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Noise emission and induced
vibration from heavy weapons
Timo Markula, Akukon Ltd
Mika Hanski, Akukon Ltd
Tapio Lahti, TL Akustiikka
European Conference of Defence
and the Environment ECDE 2015
Helsinki, 10.6.2015
Contents
• Overview of noise emission measurements of light and heavy weapons in Finland
• Induced vibration from heavy weapons
• Background
• Basics
• Measurement results
• Proposed guideline values
• Damage-safe distance
Noise emission measurements
• The noise emission of a significant portion of FDF light and heavy weapons have been measured
• The emission data is used for computational noise assessment of FDF firing ranges
• Measurement conditions affect the uncertainty of the emission data
• Artillery
• 155 K 98 (4)
• 130 K 54 (2)
• 130 TK
• 100 TK
• 122 H 63
• 122 PSH 74 (2)
• Mortars
• 120 KRH (2)
• 81 KRH (2)
• Nemo 120 (5)
• Anti-aircraft
• 23 ITK 61/95
• 12.7 ITKK 96
• standard
• muzzle brake
• Detonations
• 20 kg TNT
• 10 kg TNT
• 5 kg TNT
• 2 kg TNT
• 1 kg TNT
• 200 g TNT
• 60 g TNT
• Artillery grenades
• Mortars
• 100 TK (water impact)
• 112 RSKES APILAS
• 66 KES 88
• 40 KRKK 2005
Weapons measured
• Light infantry weapons
• 8.6 TKIV 2000
• 12.7 RSTKIV 2000
• 7.62 RK 62
• 7.62 RK 95
• live
• blank adapter
• silencer
• 9.00 PIST 80-91
• 7.62 TKIV 85
• M134D-H
• 40 KRKK 2005
• APCs and tanks
• CV9030 main weapon
• BMP-2 main weapon
• Leopard 2A4 main
weapon
• Anti-tank
• 95 S 58-61
• 112 RSKES APILAS
• inert and live
• 66 KES 88
• inert and live
Measurement conditions
• Good conditions:
• Trial firing range (muzzle blast only)
• Measurement distance: ~100 m for heavy weapons • The distance should be greater
• Large open area
• Hard ground around the weapon
• Reference explosion to assess effects of weather and to estimate the ground correction • Some issues with direct ground correction compensation
• “Other” conditions:
• Measurements of live firing at training grounds
• Measurement distance: long, variable
• Soft ground, non-flat terrain
• Influence of weather
Blast induced vibration - Background
• Finnish Defence Forces (FDF) have received complaints on building damage and annoyance
• Assessment of vibration from heavy weapons and explosions has been under development in Finland
• Pilot project on shooting vibration 2007-09
• Measurements at 3 sites (1 artillery, 2 explosion)
• Literature survey
• Project continued 2009-2014
• Measurements around 5 shooting areas
• Guide (draft) on measurements and assessment
• In-depth investigation of one artillery shooting area
Building vibration
• Impulsive and low-frequency sound waves propagate over long distances, several kilometres
• Building vibration is induced by the passing sound wave
• Figure shows the motion (strongly exaggerated)
a) b)
c) d)
Coupling to structures
Building vibration is induced by airborne sound pressure
= pressure wave = noise
and is coupled to the building structures directly
from the air
Building vibration is not a result of
groundborne vibration
(contrary to underground explosions)
Building response
• Vibration measured in several wooden one-family houses
• The façades are sensitive (right) to heavy weapon sound pressure (left) which has a maximum at low frequencies
60
70
80
90
100
110
1 2 4 8 16 31.5 63 Hz
sound exposure level LpZE, dB
-50
-40
-30
-20
-10
0
2 4 8 16 31.5 63 Hz
velocity response ratio, dB
Damage risk vs. annoyance
• Vibration is strongest on large
and structurally mobile surfaces:
outer walls, roof, intermediate
floors, windows
• Annoyance (vibration and rattle)
is caused by the vibration of these
structures
• Damage risk of foundations is
measured directly from foundations
Shooting vibration (e.g. damage risk of windows)
can and shall also be assessed by measuring
incident noise level outside the house
Assessed parameters
• Noise:
• Measurements of incident sound level outside the building
• Structural damage: unweighted sound exposure level LpZE
• Annoyance: C-weighted sound exposure level LpCE
• LpCE is widely used in Europe and the US for assessing noise annoyance of heavy weapons
• Vibration:
• Structural damage: peak vibration velocity vpeak
• Widely used to assess damage risk from blasting and excavation
• Measured from foundations of buildings
• Annoyance: Wm-weighted vibration velocity exposure level LvWE
• ISO 2631-2 Mechanical vibration and shock – Evaluation of human exposure to whole-body vibration – Vibration in buildings
• Reference level: 50 nm/s
• Adaptation of European guidelines for rail traffic vibration annoyance
Overview of measurement results
• Summary of measurement data 2007-2014: damage risk assessment
Vibration measurement points: Blue: foundation horizontal Red: foundation vertical
Incident sound exposure level LpZE
(outdoors)
0,001
0,01
0,1
1
10
peak v
ibra
tion v
elo
city v
pe
ak, m
m/s
damage risk: 5 mm/s
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
Sound e
xposure
level, L
pZ
E, dB
damage risk level: 125 dB
Overview of measurement results
• Summary of measurement data 2007-2014: annoyance assessment
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
Sound e
xposure
level, L
pC
E,
dB
annoyance level:
100 dB
Vibration measurement points: Blue: facade horizontal; Red: 1st floor vertical; Green: 2nd floor vertical
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
Vib
ration e
xposure
level, L
vW
E, dB
annoyance
level: 76 dB
Incident sound exposure level LpCE
(outdoors)
Measurement result summary
• The damage risk criteria were not exceeded in any of the residential buildings
• The annoyance criteria for noise (and vibration) was exceeded in several residential buildings
• Floor and facade vibration measurement results only represent the measured structures
• The range of structural mobility is large
• Based on our findings, both damage risk and annoyance may be assessed via noise measurements
Proposed guideline values:
damage risk
Proposed guideline values for the assessment of damage risk: Noise: incident sound exposure level outdoors LpZE ≤ 125 dB Vibration: peak vibration velocity, foundations vpeak ≤ 5 mm/s
Proposed guideline values:
annoyance
Proposed guideline values for the assessment of annoyance caused by vibration, rattle and noise: Vibration: Wm-weighted vibration velocity exposure level of floors LvWE ≤ 76 dB Noise + rattle: C-weighted sound exposure level, outdoors, single event LpCE ≤ 100 dB (= FDF noise guideline value) The FDF guideline value for noise assessment :
Noise: Average active day LAeq,r (+10 dB impulse correction) LAeq,r ≤ 55 dB
Damage-safe distance
Artillery, single shot 300 m Artillery, volley (+10 dB) 1 km Distance at which a 130 mm cannon produces LpZE ≈ 125 dB
Determination of distance:
Emission measured obliquely forward (~ 45°) Full +6 dB ground reflection, r2 point-source divergence No barriers, hills, soft ground etc. taken into account Measurement results of emission and immission agreed
well in the example pilot project Impact noise close to muzzle blast (within a few dB) Estimate +10 dB applies to exposure levels, not to peak
• Safety distance of 1 km for artillery
• Circles drawn around residential houses
• An envelope curve drawn inside the circles
• Inside the envelope, shooting noise does not exceed the damage criterion LpZE 125 dB at the houses
Damage-safe
zones