Laserfiche WebLink
NTP - Manual measurement procedure for non - impulsive noise <br />The following test procedure has been approved by the Executive Director of the MPCA for the measurement <br />of non - impulsive noise. <br />(Instrumentation, Meteorology, Location, and Survey Procedure Identical to NTP -1 Test Procedures) <br />Manual monitoring procedure: <br />• Using a hand -held sound level meter, take an instantaneous sound reading every 10 seconds and <br />record on a sample sheet. A partner is very helpful. <br />• Continue taking sound readings for one hour, which will give you 360 individual readings. An <br />example of a "sample sheet" is below. <br />• To determine the L10, take the 36th loudest (10 percent of 360 = 36) individual sound reading by <br />counting from the loudest to the quietest on the "sample sheet" In the example on the next page, the <br />L10 = 63 and is the 36th X from the top of the sheet. <br />• To determine the L50, take the 180th loudest (50 percent of 360 = 180) individual sound reading. In <br />the example, the L50 = 57 and represents the 180th X from the top of the sheet. <br />90 <br />8_ <br />80 <br />7' <br />7C <br />dBA <br />6' <br />60 <br />5` . <br />50 <br />4` <br />40 <br />Date <br />SAMPLE <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />Cx <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />L10 <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />X <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />• <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />x <br />L50 <br />Location <br />A Guide to Noise Control in <br />Minnesota • October 2008 Minnesota Pollution Control Agency <br />10 <br />