Low frequency impact sound transmission through floors

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Low frequency impact sound transmission through floors

Warnock, A. C. C.

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Low frequency impact sound transmission

through floors

Warnock, A. C. C.

www.nrc.ca/irc/ircpubs

Low Frequency Impact Sound

Transmission Through Floors

National Research

Council Canada

National Research

National Research

Council Canada

Council Canada

Conseil national

de recherches Canada

Conseil national

Conseil national

de recherches Canada

de recherches Canada

Canada

Canada

Alf Warnock

Indoor Environment Program, Acoustics

Institute for Research in Construction

National Research Council

Ottawa, Ontario

Alf Warnock

Indoor Environment Program, Acoustics

Institute for Research in Construction

National Research Council

Ottawa, Ontario

Project - possible new

impact test procedures

n

ISO tapping machine

n

JIS 1418 tire machine

n

2 experimental balls

n

walker

n

ISO tapping machine

n

JIS 1418 tire machine

n

2 experimental balls

Impact Sound Devices

NRC floor test facility

n

Room volume - 175 m

3

n

Floor area - 3.8 x 4.7 = 17.8 m

2

n

About 200 floors

n

Room volume - 175 m

3

n

Floor area - 3.8 x 4.7 = 17.8 m

2

n

About 200 floors

Measurements

n

ISO 140-6, E492 extended down

to 50 Hz

n

All others, 1 microphone, 1 m

below ceiling, max level, 35 ms

time constant, RT~0.5 s.

n

ISO 140-6, E492 extended down

to 50 Hz

n

All others, 1 microphone, 1 m

below ceiling, max level, 35 ms

time constant, RT~0.5 s.

Mean difference relative

to the walker

0

5

10

15

20

25

30

35

40

45

32

63

125

250

500

1k

2k

Frequency, Hz

Av

erage - W

a

lk

er

av

er

a

g

e,

dB

ISO Hammer

Tire

Ball1

Ball2

R

2

for different devices

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

32

63

125

250

500

1k

2k

Frequency, Hz

S

q

u

a

re o

f c

o

rrelat

io

n

c

o

ef

fi

ci

en

t

ISO

Tire

Ball1

Ball2

Floor type: ISO hammer vs walker

ISO Hammer

-20

-10

0

10

20

30

40

50

32

63

125

250

500

1k

2k

Frequency, Hz

Mean ISPL

Dif

fe

re

n

ce

, dB

Carpets

Floating top surface

Concrete surface

NRC floor test facilities

Current

Previous

Volume

175 m

3

65 m

3

Specimen size 3.8 x 4.7 m 2.4 x 2.4 m

Specimen Area

17.8 m

2

5.8 m

2

Current

Previous

Volume

175 m

3

65 m

3

Specimen size 3.8 x 4.7 m 2.4 x 2.4 m

Specimen Area

17.8 m

2

5.8 m

2

ISO tapping machine vs walker: 2 series

0

5

10

15

20

25

30

32

63

125

250

500

1k

2k

Frequency, Hz

A

v

er

age

- Wa

lk

e

r avera

ge, dB

Current

Previous

BIC

ISO Tapping machine ratings

n

IIC ≈

_≈

_≈

_{≈ 110 - L}

_n,w

n

ISO - energy sum, 50 to 2500Hz - 15 dB

n

BIC - Bodlund curve, 50 to 500 Hz, curve fit

n

IIC ≈

_≈

_≈

_{≈ 110 - L}

_n,w

n

ISO - energy sum, 50 to 2500Hz - 15 dB

Calculation of ratings

20

30

40

50

60

70

80

90

63

125

250

500

1k

2k

Frequency, Hz

Im

pa

c

t S

o

und

P

re

s

s

u

re

L

e

ve

l,

dB

Tapping machine, IIC 45

BIC 77

Walker

Single Number ratings

n

Tapping machine - Bodlund curve

weighted, 50 to 500 Hz, A weight,

loudness

n

A-weighted levels and loudness for

Ball1, Ball2, and Tire

n

Tapping machine - Bodlund curve

weighted, 50 to 500 Hz, A weight,

loudness

n

A-weighted levels and loudness for

Correlation of single number ratings for tapping machine with

walker loudness and A-weighted levels

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

IIC

ISO

50-2500

BIC

r squared

Loudness

A-weighted

Correlation of loudness and A-weighted levels for devices and

walker

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Tapping

Machine

Bodlund

weighting

Ball1

Ball2

Tire

r squared

Loudness

A-weighted

Conclusions

n

Balls work well

n

ISO hammer can work as well and

no new device is needed

n

Subjective studies would be useful

n

Balls work well

n

ISO hammer can work as well and

no new device is needed