Estimating Worker Noise Exposure In Medium noise environments in the Semiconductor Industry Oteri Oghoghomeh Portfolio Project Presentation

Transcription

1 Estimating Worker Noise Exposure In Medium noise environments in the Semiconductor Industry Oteri Oghoghomeh Portfolio Project Presentation

2 Background & Problem Statement 16pt Intel Clear Subhead 2

3 Dual Microphone Sound Level Experiment- Jamie Risenmay, CIH To evaluate effects of speaking noise on the dosimeter, an experimental dual microphone dosimetry assessment was conducted. Industrial hygienist donned a Svantek dual channel microphone dosimeter One microphone was attached to the ear under the bunny suit hood Second microphone attached to shoulder area where currently available dosimeters are designed to be located IH wore dosimeter while performing fab sound level mapping and talking to EEs along the way, total time worn was 40 minutes Settings: ACGIH (exchange rate 3 db, 80 threshold, 85 criterion, A and Slow) Both microphones were calibrated prior to use 3

4 Dual Microphone Sound Level Assessment Results- Jamie Risenmay, CIH Overall, sound levels were lower for the microphone in the ear area (green) LAVG for the two microphones had a difference of 4.4 decibels LAVG = 81.6 db for shoulder mic & 77.2 db for ear mic Both microphones had the same overall maximum sound level (96.4 db) Green= Ear Microphone Purple= Shoulder Microphone 4

5 Literature Review Bulk of previous studies focus on noise exposure assessment (EA) above 85dB OSHA OEL (Steven and Kleiner, 2012)- 5.5 db overestimation of noise exposure in medium (40-80 db) noise environments due to worker s speech In occupational environments this can result in misclassification of exposure as over the OEL 5

6 Objectives Compare alternate estimates of noise exposure assessment in medium (40-80dB) environments Recommend BKMs for task-based noise exposure assessment 6

7 Methods 16pt Intel Clear Subhead 7

8 Setting D1C Implant- factory group 4 technicians on 12 hour shifts 10.5 hours in factory & 1.5 hours on break Maintenance task with single loud noise source Homogenous exposure pattern within group JF3 Datacenter group 5 technicians on 8 hour shifts Entire shift at workstation Constant exposure patterns; different for each worker DP3 QA Testing Lab 5 technicians on 8 hour shifts Workshift spent between lab and office space Diverse exposure patterns 8

9 Exposure Assessment Personal Dosimetry Time-Activity Summary Criterion Level- 80 db- 8 hour 3 db Exchange Sound Level Maps 9

10 Calculations % Dose from Sampling Period T n =SL/(2^((LAVG-CL)/ER) %Dose n = (Cn/SL/(2^((LAVG-CL)/ER))))*100 Where, LAVG is the average sound level - (in dba) computed for the sampling period. This was computed by the personal dosimeter CL, criterion level, is the average sound pressure level (SPL) that will result in 100% dose over the criterion time. This value equals 80 db for an 8 hour shift. %Dose corrected for unsampled shift [%Dose adj (%)] Accounts for partial shift sample >OEL [Yes/No] >100 %Dose adj %Exceedance (%) % of samples >OEL ER, or Exchange Rate, which refers to how sound energy is averaged over time. Sound pressure levels double every 3 db T, or reference duration corresponds to the total length of time (in mins) a worker can be exposed to the measured noise level without going over the CL. Cn, indicated the total length of time (in mins) at a particular noise level. SL, or shift length 10

11 Sound Level Map Interpretation Results 11

12 SLM Averages Workspace contributes all significant exposure D1C-mean Lavg of maintenance area before and after task JF3-mean Lavg of 3 closest SLM readings DP3-mean Lavg for the rows workers spent most of their time 12

13 SLM Peaks Most protective estimate Highest of Lavg readings used in SLM Averages 13

14 SLM Averages VS SLM Peaks 14

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16 Task-Based Exposure Assessment Integrates L avg based on time-activity summary 16

17 A Note About Time Activity Summaries 17

18 Task-Based Exposure Assessment VS Personal Dosimetry 18

19 N%Dose Corrections Don t forget speech! Adjusts for noise not captured by the SLM snapshot %Exceedence matches the gold standard for both the 20 & 30% Dose corrections. 19

20 N%Dose Corrections 10% 20% 30% 40% 20

21 Discussion 21

22 Limitations & Discussion Discussion Partial Shift Sampling Dosimetry BKM application Analysis of different workplaces Power Conclusions Task-based assessment can provide useful to approximate personal dosimetry in low noise environments Redo study with larger sample sizes Time-activity summaries 22

23 Acknowledgements Faculty Mentors Noah Seixas, PhD Chris Simpson, PhD Edmund Seto, PhD Intel Project Advisors Shannon Philips Ron Tubby, MS, MBA, CIH, CSP Thomas Sheinfeld, CSP Mom & Family Katelynn Smith, ASP DEOHS MS ES 16 Cohort Intel TD EHS team 23

24 Questions? 16pt Intel Clear Subhead

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