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;

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.

The term emergency warning systems is used in this article as a generic term used to describe a three types of systems described in the Building Code of Australia (BCA) as follows;

  • Building Occupant Warning System
  • Sound and Intercom Systems for Emergency Purposes
  • Emergency Warning & Intercommunication System (deprecated)

Emergency warning systems alert occupants in an emergency by broadcasting a warning message or tones over a network of monitored loud speakers. Speakers are distributed throughout a building to ensure;

  • warning messages and tones satisfy a specific sound pressure level (volume) and are distinctly audible throughout all required areas of the building; and
  • warning messages intelligible (clearly understood) by the occupants.

Warning Messages & Tones

Up until 2003, Australia used alert and evacuation tones in accordance with Australian Standard AS2220.1-1989 These tones

Alert Tone

Evacuation Tone

In early 2002, we published an article called "Australia Adopts New Warning Signals" that expands on the move in Australia to move to the International Standard for Acoustics-Audible Emergency Evacuation Signal, also known as a "Temporal-Three, T-3 or Temporal Tone".

Temporal (T3) Tone

The introduction of this tone broadly coincided with the publication of Australian Standard AS1670.4-20041

Clause 4.3.3 of AS1670.4-2004 states;

Unless otherwise specified in the building emergency management plan, the alert signal duration shall be set to 0 seconds such that only the evacuation signal shall be produced.

In simple terms, in the default setting, the Alert Tone is bypassed and the Evacuation Tone is produced instantly.

According to one engineer I contacted with while researching this question, he said "this has had the effect of encouraging the use of evacuation signals without an alert."

So the caveat to this clause is the statement "unless otherwise specified in the building emergency management plan"

So what is the "building emergency management plan?"

According to Australian Standard AS3745-2010 Planning for emergencies in facilities an emergency plan is defined as follows;

1.4.9 Emergency plan
The written documentation of the emergency arrangements for a facility, generally made during the planning process. It consists of the preparedness, prevention and response activities and includes the agreed emergency roles, responsibilities, strategies, systems and arrangements.

The emergency plan shall document the organizational arrangements, systems, strategies and procedures relating to the response and management of emergencies. The Emergency Planning Committee ("EPC") in collaboration with the facility owners, managers, occupiers and employers shall determine which types of emergencies warrant specific emergency response procedures within the emergency plan.

Summary

So in summary, the Emergency Planning Committee writes the Emergency Plan. The plan may include directions to extend the duration of the Alert Signal.

I think this answers Alan's question and hopefully is of benefit to other building owners and managers.

Russ

  • 1. AS1670.4 Fire detection, warning, control and intercom systems - System design, installation and commissioning - Sound systems and intercom systems for emergency purposes
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