i document resume schultz, theodore j.; mcmahon, nancy m ... · sources of noise aircraft,...

I

f

DOCUMENT RESUME

ED 076 400 SE 015 938

AUTHOR Schultz, Theodore J.; McMahon, Nancy M.TITLE Noise Assessment Guidelines.INSTITUTION Department of Housing and Urban Development,

Washington, D.C.REPORT NO BBN-2176; H-1498PUB DATE Aug 71NOTE 37p.AVAILABLE FROM Superintendent of Documents, U.S. Government Printing

Office, Washington, D.C. 20402 ($1.25 Stock Number2300-1194)

EDRS MF-$0.65 HC-$3.29DESCRIPT')RS *Acoustical Environment; Environmental Influences;

Evaluation; *Guidelines; *Housing; InstructionalMaterials; Manuals; Screening Tests; *SiteAnalysis

IDENTIFIERS *Noise Pollution Control

ABSTRACTThe Department of Housing and Urban Development

(HUD), ir> its efforts to provide decent housing and a suitable livingenvironment, is concerned with noise as a major source ofenvironmvntal pollution. To this end, these guidelines are presentedto provide site screening techniques. The procedures described havebeen developed so that people without technical training will be ableto assess the exposure of a housing site to present and future noiseconditions. Assessment is designed as an evaluation of the site'sexposure to three major sources of noise--aircraft, roadways, andrailways. Information needed to make the assessment is listed at thebeginning of each section under headings which indicate the mostlikely source from which to obtain the information. Evaluation of thesite exposure is given in terms of acceptability categories: clearlyacceptable, normally acceptable, normally unacceptable, and clearlyunacceptable. Final evaluation is determined according to the leastfavorable category found for any of the individual sourceevaluations. A fourth, optional evaluation technique, a Walk-AwayTest, is described as useful when previous evaluations leave doubt asto the site's acceptability. Additional items included in theseguidelines are evaluation worksheets and charts for calculating data.(BL)

1 1

A

A'

AIOA P'

0

;

,s

VA.

A

e

kr' \e.,,,,,,VIV,..e

,t

a. CLrrorTriaou,u.004 41

,5*, , 4. 'j, '

6 ,?"' .1,'' A

t \' ,'s*r ' ' 4

.4)) , , , ,, I.,.

; , . ,

5

I1

. ;

b 912: G3-

6

a

a

noiseassessmentguidelines

Theodore J. SchultzNancy M. McMahon

U.S. Department of Housing and Urban DevelopmentWashington, D.C. 20410

For sale by the Superintendent of Documents, U.S. Government Printing OfficeWashington, D.C. 20402 Price $1.25

Stock Number 2300-1194

The Department of Housing and Urban Development, in its efforts to provide decenthousing and a suitable living environment, is concerned with noise as a major sourceof environmental pollution and has issued the Departmental Circular 1390.2 on NoiseAbatement and Control.

In furtherance of Section 4a of the Circular, the Office of Research and Technologyhas sponsored research to provide site screening techniques. These NoiseAssessment Guidelines do not constitute established policy of the Department.Their use as a site "screening tool" is encouraged so that HUD may evaluate theirutility.

This booklet has been prepared by Bolt Beranek and Newman Inc. under Contract No.H-1498 for the U.S. Department of Housing and Urban Development.

The authors wish to thank Mr. George E. Winzer, Chief, Urban Noise AbatementResearch Program, Office of Research and Technology, U. S. Department of Housingand Urban Development, for his technical assistance and untiring support during thecourse of this project.

BBN Report No, 2176August 1971

iii

PREFACE iii

INTRODUCTION

AIRCRAFT2

Necessary Information2

Evaluation of Site Exposure to Aircraft Noise 3

ROADWAYS6


Evaluation of Site Exposure to Roadway Noise7

Automobile Traffic8

Adjustments for Automobile Traffic8

Truck Traffic10

Adjustments for Truck Traffic 10

RAILWAYS14


Evaluation of Site Exposure to Railway Noise 15

WALK-AWAY TEST16


Exposure of Site to Overall Noise Levels 17

FINAL EVALUATION18

NOTES19

APPENDIX - Tear-out Worksheets and Figures

These guidelines are presented as part ofa continuing effort by the Department ofHousing and Urban Development to providedecent housing and a suitable living environ-ment for all Americans.

The procedures described here have beendeveloped so that people without technicaltraining will be able to assess the exposureof a housing site to present and future noiseconditions. The only materials requiredare a map of the area, a ruler (straightedge), a pencil, and perhaps a 100-ft tapemeasure. Tear-out worksheets andworking figures are contained in the backof this booklet.

All of the information you will need can beobtained from public agencies usually bytelephone. For convenience, this informa-tion is listed at the beginning of each sec-tion under headings which indicate the mostlikely source. While you are obtainingthis information, be sure to ask about anyapproved plans that may affect noise levelsat the site for example, land-use changes,changes in runway traffic, widening ofroads, and so forth. In all evaluations, youshould try to assess for the situation thatwill have the most lasting effect on the site.

