252.2. Despite section 252.1, a hoist installed before 1 April 1993 may be equipped with a belt-type friction clutch if the following conditions are met:(1) its action is neutralized by a locking mechanism between the driving part and the driven part of a drum supporting the cage used for the transportation of persons;
(2) a slip detection device between the driving part and the driven part of a drum supporting a skip opens the safety circuit of the hoist.