Survey and analysis of workers breathing patterns in actual arc welding

Transcription

1 Survey and analysis of workers breathing patterns in actual arc welding Hiroki Haruta 1), Hisashi Yuasa 1), Eriko Shimizu 1) Kazushi Kimura 1), Taizo Murakami 2), Shigeru Tanaka 3) 1) KOKEN LTD. Hanno Laboratory 568 Kawadera, Hanno, Saitama, , Japan. 2) Mizue Medical Clinic/ Keihin Occupational Health Center 6-21 Mizue-cho, Kawasaki-ku, Kawasaki, , Japan. 3) Jyumonji University Sugasawa, Niiza, Saitama, , Japan.

2 Background Arc welding in steel and machine manufacturing workplaces is one of the typical dust work in Japan. A high incidence of pneumoconiosis has been reported among arc welders due to exposure to high dust concentration. The use of high efficiency respirator such as PAPR is considered effective in protecting workers from health problems. The performance of respirator is directly affected by the amount of respiration that could vary depending on worker s work rate.

3 Investigating worker s breathing pattern in actual work conditions is essential in estimating the practical performance of respirators. We have been collecting breath samples of workers in various workplaces ( Breath Sampling ). Conference presentation related to Breath Sampling 2007 Philadelphia, American Industrial Hygiene Conference 2009 Toronto, American Industrial Hygiene Conference 2010 Hong Kong, ISRP International Conference 2011 Utunomiya, Japan Occupational Hygiene Association 2011 Tokyo, Japan Society for Occupational Health 2012 Boston, ISRP International Conference 2012 etc.

4 Study Objective To obtain the relevant data to estimate the practical performance of respirators through the sampling of worker s breathing pattern in actual workplaces.

5 Breath sampling device Breath Sampling in Workplaces Transmitter DP Sensor V T F MV: Minute volume Battery Filter *Basic performance of this device was reported at ISRP Hong Kong 2010 Flow rate (L/min) V T : Tidal volume F: Breath Frequency Time (sec) Analysis of breathing pattern and breathing data

6 Monitoring worker s dust exposure with personal sampler Personal sampler with PM4 impactor Personal sampler attached to Arc welder Dust exposure concentration Respirable dust concentration(pm4): Mass change in Backup filter Total dust concentration : Mass change in Impactor + Backup filter

7 Test procedure for worker s breath sampling Preparation (employee room) Explain the study objective and method to workers. Sign the Informed consent form. equipt Breath sampling device (Fit testing must be done) and personal dust sampler. Measurement (Workplace) End of Measurement (employee room) Workers start work as usual. Start collecting breath samples and measuring dust exposure concentration. Record workers movements with a video camera. Remove Breath sampling device (Fit testing must be done) and personal dust sampler. Interview workers about their physical conditions etc. The whole process was conducted in the presence of an industrial doctor.

8 Information on surveyed steel workplaces This survey was conducted in 4 sites of the steel works. Worker s work activities in the surveyed 4 workplaces Arc welding Gas cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

9 Information on surveyed steel workplaces Arc welding Gas cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

10 Information on surveyed steel workplaces Arc welding Gas cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

11 Information on surveyed steel workplaces Arc welding Gus cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

12 Information on surveyed steel workplaces Arc welding Gas cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

13 Information on surveyed steel workplaces Arc welding Gas cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

14 Information on surveyed steel workplaces Arc welding Gas cutting Grinding Chipping slag Cleaning a torch Carrying a steel plate

15 Principal work activities in the workplaces Work Activity Dust work: Arc welding + Gas cutting, Grinding and Chipping slag Other work: Carrying heavy objects, Hammering, Measuring, Cleaning etc.

16 Result of measurement on worker s dust exposure Respirable (PM4) and total dust concentrations and ratios Note: Arc welding dust is virtually in the range of respirable size.

17 Respirable dust concentrations in each work activity. Note: Respirable dust concentration at arc welding is considerably higher than at other work activities.

18 Results on worker s breathing pattern Example of workers breathing patterns using breath sampling device

19 Example of analysis method of breathing pattern Extracted Work work activity motion 1 0 作業の準備及び移動 Sweep Prepare up for work work area Sweep Carry metal up work plates area Throw metal Move 材料保管庫へ移動 powder to strage in a place feed hopper Agitate Carry the metal plates powder Remove Take 道具置き場へ移動 the a shovel dirt from the a locker hopper Throw metal powder in a feed hopper 430 Check 投入量を目視で確認 the amount of powder Agitate the metal powder 550 Put the 道具置き場へ移動 shovel back in the locker Remove the dirt dirt from from the the hopper 660 材料保管庫へ移動 Move to staff room Time(sec) No. No.1 No.2 No.3 No.4 No.5 Flow rate (L/min) Time (s)

20 Breathing data obtained from worker s breathing pattern Averaged minute volume and peak flow rate for each work activity

21 Estimate work rates of work activities in steel workshop WR: Predicted (W/m 2 ) Multiple linear regression equation to estimate WR (1)(2) (Predictor variables are breathing data and physique) WR= 182(V T ) + 8(F) -134(BSA) 240(T i /T tot ) R 2 = WR: Measured (W/m 2 ) Relationship between measured by a metabolic measurement system) and predicted work rate (WR) (1) 2012 Boston ISRP International Conference (2) 2012 Fukuoka Japan Occupational Hygiene Association

22 Work Class(ISO/TS ) Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Resting Light Moderate Heavy Very heavy Very very heavy MV(L/min) WR(L/min) Relationship between minute volume and estimated work rate

23 Conclusion We investigated breathing pattern and dust exposure of 13 workers engaged in arc welding in steel workshops. Activities performed by most workers included not only arc welding but also related dust activities such as Gas Cutting, Grinding and Chipping. Respirable dust concentration during arc welding was considerably higher than at the other works. The Characteristic change was found in arc welders breathing patterns, that they tended to be a small waveform during arc welding.

24 The estimated metabolic work rates for work activities in the steel workshops tended to show less intensity than that of the other workplaces surveyed previously. All of arc-welding activities, which is a high concentration dust work, were classified in the range from light to moderate works.

25 The realistically expected performance of respirator for arc welding. The current test flow rate corresponding to the breathing amount assumed in common works may be sufficient for estimating the performance for arc welding Because of the high dust concentration, using a PAPR is considered better solution. An excessively large supply flow rate is not required. It is important for the PAPR to have a feature that can still keep a positive pressure inside a facepiece during the work.

26 Future Outlook The findings in this study were derived from limited number of subjects. Also, we still continue sampling worker s breathing data in various worksites. So, with the accumulation of breathing data obtained in the actual workplaces, we will be able to increase our knowledge regarding the relationship between worker s breathing and activity.

27 Thank you for your attention Hiroki Haruta KOKEN-ltd 568, Kawadera, Hanno, Saitama, Japan,