[Code of Federal Regulations]
[Title 49, Volume 4]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR325.77]

[Page 800]
 
                        TITLE 49--TRANSPORTATION
 
                      DEPARTMENT OF TRANSPORTATION
 
PART 325_COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS
--Table of Contents
 
                      Subpart F_Correction Factors
 
Sec. 325.77  Computation of open site requirements--nonstandard sites.

    (a) If the distance between the microphone location point and the 
microphone target point is other than 50 feet (15.2 m), the test site 
must be an open site within a radius from both points which is equal to 
the distance between the microphone location point and the microphone 
target point.
    (b) Plan view diagrams of nonstandard test sites are shown in 
Figures 3 and 4. Figure 3 illustrates a test site which is larger than a 
standard test site and is based upon a 60-foot (18.3 m) distance between 
the microphone location point and the microphone target point. (See 
Sec. 325.79(b)(1) for an example of the application of the correction 
factor to a sound level reading obtained at such a site.) Figure 4 
illustrates a test site which is smaller than a standard test site and 
is based upon a 35-foot (10.7 m) distance between the microphone 
location point and the microphone target point. (See Sec. 325.79(b)(2) 
for an example of the application of the correction factor to a sound 
level reading obtained at such a site.)
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