The assessment is presented as an evalua-tion of the site's exposure to three majorsources of noise Aircraft, Roadways, andRailways. The evaluation is given in termsof the following acceptability categories:

Clearly Acceptablethe noise exposure is such that both theindoor and outdoor environments are pleasant.

Normally Acceptable

the noise exposure is great enough to be ofsome c oncern but common building con-structions will make the indoor environ-

the noise exposure is significantly moresevere so that unusual and costly building

ment acceptable, even for sleeping quarters,and the outdoor environment will be reason-ably pleasant for recreation and play.

Normally Unacceptable

1

constructions are necessary to ensure sometranquillity indoors, and barriers must beerected between the site and prominentnoise sources to make the outdoor environ-ment tolerable.

Clearly Unacceptable

the noise exposure at the site is so severethat the construction costs to make theindoor environment acceptable would beprohibitive and the outdoor environmentwould still be intolerable.

The site's expoSure to noise from each ofthese sources is evaluated according to theleast favorable category found for thatsource. For example, if the assessmentshows that the exposure to noise from threedifferent roads is Clearly Acceptable,Normally Acceptable, and Clearly Unaccept-able, then the site's exposure to roadwaynoise is Clearly Unacceptable. Similarly,if the site's exposure to roadway and railwaynoise is Normally Acceptable but its exposureto aircraft noise is Normally Unacceptable,then the final site evaluation is NormallyUnacceptable (see Worksheet A).

Another technique for assessing the noise,levels at a housing site is a simple pro-cedure called the Walk-Away Test. Thisevaluation, which is described in the fourthsection of this booklet, is optional. It maybe performed during a visit to the site orwhen the evaluations in the first three sec-tions leave some doubt as to the site's ac-ceptability.

When measuring the distance from the siteto any source, you should measure from thelocation of the dwelling nearest the sourcebecause this is the housing that will be mostseverely affected by the noise. If at anypoint during the assessment the site's ex-posure to noise is found Normally or ClearlyUnacceptable, then there is no need tocontinue the evaluations unless the locationof the dwellings can be changed or someshielding can be provided to block the noisefrom that source..

Aircraft

To evaluate a site's exposure to aircraftnoise, you will need to consider all air-ports (commercial and military) within 15miles of the site. The inforniation requiredfor this evaluation is listed below underheadings that indicate the most likelysource. Before beginning the evaluation,you should record the following informationon Worksheet B

From the FAA Area Office or the MilitaryAgency in charge of the airport:

Are NEF (Noise Exposure Forecast) orCNR (Composite Noise Rating) contoursavailable? (These contours have not yetbeen constructed for all airports. Whenavailable, they are superimposed on a mapwith a marked scale.)

Any available information about approvedplans for runway changes (extensions ornew runways).

2

From the FAA Control Tower or AirportOperator (if NEF or CNR contours are notavailable):

The number of nighttime jet operations(10:00 p.m. 7:00 a.m.).

The number of daytime jet operations(7:00 a.m. 10:00 p.m.).

Are there any supersonic jet operations ?

The flight paths of the major runways.

Any available information about expectedchanges in airport traffic e.g. , will thenumber of 000rations increase or decreasein the next ten or fifteen years? Are thereany plans for supersonic jet traffic?

In making your evaluation, use the data forthe heaviest traffic condition, whetherpresent or future.

If NEF or CNR contours are available,locate the site by referring to the markedscale.. Also locate a point roughly in thecenter of the area covered by the principalrunways.. If the site lies outside theNE F-30.(CNR-100) contour, then draw astraight line to connect these two points.Measure along this line the distancesbetween (1) the NEF-40 (CNR-115) andNEF-30 (CNR-100) contours and (2) theNEF -30 (CNR-100) contour and the site.Now use Table Ito evaluate the site'sexposure to aircraft noise.

If NEF or CNR contours are not available,determine the effective number of opera-tions for the airport as follows. Multiplythe number of nighttime jet operations by17. Then add the number of daytime jetoperations to obtain an effective total. Anysupersonic jet operation automaticallyplaces an airport in the largest category ofTable II, which governs noise acceptability(see procedure, next page). !Examplesare given in italics in the right-handcolumns.]

Example 1: The illustration at thetop of page 5 sh9ws two sites lo-cated on a map that has NEF con-tours. We draw a line from each ofthese sites to a point roughly inthe center of the area covered bythe principal runwayt.

Measuring along these linee, wefind that Site #1 lies outside theNEF -30 contour at a distancegreater than that between the NEF-30 and NEF-40 contours and thatSite #2 ties outside the NEF-30contour at a distance less thanthat between the NEF-30 and NEF-40contours.

Therefore, the exposure of Site #Ito aircraft noise is Clearly Ac-ceptable and the exposure of Site#2 is Normally Acceptable.

Example 2: The illustration at thebottom of page 5 shows an airportfor which NEF or CNR contours arenot available. The airport has 20nighttime and 125 daytime jet oper-ations.

(Continued at top of next page.)

TABLE I.

