[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR201.22]

[Page 73-74]
 
                   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. 201.22  Measurement instrumentation.

    (a) A sound level meter or alternate sound level measurement system 
that meets, as a minimum, all the requirements of American National 
Standard S1.4-1971 \1\ for a Type 1 (or S1A) instrument must be used 
with the ``fast'' or ``slow'' meter response chacteristic as specified 
in Subpart B. To insure Type 1 response, the manufacturer's instructions 
regarding mounting or orienting of the microphone, and positioning of 
the observer must be observed. In the event that a Type 1 (or S1A) 
instrument is not available for determining non-compliance with this 
regulation, the measurements may be made with a Type 2 (or S2A), but 
with the measured levels reduced by the following amount to account for 
possible measurement instrument errors pertaining to specific 
measurements and sources:
---------------------------------------------------------------------------

    \1\ American National Standards are available from the American 
National Standards Institute, Inc., 1430 Broadway, New York, NY 10018.

Table 1--Sound Level Corrections When Using a Type 2 (or S2A) Instrument
------------------------------------------------------------------------
     Measurement section                 Source             Decibels \1\
------------------------------------------------------------------------
201.24......................  Locomotives.................          0
                              Rail cars...................          0
                              Locomotive load cell test             0
                               stand.
201.26......................  Retarder....................          4
                              Car coupling................          2
201.27......................  Locomotive load cell test             0
                               stand.
                              Stationary locomotive.......          0
------------------------------------------------------------------------
\1\ Amount of correction to be subtracted from measured level (dB).

    (b) A microphone windscreen and an acoustic calibrator of the 
coupler type must be used as recommended by: (1) the manufacturer of the 
sound level meter or (2) the manufacturer of the microphone. The choice 
of both devices

[[Page 74]]

must be based on ensuring that Type 1 or 2 performance, as appropriate, 
is maintained for frequencies below 10,000 Hz.