• BSE

The Public Announcement (PA) System—One-way Emergency Voice Communication System

Updated: Oct 21, 2019

You may have heard this pre-recorded message commonly throughout the building, during a fire alarm emergency activation: “Ladies and gentlemen, your attention please. A fire alarm has been activated in the building. We are investigating the cause of the alarm. Please remain calm and standby for further instructions.”

This message is being broadcast from the Emergency Voice Communication (EVC) System The EVC System has two types of systems that are linked to the Automatic Fire Alarm System, namely the Public Announcement (PA) System (One-way type) and the Fireman Intercom (Two-way type).

In this post, we shall look into the PA System that is crucial in ensuring an orderly evacuation of personnel during emergencies and assists the in-house fire wardens, Company Emergency Response Team (CERT) and relevant authorities in fire-fighting operations

Located at the Fire Command Centre (FCC), the area is only accessible for Authorized Personnel such as the Building Management, Approved Contractors and the Regulatory Authorities.


The following regulations thus require premises to have an operationally-ready and well maintained Emergency Voice Communication (EVC) System:

  • Code of Practice for Fire Precautions in Buildings 2018 (Fire Code 2018)

  • Code of Practice for Emergency Voice Communication System in Buildings (SS 546: 2009 - formerly CP 25: 1999)

Who is responsible for the EVC System - One-way?

  • Building Owners and Council Members are responsible by regulation

  • Fire Protection Specialists, like BSE, MCST Managing agencies, and/ or technicians are engaged to assist Building Owners and Council Members

Basic features of the EVC System - One-way

  • Control stations that can enable announcements to be made, both manually and automatically to personnel, to facilitate a quick and orderly evacuation from the building in the event of emergencies

  • Network of loudspeakers installed in strategic locations of the building

  • Overriding facility to operate by silencing all the alarm sounding devices in the building, but only after the fire alarms have operated not less than 15 seconds.

  • Recording system of not less than 120 minutes continuous recording duration

  • Fault monitoring facility, power amplifiers, batteries power source, and

  • Interface with the Fire Alarm System

What kind of maintenance will the EVC System - One-way need and how often?

According to regulations, the recommended frequency of inspection, testing and maintenance of the EVC System - One-way in buildings is NOT MORE THAN THREE (3) MONTHS. However, the regulatory testing and maintenance of the EVC System - One-way are conducted ANNUALLY, in conjunction with the Fire Alarm System and its related Fire Protection equipment

For industrial buildings with a higher risk of fire incidents, more frequent testing and maintenance may be conducted to ensure Total Fire Safety in the premises.


Inspection procedure

Inspection checklist for the EVC System - One-way:

On a recommended NOT MORE THAN THREE (3) MONTHS basis:

  • Inspect that the EVC equipment is not obstructed

  • Inspect the visible indications on the control station panel

  • Inspect the risk of fire hazards near the location of the equipment

  • Inspect the availability of the operating instructions

  • Inspect the standby battery power source

On a recommended ANNUAL basis:

  • Same as the above NOT MORE THAN THREE (3) MONTHS basis

Testing procedure

The EVC System is manually tested via the simulation of a fire or fault scenario to determine the performance against the system design and regulatory requirements:

  • Measure the time required for the system to broadcast in an emergency mode

  • Test that all non-emergency functions are disabled during emergency mode

  • Test that the system is able to broadcast warning and speech signals in one or more areas simultaneously

  • Test that the system is able to receive indications of the correct functioning

  • Test the fault scenario between the communication link of the equipment and the fire alarm system

  • Test that the loudspeakers can transmit the messages based on the speech intelligibility and sound pressure level requirements

  • Test any auxiliary functions linked to the equipment

Next, defects are identified for recommendation and rectified in a timely manner.


Tips on having an optimum EVC System - One-way:

  • Ensure that the interface with the Fire Alarm System is connected and working in order, in the event of an emergency

  • Ensure that automated pre-recorded messages are able to be broadcast to all loudspeakers in the building

  • Ensure that the microphone can be used manually to broadcast to all loudspeakers in the building

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