page-10

669

Federal Aviation Administration, DOT

Pt. 150, App. A

ART

A—G

ENERAL

Sec. A150.1

Purpose.

(a) This appendix establishes a uniform

methodology for the development and prepa-
ration of airport noise exposure maps. That
methodology includes a single system of
measuring noise at airports for which there
is a highly reliable relationship between pro-
jected noise exposure and surveyed reactions
of people to noise along with a separate sin-
gle system for determining the exposure of
individuals to noise. It also identifies land
uses which, for the purpose of this part are
considered to be compatible with various ex-
posures of individuals to noise around air-
ports.

(b) This appendix provides for the use of

the FAA’s Integrated Noise Model (INM) or
an FAA approved equivalent, for developing
standardized noise exposure maps and pre-
dicting noise impacts. Noise monitoring may
be utilized by airport operators for data ac-
quisition and data refinement, but is not re-
quired by this part for the development of
noise exposure maps or airport noise compat-
ibility programs. Whenever noise monitoring
is used, under this part, it should be accom-
plished in accordance with Sec. A150.5 of this
appendix.

Sec. A150.3

Noise descriptors.

(a)

Airport Noise Measurement.

The A-

Weighted Sound Level, measured, filtered
and recorded in accordance with Sec. A150.5
of this appendix, must be employed as the
unit for the measurement of single event
noise at airports and in the areas sur-
rounding the airports.

(b)

Airport Noise Exposure.

The yearly day-

night average sound level (YDNL) must be
employed for the analysis and characteriza-
tion of multiple aircraft noise events and for
determining the cumulative exposure of indi-
viduals to noise around airports.

Sec. A150.5

Noise measurement procedures and

equipment.

(a) Sound levels must be measured or ana-

lyzed with equipment having the ‘‘A’’ fre-
quency weighting, filter characteristics, and
the ‘‘slow response’’ characteristics as de-
fined in International Electrotechnical Com-
mission (IEC) Publication No. 179, entitled
‘‘Precision Sound Level Meters’’ as incor-
porated by reference in part 150 under
§ 150.11. For purposes of this part, the toler-
ances allowed for general purpose, type 2
sound level meters in IEU 179, are accept-
able.

(b) Noise measurements and documenta-

tion must be in accordance with accepted
acoustical measurement methodology, such
as those described in American National
Standards Institute publication ANSI 51.13,
dated 1971 as revised 1979, entitled ‘‘ANS—

Methods for the Measurement of Sound Pres-
sure Levels’’; ARP No. 796, dated 1969, enti-
tled ‘‘Measurement of Aircraft Exterior
Noise in the Field’’; ‘‘Handbook of Noise
Measurement,’’ Ninth Ed. 1980, by Arnold
P.G. Peterson; or ‘‘Acoustic Noise Measure-
ment,’’ dated Jan., 1979, by J.R. Hassell and
K. Zaveri. For purposes of this part, meas-
urements intended for comparison to a State
or local standard or with another transpor-
tation noise source (including other aircraft)
must be reported in maximum A-weighted
sound levels (L

); for computation or vali-

dation of the yearly day-night average level
(L

), measurements must be reported in

sound exposure level (L

), as defined in Sec.

A150.205 of this appendix.

ART

B—N

OISE

XPOSURE

EVELOPMENT

Sec. A150.101

Noise contours and land usages.

(a) To determine the extent of the noise

impact around an airport, airport propri-
etors developing noise exposure maps in ac-
cordance with this part must develop L

contours. Continuous contours must be de-
veloped for YDNL levels of 65, 70, and 75 (ad-
ditional contours may be developed and de-
picted when appropriate). In those areas
where YDNL values are 65 YDNL or greater,
the airport operator shall identify land uses
and determine land use compatibility in ac-
cordance with the standards and procedures
of this appendix.

(b) Table 1 of this appendix describes com-

patible land use information for several land
uses as a function of YDNL values. The
ranges of YDNL values in Table 1 reflect the
statistical variability for the responses of
large groups of people to noise. Any par-
ticular level might not, therefore, accurately
assess an individual’s perception of an actual
noise environment. Compatible or non-
compatible land use is determined by com-
paring the predicted or measured YDNL val-
ues at a site with the values given. Adjust-
ments or modifications of the descriptions of
the land-use categories may be desirable
after consideration of specific local condi-
tions.

generally refer to the major use of the site.
If other uses with greater sensitivity to
noise are permitted by local government at a
site, a determination of compatibility must
be based on that use which is most adversely
affected by noise. When appropriate, noise
level reduction through incorporation of
sound attenuation into the design and con-
struction of a structure may be necessary to
achieve compatibility.

(d) For the purpose of compliance with this

part, all land uses are considered to be com-
patible with noise levels less than L

65 dB.

Local needs or values may dictate further
delineation based on local requirements or
determinations.

VerDate Sep<11>2014

08:20 May 17, 2019

Jkt 247048

PO 00000

Frm 00679

Fmt 8010

Sfmt 8002

Y:\SGML\247048.XXX

247048