SITE EXPOSURE TO AIRCRAFT NOISE

Distance from Site to the Center of the AreaCovered by the Principal Runways

AcceptabilityCategory

Outside the NEF-30 (CNR-100) contour,at a distancegreater than or equal to the distance between the Clearly AcceptableNEF-30 and NEF-40 (CNR-100, CNR-115) contours

Outside the NEF-30 (CNR-100) contour, at a distanceless than the distance between the NEF -30 and NEF-40 Normally Acceptable(CNR-100, CNR-115) contours

Between the NEF-30 and NEF-40 (CNR-100, CNR-115)contours Normally Unacceptable

Within the NEF-40 (CNR-115) contour Clearly Unacceptable

3

On a map of the area which shows the prin-cipal runways, mark the locations of thesite and of the center of the area coveredby the principal runways. Then, usingthe distances below, you can constructapproximate NEF-40 and NEF-30 contoursfor the major runways and flight pathsmost likely to affect the site. Again useTable Ito evaluate the site's exposure toaircraft noise,

Construction of Approximate NEF ContoursUsing the Distances in Table II.

Example 2 (continued)There are no supersonic flights andso we determine the effective num-be of operations as follows:

20 (nighttime) x 17 = 340

Add to this the actual numberof daytime operations:340 t 125 (daytime) = 465

Using the distances in Table II, weconstruct approximate NEF contoursand then draw a line from the siteto a point roughly in the center ofthe area covered by the principalrunways. Measuring along this line,we find that the site lies outsidethe NEF-30 contour at a distancegrater than that bet&een the NEF-30 and NEP-40 contours. Therefore,the site's exposure to aircraftnoise is Clearly Acceptable.

TABLE II.

DISTANCES FOR APPROXIMATE NEF CONTOURS

Effective Numberof

Operations

Distances-NEF 30

0to

Contour

0

DistancesNEF 40

0

toContour

0 50 1000 ft 1 mile 0 0

51 500 1/2 mile 3 miles 1000 ft 1 mile

501 1300 1 1/2 miles 6 miles 2000 ft 2 1/2 miles

More than 1300or any supersonicjet operations

2 miles 10 miles 3000 ft 4 miles

4

30

40

/,I..

SITE 1i CLEARLYACCEPTABLE

30

NORMALLYACCEPTABLE

SITE 2-.

\Example of NEF Contours

Example of Approximate NE F Contours Drawn for An Airport With An Effective N..mber ofOperations Between 51 and 500.

5

Roadways

11

To evaluate a site's exposure to roadwaynoise, you will need to consider all majorroads within 1000 ft of the site. Theinformation required for this evaluation islisted below under headings that indicatethe most likely source. Before beginningthe evaluation, you should try to obtain anyavailable information about approved plansfor roadway changes (e.g., wideningexisting roads or building new roads) andabout expected changes in read traffic(e.g. , will the traffic on this road increasesignificantly in the next ten or fifteenyears?). Then, record the followinginformation on Worksheet C

From an area map and/or the City (County)Engineer:

The distances from the site to the center-lines of the nearest and farthest lanes oftraffic.

6

1-4.1 to.

From the City (County) Director of Traffic:

The peak hourly automobile traffic flowin both directions, combined.

The peak number of trucks (buses)* perhour in each direction. (If the road hasa gradient of 3% or more, record uphilland downhill numbers separately as thesefigures will be necessary later; if not,simply record the total number of trucks. )

Note: you may also need to make adjust-ments for the following circumstances:

A road gradient of 3% or moreStop-and-go TrafficMean SpeedA Barrier

The information required for these adjust-ments can be obtained from the City (County)Director of Traffic.

*Buses count as trucks

Traffic surveys show that the level of road-way noise depends on the percentage oftrucks in the total traffic volume. Toaccount for this effect, these guidelinesprovide for separate evaluation of auto-mobile and truck traffic.

Before proceeding with these separateevaluations, however, determine theeffective distance from the site to eachroad by locating on Figure 1 the distancesfrom the site to the centerlines of thenearest and farthest lanes of traffic.

[Large-scale work-sheet figures are con-tained in pouch at the back of the book. ]

RAILWAYNO.1

ExamplesThe site .shown b4low is exposed t7noise from three major roads:Road #1 has four lanes, each 12 ftwide, and a 30-ft wide Iredian stripwhich accomodates a rapid transitline. Read #2 has four lanes, each12 ft wide. Road 113 has six lanes,each 15 ft wide, and a medi -rn tip35 ft wide.

The distances shown below will beused for all roadway examples ::nthis boo;clet.

300'

366'

rib-.

I

-- - --- - -

318'

Ise

I

210'

320'

TOAIRPORT

150 186'

TOP SIGN

EFFECTIVE

ROAD NO.(1

7ROAD NO. 2

DISTANCEIS 166 FT)

ROAD NO. 3f(EFFECTIVEDISTANCE IS

260 FT)

I

....=...,..,...

( EFFECTIVEDISTANCE IS330 FT)

i.,...r.......m.mw

Plan View of Site Showing How Distances Should be Measured From the Location of the DwellingNearest to the Source.

