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<br />L <br /> <br />NTP-2 Test Procedure <br /> <br />NTP-2 TEST PROCEDURE <br />MANUAL METHOD FOR <br />THE MEASUREMENT OF NON-IMPULSIVE NOISE <br /> <br />The following test procedure has been approved by the Executive Director of the <br />Minnesota Pollution Control Agency for the measurement of non-impulsive noise. <br /> <br />(A - D Identical to NTP-I Test Procedures) <br /> <br />E. MANUAL MONITORING PROCEDURE: <br /> <br />}> Using a hand-held sound level meter, take an instantaneous sound reading every 10 seconds <br />and record on a "sample sheet." An example of a "sample sheet" is on the next page. <br />}> Continue taking sound readings for one hour, which will give you 360 individual readings. <br />}> To determine the L10, take the 36th loudest (10% of360 = 36) individual sound reading by <br />counting from the loudest to the quietest on the "sample sheet." In the example on the next <br />page, the LI 0 = 63 and is the 36th X from the top ofthe sheet. <br />}> To determine the L50, take the I 80th loudest (50% of 360 = 180) individual sound reading. <br />In the example, the L50 = 57 and represents the 180th X from the top of the sheet. <br /> <br />13 <br />