Determining levels of confinement in the project planning stage is important to the engineer who must design systems that accommodate security needs while adhering to cost requirements. Confinement levels 1 and 2 consist of housing units in a dormitory or noncell configuration and have the fewest security features. In levels 3 and 4, units are individual cells providing medium or maximum security. At the fifth level, segregated housing, movement of inmates is limited and heavily controlled by staff. For each level, specific design features, established by State, county, or Federal authority, are required. Lavatory fixtures should be vandal-proof and designed to make concealment of contraband difficult. In two-tier design housing units, each tier should have a water fountain, toilet areas, floor drains, and a mop sink. Hot water heater selection should be based on the heating medium, number of showers, and size of the inmate population. The location of distribution and drainage systems should be chosen to provide the necessary security and maintenance access. Fire suppression systems must comply with standards. Reliability is the key concern in design of electrical systems. Public utility power is backed-up by an onsite generator. Uninterruptible power systems address the power reliability needs of data processing equipment.