Effective Distance (cont'd):

Now lay a straight-edge to connect thesetwo distances and read off the value at thepoint where the straight-edge crosses themiddle scale. This value is the effectivedistance to the road and should be recordedon line 4.

The numbers in Figure 2, which is used toevaluate the site's exposure to automobilenoise, were arrived at with the followingassumptions:

There is no traffic signal or stop signwithin 800 ft of the site.The mean automobile traffic speed is60 mph.There is line-of-sight exposure fromthe site to the road i.e., there is nobarrier which effectively shields thesite from the road.

If a road meets these three conditions,proceed to Figure 2 for an immediateevaluation of the site's exposure to theautomobile noise from that road.

Butis any of these conditions are different,mike the necessary adjustment(s) and thenust Figure 2 for the evaluation.

Stop-antj-go Traffic:

If there i:, a traffic signal or stop signwithin 860 ft of the site, multiply the totalnumber of automobiles per hour by 0.1.Record your answer on line 5.

Mean Traffic .peed:

If there is no traffic signal or stop signwithin 800 ft of the site and the mean auto-mobile speed is ether than 60 mph, multiplythe total number of automobiles by theappropriate adjustment factor (top of nextpage). Record your answer on line 6.

Exampl,e 1: Road fit The distancefrom he site to the centerline ofthe ne.lrest lane of traffic is 300 ftThe di.'tance to the centerline of thefarthest lane of traffic is 366 ft.Figure ' shows that the effectivedistance from the site to this roadis 330 P. Road #2 The distanceto the centerline of the nearestlane of traffic is 150 ft. Thedistance :o the centerline of thefarthest 7.7ne of traffic is 186 ft.Figure 1 si;ows that the effectivedistance frlm the site to this roadis 166 ft. Road #3 The distanceto the centerline of the nearestlane of traf.f'ic is 210 ft. The dis-tance to the centerline of thefarthest lane of traffic is 320 ft.Figure 1 shows that the effectivedistance from the site to this roadis 260 ft.

1000 c41:w900

f.600700700

600 600

500

400

500

400

300

283200

7:--

ROAD 140.1 330 -11366

3320 00

260ROAD NO.3

130

c1640,m".ROAD NO.2

200186

100 10090 9960

60

ao70

60

so1

50

40

30

40

30

20

to

20

10DISTANCE TO EFFECTIVE DISTANCE TOCENTERLINE OF DISTANCE CENTERLINE OFNEAREST LANE FARTHEST LANE

Example of How Figure 1 is Used to DetermineEffective Distances.

Mean Traffic Speed Adjustment Factor

20 (mph) 0.1225 0.1830 0.2535 0.3240 0.4045 0.5550 0.7055 0.8560 1.0065 1.2070 1.40

Barrier Adjustment:

This adjustment affects distance and appliesequally to automobiles and trucks on thesame road. Therefore, instructions forthis adjustment appear after those for trucktraffic.

40,000

30.000 -

20,000 -

10.000

80002 7000

60005000

12 4000

3000

o 2000

o WW2o 400'" 700./ 600

500CC

= 4000300

200

ICO

W-70

IO

111111 I 1 11111

CLEARLYUNACCEPTABLE

NORMALLYUNACCEPTABLE

EXAMPLE4

NORMALLYACCEPTABLE

EXAMPL

EXAMPLE12

1 1 111t 14)1

CLEARLYACCEPTABLE

Si)1,11- 1111120 30 40 50 60 80 100 200 300 400 600 8001000

EFFECTIVE OISTANCE (FT)

Example of How Figure 2 is Used to EvaluateSite Exposure to Automobile Noise.

9

Example 2: Road #1 meets the threeconditions that allow for an imme-diate evaluation. In obtainin,F theinformation necessary for thisevaluation, we found that the hourlyautomobile flow is 800 vehicles.On Figure 2, we locate on thevertical scale the point repre-senting 800 vehicles/hr and onthe horizontal scale the pointrepresenting 330 ft. (Note thatwe must estimate the location ofthis point.) Using a straight-edge, we draw lines to connectthese two values and find thatthe site's exposure to automobilenoise from this road is NormallyAcceptable.

Example 3: Road #2 has a stop signat 750 ft from the site. The hourlyautomobile flow is reported as being900 vehicles. We adjust for stop-and-go traffic

900 x 0.1 = 90 vehicles

and find from Figure 2 that theexposure to automobile noise isClearly Acceptable.

Example 4: Road #3 is a depressedhighway. There is no traffic signalor stop sign and the mean speed is60 mph. The hourly automobile flowis 1200 vehicles. The road profileshields all residential levels ofthe housing from line-of-sight tothe traffic. The only adjustmentthat can be made is the barrieradjustment. This adjustment isnecessary, however, only when thesite's exposure to noise has beenfound Clearly or Normally Un-acceptable. Figure 2 shows thatthe exposure to automobile noiseis Normally Acceptable. Therefore,no adjustment for barrier isnecessary.

