Fire Alarm Audio Applications Guide - CFAA

1 fire Alarm Audio Applications Guide Guideline for Designing Emergency Voice/ Alarm Communications Systems for Speech Intelligibility 579-769. Rev. B. 2004 Tyco Safety Products - Westminster. All rights reserved. Printed in the All specifications and other information shown were current as of publication, and are subject to change without notice. Copyrights and Trademarks Copyrights Copyright 2004 Tyco Safety Products Westminster. All rights reserved. All specifications and other information shown were current as of document revision date, and are subject to change without notice. Printed in the United States of America.

2 Trademarks Tyco, Simplex, and the Simplex logo are trademarks of Tyco International Services (AG) or its affiliates in the and/or other countries. All other products are trademarks of their respective manufacturers. All registered and unregistered trademarks are the sole property of their respective companies. Notice This Guide is intended as an informational resource and is not intended to provide definitive legal, engineering, design or architectural advice. Legal, engineering, design, or architectural requirements and interpretations may vary from jurisdiction to jurisdiction or project to project. Therefore, no warranty or representation is made about the sufficiency of any of the contents of this Guide .

3 Tyco Safety Products Westminster, disclaims any and all liability for damages of any sort claimed to result from the use of this Guide . This Guide is distributed with no warranties whatsoever, including but not limited to, warranties of merchantability or fitness for a particular purpose. Readers with specific questions should consult the appropriate advisor. Table of Contents Chapter 1. Audio Intelligibility Overview Introduction .. 1-1. Chapters of this Publication .. 1-1. In this Chapter .. 1-1. Importance of Audible and Intelligible Emergency Communications .. 1-2. Audio Intelligibility Importance .. 1-2.

4 Designing for Intelligibility .. 1-2. Chapter 2. Background Information Introduction .. 2-1. In this Chapter .. 2-1. Basic Audio 2-2. Ohm's Law and the 2-2. Adding 2-3. Sound and 2-4. The Relationship Between Sound and Hearing .. 2-4. The Nature of Speech .. 2-5. Introduction .. 2-5. Consonants and Vowels .. 2-5. Room 2-6. Introduction .. 2-6. Reverberation .. 2-6. Estimating Reverberation Times .. 2-7. Countering the Effects of Reverberation .. 2-7. Speaker 2-9. Inverse Square 2-9. 2-10. Speaker Dispersion Angle and Q .. 2-10. Speaker 2-12. Power Rating .. 2-14. Speaker 2-14. Distributed Wall Mounted 2-15. Introduction.

5 2-15. 2-15. Disadvantages .. 2-15. Design of a Distributed Wall Mount System .. 2-16. Chapter 3. Audio Intelligibility Introduction .. 3-1. In this Chapter .. 3-1. iii Influences and 3-2. Introduction .. 3-2. Background Noise .. 3-3. Reverberation .. 3-4. 3-5. Microphone Technique .. 3-5. Measures of Intelligibility .. 3-6. Introduction .. 3-6. The Common Intelligibility Scale (CIS) .. 3-6. The STI Method .. 3-7. STIpa .. 3-7. 3-7. RASTI .. 3-7. Percent (%) 3-7. Phonetically Balanced Word Scores .. 3-7. Practical Measurement of Intelligibility .. 3-8. Introduction .. 3-8. Tools for Predicting Intelligibility.

6 3-9. Introduction .. 3-9. Acoustical Modeling Software .. 3-9. Chapter 4. Emergency Voice/ Alarm Communications Systems Introduction .. 4-1. In this Chapter .. 4-1. A Typical Emergency Voice/ Alarm Communications System .. 4-2. Typical Emergency Voice/ Alarm Communications 4-2. 4-2. Parts of an Emergency Voice/ Alarm Communications System .. 4-3. Command Center .. 4-3. Audio Riser .. 4-3. Transponder .. 4-3. Speaker Circuits .. 4-4. Chapter 5. Regulatory Issues Introduction .. 5-1. In this Chapter .. 5-1. Audibility .. 5-2. Tones and SPL .. 5-2. High Background Noise .. 5-3. Large Areas .. 5-3. Intelligibility.

7 5-4. Intelligibility .. 5-4. Intelligibility Certification .. 5-5. iv Chapter 6. Speaker System Design Method Introduction .. 6-1. In this Chapter .. 6-1. Speaker Design Method .. 6-2. Introduction .. 6-2. Step 1: Room 6-2. Step 2: Calculate the Number of Speakers .. 6-2. Step 3: Audio Power and Individual Speaker Wattage Tap .. 6-2. Step 4: Model Design to Predict 6-2. Step 5: Verify Final Installation .. 6-2. Recommendations for Maximizing System 6-3. Maximizing Intelligibility .. 6-3. Applying the Methods .. 6-4. Design 6-4. Example 1: Office Space .. 6-4. Example 2: 6-6. Example 3: 6-8. Example 4: Lobby.

8 6-10. Conclusion .. 6-13. In 6-13. Chapter 7. Glossary of Terms Introduction .. 7-1. In this Chapter .. 7-1. 7-2. Glossary or Terms .. 7-2. Index .. I-1. v Related Publications Related Publications Refer to the publications and web sites listed below for more information regarding sound, speech, and Audio intelligibility: Acoustics The Construction and Calibration of Speech Intelligibility Tests ISO/TR 4870:1991(E). American National Standard Methods for Calculation of the Speech Intelligibility Index (ANSI ). Handbook for Sound Engineers, Third Edition, Glen M. Ballou, Editor, published by Butterworth-Heinemann, Woburn, MA.

9 The Limits of Wide Dispersion (White Paper), Atlas Sound ( ). National fire Alarm Code (NFPA 72) 2002 Edition, published by National fire Protection Association, ( ). Objective Rating of Speech Intelligibility by Speech Transmission Index, International Electrotechnical Commission (IEC), 60268-16, Second Edition, 1998-03. Speech Intelligibility A JBL Professional Technical Note, JBL Professional, Northbridge, CA. Sound System Design Reference Manual, JBL Professional Northbridge, CA. Sound Systems for Emergency Purposes, International Electrotechnical Commission (IEC), 60849, 1998-02. Sound System Engineering, by Don & Carolyn Davis, published by Howard Sams & Co.

10 Tyco Safety Products publications: STI-CIS System Users Guide (579-377). iTool Installation and User's Guide (579-772). vi Chapter 1. Audio Intelligibility Overview Introduction INTELLIGIBILITY The capability of being understood or comprehended. In simple terms, intelligibility is an evaluation of changes that occur to speech that impact comprehension. More specifically, intelligibility is concerned with evaluating reductions of the modulations of speech that cause undesired reductions in speech comprehension. These modulation reductions can also be thought of as a degradation of signal (speech) to noise ratio.