-32 (the restrictions applied during the regime of solitary confinement should be those strictly necessary in the circumstances of the case), nondiscrimination (authorities should not take into consideration irrelevant matters upon deciding on the imposition of solitary confinement, e.g. sexual orientation).52 3.3. Duration of solitary confinement After the introduction of the revised United Nations Standard Minimum Rules for the Treatment of Prisoners (Mandela Rules) in 2015, human rights bodies often refer to the Mandela Rules as the international standard regarding the duration of solitary confinement. In this regard, Rule 44 of the Mandela Rules indicates that prolonged solitary confinement, i.e. the confinement of a detainee for more than 15 days, should be prohibited. Also, subsequent measures of solitary confinement which de facto prolong the time spent by the detainee under this measure, should be prohibited (CAT53 , SRT54 , CPT55 , EPR56 ) along with prolonged and indefinite solitary confinement (Mandela Rules57 , ECtHR58). In the case of disciplinary solitary confinement, the CPT recommends 14 days as the maximum time limit, and adds that sequential disciplinary sentences resulting in an uninterrupted period of solitary confinement in excess of the maximum period should be prohibited.59 The 2020 revised version of the EPR does not directly set a specific maximum number of days for solitary confinement as a disciplinary measure, but specifies that it should be set by national law.60 When setting a maximum, a national government has to set a period that would not be so long that it would amount to inhuman or degrading punishment and thereby infringe article 3 of the ECHR (freedom from torture). In evaluating where the set period meets this test one can rely on the 14 and 15 day maxima set respectively by the CPT, and the Nelson Mandela rules.61 Any maximum period of much 52.European Committee for the Prevention of Torture, 2011, §55. 53. Committee against Torture, Report of the Committee against Torture, A/69/44, New York, 2014, §61(12). 54. United Nations General Assembly, 2011, §§75, 87, 89-91, 93, 95-99. 55. European Committee for the Prevention of Torture, 2011, §§56-61. 56. EPR 60.6.e. 57. Mandela Rules 45. 58. European Court of Human Rights, Case of Ramirez Sanchez v. France, §145. 59. European Committee for the Prevention of Torture, 2011, §§56-61. 60. EPR 60.6.d. 61. See the Commentary to Rule 60.6.d of the 2020 EPR.