Most chemical factories use harmful substances in their production which, when transported, stored and processed, may endanger human health and life. Experience from all over the world suggests that despite stringent regulations and great care in performing such activities, there is still a certain level of risk of leakage of such substances and environmental pollution. Therefore, the presence of harmful materials must be monitored continuously and all effective safety measures adopted after they exceed the legally permissible concentrations.

A minimum of two potentially dangerous concentration levels of hazardous substances are usually distinguished and monitored:

• Increased concentrations – the interval of concentrations of hazardous substances exceeding the standard values not yet endangering human health.
• Emergency concentrations – the interval of concentrations of hazardous substances exceeding the legally permissible values and seriously endangering human health.

The number of specific concentration levels of hazardous substances to be monitored can be even higher. It is given by the relevant laws, standards, or internal company regulations, and it also depends on types of hazardous material.

The solution of an early warning system in the chemical industry was designed as a sophisticated, integrated monitoring, warning and notification system.  As a first step, the system provides direct monitoring of the occurrence of hazardous substances and their concentration levels. For the sake of greater safety, its monitoring sensors are independent of other technological systems that control chemical production and are connected to the Amadeo PA system. A minimum of two potentially dangerous concentration levels of hazardous substances is set for the measurement of dangerous concentrations. If the values measured fall within the interval of increased concentrations, the system notifies the operators as a second step, or, in unmanned operations, notifies the duty members of the responsible staff. These people can verify the reasons for the increase in concentrations and take the appropriate safety measures without declaring a state of emergency. Once the values measured exceed the threshold level for emergency concentrations, broadcasting of a warning message is then activated. Depending on a type of substance and applicable regulations, the broadcasting activation can be delayed, thereby providing the operators with extra time for verifying the concentrations using an alternative method and preventing a false alarm. After the confirmation and activation of mass warning, the system allows automation of all related processes. Furthermore, it will enable the activation of selected industrial units, the industrial area as a whole, or even the local population.

This technological solution is appropriate when:

• Operational and early warning monitoring systems need to be separated, which is due to different settings of hazardous substance concentration levels.
• No operational monitoring system is available.
• A high level of process automation or an unmanned control centre is required.
• Different system responses to several dangerous concentration levels of hazardous substances are required.

The system consists of the following elements:

• The main manned or unmanned control centre
• Radio-controlled Amadeo PA units, optionally equipped with additional modules to increase the number of inputs for monitoring sensors
• Sensors monitoring the occurrence of hazardous substances
• 100 V PA loudspeakers
• Powerful pressure loudspeakers
• Emergency beacons

Regarding the degree of risk, the warning system can cover only the industrial units in danger, or it can also cover a wider area and send a warning to the local population. In noisy operations, a visual signalling system is used to enhance the effectiveness of the warning signal distribution. The system can be connected to the superior national early warning system managed at both national and municipal levels.