1. Sound Power Testing Techniques for Powered Hand Tools Brian Kim Edward Zechmann, M.S. Chuck Hayden, M.S., P.E. Dept of Health and Human Services US Public Health Service Centers for Disease Control and Prevention National Institute for Occupational Safety and Health

2. Overview Approx. 70 tools tested since April 2009 Standards Facilities and Equipment Set up at Unloaded and Loaded Condition Comparisons of Unloaded and Loaded Conditions

3. Standards ANSI S12.15-1992 – Tool Testing Standard – Specifies Test Jigs – Loading conditions ISO 3744:1994(E) –Measurement Standard – 10-Microphone Array – Engineering Grade Standard

4. Measure Sound Power – Sound Intensity integrated over measurement surface Laboratory Environment – Hemi-Anechoic Chamber – Monitoring Equipment Electrical power, humidity, speed, feed rate, etc. Equipment and Facilities

5. Steel Structure Reference Sound Source (RSS) 11 th Microphone One Microphone of the ten-microphone array Hemi-Anechoic Lab

6. Unloaded Test - Grinder

7. Loaded Test Jig Circular saw Tools held by hand to cut wood Oak Boards Resiliently Mounted

8. Idling Full Speed Lower Amplitude 97 dBA Cutting Oak Boards Greater Amplitude 109 dBA Circular Saw Milwaukee 6390-20 Continuous Noise in Both Loaded and Unloaded Conditions