Oil and gas enterprises deal with extraction, transportation or processing of highly flammable or explosive materials. This is taken into consideration in their technological process and the warning systems in these companies are usually used for two purposes:

• To inform employees of operating conditions, which, even though they are standard from the technological point of view, represent a higher risk of explosion or fire;
• To inform employees of actual accidents and to perform their evacuation;

Depending on the potential hazards, the analysis of which is carried out in accordance with applicable standards, these warning systems are established based on the regulations applicable for fire prevention and general occupational health and safety protection or, if a certain risk threshold is exceeded, based on the applicable civil defence regulations.

The solution is based on risk analysis typical for this type of the company and is designed on the basis of the AMADEO system and VEKTRA software. It can also be used for direct evacuation broadcasting or it can be connected to an existing broadcasting system. It consists of:

• A dispatching centre;
• Radio-controlled AMADEO radio units;
• Loudspeakers for the 100 V circuits;
• High-power pressure distribution systems;
• Optical alarm devices;

Depending on the extent of the hazards the acoustic system covers only the threatened workplaces in the company’s premises or it also provides the coverage of the surrounding area in order to warn the people living close to the company in question. Visual alarms are used in the noisy operations to increase the efficiency of the warning message broadcasting. The system can be connected to a superior public address system managed by the state of a municipality. The sensors can be connected directly to the radio units but it is more common to connect them to the existing complex technological monitoring systems.

Dispatching centre
The main tasks of the dispatching centre are as follows:

• Continuous monitoring of the status/functioning of the entire system;
• Monitoring the conditions of the production technology and the hazardous material levels;
• In the case of a higher risk noticed during the operation the relevant notifications are activated or if activated locally, the operators are notified;
• In the case of an emergency situation the relevant warning notifications and visual alarms are activated. In the case of the local activation the centre can activate other radio units considering the threat criticality;
• It activates the notification process, i.e. calling up people in charge to the workplace in the case of an emergency situation and informing the relevant institutions on such situation occurrence;
• Recording the dispatching centre communication for its future analysis;

It consists of:

• A computer equipped with the VEKTRA software;
• Additional notification and recording modules;
• AMADEO central office or a central communication unit; 

Local AMADEO radio units
Individual operations are equipped with AMADEO radio units used as autonomous systems locally reacting to individual operating conditions. They forward status information to the dispatching workplace, from where they also receive activation-related instructions. Radio unit behaviour algorithms are defined via their configuration and programming. They can also work in autonomous mode if communication with the superior dispatching workplace is interrupted. 100V line circuits and loudspeakers with 5 - 20W output are used to broadcast acoustic warning messages in the internal premises with standard background noise. Noisy plant shops and external areas require the use of high-power horn loudspeakers with 150-300W output. Beacons are applied to make the warning process in noisy operations more efficient.

Communication network
This type of the solution mainly uses radio communication infrastructure. TCP/IP network communication or any other line-based communication is rarely used due to the high establishment cost of the high-quality underground lines between individual operations and due to the simple susceptibility of aerial lines to failures. Just like the radio units, network communication is backed up for 72 hours of operation during a power outage.

System control
The system can be controlled:

• From the dispatching centre;
• From local control units connected to the radio units; depending on their configuration they can even control other radio units;
• From other monitoring and control systems;

• To carry out the warning process in several separate buildings at once;
• For noisy operations that are threatened;
• For simultaneous external and internal sound distribution;
• If the system must stay locally-controllable even in the case of a failure at the dispatching centre;
• If a combination of operation notifications and warning notifications is required - defining priorities, interruptions and notification reactivation etc.
• If an automated notification process is required in order to call in supervisory to the workplace;
• For the purposes of connecting the facility’s monitoring and control system (SCADA);
• To back up the system with regards to a power outage;