If they do not have a limitation of use, TENDON ropes can be stored unused for up to 5 years.
Optimal storage conditions are a prerequisite, which are:
- a clean place, protected from light,
- no chemical, physical or mechanical influences,
- a temperature of 15 - 25 °C,
- relative humidity approx. 65 %.
The rope must also be inspected annually by a competent person authorized by the manufacturer.
In the complex process of rope production, the fibres enter a state of mechanical stress and with increasing length of storage they undergo so-called retardation and relaxation. This means the polymer’s macromolecules are “relieving”. But this phenomenon is not harmful, it is even associated with an improvement in dynamic properties. Research has shown that the results of dynamic behaviour tests on ropes stored for several years (optimally) often lie above the values that were measured at the time after manufacture. Polyamide also does not contain any additives or plasticizers (such as PVC) that could be released. Therefore, there is no embrittlement.
Standardized treatment of the fibres with nanotechnology gives the ropes additional protection.
As a matter of interest:
Safety studies conducted in the past by climbing associations have shown a residual capacity of two standard falls for some ropes that had been used and stored, but were manufactured in the early 1960s!