Types of rope
There are basically three different types of rope, each best suited for different applications, which are tested according to different standards.
Single ropes are the most common type of ropes used. Depending upon diameter and length they can be used for most conditions. The main advantage is simple handling. A disadvantage is that only routes up to a half rope length high, with subsequent lowering or rappelling, can be climbed.
Single ropes come in diameters of approximately 8,9 to 11 mm and weigh between 52 to 77 grams per meter. Single ropes, withstand at least five falls with an 80 kg mass
Twin ropes must only be used in pairs and are clipped together into each piece of protection, as with single rope technique (= Twin rope technique). The two ropes offer redundancy and thus, increased safety in the case of shock loading over a sharp edge. They are therefore especially suited for alpine climbing or demanding routes where retreat may be necessary. They offer the highest safety margin and allow full length rappels. With diameters from approximately 7,5 to 8,5 mm and a weight of between 38 to 45 grams per meter they are, together, about as heavy as the heaviest single ropes. With standard testing the ropes must withstand 12 falls with an 80 kg mass.
Half (Double) Ropes
Half ropes, with regard to strength and weight, lie between single and twin ropes. They only offer standard safety when they are used as a pair. But here you have the choice between twin rope technique, where both ropes run parallel through the protection and half rope technique, where the «left» and «right» ropes run separately through different protection points. This technique allows friction to be reduced in the case where protection points are widely spread and reduces impact force. This is of benefit when climbing traditionally protected routes. A belay method which enables the independent control of each rope must be used. Half ropes are tested singly with a 55 kg mass and must withstand five standard falls. They come in diameters from 8 to 9 mm and weigh 41 to 55 grams per meter. In single strand form they are suitable to belay two seconds.