1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Sound of SilenceSolving Noise Problems with Windows

(Apologies to Theodore Geisel and Chuck Jones)

George TorokNational Capital Region Manager

& Technical Specialist

BUILDING CONSULTANTS INC.

Building Science SpecialistsContract AdministratorsReserve Fund PlannersConsulting Engineers

Newmarket 1-800-838-8183 Ottawa

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

The easy bit:•The owners of a 13 storey, 1970svintage apartment building wanted to replace windows to address convenience, comfort and aestheticissues, justified by reduced energy bills.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

The tricky bit:•The building was located next to a busy commuter and regional train station.

•The train line was also used frequently by freight trains.

•Nearby was a level crossing.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

The hidden trap:•noise,

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

The hidden trap:•noise, noise,

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

The hidden trap:•noise, noise, NOISE!

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

The hidden trap:•noise, noise, NOISE!•Typical resident response: “You get used to it.”

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

Why it’s a trap:•Existing windows were typical 1970s vintage high-rise type, fixed-over-slider:• Thermally broken, open-back, 4 ½ in. aluminum frame.• Fixed glazed section consisted of fixed exterior pane and

removable interior sash, about 3 in. between, no weatherstrip, cavity drains to sliding section below.

• Operable section consisted of double-run of single-glazed sashes, 3 – 4 in. cavity between, drained to exterior, worn pile weatherstrip.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The ProblemRemovable inner sash panel

Fixed outer sash panel ~ 3 in.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Problem

Why it’s a trap:•Typical new replacement windows have similar frame, layout and sliding sash arrangement, but:• Fixed glazing consists of sealed, double glazed, insulating

glass units with 1/2 in. wide cavity.• Reduction of cavity width from 3 in. to 1/2 in. would

increase sound transmission (reduce transmission loss), causing more train noise to enter the apartments.

• A “typical” off-the-shelf replacement window would degrade acoustical performance!

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

The ProblemBest Guess for Existing Condition:• both panes 4.76 mm glass,• 100 mm unsealed air filled cavity.

Female voice range

Male voice range

Train noise range

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

The ProblemBest Guess for Existing Condition:• both panes 4.76 mm glass,• 100 mm unsealed air filled cavity.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

The ProblemBest Guess for Existing Condition:• both panes 4.76 mm glass,• 100 mm unsealed air filled cavity.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

Train noise, human voice, and weak acoustic performance of glass coincide.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Other Problems

What we couldn’t do:•Change the configurationof the windows:• 13 mm cavity width for

insulating glass units desirable for optimum thermal performance.

• 22 mm typical overall insulating glass unit thickness to suit available frames (typical for GTA high-rise at the time).

• Retain double-run of single-glazed sashes for operable portion (too costly to change to hinged vent).

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Other Problems

What we could do:•Maintain or improve acousticperformance of sliding sashes:• Air gap between sashes spaced

about the same as existing to maintain existing acoustic performance.

• Specify high level of air leakage resistance (A3) to improve acoustic performance, at least in the short term(an air leak is a sound leak).

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Other Problems

What we could do:•Maintain or improve acoustic performance of insulating glassunits, but:• Sound transmission loss data not available for 4 mm thick

glass required for wind load resistance (CGSB-12.20).• Use available data (IGMA, NRCC, etc.) and interpolate:

• for 3 mm and 6 mm thick glass.• for monolithic and laminated glass. • for various types of windows.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Principles

At very low frequencies:•Sound transmission through glass is controlled by the shape (aspect ratio) of glass, which affects its flexibility (stiffness).

•Control by:• Change window shape.• Increase glass thickness (makes glass stiffer when size

is not changed).

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Principles

At low frequencies:•Parallel glass panes, separated by an air space, will vibrate together and transmit some sounds very efficiently (‘mass-spring-mass resonance’).

•Control by:• Change the stiffness of the spring between the panes

(width of the cavity).• Change the vibration frequency of one pane of glass

(use one pane at least 30% thinner than the other and/or one pane of laminated glass).

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Principles

At middle and through high frequencies:•Sound transmission is controlled by the weight (mass) of glass.

•Control by:• Increase weight (thickness) of the glass.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Principles

At high frequencies:•Vibration of the air (sound) parallel to glass surfaces, matches the vibration pattern in the glass, transmitting sound very efficiently (‘coincidence dip’).

•Control by:• Use double glazing to introduce a “spring” (cavity)

to absorb vibration energy.• Make one pane of glass at least 30% thinner so that

vibrations are not synchronized and thus, sound transfer is less efficient.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Frequency (Hz)

Soun

d R

educ

tion

Inde

x(I

ncid

ent /

Tra

nsm

itted

, dB

)

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Sound Reduction by Windows – Fixed GlazingFrom “Measurements in Building Acoustics” by Bruel & Kjaer, January 1988

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

Principles

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

The Usual Solution

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

Best Guess for Existing Condition:• both panes 4.76 mm glass,• 100 mm unsealed air filled cavity.

