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Fire Protection Specialists

With over 135 years of experience, Wormald is the specialist in fire safety in Australia.

Fire Protection Specialists

With over 130 years of experience, Wormald is the specialist in fire safety in Australia.

STI-CIS Speech Intelligibility Meter


A sound level meter and speech intelligibility analyser using the Speech Transmission Index – Common Intelligibility Scale (STI-CIS) methods of measurement, is used together with the TALKBox and STI-PA sound source, to test Sound Systems For Emergency Purposes installed to AS 1670.4 for compliance with intelligibility and audibility requirements.

Sound systems for emergency purposes play an important role in the orderly evacuation of buildings during emergencies. Australian Standard AS1670.4 requires that voice messages be intelligible. This requirement ensures that vital emergency messages transmitted through a building’s sound systems for emergency purposes can be clearly heard and understood. The STI-CIS Meter, a technological break through, is a tool for making objective measurements and validation of compliance with both audibility and intelligibility requirements. Should a real emergency occur, the occupants of your building will be able to hear, understand and respond to the vital life-safety information your system is designed to provide.

The STI-CIS portable tools enable you to do the following:

    • Perform objective testing of the intelligibility of sound systems for emergency purposes using the internationally recognised Speech Transmission Index method as specified in Annex B, Clause B1 of IEC 60849.
    • Simplify the test process. Simple and easy to use, the “two-button” design of the STI-CIS Meter allows voice intelligibility to be measured by anyone, in any location.
    • Minimise testing downtime and disruption. Each intelligibility measurement requires only 15 seconds, so test time is minimised.
    • Conduct testing in an occupied building. A test signal that simulates human speech is broadcast during testing. Because the test signal is neutral in tone and content, testing can be conducted in an occupied building without triggering an alarm response from occupants. (Pre-notification of building occupants in advance of testing is always recommended.)

Wormald Direct provides easy, instant access
to data relating to Service Calls and Test Results


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Alarm & Evacuation Enquiry

Alarm & Evacuation Enquiry