TESTS OF THE MECHANICAL STRENGTH OF SELECTED CLIMBING ROPES USED BY THE STATE FIRE SERVICE WITH RESPECT TO DAMAGE OCCURRING DURING RESCUE OPERATIONS

Abstract

The paper deals with the issue of mechanical strength of climbing ropes. These ropes are exposed to the influence of exploitation factors both during training and in rescue operations. Among others, they may sustain mechanical, thermal and chemical damage. The study attempted to provide an evaluation of the effect this damage has on the mechanical strength and extensibility of ropes. The tests were carried out in laboratory conditions, and the courses of force in the function of deformation and impact of force on deformation were recorded. An unfavourable influence of some types of damage on the strength and extensibility of ropes was demonstrated. Mechanical and thermal stresses mainly cause damage to the rope sheath. Their effect on endurance is similar. The remaining strength of the rope is slightly above the minimum allowable tensile strength. On the other hand, the chemical treatment did not cause a noticeable decrease in the rope’s strength.