Female voice range

Male voice range

Train noise range

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)0 125 250 500 1,000 2,000 4,000 8,000

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

Train noise, human voice, and weak acoustic performance of glass coincide.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

A Better Solution

One Step Better (correct depth):one pane 3 mm glass,• 13mm sealed air-filled cavity,• one pane 6 mm glass.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)0 125 250 500 1,000 2,000 4,000 8,000

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

One Step Better (correct depth):one pane 3 mm glass,• 13mm sealed air-filled cavity,• one pane 6 mm glass.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

ResonanceControlled

Mass ControlledStiffnessControlled

CoincidenceControlled

“CoincidenceDip”

Increase mass(thickness)

Increase damping

Increasedamping

Increasestiffness

(thickness)

Damping Methods:• Double glazing• Unequal pane thickness• Laminated glass• Change cavity width

Better noise isolation except at very low and high frequencies.

One Step Better (correct depth):one pane 3 mm glass,• 13mm sealed air-filled cavity,• one pane 6 mm glass.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

An even Better SolutionTwo steps better (but too thick):• one pane 6 mm monolithic glass,• 13 mm unsealed air filled cavity,• one pane 6 mm laminated glass.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

One Step Better (correct depth):one pane 3 mm glass,• 13mm sealed air-filled cavity,• one pane 6 mm glass.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

Two steps better (but too thick):• one pane 6 mm monolithic glass,• 13 mm unsealed air filled cavity,• one pane 6 mm laminated glass.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

R e so n a n c eC o n tr o lle d

M a ss C o n tr o lle dS tiffn e ssC o n tr o lled

C o in c id e n c eC o n tr o lle d

“ C o in c id e n c eD ip ”

In c re a se m a ss( th ic k n e ss )

In c re a se d a m p in g

In c re a sed a m p in g

In c re a ses tif fn ess

( th ic k n e ss )

D a m p in g M e th o d s :• D o u b le g la z in g• U n e q u a l p a n e th ic k n e ss• L a m in a te d g la ss• C h an g e c a v ity w id th

R e so n a n c eC o n tr o lle d

M a ss C o n tr o lle dS tiffn e ssC o n tr o lled

C o in c id e n c eC o n tr o lle d

“ C o in c id e n c eD ip ”

In c re a se m a ss( th ic k n e ss )

In c re a se d a m p in g

In c re a sed a m p in g

In c re a ses tif fn ess

( th ic k n e ss )

D a m p in g M e th o d s :• D o u b le g la z in g• U n e q u a l p a n e th ic k n e ss• L a m in a te d g la ss• C h an g e c a v ity w id th

One Step Better (correct depth):one pane 3 mm glass,• 13mm sealed air-filled cavity,• one pane 6 mm glass.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

Two steps better (but too thick):• one pane 6 mm monolithic glass,• 13 mm unsealed air filled cavity,• one pane 6 mm laminated glass.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

R e so n a n c eC o n tr o lle d

M a ss C o n tr o lle dS tiffn e ssC o n tr o lled

C o in c id e n c eC o n tr o lle d

“ C o in c id e n c eD ip ”

In c re a se m a ss( th ic k n e ss )

In c re a se d a m p in g

In c re a sed a m p in g

In c re a ses tif fn ess

( th ic k n e ss )

D a m p in g M e th o d s :• D o u b le g la z in g• U n e q u a l p a n e th ic k n e ss• L a m in a te d g la ss• C h an g e c a v ity w id th

R e so n a n c eC o n tr o lle d

M a ss C o n tr o lle dS tiffn e ssC o n tr o lled

C o in c id e n c eC o n tr o lle d

“ C o in c id e n c eD ip ”

In c re a se m a ss( th ic k n e ss )

In c re a se d a m p in g

In c re a sed a m p in g

In c re a ses tif fn ess

( th ic k n e ss )

D a m p in g M e th o d s :• D o u b le g la z in g• U n e q u a l p a n e th ic k n e ss• L a m in a te d g la ss• C h an g e c a v ity w id th

Much better noise isolation except at very high frequencies.

One Step Better (correct depth):one pane 3 mm glass,• 13mm sealed air-filled cavity,• one pane 6 mm glass.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Soun

d Tr

ansm

issi

on L

oss (

dB)

60

50

40

30

20

0

0 125 250 500 1,000 2,000 4,000 8,000Frequency (Hz)

The GRG Solution

The GRG Solution (compromise):• one pane 4mm glass• 13 mm sealed, argon filled cavity• one pane 6 mm laminated glass.

Best Guess for Existing Condition:• both panes 4.76 mm glass,• 100 mm unsealed air filled cavity.

The Usual Solution:• both panes 3 mm glass,• 13mm sealed air-filled cavity.

Expected range of compromise similar to estimated original performance (likely lower than blue line).

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

What did the Client Hear?

Less is more:•Residents in mock-up apartments reported a decrease in train noise.

•General installation proceeded with modified windows.

•As project proceeded, other residents also reported reduced train noise levels.

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

Questions?1-800-838-8183…Problem Solved.

BECOR Brag SessionDecember 8, 2009

1-800-838-8183BECOR Brag Session

December 8, 2009…Problem Solved.

The Sound of SilenceSolving Noise Problems with Windows

George TorokNational Capital Region Manager

& Technical Specialist

BUILDING CONSULTANTS INC.

Building Science SpecialistsContract AdministratorsReserve Fund PlannersConsulting Engineers

Newmarket 1-800-838-8183 Ottawa