Noise Barrier Material Noise Barrier Material Evaluation & SelectionEvaluation & Selection

Mia WatersMia WatersWashington State Department of TransportationWashington State Department of Transportation

TRB ADC40, Transportation Related Noise & VibrationTRB ADC40, Transportation Related Noise & VibrationWilliamsburg, VA Williamsburg, VA July 11, 2006July 11, 2006

Moving past the State of Moving past the State of traditional concrete…traditional concrete…

Why?Why? Cost of keeping traditionsCost of keeping traditions A new world of materials in developmentA new world of materials in development Ability to have choices / provisional optionsAbility to have choices / provisional options

What?What? plastic – metal – composite – wood - transparent – plastic – metal – composite – wood - transparent –

translucent – absorptive – canted – recycled – easily translucent – absorptive – canted – recycled – easily replaced – lower cost – light weight - and more…replaced – lower cost – light weight - and more…

Where?Where? Vertical and horizontalVertical and horizontal

How?How? Use the process & criteria that fit your organization…Use the process & criteria that fit your organization…

Rating Criteria?Rating Criteria? Transmission Loss (TL)Transmission Loss (TL) Sound Transmission Class (STC)Sound Transmission Class (STC) Other?Other?

CostCost Foundation needsFoundation needs Ease of installationEase of installation Ease of replacementEase of replacement Graffiti resistance / clean-abilityGraffiti resistance / clean-ability AbsorptionAbsorption Aging – longevity - durabilityAging – longevity - durability Aesthetic characteristicsAesthetic characteristics WeightWeight Crash test worthinessCrash test worthiness Approved by others? Who?Approved by others? Who?

As you mentioned, the weakness in the STC is that it does not As you mentioned, the weakness in the STC is that it does not anticipate fully the low frequency content of the traffic noise. anticipate fully the low frequency content of the traffic noise. Thus, a barrier with an STC 20 rating could produce less than a Thus, a barrier with an STC 20 rating could produce less than a 20 dBA direct reduction of typical traffic sound passing through it.20 dBA direct reduction of typical traffic sound passing through it.

Ideally, what you want to do is to create a standardized traffic Ideally, what you want to do is to create a standardized traffic spectrum, compute the overall A-weighted level of that spectrum, spectrum, compute the overall A-weighted level of that spectrum, the subtract the TL's of the barrier from that spectrum at each the subtract the TL's of the barrier from that spectrum at each frequency, compute the overall A-weighted level of the resulting frequency, compute the overall A-weighted level of the resulting spectrum, and then take the difference between the two overall A-spectrum, and then take the difference between the two overall A-weighted levels.weighted levels.

(Ref. N Stewart)(Ref. N Stewart)

Selection criteria optionsSelection criteria options

EuropeEurope JapanJapan CanadaCanada Various US statesVarious US states

A recommended US national criteria?A recommended US national criteria?

European selection European selection criteriacriteria

EN1793 (5)EN1793 (5) 1. “Road traffic noise reducing devices — Test method for determining the acoustic performance — Part 1: Intrinsic characteristics of sound absorption”, EN 1793-1 (1997). 2. “Road traffic noise reducing devices — Test method for determining the acoustic performance — Part 1: Intrinsic characteristics of airborne sound insulation”, EN 1793-2 (1997). 3. “Road traffic noise reducing devices — Test method for determining the acoustic performance — Part 1: Normalized traffic noise spectrum”, EN 1793-3 (1997). 4. “Road traffic noise reducing devices — Test method for determining the acoustic performance — Part 5: Intrinsic characteristics - In situ values of sound reflection and airborne sound insulation”, ENV 1793-5 (2002). 5. “Road traffic noise reducing devices — Test method for determining the acoustic performance — Part 4: Intrinsic characteristics - In situ values of sound diffraction”, prENV 1793-4 (2002).

