4 Friction and drum hoists 4 These hoists typically have lower capital costs when compar ed to drum hoists due to characteristic lighter , single-drum constructions and lower installed power r equir ements. Koepe drums ar e subjected to high cyclic fatigue loads, typically r eversed during every drum r evolution. Design is of necessity for infnite fatigue life. The head r opes of a Koepe hoist ar e subjected to cyclic variations in operating loads due to the r equir ed use of tail, or balancing r opes. For adequate r ope life, the static load range should be limited to appr oxi - mately 12 of the r ope br eaking str ength. Regular r ope maintenance and r eplacement is essential on these hoists. Koepe hoists ar e not normally favour ed for depths of wind gr eater than 1800 m. However , for depths within the 1800 m range, very large payloads can be handled by incr easing the number of head r opes. Koepe hoists fr equently fnd application as service hoists for men and materials