1. The department of corrections and rehabilitation shall, following inspection pursuant to section 12-44.1-24, grade correctional facilities as to length of allowable inmate confinement based upon construction, size, and usage, as follows:
a. "Grade one" means a correctional facility for confining inmates not more than one year.
b. "Grade two" means a correctional facility for confining inmates not more than ninety days.
c. "Grade three" means a correctional facility for confining inmates not more than ninety-six hours.
d. "Grade four" means an adult lockup or court holding facility in which individuals may not be detained overnight.
2. The length of confinement of a prisoner may be temporarily increased on a case-by-case basis in grade one and grade two correctional facilities upon the request of the administrator and the approval of the department of corrections and rehabilitation.