No child may be subjected to mechanical or chemical restraints, seclusion, or another form of physical coercion or restraint unless the action is authorized by a physician as being required to prevent a child from taking actions which are dangerous to himself or to others or prevent an imminent and substantial disruption of the therapeutic setting of the facility. The authorization for the action must be entered in the child’s record within one hour of the action. The authorizations are not valid for more than eight hours unless approved by the facility director or his designee. No child in an inpatient treatment facility of the department may be subjected to corporal punishment.