The numbers in Figure 3, which is -used toevaluate the site's exposure to truck noise,were arrived at with the following assump-tions:

There is a road gradient of less than3 %.

There is no traffic signal or stop signwithin 800 ft of the site.

The mean truck traffic speed is 30 mph

There is line-of-sight exposure fromthe site to the road i.e., there is nobarrier which effectively shields thesite from the road.

If a road meets these four conditions,proceed to Figure 3 for an immediateevaluation of the site's exposure to trucknoise from that road.

But

if any of the conditions are different, makethe necessary adjustment(s) listed belowand then use Figure 3 for the evaluation.

Road Gradient:

If there is a gradient of 3% or more, multi-ply the number of trucks per hour in the up-hill direction by the appropriate adjustmentfactor.

% of Gradient

3-45-6 %

More than 6 %

AdjustmentFactor

1.41.72.5

Add to this adjusted figure the number oftrucks per hour in the downhill directionand record your answer on line 7.

10

Example 5: Road #1 meets the fourconditions that allow for an imme-diate evaluation. The hourly truckflow is 60 vehicles. Figure 3 showsthat the site 's exposure to trucknoise from this road is NormallyAcceptable.

Example 6: Road #2 has a stop signat 750 ft from the site. There isalso a road gradient of 4%. Notrucks are allowed on this road, but4 buses per hour are scheduled 2in each direction.

We adjust first for gradient

uphill: 2 x 1.4 = 2.8 vehicles

downhill: 2. vehicles

total f 4.8 vehicles

And then adjust for stop-and-gotraffic ( see next page)

4.8 x 5 = 24 vehicles (per hour)

4000

3000

2000

19008900800700

g 603300400

300

2000-1

'900M 801- 78

11 60SO

CI 40

30

1098710 30 40 5060 80 100 200 300 400 603 800 1000

EFFECTIVE OISTANCE (FT)

Example of How Figure 3 is Used to Evaluatethe Site's Exposure to Truck Noise.

Stop-and-go Traffic:

If there is a traffic signal or stop signwithin 800 ft of the site, multiply by 5 thetotal number of trucks. Record youranswer on line 8. (If the truck traffic hasalready been adjusted for gradient, use thenumber on Line 7; if not, use the numberof trucks on line 3c for this calculation.)

Mean Traffic Speed:

Make this adjustment only if there is notraffic signal or stop sign within 800 ft ofthe site and the mean speed is not 30 mph.

If the mean truck speed differs with directiontreat the uphill and downhill traffic separately.Multiply each by the appropriate adjustmentfactor below.

Add these two numbers and record youranswer on line 9. (Remember that theuphill traffic may 'have been adjustedfor rc.-Ad gradient.)

But

if the mean truck speed is the same for bothdirections, then multiply the total number oftrucks (:rom either line 3c or line 7) by theappropriate adjustment factor. Record youranswer on line 9.

Mean Traffic Speed(mph)

AdjustmentFactor

20 1.6025 1.2030 1.0035 0.8840 0.7545 0.6950 0.6355 0.5760 0. 5065 0.4670 0.43

11

Example 6 (continued)Figure 3 shows that the exposure totruck (bus) ) noise from this road isNormally Acceptable.

Example 7: The profile of Road #3shields all residential levels ofthe housing from line-of-sight tothe traffic. The mean truck speedis 50 mph. The hourly truck flowis 175 vehicles. We adjust for meanspeed

175 x 0.63 = 110.25= 110 vehicles

and find from Figure 3 that exposureto truck noise is Normally Unaccept-able. Therefore, we proceed withthe barrier adjustment (see nextpage).

Example 7 ( cont* ): Road #3 has beendepressed 25 ft from the 150 ftelevation of the natural terrain.The actual road elevation, there-fore, is 125. ft. We find theeffective road elevation to be

145 5 = 130 ft.

Six stories are planned for thehousing, which is located at anelevation of 130 ft. The effectivesite elevation for the highest story is:

6 x 10 = 60 f 130 - 5 = 185 ft.

ROADNO. 2

ELEVATIONOF

SITE130'

ELEVATION

TERRAIN150'

ELEVATION

ROAD125'

ROADNO.3

Detail of Site Showing the MeasurementsNecessary for a Barrier Adjustment.

25'

Barrier Adjustment:

Note: A barrier may be formed by the roadprofile, by a solid wall or embankment, bya continuous row of buildings, or by theterrain itself. To be an effective shield,however, the barrier must block all resi-dential levels of all buildings from line-of-sight to the road, and it must not have anygaps that would allow noise to leak through.

This adjustment is necessary only when thesite's exposure to noise from a road hasbeen found Normally or Clearly Unaccept-able.

To make the barrier adjustment, youshould first record on line 10 the distancebetween the site and the barrier and online 11 the distance between the center ofthe road and the barrier; then you shoulddetermine the differences in effectiveelevation between (1) the site and the roadand (2) the barrier and the road as follows:

Step 1. From the City (County) Engineer,obtain the elevation of the road. (Roadsmay be elevated above the natural terrainor may be depressed, as in our example;make certain, therefore, that the figureyou obtain for road elevation takes any suchchange into account.) Add 5 ft to this figurato obtain the effective road elevation andrecord your answer on line 12.

