isolation
(32) the term “isolation”— (A) means any instance in which a youth is confined alone for more than 15 minutes in a room or cell; and (B) does not include— (i) confinement during regularly scheduled sleeping hours; (ii) separation based on a treatment program approved by a licensed medical or mental health professional; (iii) confinement or separation that is requested by the youth; or (iv) the separation of the youth from a group in a nonlocked setting for the limited purpose of calming;