Impulse noise levels generated by starter pistols Authors: Jacob Soendergaard, Deanna K. Meinke, Michael Stewart, Donald S. Finan, James E. Lankford, Greg A. Flamme, William J. Murphy and Amir Khan.
Background Motivation Letter from Paul Murphy nobody recognizes his concern No published data on this issue (Firearm connotation, starting advantage) Impulse Hazard starts at 140dB (NIOSH), 120dB for kids (WHO) Experiment 1 (Directionality) Experiment 2 (Comparison) Experiment 3 (Track) 2
Background - Use of Starter Devices High school (NFHS) recommends http://www.nfhs.org/ - see Rule 3.9.9 University (NCAA) requires http://www.ncaapublications.com/productdownloads/tf12.pdf - see RULE 5, Article 2. Pro athletics (IAAF) dictates http://www.iaaf.org/mm/document/competitions/technicalare a/05/47/81/20091027115916_httppostedfile_comprules2010_ web_26oct09_17166.pdf - see RULE 162.3 3
Data collection setup (pt1: Noise Sources) Firearms: 4.22 caliber Italian Model 314 Starter Pistol (2009, 2010, 2011).22 caliber K-22 Masterpiece Long Rifle (2010).32 caliber 6 shot H&R Model 960 Starter Pistol (2011).32 caliber 6 shot H&R Model 732 Pistol (2011) a matched set. (Courtesy of Paul Murphy)
Data collection setup (pt2: Data Capture) Instrumentation: 1/8 microphones (sens 1mV/Pa) 1/4 preamplifiers (Signal carrying capacity ±50V) Power modules (20dB attenuation available) A/D and Data Acquisition board (4ch sampling: 800kS/s, ±10V, 16-bit resolution) 5
Data Analysis Text files containing 1,600,000 entries. (4ch s 0.5sec sampled at 800kS/s data) Graphs and tables that make sense! MATLAB wizards performed DC offsetting, found peak SPL values, Leq s, A & B durations, averaging and generated graphs. 6
Experiment Setup (1. Directionality) 7 Mic0 (50cm left of muzzle) Mic1 (50cm front of muzzle) Mic2 (50cm right of muzzle) Mic3 (50cm behind muzzle, close to shooters ear)
Experiment Condition (1. Directionality).22 Caliber Directionality Study Ammo: Starter Pistol w/.22 short blank black powder Winchester Direction: Vertical Horizontal 8
Experiment Results (1. Directionality) -------- 5700Pa = 169dB -------- 2000Pa = 160dB -------- 5000Pa = 168dB 9
Experiment Conclusion (1. Directionality) Location of acoustic center? Very intense! 166dB SPLpeak at shooter s ear. (4000Pa) Why so intense? No bullet theory? 10
Experiment Setup (2. Comparison) Mic0 Shooters ear Mic1 10cm off Chamber Mic2 10cm off Muzzle Mic3 1.5m downrange 11
Experiment Conditions (2. Comparison).22 Caliber Comparison Study Firearm and Ammo: Starter Pistol w/.22 short blank black powder Winchester K-22 Masterpiece w/.22 long rifle CCI K-22 Masterpiece w/.22 short blank black powder Winchester K-22 Masterpiece w/.22 short Winchester 12
Results @shooters ear Starter Pistol w/ blanks K-22 w/ CCI LR K-22 w/ blanks K-22 w/ shorts 13
Experiment Results (2. Comparison) Averages over 5 shots mic0 mic1 mic2 mic3 Units 5cm shooter ear 10cm chamber 10cm muzzle 1.5m ahead of muzzle Starter Pistol 3692.2 18898.8 14037.6 1494.6 Pa K-22 w/ CCI LR 1603.9 21784.4 11115.6 1002.6 Pa K-22 w/ blanks 490.9 1574.2 9999.0 1814.4 Pa K-22 w/ shorts 1142.9 14273.8 8009.0 1089.2 Pa -- -- -- -- Starter Pistol 165.3 179.5 176.9 157.5 db K-22 w/ CCI LR 158.1 180.7 174.9 154.0 db K-22 w/ blanks 147.8 157.9 174.0 159.2 db K-22 w/ shorts 155.1 177.1 172.1 154.7 db 14
