PART IX—INVESTIGATIONS OR SITTINGS OF ICC IN KENYA
166. (3) If an ICC prisoner is directed to be detained in a prison under subsection (1), the prisoner shall be treated in conformity with international human rights law and the Prisons Act, so far as applicable and with all necessary modifications, shall apply with respect to that prisoner as if the prisoner had been remanded in custody or sentenced to imprisonment for an offence against the law of Kenya, as the case may require, and is liable to be detained in a prison under such an order or sentence.
Conditions of imprisonment / detention - international treaty standards
EDIT.