LAS (local alerting systems) and mating with PAGA networks

The modern emergency alerting facilities, including voice address, are the most important part of the integrated security system at the industrial site.

An alerting system has to be constructed with due regard not only to the area, and the number of rooms at the enterprise, but also the architectural peculiarities of the building, its plan, the acoustic properties of the material, etc.

Local alerting systems operate automatically and are intended for alerting in small zones. When an emergency situation occurs, the LAS is used for public address, provides for evacuation messages transmission, commands the evacuation, prevents panic from occurring. A LAS includes sirens for alarm signals, equipment for speech or voice messages, indicator lamps and lighting devices. For creating of large alerting zones, and mating with PAGA networks, equipment manufactured by the Telegrafia company is used.

eng5.jpg ·         The PAVIANelectronic siren (External warnings / large systems)


·         The SCREAMER electronic siren (Internal / external warnings)

Sirens can be used either as separate, locally controlled equipment, or as a part of the alerting system. The latter is more common. Small alerting systems consist of several sirens, while large ones can include thousands sirens.

Very high requirements are imposed upon the self-diagnostic functions of the sirens and the infrastructure related to them. When an ES occurs, there are power drops practically every time, and also failures in the telecommunication infrastructure. In most cases the standard telecommunication infrastructures do not comply with long-term reserve requirements for situations of power outages. These are the reasons why large alerting system practically always use two independent channels to control a network of sirens.

Organization of alerting systems


  • The activation speed, even for small alerting and warning systems, is measured by tens of seconds: 350 sirens can be activated in approximately 20 seconds
  • The speed of obtaining feedback information (performed approximately within 1 minute) about activation of sirens is measured in minutes: from 350 sirens