Overview of EVC Systems.pptx

Overview of Emergency Voice
Communication System
By Rasel Md
Prepare By Rasel-Senior Project Engineer-Globalwid M&E

What is the Emergency Voice Communication System?
Emergency voice communication
(or EVC) systems provide two-way
communication during the
evacuation of a building during a
fire or other emergency.

Two types of emergency voice communication system (VCS):-
1.One-way VCS
A. A network of loudspeakers installed at strategic positions
2. Two-way VCS
A. A network of loudspeakers installed at strategic positions
B. A network of telephone handsets located at designated areas
Apart from VCS, there is the Public Address (PA) system.
The Need For VCS
1. Success of fire-fighting/rescue operations dependent on reliable voice communications among officers at scene
2. Occupants can be advised of the situation via VCS
3. Portable radio sets used by responders subjected to “blind spots”

One-way VCS to be provided as follows:-
1. For all large buildings under Purpose Groups III (not applicable to primary school, secondary school and
junior colleges), IV, V, VI, VII & VIII with gross floor area greater than 5000m² or having a total occupant load
exceeding 1000 persons; or
2. For all buildings belonging to Purpose Groups III, IV, V, VI, VII, and VIII of more than 24m in habitable
height.
Exception
For hotel or health care buildings of less than 24m in habitable height, gross floor area (GFA) not greater than
5000m² and total occupant load (OL) not exceeding 1,000 persons, an ordinary PA system shall be provided.
Loudspeakers for the ordinary PA system shall be provided in every lift lobby, staircase enclosure and other
strategic positions within audible distance of all parts of all storeys throughout the building.

Two-way VCS to be provided between the Fire Command Centre (FCC) and the following areas:-
1.Every fire-fighting lobby, including 1st storey;
2.All fire-fighting related mechanical equipment rooms inclusive of sprinkler pump room, wet rising main pump room, hose reel pump room,
switch rooms and generator rooms;
3.All rooms housing smoke control equipment;
4.All lift machine rooms;
5.Fire lift;
Where the lift car is equipped with built-in intercom system that complies with clause 9 of SS546, the two-way VCS can be exempted
6. Each area of refuge; and
7. Air-handling control rooms. Where AHU can be remotely monitored and controlled at the FCC, and cannot be by-passed locally, and the
electrical cabling between AHU rooms and FCC are fire-rated, the two-way communication system can be exempted.

Why use a Emergency Voice Communication System?
Where a one/two-way emergency communication system is required, it shall
comply with the requirements stipulated in SS 546: Code of Practice for
Emergency Voice Communication Systems in Buildings

Why Emergency Voice Communication System a
mandatory requirement?
• A One-way Emergency Voice Communication (EVC) System on the other
hand is a mandatory requirement by the Fire Code. The Fire Code requires
such systems to be designed, installed and maintained according to SS546
requirement as it is part of the fire safety system.

Why use one-way EVC System?
The primary purpose of the one-way EVC system is to enable announcements
to be made, both manually and automatically to individual, or collective groups
of zones, to facilitate a quick and orderly Evacuation of occupants in the
building in an Emergency Situation.
The effectiveness of the Emergency Voice Communication System depends on
the quality of the announcements. It shall be heard loud and clear. The building
shall be zoned such that it shall be possible to make announcements to
individual floor. Staircase cores may be group into one zone where appropriate.

What is a Emergency Voice Communication
System made up of?
Components forming the System - 5 Items
1. Ceiling Loudspeakers
2. Box Loudspeakers
3. Horn Loudspeakers
4. Control Station
5. Emergency Alarm Call Station

One-way Emergency Voice Communication System
– Loud Speakers
Loud Speakers - Design
• Speaker selection
• Estimate required sound level
• Determine speaker spacing
• Speaker layout
• Determine speaker load
• Determine speaker cable size

Areas required to install sufficient quantity of
loudspeaker.
-Habitable room
-Basement areas
-Escape staircases
-Staircase lobbies and lift lobbies forming parts of the means of escape
-Main entrance lobby
-Corridors leading to exits
-Service areas where people may be working
-Area of refuge
-Assembly areas
-Lift cars and
-Any other locations as may be required by the relevant authority

One-way Emergency Voice Communication System
– Loud speakers

Interfacing to Fire Alarm & Messages
Pre-recorded Message
The recording should be made, where possible, by persons trained in the proper use of the
microphone
Alert messages shall be broadcast in a minimum of 2 cycles and continue until manually silenced or
superseded, manually or automatically, by an evacuation message or by a 2nd alert messages
Evacuation messages shall be broadcasted in a minimum of 2 cycles and continued until manually
silenced.
NOTE: Time gap between the 2 cycles and the next two cycles are important.
* Too short – listeners might not realize that the message has ended
* Too long – listeners’ safety could be put at risk while they await a repeat message for clarification

Thank You

Overview of EVC Systems.pptx

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