EN1794 (2)EN1794 (2) 1. “Road traffic noise reducing devices — Non-acoustic performance — Part 1: Mechanical performances and stability requirements”, EN 1794-1 (1998). 2. “Road traffic noise reducing devices — Non-acoustic performance — Part 2: General safety and environmental requirements”, EN 1794-2 (1998).

EN14388 (1)EN14388 (1) “Road traffic noise reducing devices — Specifications”, prEN 14388 (2002).

EN14389 (2)EN14389 (2) 1. “Road traffic noise reducing devices — Long term performance or road traffic noise reducing devices — Part 1: Acoustical parameters”, prEN 14389-1 (2002). 2. “Road traffic noise reducing devices — Long term performance or road traffic noise reducing devices — Part 1: Non-acoustical parameters”, prEN 14389-2 (not published).

EN14990 EN14990 draftdraft Precast concrete barriersPrecast concrete barriers

Where to find discussions of the standards:Where to find discussions of the standards: http://www.cenorm.be/catweb/93.080.30.htmhttp://www.cenorm.be/catweb/93.080.30.htm http://www.atech-acoustictechnologies.com/en/at_5_4.cfmhttp://www.atech-acoustictechnologies.com/en/at_5_4.cfm http://http://www.cenorm.be/newapproach/cen/stdlist.asp?dir_areawww.cenorm.be/newapproach/cen/stdlist.asp?dir_area=89/106/EEC&prod_fam=CEN/TC%20229=89/106/EEC&prod_fam=CEN/TC%20229

Courtesy of Ulf Sandberg & Jean-Pierre ClairboisCourtesy of Ulf Sandberg & Jean-Pierre Clairbois

JapanJapan

ISO 10847 (1997)ISO 10847 (1997)

Recent interest, noise reducing devices Recent interest, noise reducing devices on top of barriers, interested in a on top of barriers, interested in a modified version of EN 1793-4 modified version of EN 1793-4

Reference Kohei YamamotoReference Kohei Yamamoto

CanadaCanada

Canadian Standards Association (CSA) Z107.9Canadian Standards Association (CSA) Z107.9

Focus on material and design…Focus on material and design…

Takes the noise barrier height into consideration Takes the noise barrier height into consideration when determining required TLwhen determining required TL

Note that the Canadian maximum wall height is 5 Note that the Canadian maximum wall height is 5 M (about 16 feet).M (about 16 feet).

United StatesUnited States

Nevada Nevada (Sound Wall Eval. Manual, STC of 25 dB)(Sound Wall Eval. Manual, STC of 25 dB)

Virginia Virginia (has approved list, how were products (has approved list, how were products chosen?)chosen?)

Florida Florida (temp. design bulletin C03-04 – identifies (temp. design bulletin C03-04 – identifies specific criteria related and unrelated to noise when specific criteria related and unrelated to noise when evaluating materials. FDOT requires an STC of 20 dB)evaluating materials. FDOT requires an STC of 20 dB)

Wisconsin Wisconsin (TL 20 dB, all frequencies)(TL 20 dB, all frequencies)

What did WSDOT want?What did WSDOT want?

SimplicitySimplicity Ease of finding the data in the Ease of finding the data in the

application/literatureapplication/literature Protection of residents Protection of residents (reduce complaints of less (reduce complaints of less

protection when using alternative materials)protection when using alternative materials)

ChallengesChallenges

FHWA guidance recommends FHWA guidance recommends transmissions loss in dBA transmissions loss in dBA (but some note that TL (but some note that TL

doesn’t exist in dBA)doesn’t exist in dBA) Independent laboratory testing is in dBIndependent laboratory testing is in dB

Sound Transmission Class of 25 dB Sound Transmission Class of 25 dB representative enough? It only uses a representative enough? It only uses a few frequencies to calculate it…few frequencies to calculate it…

Debate…choicesDebate…choices

US and other countries decide on an ISO standard?US and other countries decide on an ISO standard? US National list of approved materials?US National list of approved materials? Low tech - if a product can meet the structural requirements of the Low tech - if a product can meet the structural requirements of the

