If you've ever looked closely at one of our ratchet strap labels, you may have spotted the term BFmin. This is short for minimum breaking force – a very important measurement, and one that's often misunderstood.
Basically, the minimum breaking force is your brand new ratchet strap's absolute limit. If the strap is subjected to forces equalling or exceeding the BFmin, the strap will fail.
BFmin should not be confused with the strap's lashing capacity (LC), which refers to the maximum force your ratchet strap is designed to sustain in actual working conditions.
Read on to learn more about BFmin and what it actually means in relation to our ratchet straps.
What is minimum breaking force?
Minimum breaking force is the smallest amount of force that will cause a ratchet strap to break under test conditions. For example, if a ratchet strap has a BFmin of 5000 decanewtons (daN), this means the strap will fail if subjected to 5000daN of force.
However, this figure should never be treated as the strap's safe working limit. Pushing a lashing strap close to its breaking point may damage the strap even if it doesn't fail completely.
That is why ratchet straps are also labelled with another very important figure: lashing capacity.
Minimum breaking force vs lashing capacity
While minimum breaking force tells you the point at which a ratchet strap will break, lashing capacity – or LC for short – tells you the maximum force that strap is actually designed to sustain in a straight pull.
When choosing ratchet straps, lashing capacity is the figure you should be using to decide whether or not a strap is suitable for the task at hand. The strap should never be used in a situation where the expected force exceeds its stated LC.
For example, a Tensys ratchet strap label may show:
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LC: 2500daN
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BFmin: 5000daN (when new)
In this example, the ratchet strap has a safety factor of 2:1 because the breaking force is twice the lashing capacity. For safe load restraint, always base your calculations on each strap's lashing capacity, not the minimum breaking force.
On Tensys ratchet straps, the minimum breaking force is printed clearly on the product label, along with other key details such as the serial number, date of manufacture, webbing type and of course lashing capacity. Before using any ratchet strap, always check the label to ensure that the lashing is suitable for the load and application. You should also inspect each of your ratchet straps for signs of damage before every use.