VCRs: the weak link
The video cassette recorder (VCR), commonly used in most school surveillance systems, is the weakest link in the video system due to its mechanical nature. (The more reliable but much more expensive digital recorder is discussed later.) Industrial quality VCRs range in price from $500 to $4000. A school can plan to spend approximately $500 to $1,200 for a good-quality VCR appropriate for most of its applications. (This price range does not necessarily include some of the desirable features discussed later.) The inexpensive $200 VCR is not recommended for nonhome use.
Unfortunately, the most ignored maintenance task in most school security departments is the regular servicing and cleaning of VCRs. VCR heads should be cleaned after every 100 hours of useabout every 4 days of constant recording. This head cleaning can be accomplished using isopropyl alcohol and industrial swabs and takes about 10 minutes. The cleaning tapes that are available to clean VCR heads are not recommended, as they can cause excessive wear on the heads. The entire VCR unit should be serviced every 2,400 hours, or about every 3 months of constant use. This complete servicing includes replacement of bands and rubber components. If well-serviced, a typical VCR will last about 4-5 years with constant use. At least one moderately expensive ($200-$300) head replacement should be expected during this time.
Premium-quality tapes are recommended for the constant use experienced in most school applications. These tapes will cost about $10 each and are available from your VCR vendor. Their expected quality lifespan is about 25 recordings. Recording over the same tape indefinitely is not recommended because this practice introduces several logistical problems. Sometimes incidents are reported several days after they occur, and the video of the incident has already been recorded over.
A good recording plan includes 6 new tapes every fall
and spring, labeled Monday, Tuesday, . . . Friday, and Weekend. Each morning, the appropriate tape is put into the VCR. When an incident occurs, that particular tape should be pulled and labeled as "removed," along with the date it was most recently recorded on. A new tape labeled with that day of the week should replace the original. If faithfully done, this will probably be adequate for most schools. By replacing the tapes every spring and fall, the tape quality is not compromised.
VCRs, which operate at temperatures between 32°F and 104°F, need to be used indoors where relative humidity is less than 80 percent and the air is free of noncondensing moisture. Because an industrial time-lapse recorder is designed to run 24 hours a day for long periods of time, proper physical location of the unit must be considered. Recorders generate heat, and because heat is the worst enemy of the recorder (next to dirt), the recorder must be placed in a well-ventilated location. If the recorder is to be installed in an environment where there is a lot of dust or dirt in the air, provisions must be made to keep the unit clean. (A single grain of dirt in the right place can crack a video head.) If a recorder must be placed in a dirty environment, a housing with a fan, vent holes, and filters should be used.
Another important consideration in setting up a VCR is locating it in a secure, protected area (exhibit 2.15). VCRs are attractive targets for thieves, but even more importantly, tapes can be stolen or destroyed if there is an illegal incident to be covered up. VCRs should usually be placed in a strong locking cabinet within a locked room. Only the school principal and one security person should have the key to this cabinet.
Research Report: The Appropriate and Effective Use of Security Technologies in U.S. Schools