Step 2. From the applicant, obtain the groundelevation of the site and the number ofstories in the proposed housing. Multiplythe number of stories by 10 ft. Add the siteelevation and then subtract 5 ft from thistotal to obtain the effective rite elevation.Record your answer on line 13.

Step 3. From the City (County) Engineer ora contour map, obtain the elevation of theterrain where the barrier is located. Addthe actual height: of the barrier to obtain theeffective barrier elevation. Record youranswer on line 14. (Note that in some casesas in our example, the barrier is formed bythe road profile and the elevation of theterrain is the effective barrier elevation.)

12

Example 7 (continued)The barrier, which is formed by theroad profile, has no height otherthan the 150 ft elevation of thenatural terrain. Thus, theeffective barrier elevation is150 ft.

The difference in effective rlevationbetween (1) the site and the roadis 55 ft and (2) the barrier andthe road is 20 ft.

We now use Figure 4 to find thebarrier adjustment factor.

Example of Barrier Adjustment

The distance from the site tothe barrier is 200 ft.The distance from the center ofthe road to the barrier is 70 ft.The difference in effective ele-vation between the site and theroad is 55 ft.The difference in effective ele-vation between the barrier andthe road is 20 ft.

On the vertical scale of Graph 1, wemark 200 ft and draw a straighthorizontal line to meet the curvemarked 70 ft. Then, we draw avertical line down to Graph 2 tomeet the point which represents55 ft (note that we must guess thelocation) and a horizontal line overto Graph 3 to meet the curve marked20 ft.

(Note: If the Zine from Graph 2does not meet the appropriate curveon Graph 3, then the barrier is notan effective shield and there is noadjustment.)

Next.., we draw a vertical Zine up toGraph 4 to meet the curve marked 4(which is the number intersected bythe line going from Graph 1 toGraph 2) and a horizontal line overto Graph 5 to meet the curve marked200 ft. From Graph 5, we draw avertical Zine down to the adjustmentscale and find that our multiplieris 1.8.

1

Record the difference in effective elevationbetween the site (line 13) and the road(line 12) on line 15. Record the differencein effective elevation between the barrier(line 14) and the road (line 12) on line 16.

To find the barrier adjustment factor, youwill need Figure 4, a straight edge, and theinformation recorded on lines 10, 11, 15,and 16. The Example of Barrier Adjustmentexplains how to use Figure 4.

When you have determined the barrieradjustment factor, multiply line 4, theeffective distance, by the adjustment factorto obtain the adjusted distance from the siteto the road. Record your answer on line 17.

0Z 4004W1- 500

In200

ZMWwWEEXmI-4Wm

W0Z4I-W0

zWWXI-WW

YZ4OXPI40>W M..JW CI

ZZ 4WWW I-Z 0W

WU.U.0

DISTANCE BETWEEN THE CENTEROF THE ROAD AND THE BARRIER (FT)

Iadoz01-.z0aze04,

I-= ,r,0W 0cn %

WCt

0.,Z l'

1.

Example 7 (continued)Using this multiplier, we adjust theeffective distance

260 x 1.8 = 468 ft

and find from Figure 3 that thesite's exposure to truck noise fromthis road is Normally Acceptable.

DISTANCE BETWEEN SITE ANDBARRIER (FT)

2 3 4 5 7 10 Is 20 50 40 50 70 100

DIFFERENCE IN ELEVATION BETWEENBARRIER AND ROADWAY (FT)

Example of How Figure 4 is Used to Find the Adjustment Factor.

13487 -43 0 - 72 - 2

I I l _ I I I I I I I II I I.-412 1 iii is ZO 25 3 5 7 2 9 10 II 11

BARRIER ADJUSTMENT FACTOR

Railways

. IA3

To evaluate a site's exposure to railwaynoise, you will need to consider all above-.ound rapid transit lines and railroads

wjthin 3000 ft of the site. The informationrequired for this evaluation is listed belowunder headings that indicate the most likelysource.

Before Oeginning the evaluation, you shouldrecord the following information onWorksheet D

From an area map and/or the (County)Engineer:

The distance from the site to the railwayright-of-way.

Does a barrier effectively shield the sitefrom the railway? (Re:nember that aneffective barrier blocks all residentiallevels of all buildings from line-of-sightto the railway and has no gaps that wouldallow noise to leak through.)

14

From the Supervisor of CustomerRelations for the railway:

The number of nighttime (10:00 p.m.7 :00 'a.m. ) railway operations.

Any available information about approvedplans for changing the number of nighttimeoperations.

The distances in Table III were arrived atwith the assumption that there are 10 ormore nighttime (10:00 p.m. 7:00 a. m. )railway operations.

If a railway has 10 or more nighttimeoperations, proceed to Table III for animmediate evaluation of the site's exposureto noise from that railway.

