; (II) a protective custody unit described in paragraph (3); or (III) a mental health treatment program as described in subsection (c)(2); (B) the inmate is lesbian, gay, bisexual, transgender (as defined in section 115.5 of title 28, Code of Federal Regulations, or any successor thereto), intersex (as defined in section 115.5 of title 28, Code of Federal Regulations, or any successor thereto), or gender nonconforming (as defined in section 115.5 of title 28, Code of Federal Regulations, or any successor thereto), when such placement is solely on the basis of such identification or status; or (C) the inmate is HIV positive, if the placement is solely on the basis of the HIV positive status of the inmate. (5) Special housing units The Director shall— (A) limit administrative segregation— (i) to situations in which such segregation is necessary to— (I) control a substantial and immediate threat that cannot be addressed through alternative housing; or (II) temporarily house an inmate pending transfer, pending classification, or pending resolution of another temporary administrative matter; and (ii) to a duration of not more than 15 consecutive days, and not more than 20 days in a 60-day period, unless— (I) the inmate requests to remain in administrative segregation under paragraph (3)(D)(i); or (II) in order to address the continued existence of a substantial and immediate threat, a multidisciplinary staff committee approves a temporary extension, which— (aa) may not be longer than 15 days; and (bb) shall be reviewed by the multidisciplinary staff committee every 3 days during the period of the extension, in order to confirm the continued existence of the substantial and immediate threat; (B) limit disciplinary segregation— (i) to situations in which such segregation is necessary to punish an inmate who has been found to have committed a significant and serious disciplinary infraction by a Disciplinary Hearing Officer and alternative sanctions would not adequately regulate the behavior of the inmate