(1) The rules and standards promulgated under section 62(3) shall not prohibit the housing of 2 or more inmates in a county jail cell which is designed and constructed for housing 2 or more inmates, and which meets all of the following conditions:

    (a) The basic cell has at least 25 square feet in area per inmate or, if the inmates are confined in the cell for 10 or more hours per day, at least 35 square feet in area per inmate. This subdivision only applies to cells constructed after January 1, 1988.

    (b) The cell provides access to a day area that is available for use by other than those being disciplined. The day area shall contain at least 20 additional square feet of space per inmate. This subdivision only applies to cells constructed after January 1, 1988.

    (c) The cell complies with other rules and standards for multiple occupancy housing in jails, as promulgated under section 62(3).

    (2) For purposes of housing inmates as provided for under this section, the sheriff of the county shall develop and implement a classification system classifying the county jail population according to all of the following:

    (a) Behavior characteristics.

    (b) Similar physical characteristics.

    (c) Age.

    (d) Type of crime committed and criminal history.

    (e) Gender.

    (3) The classification system under subsection (2) shall be submitted to and approved by the department.

    (4) Cells in which 2 or more inmates are housed shall have doors which allow visual supervision, and inmates shall be under visual supervision at least every hour.