Experiment Conclusion (2. Comparison) At the shooters ear a blocked barrel.22 caliber Starter Pistol produces significantly higher peak sound pressure levels (7-18dB) than a comparable.22 caliber pistol, regardless of ammunition. 15
Experiment details (3. Track Setup) 1) Conduct a.32 caliber comparison 2) Full scale track measurement.32 Pistol.32 Starter Pistol 16
Experiment Setup (3.1 Comparison) Mic0 Shooters ear Mic1 10cm off Chamber Mic2 10cm off Muzzle Mic3 1.5m downrange 17
Results @shooters ear 2000 1500 1000.32 Starter Pistol w/ blanks Pressure, PA 500 0-500 -1000 2000 1500 1000 500 0-500 -1000 2000 1500 1000 500 0-500.32 Pistol w/ live ammo.32 Pistol w/ blanks -1000 0.5 0 0.5 1 1.5 2 Time, ms 18
Experiment Results (3.1 Comparison) Averages over 5 shots mic0 mic1 mic2 mic3 Units 5cm shooter ear 10cm chamber 10cm muzzle 1.5m ahead of muzzle.32 Starter Pistol 157.6 179.3 182.0 157.4 db.32 w/ blanks 151.2 166.3 174.3 161.7 db.32 w/ W325 152.7 168.5 176.5 157.2 db Remember the.22 Starter?.22 Starter Pistol 165.3 179.5 176.9 157.5 db 19
Experiment Setup (Real World Setting) Olympic Lane width 1.22m 20
Experiment Setup (3.2 Track) Starter Pistol Noise at 3 designated locations. A. General High School recommendation: ~60cm inside the oval, 10m in front of the athletes. B. Alternative position that adheres to recommendations: inline with the athletes, 10m inside the oval. C. Worst case scenario: 3m inside the oval. A. B. C. 21
Experiment Setup (3.2 Track) 22
Experiment Results (3.2 Track) Shooter Lane 1 Lane 4 Lane 8 Units Mic0 Mic1 Mic2 Mic3.22 cal -- -- -- -- Pos A 167.2 135.6 134.8 132.0 db Pos B 166.1 135.5 132.7 128.7 db Pos C 165.3 147.8 139.6 133.9 db.32 cal -- -- -- -- Pos A 165.0 134.0 133.0 131.1 db Pos B 163.2 136.6 132.8 127.8 db Pos C 164.7 146.7 139.0 133.3 db A. Impulse Hazard for adults: 140dB (NIOSH) Impulse Hazard for kids: 120dB (WHO) B. C. 23 120dB!!
Experiment Conclusion (3.2 Track) Use of Hearing protection is REQUIRED for shooter. Closest athletes and potentially some spectators are at risk according to current NIOSH and WHO guidelines. Question: Choice of starter? 24
Implications: Gun vs electronic NCAA Electronic Starter conditions: 112dB at 15 feet (5m) Using a Starter Pistol, which generates 166dB at 0.5m, the shooter will have to be 256 meters(!!) from the athletes to adhere to Electronic Starter requirements. 25
Implications: rule book change I thought you might be interested in new language in the 2012 National Federation Track & Field Book: Starters and Assistant Starters need to position themselves to fairly observe the start of each race. Positioning should minimize the exposure of competitors, officials and spectators to the report of the starting device. There is no further explanation. At a minimum, this is a small victory, and you and your group merit much credit. Paul Murphy 26
Thanks, Rudyard Gangsters! (From left to right in picture) Amir Khan Jacob Soendergaard Greg A. Flamme James E. Lankford Michael Stewart Deanna K. Meinke Donald S. Finan William J. Murphy 27 The findings and conclusions in this presentation have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.