[Code of Federal Regulations]
[Title 40, Volume 24]
[Revised as of July 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR201.27]
[Page 80-81]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 201_NOISE EMISSION STANDARDS FOR TRANSPORTATION EQUIPMENT; INTERSTATE
RAIL CARRIERS--Table of Contents
Subpart C_Measurement Criteria
Sec. 201.27 Procedures for: (1) Determining applicability of the
locomotive load cell test stand standard and switcher locomotive standard
by noise measurement on a receiving property; (2) measurement of
locomotive load cell test stands more than 120 meters (400 feet) on a
receiving property.
(a) Microphone. The microphone must be located at a receiving
property measurement location and must be positioned at a height between
1.2 and 1.5 meters (4 and 5 feet) above the ground. Its position with
respect to the equipment must be in accordance with the manufacturers'
recommendations for Type 1 or 2 performance as appropriate. No person
may stand between the microphone and the equipment being measured or be
otherwise positioned relative to the microphone at variance to the
manufacturers' recommendations for Type 1 or Type 2 performance as
appropriate.
(b) Data. (1) When there is evidence that at least one of these two
types of nearly steady state sound sources is affecting the noise
environment, the following measurements must be made. The purpose of
these measurements is to determine the A-weighted L90
statistical sound level, which is to be used as described in
subparagraph (c) below to determine the applicability of the source
standards. Before this determination can be made, the measured
L90 is to be ``validated'' by comparing the measured
L10 and L99 statistical sound levels. If the
difference between these levels is sufficiently small (4 dB or less),
the source(s) being measured is considered to be a nearly steady state
source.
(2) Data shall be collected by measuring the instantaneous A-
weighted sound level (FAST) at a rate of at least once each 10 seconds
for a measurement period of at least 15 minutes and until 100
measurements are obtained. The data may be taken manually by direct
reading of the indicator at 10 second intervals (1
second), or by attaching a statistical analyzer, graphic level recorder,
or other equivalent device to the sound level meter for a more
continuous recording of the instantaneous sound level.
(3) The data shall be analyzed to determine the levels exceeded 99%,
90%, and 10% of the time, i.e., L99, L90, and
L10, respectively. The value of L90 is considered
a valid measure of the A-weighted sound level for the standards in Sec.
201.16 only if the difference between L10 and L99
has a value of 4 dB or less. If a measured value of L90 is
not valid for this purpose, measurements may be taken over a longer
period to attempt to improve the certainty of the measurement and to
validate L90. If L90 is valid and is less than the
level in applicable standards for these source types, the sources are in
compliance. If the measured value of L90 is valid and exceeds
the initial 65 dB requirement for any of the source types that appear to
be affecting the noise environments, the evaluation according to the
following paragraph (c) is required.
(c) Determination of applicability of the standard when
L90 is validated and is in excess of one or more of the
source standards. The following procedures must be
[[Page 81]]
used to determine the compliance of the various source types when
L90 is validated and in excess of one or more of the
applicable standards.
(1) The principal direction of the nearly steady-state sound at the
measurement location must be determined, if possible, by listening to
the sound and localizing its apparent source(s). If the observer is
clearly convinced by this localization process that the sound emanates
only from one or both of these two sources, then:
(i) If only stationary locomotive(s), including at least one
switcher locomotive, are present, the value of L90 is the
value of the A-weighted sound level to be used in determining if the 65
dB requirement is exceeded and compliance with the standards in
Sec. Sec. 201.11(c) and 201.12(c) is necessary.
(ii) If only a locomotive load cell test stand and the locomotive
being tested are present and operating, the value of L90 is
the value of the A-weighted sound level to be used in determining
applicability of the standard in Sec. 201.16.
(iii) If a locomotive load cell test stand(s) and the locomotive
being tested are present and operating with stationary locomotive(s),
including at least one switcher locomotive, the value L90
minus 3 dB is the value of the A-weighted sound level to be used in
determining applicability of the standards in Sec. Sec. 201.11(c),
201.12(c) and 201.16.
(iv) If a locomotive load cell test stand(s) and the locomotive
being tested are present and operating, and a stationary locomotive(s)
is present, and if the nearly steady-state sound level is observed to
change by 10 dB, coincident with evidence of a change in operation of
the locomotive load cell test stand but without apparent change in the
location of stationary locomotives, another measurement of
L90 must be made in accordance with paragraph (b) of this
section. If this additional measure of L90 is validated and
differs from the initial measure of L90 by an absolute value
of 10 dB or more, then the higher value of L90 is the value
of the A-weighted sound level to be used in determining applicability of
the standard in Sec. 201.16.
(2) In order to accomplish the comparison demonstration of paragraph
(c)(3) of this section, when one or more source types is found not to be
in compliance with the applicable standard(s), documentation of noise
source information shall be necessary. This will include, but not be
limited to, the approximate location of all sources of each source type
present and the microphone position on a diagram of the particular
railroad facility, and the distances between the microphone location and
each of the sources must be estimated and reported. Additionally, if
other rail or non-rail noise sources are detected, they must be
identified and similarly reported.
(3) If it can be demonstrated that the validated L90 is
less than 5 dB greater than any L90 measured at the same
receiving property location when the source types that were operating
during the initial measurement(s) are either turned off or moved, such
that they can no longer be detected, the initial value(s) of
L90 must not be used for determining applicability to the
standards. This demonstration must be made at a time of day comparable
to that of the initial measurements and when all other conditions are
acoustically similar to those reported in paragraph (c)(2) of this
section.
[45 FR 1263, Jan. 4, 1980; 47 FR 14709, Apr. 6, 1982]