an indicator of a rash of events that are about to occur?
Load-strap specification - what's that?
As for all safety-critical components, load-straps must be purchased against a supplier's Certificate of Specification compliance. Certain suppliers are selling load-straps where the only certification lies in the retail sticker price - it's cheap! It's what's available from garage-based sewing machines and is couched in the simplified expression of 'a nine-metre tie-down' without any reference to rated assembly strength or certified specification.
The difference in price between a quality load-strap that matches certified performance specification and an uncertified item is only R8.00.
Here's a brief specification checklist:
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A strap is not always a strap and the weakest link test applies. Rated assembly strength of a load-strap must be tested on a complete unit with webbing attached to ancillary hooks and tensioning devices. The certificate of specification compliance should provide this detail as well as the authority.
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A quality load-strap should be manufactured from polyester and should be heat-set and waterproofed with polyurethane so as to stiffen the strap and provide impact resistance while preventing fraying.
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Henred Fruehauf applies British Standard BS 5759: 1979 as its benchmark for load-strap specification. This sets out exactly how load-strap strength should be calculated, how webbing should be stitched during make-up and how it should be marked and cared for in practice. For reference purposes, Australian Standard AS\NZS4380.1996 is also a good benchmark as Australian Design Rule (ADR) is acceptable in South Africa.
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Local legislation under Reg. 246 - 'manner in which goods to be carried' - seems to be more concerned that the only item that can come into contact with a road surface is a "static chain". The regulation does not even cross-reference a reader to the SABS Code of Practice - in this case, SABS 0187 - Code of Practice for Cargo Securement on Vehicles. SABS 0187, however ignored, is another benchmark.
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A supplier must also provide written instructions for load-strap care and maintenance that can be extended into driver and loading-crew training.
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This is what happens to a load strap hook made of mild steel - it looks fine on the left but when placed under strain it opens and lets a load spill onto the road.
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Wolfgang Lehmann, group warranty manager, Henred Fruehauf Trailers - "One cannot purchase safety critical components on price and face value. Apart from matching laid down specification criteria, safety critical parts must be subject to stress under validated test conditions. This is when we find the weakest link - a failure in test conditions is far better than a failure on the road accompanied by loss of life." |
Crime drives price and reduces safety
Interesting is that the high rate of crime in South Africa has once again had an influence on consumer habits. According to Arnold Sommer, group sales manager of Cargo Control Systems: "Transporters are price-driven at the expense of quality due to load strap theft. The disappearance rate of load-straps on the road makes replacement at the lowest cost the only consideration."
While one can extend a certain amount of empathy in this regard, Sommer says this is short sighted. "The cheapest tie-down that fails is the most expensive purchase decision so to replace stolen straps at the cheapest price is not a wise move. We regularly witness operators willing to risk loosing their loads for the sake of a mere R8.00 strap."
Common language
Given all this, it is important to get down to a common language on load-strap strength and to ensure that sufficient load-strap capacity is applied based on the following definitions:
Breaking strength of a complete load-strap assembly:
This is certified by a supplier and rated in kilo-Newtons (kN).
Rated assembly strength (RAS).
This is where operational safety factors are introduced. RAS is based on the formula:
RAS = Breaking strength (kN)
2 x 9,81
Example: A strap assembly has a breaking strength of 43kN. The RAS will be 43 ÷ (2 x 9.81) = 2,19 tons. So the breaking strength of a load-strap assembly may be 4 tons but it's rated assembly strength is only 2 tons. An operator who wants to carry 24 tons of cargo requires a minimum of 12 load-straps that are rated at 4 tons breaking-strength.
Extend safety into corners
Load fastening is a science that extends into corners, specifically re-usable polypropylene corners. Placed on the top corners of cargo, a 'polyprop' corner spreads load-strap pressure and provides a wider securing area. At the same time, it minimises damage and abrasion to cargo, tarpaulins and straps.
A high quality 'polyprop' corner will have a prismatic finish on the inside surface of the corner to prevent it from slipping off cargo. Other qualities will be acid resistance and protection against UV damage for at least five years.
"The test of a 'corner'," says Arnold Sommer, "is to jump on it! A corner which retains its shape after this bashing might last in service for repeated use."
'Polyprop' corners are simple and effective load-securing devices that should be included with goods in transit training. Also ensure there is a secure place to store 'polyprop' corners when travelling without a load. I have seen these ineffectively secured on flat-deck trailers.
Beware transit liability claims
Goods-in-transit cover is made complex by extended contracting chains that include consignors, load brokers, transporters and their sub-contractors. When a load-strap breaks and cargo is lost, all these parties usually end up pointing fingers at each other.
It is clear that, unless a discipline of following a checklist is adhered to, total confusion can arise as to where liability rests in the event of a loss. The following is a guideline checklist.
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Who is responsible for insurance between the consignor and the broker?
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Are assumptions being made that adequate cover is present between broker and between each party in the chain of contracting transporters?
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If the liability is being handed over in writing each time the load is subcontracted, then the following applies:
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Does the sub-contractor have cover?
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Has the sub-contractor paid his premiums, with policies in force?
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Does the sub-contractor accept liability?
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Is the load limit, i.e. the goods in transit total value, adequate for your cargo?
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Have you had sight of a policy that has not lapsed?
Owner-drivers cannot afford loss
Owner-drivers are known to top up engine lubrication with inferior grade oil just because it is cheaper and saves operating cost - never mind reduced engine life. It is easy for this philosophy to extend into cargo securing systems but the question to ask is: Can an owner-driver afford cargo loss or downtime due to vehicle damage? The answer is an emphatic no. They must be trained to search for the best in terms of safety critical items - and load-straps are part of this category.
Anyone operating trucks must practice 'management by walking around' - what we term MWA. Load securing systems must be part of an MWA activity. Are we doing this right?
If not, let's start doing it right for it is all part of a process of ethics, standards, road safety and the quality of life in South Africa. I, for one, will crusade on this issue as I live next to shoddy tie-downs on our choked freeways. Expect more pics of proof!
