Shooting Ranges and Sound Table of Contents Table of Contents LIST OF TABLES .............................................................................................................IV LIST OF FIGURES ............................................................................................................V ABOUT THIS DOCUMENT ..............................................................................................VI EXECUTIVE SUMMARY ................................................................................................VII 1 INTRODUCTION ....................................................................................................... 8 1.1 PHYSICS OF SOUND ........................................................................................ 8 1.1.1 Sound Waves .............................................................................................. 8 1.1.2 Frequency .................................................................................................... 8 1.1.3 Sound Pressure ........................................................................................... 9 1.1.4 Sound Pressure Levels, Decibels ................................................................ 9 1.1.5 Directivity ..................................................................................................... 9 1.2 MECHANISMS OF NOISE GENERATION AND SHOOTING NOISE GENERATION ............................................................................................................... 9 1.2.1 Shock Wave ................................................................................................ 9 1.2.2 Vibrating Surfaces ..................................................................................... 10 1.3 SOUND CHARACTERISTICS OF FIREARMS ................................................ 10 1.4 SOUND PROPAGATION ................................................................................. 12 1.4.1 Distance ..................................................................................................... 12 1.4.2 Ground Effect ............................................................................................ 12 1.4.3 Air Absorption ............................................................................................ 12 1.4.4 Weather, Wind and Temperature Inversion ............................................... 13 1.5 HUMAN SENSITIVITY ...................................................................................... 13 1.6 SOUND MEASUREMENT ................................................................................ 13 1.6.1 Constant Sounds ....................................................................................... 13 1.6.2 Time-Varying Sounds ................................................................................ 16 1.6.3 Impulsive Sounds ...................................................................................... 17 1.6.4 Measuring Sound Levels From Firearms .................................................. 18 2 SOUND LEVEL ASSESSMENT .............................................................................. 19 2.1 PHILOSOPHY OF CRITERION SOUND LEVEL DEVELOPMENT ................. 19 2.1.1 Fixed Criterion Sound Levels .................................................................... 19 2.1.2 Background Sound Levels as Criteria ....................................................... 20 2.1.3 Hybrid Sound Level Criteria ....................................................................... 20 2.2 POINT OF RECEPTION SELECTION ............................................................. 22 Shooting Ranges and Sound ii Table of Contents 3 SOUND LEVEL MEASUREMENTS ........................................................................ 23 3.1 SOUND LEVEL METER REQUIREMENTS ..................................................... 23 3.1.1 Sound Level Meter Types .......................................................................... 23 3.1.2 Sound Level Meter Calibration .................................................................. 23 3.1.3 Accessories Required for Sound Level Meters ......................................... 23 3.2 SOUND LEVEL MEASUREMENT PROCEDURES ......................................... 24 3.2.1 Calibration ................................................................................................. 24 3.2.2 Weather Conditions ................................................................................... 24 3.2.3 Recording .................................................................................................. 24 3.3 SOUND LEVEL MEASUREMENT PERSONNEL ............................................ 25 4 RANGE CONSTRUCTION PLANNING ADVICE .................................................... 26 4.1 DESIGN CONSIDERATIONS FOR OUTDOOR AND INDOOR RANGES ...... 26 4.1.1 Design Considerations – Outdoor Ranges ................................................ 26 4.1.2 Design Considerations – Indoor Ranges ................................................... 29 4.2 PLANNING FOR SHOOTING RANGES .......................................................... 30 4.2.1 Outdoor Ranges ........................................................................................ 30 4.2.2 Indoor Ranges ........................................................................................... 32 5 ABATEMENT TECHNIQUES .................................................................................. 33 5.1 NOISE ABATEMENT TECHNIQUES FOR OUTDOOR SHOOTING RANGES 33 5.1.1 Natural Hill ................................................................................................. 33 5.1.2 Barriers at Sides ........................................................................................ 34 5.1.3 Barrier Behind Shooter .............................................................................. 35 5.2 NOISE ABATEMENT TECHNIQUES FOR INDOOR SHOOTING RANGES ... 36 5.2.1 Walls .......................................................................................................... 36 5.3 PRACTICAL MEASURES OF NOISE CONTROL ............................................ 36 5.3.1 Outdoor Shooting Ranges ......................................................................... 36 5.3.2 Indoor Shooting Ranges ............................................................................ 37 6 GLOSSARY ............................................................................................................. 38 7 REFERENCES ........................................................................................................ 41 Shooting Ranges and Sound iii 0BLIST OF TABLES LIST OF TABLES Table 1: Sound Pressure Levels of Firearms Being Measured at 10 m from the Muzzle (Downrange) ................................................................................................................... 11 Table 2: Typical Sound Pressure Level Encountered in Daily Life ................................. 15 Table 3: Sound Levels, dBAl, 100m from Indoor Range (Sound Pressure of the Handgun Being Measured is 160 dBAl at 600 mm) ........................................................................ 36 Shooting Ranges and Sound iv 1BList of Figures LIST OF FIGURES Figure 1: Directivity of a Typical Rifle at 10 m ................................................................. 11 Figure 2: Directivity of a Typical Shotgun at 10 m ........................................................... 12 Figure 3: Frequency Characteristics of A-Weighting and C-Weighting ........................... 14 Figure 4: Attenuation Over Distance – No Ground Effect ............................................... 26 Figure 5: Attenuation over Distance with Ground Effect ................................................. 27 Figure 6: Attenuation Over Distance With and Without Berm ......................................... 28 Figure 7: Noise Reduction Across the Wall ..................................................................... 29 Figure 8: Attenuation Over Distance With and Without Hill ............................................. 33 Figure 9: Attenuation Over Distance With and Without Side Barriers ............................. 34 Figure 10: Attenuation Over Distance With and Without Barrier Behind Shooter ........... 35 Shooting Ranges and Sound v About this Document ABOUT THIS DOCUMENT “Shooting Ranges and Sound” was written in March 1999 by the following Subject Matter Experts: ¾ John C. Swallow, M.A.Sc., P.Eng. ¾ John Hemingway, M.Phil., P.Eng. ¾ Pearlie Yung, M.Sc. “Shooting Ranges and Sound” was edited by: Technical Documentation and Graphics Section Information Management Branch IM/IT Business Solutions CIO Sector RCMP Headquarters 3000 Merivale Road. M-8 Ottawa, Ontario, Canada K1A 0R2 Fax: (613) 825-9617 © (2007) HER MAJESTY THE QUEEN IN RIGHT OF CANADA as represented by the Royal Canadian Mounted Police (RCMP) PDF Version Navigation To view a specific page, enter the page number in the Navigation toolbar located at the bottom of the page and press the Enter key. Text in blue font indicates a hyperlink; click the link to view related information. To return to the original page, click Previous View on the Navigation toolbar. Shooting Ranges and Sound vi Executive Summary EXECUTIVE SUMMARY “Shooting Ranges and Sound” is a document intended for those people not trained in acoustics, who would like to gain an understanding of the propagation and control of sound and firearm noise. Such persons might be involved in the planning, construction