EWIS

Evacuation Tones in Aged Care Facilities

AS 1670.4-2004Almost every day we receive a telephone call or email from the public asking what appears to be a simple question about fire protection.

Over the weekend, I received the following email from 'Alan' asking about the operation of an emergency warning system;

Has there been any recent changes to the alert sequence; alert,evac then voice over. we have been told that the system must go direct to voice over {evacuate evacuate} this would cause serious problems in the aged care industry.

Before I answer the question, it is important that we go over a couple of background issues;

Emergency Warning Systems - Principle of Operation

For many of us, the first time we learn about an emergency, is when we hear the telltale signs of an emergency warning system in operation.

A emergency warning system is a life safety system installed to safeguard occupants from illness or injury by warning them of a fire or emergency and to safeguard occupants during the orderly evacuation of a building in an emergency. They assist in these two functions by;

  • providing mass notification of an emergency; and
  • providing a method to communicate with and direct building occupants in the event of an emergency.

How long will my fire panel battery last?

I have been asked to discuss the reasons why we recommend the installation of a second (tertiary) set of backup batteries installed in parallel to the existing main (secondary) batteries installed within a fire panel during a planned mains power shut down.

Example
The building owner contacted us to advise they plan to shut down the power to their building for a period of 8 - 12 hours for maintenance purposes. The planned shut down will also remove mains power from the fire panel.

There is a small fire panel installed on site designed to Australian Standard AS1670.1-2004, fitted with an occupant warning system.

In this example the customer wanted to know if it is necessary to install tertiary backup batteries.

How to measure EWIS or PS speaker zone impedance

Impedance is a measure of the opposition to the flow of an alternating current in a circuit; the aggregation of its resistance, inductive and capacitive reactance. Represented by the symbol Z.

AS1670 Calculating Power Supply Requirements for Fire Alarm Systems

3.16 POWER SOURCES

3.16.1 Primary power source

The CIE shall be energized by a reliable source of supply and shall be connected in accordance with AS/NZS 3000. The power source shall be either?
(a) an a.c. supply from an electricity authority; or
(b) a source equal in quality and reliability to Clause 3.16.1(a). The primary power source shall be capable of operating the system including the occupant warning system as per Clause 3.22(b).

3.16.2 Secondary power source