Iowa Code § 356.21: Control and punishment.

The officer having charge of any prisoner may use such means as are necessary to prevent the prisoner’s escape, and if the prisoner attempts to escape or if, being convicted, the prisoner refuses to labor, the officer having the prisoner in charge may, to secure the prisoner or cause the prisoner to labor, deal with the prisoner as with other disorderly or refractory prisoners. Such punishment shall be inflicted within the jail or jail enclosure, and the time of such solitary confinement shall not be considered as any part of the time for which the prisoner is sentenced.