[Code of Federal Regulations]
[Title 16, Volume 2]
[Revised as of January 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 16CFR1500.47]

[Page 454-455]
 
                     TITLE 16--COMMERCIAL PRACTICES
 
             CHAPTER II--CONSUMER PRODUCT SAFETY COMMISSION
 
PART 1500_HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS--Table of Contents
 
Sec. 1500.47  Method for determining the sound pressure level produced by toy caps.

    (a) Equipment required. The equipment for the test includes a 
microphone, a preamplifier (if required), and an oscilloscope.
    (1) The microphone-preamplifier system shall have a free-field 
response uniform to within 2 decibels from 50 
hertz to 70 kilohertz or beyond and a dynamic range covering the 
interval 70 to 160 decibels relative to 20 micronewtons per square 
meters. Depending on the model, the microphone shall be used at normal 
or at grazing incidence, whichever gives the most uniform free-field 
response. The microphone shall be calibrated both before and after the 
test of a model of cap. The calibration shall be accurate to within 
1 decibel. If the calibration is of the pressure 
type or of the piston-phone plus electrostatic actuator type, it shall 
be corrected to free-field conditions in accordance with the 
manufacturer's instructions.
    (2) The oscilloscope shall be the storage type or one equipped with 
a camera. It shall have a response uniform to within 1 decibel from 50 hertz to 250 kilohertz or higher. It 
shall be calibrated to within 1 decibel against an 
external voltage source periodically during the tests.
    (b) Procedure. (1) Use the type pistol that would ordinarily be used 
with the caps being tested. Place the pistol and testing equipment so 
that neither the pistol nor the microphone is closer than 1 meter from 
any wall, floor, ceiling, or other large obstruction. Locate the pistol 
and the microphone in the same horizontal plane with a distance of 25 
centimeters between the diaphragm of the microphone and the position of 
the explosive. Measure the peak sound pressure level at each of the six 
designated orientations of the pistol with respect to the measuring

[[Page 455]]

microphone. The 0[deg] orientation corresponds to the muzzle of the 
pistol pointing at the microphone. The 90[deg], 180[deg], and 270[deg] 
orientations are measured in a clockwise direction when looking down on 
the pistol with its barrel horizontal, as illustrated by the following 
figure:
[GRAPHIC] [TIFF OMITTED] TC03OC91.055

    (2) The hammer and trigger orientations are obtained by rotating the 
pistol about the axis of the barrel, when the pistol is in the 90[deg] 
or 270[deg] orientation, so that the hammer and the trigger are each 
respectively closest to and in the same horizontal plane with the 
microphone.
    (3) Fire 10 shots at each of the six orientations, obtaining 
readings on the oscilloscope of the maximum peak voltage for each shot. 
Average the results of the 10 firings for each of the six orientations.
    (4) Using the orientation that yields the highest average value, 
convert the value to sound pressure levels in decibels relative to 20 
micronewtons per square meter using the response to the calibrated 
measuring microphone.