Topics Covered:

Central station alarm systems
Local alarm systems
Police connect systems
Extent of protection

Central Station Alarm Systems

A central station alarm is one in which the operations of electrical protection circuits and devices are signaled automatically to a “central station.” The “central station” is an independently owned, controlled, and operated facility that furnishes supervised protective signaling services and has no interest in the protected property. The central station maintains records of times the alarms are turned on and off, and has trained operators and guards in attendance twenty-four hours a day.

Central station systems are graded A/AA through C/CC, with AA being the best (although the commercial lines manual does not distinguish between, for example, “A” and “AA”). In order to receive the AA grade, the alarm system must have an approved line security feature—in other words, be able to detect any attempt to tamper with the connecting line between the central station and the protected premises. An alarm company guard must be able to reach the premises within fifteen minutes under normal conditions. The protected premises must have prearranged openings and closings.

Before continuing, clarification of two items is in order. First, “prearranged openings and closings” means that the alarm system will be disengaged automatically at certain times at the central station. At these times turning the alarm off or on at the premises by means of an outside key is unnecessary. The central station records the times the alarm is turned on and off, and who turns the alarm on and off during hours the building is normally closed. Every subscriber must submit times and days the premises are normally open and closed. As long as the subscriber opens the building within one hour after the prearranged opening or sets the alarm within one-half hour of the prearranged closing, no phone calls need to be made to the central station. If a subscriber needs to enter or leave the premises at other than the specified times, he or she must call the central station, using an appropriate code for identification. The central station makes time-stamped records of all openings and closings, which are kept for at least a year. Second, the commercial lines manual refers to “keys” or “no keys.” This means that the responding service does or does not have keys to the premises.

Central station alarm systems may also be graded “A.” There is no tamper-proof requirement; however, prearranged openings and closings are maintained. An alarm company guard must be able to reach the building within fifteen minutes under normal conditions. A “B” grade means that the alarm company guard  must be able to reach the premises within twenty minutes from the time an alarm is received; and, for a “C” grade, thirty minutes. Both of these grades assume prearranged openings and closings.

Local Alarm Systems

The protective circuits and devices of a local alarm are connected to an enclosed and tamper-protected bell, siren, or other loud-sounding device attached to an outside wall of the building in which the property is situated. The operation of a local alarm system is partially under the control of the property owners or others (such as a tenant) with an interest in the property to be protected. However, the local systems must be maintained under the care and inspection service of the installing company.

Grades vary for local alarms depending on the amount of electrical prevention against tampering. For example, grade A requires the sounding device to be electrically lined, while a grade B alarm may be electrically interfered with.

Police Connect Systems

A police connect system is one in which signals from the protected premises are also received at a constantly attended police station. All of the grade requirements for local burglar alarm systems in regards to tamper-resistant installation apply, except that the bell at the protected premises may have a delay of up to five minutes so the police may respond before the bell rings. These systems must be maintained and inspected at least once a year by the installing company.

Extent of Protection

The “extent of protection” is indicated by numbers 1, 2, or 3, with “1″ being the best. The number refers to the extent the alarm system protects the means of access to the premises—in other words, the extent of the installation. Installation 1 means that all windows, doors, transoms, skylights, or other openings leading from the premises are protected. All ceilings, floors, halls, party partitions, and building walls enclosing the premises are secured. Exempt from this requirement are building walls exposed to the street or public highway, or which are at least two stories above the roof of an adjoining building. Installation 1 does not apply to local alarms.

Installation 2 comprises three possibilities. The first is that all inaccessible windows must be protected with traps, and all accessible windows (except stationary show windows), doors, transoms, skylights, and other openings leading from the premises are protected with screens or burglar foils or traps. Finally, all ceilings, floors not constructed of concrete, halls, partitions, and party walls enclosing the premises must be protected with burglar foils or traps.

The second installation 2 possibility is that supervisory contacts only protect all movable openings leading from the premises, and provide a system of invisible radiation able to detect four steps of movement. The third installation qualifying as “2″ is one in which all inaccessible windows are protected by traps, and all accessible windows, doors, transoms, skylights and other openings leading from the premises are protected by screens, foils or traps. This installation must provide a network of invisible beams to subdivide the floor space of each floor or separate section of the protected area into three approximately equal areas, and more where necessary, to achieve at least one subdivision per thousand square feet of floor space.

Installation 3 also has three possibilities. The first is that all accessible windows, doors, transoms, skylights, or other openings leading from the premises are protected by screens, foils, or traps. The second is one in which all movable accessible openings leading from the premises are protected with contacts only. Invisible rays or channels of radiation with the minimum overall length of the rays or radiation equal to the longest dimensions of the area or areas so movement through the channel is detected must be provided. Finally, the third of the installation 3 possibilities is that contacts protect all doors leading from the protected area, and a system of invisible radiation to all sections of the enclosed area capable of detecting four-step movement is provided.