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可分成定性(qualitative)與定量(quantitative)兩類。目前在美國OSHA(Occupational Safety and Health Administration)的規範中共有4種定性密合度測試法以及3種定量密合度測試法被認可[8]。其中定性測試是依靠受測者對測試物質的味覺、嗅覺或是刺激等自覺反應有或
無,來作為是否通過密合度測試的依據。一旦
受測者在測試過程中感覺或偵測到測試物質的
存在,即表示呼吸防護具未達到適當的密合。
定性密合度測試所使用的試劑成分包括香蕉油
(isoamyl acetate,學名醋酸異戊酯)、糖精(saccharin)、苦味劑(Bitrex)、或刺激性煙霧(irritant smoke)等。在實際測試時,除了香蕉油是以氣體分子狀態之外,其餘3項均是屬於粒狀物質,其中,美國NIOSH(National Institute for Occupational Safety and Health)並不建議使用刺激性煙霧法。在定量測試方面則
[1] Rengasamy S, King WP, Eimer BC, Shaffer RE. Filtration performance of NIOSH-approved N95 and P100 filtering facepiece respirators against 4 to 30 nanometer-size nanoparticles. Journal of Occupational and Environmental Hygiene 2008; 5: 556-64.
[2] Eshbaugh JP, Gardner PD, Richardson AW, Hofacre KC. N95 and p100 respirator filter efficiency under high constant and cyclic flow. Journal of Occupational and Environmental Hygiene 2009; 6: 52-61.
[3] He X, Grinshpun SA, Reponen T, Yermakov M, McKay R , Haru ta H , Kimura K .
Laboratory evaluation of the particle size effect on the performance of an elastomeric half-
勞動及職業安全衛生研究季刊 民國105年9月 第24卷第3期 第213-236頁
222
mask respirator against ultrafine combustion particles. The Annals of Occupational Hygience 2013; 57: 884-97.
[4] Coffey CC, Campbell DL, Zhuang Z. Simulated workplace performance of N95 respirators. American Industrial Hygiene Association Journal 1999; 60: 618-24.
[5] Campbell DL, Coffey CC, Lenhart SW. Respiratory Protection as a Function of Respirator Fitting Characteristics and Fit-Test Accuracy. AIHAJ - American Industrial Hygiene Association 2001; 62: 36-44.
[6] Coffey CC, Lawrence RB, Campbell DL, Zhuang Z, Calvert CA, Jensen PA. Fitting characteristics of eighteen N95 filtering-facepiece respirators. Journal of Occupational and Environmental Hygiene 2004; 1: 262-71.
[7] Lawrence RB, Duling MG, Calvert CA, Coffey CC. Comparison of performance of three different types of respiratory protection devices. Journal of Occupational and Environmental Hygiene 2006; 3: 465-74.
[8] OSHA. Respiratory Protection Standard (29 CFR 1910.134), 1998, Washington, DC: US Government Printing Office, Office of the Federal Register; 1998.
[9] NIOSH. Framework for Setting the NIOSH PPT Program Action Plan for Healthcare Worker Personal Protective Equipment: 2013-2018, draft, Version 7 June 2013.
[10] IOM. Preparing for an Influenza Pandemic: Personal Protective Equipment for Healthcare Workers. Washington, DC: The National Academies Press; 2008.
[11] Mullins HE, Danisch SG, Johnston AR.
Development of a new qualitative test for fit testing respirators. American Industrial Hygiene Association Journal 1995; 56: 1068-73.
[12] Han DH, Willeke K, Colton CE. Quantitative fit testing techniques and regulations for tight-fitting respirators: current methods measuring aerosol or air leakage, and new developments. American Industrial Hygiene Association Journal 1997; 58: 219-28.
[13] 3M. Qualitative Fit Test Apparatus FT-10 (Sweet) and FT-30 (Bitter). 2005. (Accessed June 1, 2016)(http://multimedia.3m.com/mws/mediawebserver?6666660Zjcf6lVs6EV s666qg9COrrrrQ-).
