; and (II) limiting disciplinary segregation to a duration of not more than 90 days, for a second or subsequent such prohibited act; and (vi) in addition to any other limitation under this subparagraph, limiting disciplinary segregation to a duration of not more than 30 consecutive days, and not more than 40 days in any 60-day period, unless a multidisciplinary staff committee, in consultation with the disciplinary hearing officer who presided over the disciplinary hearing for the inmate, determines that the significant and serious disciplinary infraction which the inmate was found to have committed is of such an egregious and violent nature that a longer sanction is appropriate and approves a longer sanction; (C) ensure that any time spent in administrative segregation during an investigation into an alleged offense is for as short a duration as possible, is not longer than 15 consecutive days, and is credited as time served for a disciplinary segregation sentence; (D) ensure that concurrent sentences are imposed for disciplinary violations arising from the same episode; and (E) ensure that an inmate may be released from disciplinary segregation for good behavior before completing the term of the inmate, unless the inmate poses a substantial and immediate threat to the safety of other inmates, staff, or the public. (7) Special management units The Director of the Bureau of Prisons shall eliminate the use of special management units. (8) Administrative maximum facilities The Director of the Bureau of Prisons shall— (A) limit segregation in an administrative maximum facility to situations in which such segregation is necessary to— (i) implement special administrative measures, as directed by the Attorney General; or (ii) house an inmate who has been found to have committed a significant and serious disciplinary infraction by a disciplinary hearing officer and who poses an ongoing significant and serious threat to the safety of other inmates, staff, or the public that cannot be addressed through alternative housing