Sound Systems For Emergency Warning Systems

Sound_Systems_For_Emergency_Warning_Systems_webEmergency Warning & Information Systems (EWIS) are very much a part of life these days. They are mandatory for most commercial buildings and public spaces and must comply with very specific standards.  

We regularly receive support calls asking if a particular product is “EWIS compliant”. Unfortunately, there is no simple answer to this question as the Australian standards are not product specific, they are system standards. There is no “EWIS approved” standard that applies to individual products (at least with respect to sound systems). The following article attempts to explain the relevant standards and (hopefully) address some of the apparent confusion over this.

Standards, Standards and more standards…

It is no wonder that confusion abounds when talking about EWIS systems as there are multiple standards out there that refer to or partially cover EWIS systems. A Google search under “emergency sound system standards” returns 959,000 hits! Including links to suppliers product and standards published by various organisations including, but not limited to, UL (Underwriters laboratories), ISO (International Organisation for Standardisation), IEC (International Electro technical Commission), AS (Standards Australia), and BCA (Building Code or Australia). The first hurdle is to work out which of these you need to comply with!

In Australia, the two most relevant standards are AS1670.4 and AS60849. Note my use of the term “most relevant” as these standards make reference to other standards documents and to BCA documents. However, AS1670.4 and AS60849 cover the majority of technical requirements specific to sound system applications. I would love to be allowed to reproduce these documents as part of this article; however, the good folk at Standards Australia tend to take a dim view of this. So if you wish to obtain a copy of these documents you will need to purchase them from Standards Australia. They can be purchased online at AS1670.4 and AS60849 will set you back around $93.00 each for print on paper versions, or $84.00 each for electronic copies. Please don’t email me complaining about these prices, for what it’s worth, I agree, but I don’t want to start a Standards Australia rant in this issue.

I can however summarise for you without ending up in court (at least I hope so)…

AS1670.4 – 2004

Fire Detection, warning, control and intercom systems – System Design, installation & commissioning.  Part 4: Sound Systems and Intercom systems for emergency purposes.

This document details the technical requirements for an emergency warning sound system including required sound pressure level, coverage and intelligibility, cabling requirements, component monitoring, error reporting, and operation under mains fail conditions.


Sound systems for Emergency purposes (IEC 60849:1998 MOD)

This document is an adaptation of the international IEC standard of the same number. The document details the IEC requirements and shows local variations applied to the Australian standard.

A common theme of both documents is they specify requirements of the system as whole, not individual components. AS1670.4 section 4.2 states; “The individual components shall be compatible and selected in order to achieve stable and reliable performance. The system shall use components in accordance with the component manufacturer’s specifications.”

In other words, it is up to the system designer to select suitable components and design a system to comply with the (system) standards. The standards do not dictate what components you must use.

Yes, it is true that several manufacturers offer components with features designed specifically to suit EWIS applications, but this does not constitute any form of approval and certainly does not exclude other products from these applications. As long as the SYSTEM meets the standards, you are free to use whatever components you wish (in context of the sound system).

Conversely; occasionally you may see manufactures who claim IEC60849 (or alternate standard) compliance on their product specification sheets. This should be read as “designed to meet the intent of <standard number> if used according to instructions”. However, this is no guarantee of system compliance as it is possible to build a system entirely from “compliant” products, yet the system could fail to meet specifications due to design or installation errors (e.g. poor loudspeaker placement). The responsibility of compliance lies entirely with the system designer and/or installer.

Let’s use this understanding to address some of our frequently asked questions regarding  EWIS systems:

1. Our venue has an existing performance system, however I have been told it cannot be used for EWIS and we must install a separate sound system for EWIS announcements.

Not True. You may use the existing system for EWIS announcements as long as it is engineered to comply with the standards listed above. In some situations, this may involve adding facilities for operation under mains fail conditions and/or load monitoring. However, it is definitely not true to say the performance system CANNOT be used.

2. Loudspeaker model XYZ cannot be used for EWIS applications as it does not incorporate DC load monitoring.

Not True. The standards demand load monitoring; however, they do not state how this must be implemented. Yes DC monitoring is one way to do it, but any method that meets the requirements of the standard is acceptable. AS1670.4 section 4.4.3 states (regarding supervision of signal lines); “Loudspeaker lines between sound system CIE and loudspeakers: Open-circuit and short-circuit”. Many amplifiers include load monitoring facilities that meet this requirement, but do not require DC load monitoring. 

3. EWIS systems cannot be used for any purpose other than EWIS announcements and/or alerts.

Not True. AS1670.4 Section 4.3.9 (Use of sound system for non-emergency purposes) states (minor rewording for clarification); “The sound system may be used for public address or background music under non-emergency conditions provided that:
          a) The CIE is designed to override these functions…
          b) The power supply has sufficient capacity…
          c) The system integrity is maintained (in other words you can’t do a manual re-patch)
          d) Specified continuous fault monitoring and indication is maintained”

I trust this article has assisted in some form to clarify the bewildering maze of standards relating to emergency waring sound systems, and hopefully may have busted a few myths in the process.  If you are actively working in this area or considering entering this market, I strongly encourage you to purchase and become familiar with the relevant standards documents. These are legally binding documents and let’s face it, the ultimate purpose of these systems is to save lives, and this should never be under engineered.

Jeff MacKenzie
Manager, Technical Resource Group – Jands Pty Ltd

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