But

if a railway has fewer than 10 nighttimeoperations, multiply the distance from thesite to that railway by the appropriate ad-justment factor; then proceed to Table III.

Number of NighttimeRailway Operations

AdjustmentFactor

1 2 operations 3.33 5 operations 1 . 76 9 operations 1 . 2

Example 1: The distance from thesite to Railway #1 is 318 ft.There are 2 nighttime operationsand there is direct Zine-of-sightto the right-of-way. Since thereare fewer than 10 nighttime opera-tions, we adjust the distance asfollows:

318 ft x 3.3 = 1049 ft

and then proceed to Table III wherewe find that the exposure to noisefrom this railway is Normally Ac-ceptable.

Example 2: The distance from thesite to Railway #2 is 550 ft. Thereare 20 nighttime railway operationsand the site is completely shieldedfrom the right-of-way. Since thereare more than 10 nighttime opera-tions, we proceed immediately toTable III and find that the site'sexposure to noise from this railwayis Clearly Acceptable.

TABLE 111.

SITE EXPOSURE TO RAILWAY NOISE

Distance from Site to Right-of-Way:(Possibly adjusted for number

of nighttime operations)Acceptability

Category

Line-of-Sight Exposure Shielded Exposure

More than 3000 ft

Between 601 and 3000 ft


Less than 100 ft

More than 500 ft



Less than 50 ft

Clearly Acceptable

Normally Acceptable

Normally Unacceptable

Clearly Unacceptable

15

Walk -Away Test

-

IIMP wow fa

.41111411L

et 111.

JIMA", lir zorjr-p...

:*

IPAfiltt,t 4;":'

4,0, 4 A;

11 .:,

.14Vq..4,ov

gol.

.:

,Mt

.t;T4,471.1L'ff T070,-.1P "

A!. . at':V!,;;;;'''''f 'tr;414r;1* 13#1.

The Walk-Away Test is an optional evalua-tion that may be performed during any visitto the site. However, when the site'sexposure to more than one source of noiseis found Normally rather than ClearlyAcceptable, the Walk-Away Test isstrongly recommended as means of as-sessing the cumulative effects of noisefrom various :sources.

The Walk-Away Test has been designed toevaluate without reference to specificsources the overall noise condition at asite. Since noise may vary during a 24-hour period, this test should be performedat those hours when noise is apt to be mostsevere i.e. , during the peak morning andafternoon traffic periods and at thosehours when noise is apt to be most annoy-ing i.e. , between 10:00 p. m. and mid-night when people are trying to go to sleep.

When performing a Walk-Away Test, youshould record the following information onWorksheet E

The date and time of the visit to the site.

The average of distances where understand-ing just becomes difficult.

16

The Walk-Away Test requires two menwho exchange roles as speaker and listener;thus, each person should have normal hear-ing and an average voice. To perform thetest, you will need a 100-ft tape measureand some reading material with which bothpersons are unfamiliar.

The speaker should stand at fixed location,while the listener, starting at a distance of2 or 3 ft, backs slowly away. The speakershould hold the reading material at chestheight in such a way as not to block thedirect path from himself to the listener.He should not raise his voice in an attemptto maintain communication.

At some point the listener will find that hecan understand only a scattered word ortwo over a period of 10 seconds or more.At this point, measure the distance be-tween the listener and the speaker.

For consistent and accurate results, thisprocedure should be repeated several timesduring each visit and the distances shouldbe averaged. Also, the roles of speakerand listener should be reversed to averageout variations of normal speaking levelsand hearing acuity. After each visit, .

evaluate the site's overall noise levels byusing Table IV.

Example: The site's exposure toboth roadway and railway noise hasbeen evaluated as Normally Accept-able. Therefore, we assess theoverall noise levels during threeseparate weekday visits to the site.During Visit #1, made between 8:00and 9:00 a.m., the distances whereunderstanding just became difficultwere 50 ft, 55 ft, and 54 ft for anaverage of 53 ft. The average ofdistances for Visit #2, made be-tween 4:00 and 5:00 p.m., ..Jas 47 ftand for Visit #3, made beuween 10:00and 11:00 p.m., was 68 ft.

Table IV shows that during eachvisit, the overall noise level atthe site was Normally Acceptable.

TABLE IV.

SITE EXPOSURE TO OVERALL NOISE LEVELS

Distance WhereUnderstanding Acceptability Category

Becomes Very Difficult

More than 70 ft Clearly Acceptable26 70 ft Normally Acceptable7 25 ft Normally Unacceptable

Less than 7 ft Clearly Unacceptable

17

When you have completed the evaluations of the noise from aircraft, roadways and railways,enter these results cn Worksheet A Site Evaluation, and determine the final evaluationaccording to the least favorable category found for any of the individual source evaluations.

18

This space is provided for any notes you may wish to make during the evaluation.