AASHTO Guide for the Structural Design of Sound Barriers AND is light AASHTO Guide for the Structural Design of Sound Barriers AND is light tight (the flashlight test) then it will have enough mass to meet low tight (the flashlight test) then it will have enough mass to meet low frequency TL requirements and with no gaps in the wall, will meet high frequency TL requirements and with no gaps in the wall, will meet high frequency TL requirements frequency TL requirements (ref. Figallo)(ref. Figallo)

ANSI 12.8 ANSI 12.8 (1987) Methods for Determination of Insertion Loss of Outdoor Noise Barriers(1987) Methods for Determination of Insertion Loss of Outdoor Noise Barriers ISO 10847 ISO 10847 In-situ determination of insertion loss of outdoor noise barriers of all typesIn-situ determination of insertion loss of outdoor noise barriers of all types CSA Z107.9 – CSA Z107.9 – in discussion for adoption by ANSIin discussion for adoption by ANSI DIN (EN) 1793 – DIN (EN) 1793 – test method for determining acoustical performancetest method for determining acoustical performance ASTM E1332. ASTM E1332. The difference is that the spectrum specified in E 1332 is a generalized The difference is that the spectrum specified in E 1332 is a generalized

transportation noise spectrum averaging in some aircraft and rail noise rather than just traffic noise. transportation noise spectrum averaging in some aircraft and rail noise rather than just traffic noise. This rating was developed for exterior walls of buildings subjected to transportation noise. E 1332 This rating was developed for exterior walls of buildings subjected to transportation noise. E 1332 requires TL data down to 80 Hz for the rating. Labs do not always report results below 100 or 125 Hz.requires TL data down to 80 Hz for the rating. Labs do not always report results below 100 or 125 Hz.

Thanks for input from…Thanks for input from…

Larry FinegoldLarry Finegold Ulf SandbergUlf Sandberg Jean-Pierre ClairboisJean-Pierre Clairbois Shawn GilbertsonShawn Gilbertson Jim LaughlinJim Laughlin Soren PedersenSoren Pedersen Tim KelsallTim Kelsall Chris MengeChris Menge Mariano BerriosMariano Berrios Areg GharabegianAreg Gharabegian Roger WaysonRoger Wayson Amy CostelloAmy Costello Noral StewartNoral Stewart

Gary FigalloGary Figallo Bill BowlbyBill Bowlby Ken PolcakKen Polcak Rich PeppinRich Peppin Bob MeroBob Mero Win LindemanWin Lindeman Jay WaldschmidtJay Waldschmidt Patrick HarrisonPatrick Harrison Dave GoodwinDave Goodwin David Freudenrich David Freudenrich Jim ChambersJim Chambers Gary EhrlichGary Ehrlich Micah DowningMicah Downing

What did WSDOT finally What did WSDOT finally choose…for now?choose…for now?

Unconditional approval from acoustics group of Unconditional approval from acoustics group of Transmission Loss (TL) of 20 dB for all measured Transmission Loss (TL) of 20 dB for all measured frequenciesfrequencies

Conditional approval – limited use for TL for product Conditional approval – limited use for TL for product with any measured frequency at less than 20 dB, e.g.,with any measured frequency at less than 20 dB, e.g., Temporary barriersTemporary barriers Low truck volume roadwaysLow truck volume roadways

Flexibility for other parameter depending on project needs, Flexibility for other parameter depending on project needs, safety, cost, and aesthetic choice.safety, cost, and aesthetic choice.

To understand the breadth and interest of To understand the breadth and interest of replies, all messages and advice replies, all messages and advice received by WSDOT on this topic will be received by WSDOT on this topic will be put onto the WSDOT website by July 20put onto the WSDOT website by July 20thth at:at:

http://www.wsdot.wa.gov/regions/Northwest/rp&s/http://www.wsdot.wa.gov/regions/Northwest/rp&s/environmental/aae/default.htmenvironmental/aae/default.htm