Hardware costs and manpower costs
Most hand-held metal detectors on the market range from about $20 to about $350. Schools should plan to spend between $150 and $200 for detectors that have desirable features, including a long detection paddle (to reduce the amount of passes necessary across a person's body), a warning light or beep when the batteries are beginning to run low, and an audible feedback alarm that squeals louder or changes pitch for larger suspicious items and softer for less suspicious items (such as a zipper). Even the least expensive detectors will work, but more time may be required to perform a complete scan, and the procedures for the scan may be more intrusive. These smaller detectors are convenient if a school administrator or security person wishes to carry a smaller detector on their belt at all times.
Hand-held metal detectors run on either a 9-volt battery or on a rechargeable NiCad battery. A new or freshly recharged battery will last for approximately 1 hour of constant scanning. The rechargeable units may require that the battery be recharged by itself. Other hand-held detectors have a jack or plug built into them so it is unnecessary to remove the battery to recharge. (It is suggested that, for hand-held detectors that are used very infrequently, such as once a month, batteries should be removed when the unit is not in use.) A staff member should be assigned the responsibility for recharging batteries each night and/or making certain that new batteries are always available.
Obviously, manpower costs drive the use of hand-held metal detectors. As mentioned in the section on throughput, a trained operator can scan approximately two people per minute. For each operator and all backup operators, a thorough training course along with some practice time should take no more than an hour at the beginning of each school year. A school should not forget to formally train security personnel who are hired after the start of the school year. (Some metal detector vendors provide an instructional videotape that can be useful, but the tape should not be used as the only source of initial training and practice.)
Research Report: The Appropriate and Effective Use of Security Technologies in U.S. Schools