19

WORKSHEET A Site Evaluation

Site Location:

ProgramProject Name

Locality

File Number

Sponsor's Name

Street AddressCity, StatePhone

Least Favorable Category found for

1. Aircraft Noise2 Roadway Noise3. Railway Noise

4. Walk-Away Test(if conducted)

Final Site Evaluation Least FavorableCategory Above:

Clip this worksheet to the top of a packagecontaining Worksheets B E and Figs. 1-4.

Noise Assessment Guidelines

Date:

Signature:


WORKSHEET B Aircraft Noise

List all airports within 15 miles of the site: Acceptability Category:

1.

2.

3.

Necessary Information:

1. Are NEF or CNR contours available?(yes/no)

2. Number of nighttime jet operations:

3. Number of daytime jet operations:

4. Any supersonic jet operations?(yes/no)

Airport #1 Airport #2 Airport 113


Worksheet C Roadway Noi.qe

List all major roads within 1000 ft of the Acceptability Category:site: Automobiles Trucks

1.

9

3.

4.


1. The distance in feet from the sitethe centerline of

a. nearest lane:b. farthest lane:

2. The total number of automobiles perhour in both directions:

3. The number of trucks per houra. uphill direction:b. downhill direction:c. both directions:

4. Effective distance from site to road:

Adjustments for Automobile Traffic5. Stop-and-go:

6. Mean speed:

Adjustments for Truck Traffic7. Road gradient:

8. Stop-and-go:

9. Mean speed:

Barrier Adjustment10. Distance from site to barrier:11. Distance from center of road to

barrier:12. Effective elevation of road:

13. Effective elevation of site:

14. Effective elevation of barrier:15. Difference in elevation between site

and road:

Road #1 Road #2 Road 113 Road 114

(Over)

Worksheet C (Continued)

16. Difference in elevation between barrierand road:

17. Adjusted distance:

-)-


Road #1 Road #2 Road #3 Road 114

Date:

Signature:


WORKSHEET D Railway Noise

List all railways within 3000 ft of the site: Acceptability Category:

1.

2.

3.


1. Distance in feet from the site to therailway right-of-way:

2. Type of exposure (line-of-sight orshielded):

3. Number of nighttime operations:

Railway #1

Date:

Signature:

Railway #2 Railway #3

11111111111.1111111111.111.1=11111.11111M


WORKSHEET E Walk-Away Test

Date and time of each visit to the site: Acceptability Category:

1.

2.

>. 3.

Average of distances:

Visit #1

Date:

Signature:

Visit #2 Visit #3

1000 =900800 =700 =600

500=

=

400 7----=-

300

200

100908070

60

50

===

40

30

20

=

1

1000900800700

600

500

400

300

200

=

=1--

10DISTANCE TOCENTERLINE OFNEAREST LANE

Figure 1.

EFFECTIVEDISTANCE

100908070

60

50

40

30

20

10

DISTANCE TOCENTERLINE OFFARTHEST LANE

40,000

30,000

20,000

10,000

8000700060005000

4000

3000

0u- 2000

CC

0

1000

800700600500

400

300

200

100

8070

10

CLEARLYUNACCEPTABLE

CLEARLYACCEPTABLE

Figure 2.

20 30 40 50 60 80 100 200 300 400EFFECTIVE DISTANCE (FT)

1 -I -I- I

600 800 1000

4000

3000

2000

1000900800700600500

400

300

200

1009080706050

40

30

20

10

CLEARLYUNACCEPTABLE

NORMALLYUNACCEPTABLE

10

Figure 3.

NORMALLYACCEPTABLE

I I 1 1 1 1 1 1 1 I I 1 1 1 1 1 1

EFFECTIVE DISTANCE (FT)

U. S. GOVERNMENT PRINTING OFFICE:1972 0 - 487.149

20 30 40 50 60 80 100 200 300 400 600 8001000

I

CLEARLYACCEPTABLE

0Z 6004W

400

F.- ---- 300

C7) ti.-. . . . 200

Z CC 150W wW "--

(I 1001-' < 80W coCO 60

0W 40

Z 304CO1 20

5 15

1000800

zww3It--wu..co

>-z<c)i=c1>04.4wm- JW 0

ZZ <I

W Wi'"

Z (i)WCCWU.1.t.

5

10

DISTANCE BETWEEN THE CENTEROF THE ROAD AND THE BARRIER (FT)

1000 700 400 200 100 70 40 20

1

1 1.5 2 3I 1 1 1 1 U 1 1 1 1 1 1 1 1 1 1

4 5 8 10 15 20 30 40 60 80 100

r1=1.

xa.<cc

z0IzOa.

z...0°o 10

01--- ti,0

wq.0

cncc nN-W A1-Z

q.

5 7 10 15

DIFFERENCE IN ELEVBARRIER AND

4 5 7 10 15 20 30 40 50 70 100

FERENCE IN ELEVATION BETWEENBARRIER AND ROADWAY (FT)

DISTANCE BETWEEN SITE ANDBARRIER (FT)

ao

so

NO

1.0 1.2 1.4 1.6 1.8 2.0 2.5 3 4 5 6 7 8 9 10 11 11

BARRIER ADJUSTMENT FACTOR

_ _ .Eigure 4 -,4