12 UNITED NATIONS STANDARD MINIMUM RULES FOR THE TREATMENT OF PRISONERS (c) The authority competent to impose such sanctions; (d) Any form of involuntary separation from the general prison population, such as solitary confinement, isolation, segregation, special care units or restricted housing, whether as a disciplinary sanction or for the maintenance of order and security, including promulgating policies and procedures governing the use and review of, admission to and release from any form of involuntary separation. Rule 38 1. Prison administrations are encouraged to use, to the extent possible, conflict prevention, mediation or any other alternative dispute resolution mechanism to prevent disciplinary offences or to resolve conflicts. 2. For prisoners who are, or have been, separated, the prison administration shall take the necessary measures to alleviate the potential detrimental effects of their confinement on them and on their community following their release from prison. Rule 39 1. No prisoner shall be sanctioned except in accordance with the terms of the law or regulation referred to in rule 37 and the principles of fairness and due process. A prisoner shall never be sanctioned twice for the same act or offence. 2. Prison administrations shall ensure proportionality between a disciplinary sanction and the offence for which it is established, and shall keep a proper record of all disciplinary sanctions imposed. 3. Before imposing disciplinary sanctions, prison administrations shall consider whether and how a prisoner’s mental illness or developmental disability may have contributed to his or her conduct and the commission of the offence or act underlying the disciplinary charge. Prison administrations shall not sanction any conduct of a prisoner that is considered to be the direct result of his or her mental illness or intellectual disability. Rule 40 1. No prisoner shall be employed, in the service of the prison, in any disciplinary capacity. 2. This rule shall not, however, impede the proper functioning of systems based on self-government, under which specified social, educational or sports activities or responsibilities are entrusted, under supervision, to prisoners who are formed into groups for the purposes of treatment.