[14] TSI. Respirator Fit Testers. 2012. (Accessed June 1, 2016)(http://www.tsi.com/uploadedFiles/_Site_Root/Products/Literature/Manu als/Q-Fit-Manual.pdf).
[15] Young DF, Munson BR, Okiishi TH. A brief introduction to fluid mechanics. 2nd ed. New York: John Wiley & Sons; 1997.
[16] Belyaev SP, Levin LM. Techniques for collection of representative aerosol samples. Journal of Aerosol Science 1974; 5: 325-38.
[17] Hangal S, Willeke K. Overall efficiency of tubular inlets sampling at 0-90 degrees from horizontal aerosol flows. Atmospheric Environment. Part A. General Topics 1990; 24: 2379-86.
[18] Pich J. Theory of gravitational deposition of particles from laminar flows in channels. Journal of Aerosol Science 1972; 3: 351-61.
[19] Chen CC, Huang SH. The Effects of Particle Charge on the Performance of a Filtering Facepiece. American Industrial Hygiene
223
以醫療用霧化器執行呼吸防護具定性密合度測試之可行性探討
Association Journal, 1998; 59: 227-33.[20] Huang SH, Chen CW, Chang CP, Lai CY,
Chen CC. Penetration of 4.5 nm to aerosol particles through fibrous filters. Journal of Aerosol Science 2007; 38: 719-27.
[21] Huang SH, Chen CW, Kuo YM, Lai CY, McKay R, Chen CC. Factors Affecting Filter
Penetration and Quality Factor of Particulate Respirators Aerosol and Air Quality Research 2013; 13: 162-71.
Journal of Labor, Occupational Safety and Health 24: 213-236 (2016)
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Research Articles
A Study on the Feasibility of Conducting Qualitative Fit Test by Using Pneumatic Medical Nebulizers
Sheng-Hsiu Huang1 Chia-Wei Hsu1
Wei-Chih Kuo1 Chun-Wan Chen2
Chih-Chieh Chen1
1 Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University
2 Institute of Labor, Occupational Safety and Health, Ministry of Labor
Abstract
Although it has been widely recognized that fit testing is a critical requirement for ensuring the efficacy of tight fitting respirators, it may not always be complied with for various reasons, including availability, cost and time. Therefore, a less burdensome fit test method for respirators may help increase compliance. In this study, the particle size distributions generated by commercially available aerosol nebulizers (3M FT-10 and TSI Q-Fit) for qualitative fit test and pneumatic medical nebulizers were explored, respectively. Then, a combination of a filtering facepiece and a controlled leakage was used to calculate the fit factors according to the particle size distributions and defined aerosol penetration data. The result showed that inexpensive pneumatic medical nebulizers could be substitutions for the 3M FT-10 and the TSI Q-Fit aerosol generators.
Keywords: Wood dust, Bioaerosol, Mycotoxins
Accepted 4 June, 2016 Correspondence to: Sheng-Hsiu Huang, Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Room718, No.17, Xuzhou Rd., Taipei, 100, Taiwan(R.O.C), Email address: [email protected]
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Introduction
When using a tight fitting respirator, the seal between the edges of the respirator and your face is the most critical and uncertain factor that affecting the effectiveness of respirator use [1-3]. Considerable relevant research has shown that performing a fit test has a positive effect on the protection level that a respirator can offer[4-7]. Therefore, according to federal laws in the U.S. [8], fit testing of all negative or positive pressure tight-fitting facepiece respirators is required prior to initial use, whenever a different respirator facepiece is used, and at least annually thereafter. An additional fit test is required whenever there are changes in the user's physical condition that could affect respirator fit (e.g., facial scarring, dental changes, cosmetic surgery, or an obvious change in body weight). The employer must be fit tested with the same make, model, style, and size of respirator that will be used. On the other hand, although the general public in Taiwan has gradually been realizing the importance of fit testing, the implementation of testing in workplaces is still rare domestically. According to the previous literature, poor accessibility, high prices, long implementation time, and other factors have been common excuses for not carrying out fit testing [9,10]. