§1. In all houses, cloister adapted to the character and mission of the institute is to be observed according to the determinations of proper law, with some part of a religious house always reserved to the members alone.
§2. A stricter discipline of cloister must be observed in monasteries ordered to contemplative life.
§3. Monasteries of nuns which are ordered entirely to contemplative life must observe papal cloister, that is, cloister according to the norms given by the Apostolic See. Other monasteries of nuns are to observe a cloister adapted to their proper character and defined in the constitutions.
§4. For a just cause, a diocesan bishop has the faculty of entering the cloister of monasteries of nuns which are in his diocese and, for a grave cause and with the consent of the superior, of permitting others to be admitted to the cloister and the nuns to leave it for a truly necessary period of time.
Source: Code of Canon Law (Vatican.va)