The systems used to make the people in the building aware of a situation are called the Public Address and Announcement System. Such systems are called Emergency Announcement and Voice Evacuation Systems if this announcement system is considered to continue to be used in case of a disaster such as fire and earthquake and to make an understandable announcement in case of an emergency without being dependent on humans.
The main differences between the Public Address and the Emergency Announcement consist of a clear announcement above a certain value of the ambient sound level, controllability, auxiliary power supply, fire resistant installation, certificates that can be used for this purpose and that it has these qualifications.
In other words, the Public Address and Announcement System does not guarantee operation under the disaster conditions. It is used for announcing general information and/or broadcasting background music. The Emergency Announcement and Voice Evacuation System, on the other hand, is not mandatory to be used in the normal operation, but it aims to continue to function in an emergency case and evacuate the people in the building by directing them vocally.
Today, Emergency Announcement and Voice Evacuation Systems can be used for both purposes in certain applications. However, the opposite constitutes an unacceptable situation. In other words, the Public Address Systems can never be used as Emergency Announcement and Voice Evacuation Systems.
When protecting life in an emergency case is concerned, the Emergency Announcement and Voice Evacuation Systems must be installed in accordance with certain rules.
Although there are different standards in each region or country, EN-54-4, EN54-14, EN-54-16, EN-54-24 and EN-54-32 standards in the countries of the European Union, BS-5839-8, BS-EN-60849 standards in the United Kingdom, NFPA72 and NFPA101 Application Codes in the United States are generally the guidelines, standards and regulations that are referred to in the designs.
In addition to the above-mentioned standards, where the emergency announcement systems should be used in the projects in our country is described in the Section 7 under the Article 81 of the Regulation on Fire Protection of Buildings (2015).
5 Basic Criteria in Emergency Announcement Design
Sound Level Measurement: The first step in the design of an emergency announcement system is the measurement of the ambient noise sound level. It is desirable that the value of the announcement volume to be obtained according to the standards taken as a basis in the design is above a certain amount of the ambient noise sound intensity. This may vary depending on the standards.
Speakers: The second step is to select and place the speakers. It should be of the type suitable for the ambient conditions of the place to be used. In addition, an appropriate number and frequency of placement should be made in order to obtain the desired announcement sound intensity in dB. The speakers should be designed according to the sound intensity dB (decibel) values they generate, not Watt values that are the power values that they consume.
Alarm Zones: The third step is to determine the alarm zones according to both the facility conditions, the emergency escape action plan and the standards taken as a basis for the design. The alarm zone structure is also important for the installation.
System Center: The fourth is the planning of the system center. The power calculations are made according to the number and power values of the speaker and the number and system central architecture of the amplifiers are determined. The location and number of the announcement point should be determined at this stage. In case of power cut off, the backup power supplies should also be provided to meet the energy needs of the system center.
Certification and Documentation: As a last step, the project and documentation must be necessarily requested.
It is very important to certify that all the equipment that constitutes the system is manufactured in accordance with the relevant standards. Otherwise, the operating performance and emergency operation of the system cannot be guaranteed. For example, if the project is designed according to EN norms, EN54-24 certificates should be requested for speakers and EN54-16 certificates for system central equipment (control unit, inspection modules, redundant power supply, amplifiers, etc.).
