Bells, Buzzers, Horns........ Voice Alarm and Voice Evacuation systems have their SAY!
Voice Alarm (VA) and Voice EVAC (VEVAC) systems typically co-reside with other alarm (mostly fire alarms) and emergency based systems to provide spoken alarm, evacuation information and instructions. Commonly integrated with complex / high-end fire systems, Voice Alarm systems are specially designed Public Address (PA) installations that can be seen in many situations, especially public assembly areas (stations, airports, shopping centres etc..) Typical voice evacuation messages provide clear instructional information about the alarm, emergency and evacuation procedures.
This diagram shows a typical example of an evacuation period following the start of a fire. It shows how a Voice Alarm application compares with a conventional 'bells & sounder' based fire alarm to shorten the overall evacuation time.
Careful consideration to the system design, building design and defined escape routes are extremely important to any conventional alarm or evacuation based system. A VA / EVAC based system also carries these considerations, but has additional design aspects and considerations. The following are summary outlines of specific standards and regulations governing the design and implementation of Voice Alarm / EVAC products and systems:
BS5839 is a British Standards code of practice for ‘Fire detection and alarm systems for buildings’. BS5839 part 8, covers the 'code of practice for emergency voice communication systems'. It is important to recognise specific design considerations for VA / EVAC systems, part 8 of this respective British Standard covers these details. BS5839-8:2013, supersedes BS5839-8:2008.
Whilst BS5839-8 provides some specific requirements of voice and emergency systems, the details with regards to audio 'specification' are defined only briefly and within codes or practice, and does not directly cover aspects of audio performance. BS 7443 (now BS EN 60849) was developed and introduced to cover audio specifications and performances such as: audibility and intelligibility.
It is obviously very important that any 'Voice' based alarm and EVAC system is well designed so that the audio and spoken messages are clear and intelligible. This standard works together with BS5839-8, and provides a basis for consideration the building acoustics when designing a Voice Alarm (VA) EVAC system.
BS EN 54 is a suite of European guidelines which aims to harmonise fire detection and fire alarm systems design, installation and servicing within the EU. First published in 1996, confused markets and competitive country codes of practice (CoP), has seen EN54 take quite some time to establish itself amongst the individual EU country standards. April 2011, saw agreement and EU directive to see EN54 replace most country standards and CoP's. However, there has been individual country resistance. Most EU countries (24 out of 27) have adopted the EN54 directive. The UK has not - with the progession of BS5839 to update in 2013, it is unlear as to the long term plans for BS EN 54, some expect the UK to align with Europe and adopt sometime BS EN 54 in the near future.
The following are specific sections of BS EN 54 which relate to Voice Alarm (VA) / EVAC Systems:
- BS EN 54-4 (Power Supply Equipment)
- BS EN 54-16 (Voice Alarm Control and Indicating Equipment - VACIE)
- BS EN 54-24 (Voice Alarm devices / Loudspeakers)
Specifies requirements, methods of test and performance criteria for power supply equipment of fire detection and fire alarm systems installed in buildings (fire alarm and voice alarm products and equipment). Example requirements would include power supplies to all associated control, indicating, routing, processing products and equipment (routing matrix, mixers, amplifiers, announcement storage devices, etc...)
Originally based on EN-2 (fire alarm products and equipment), EN-16 covers all of the associated 'electronics' products and components of a Voice Alarm (VA) / EVAC system, (amplifiers, mixers, processing etc...). The general requirements of EN54-16 are to: provide indication and display requirements of the system’s state (quiescent, voice alarm and / or fault warning) including power supplies.
Loudspeakers used in Voice Alarm (VA) applications play a central role in delivering instructional evacuation information. It is crucial therefore, for VA loudspeakers to achieve a minimum acoustical performance, as well as constructional and environmental requirements, to be suitable for use in VA / EVAC applications (thermal fuse, ceramic connection blocks and end of line / EOL monitoring of speakers).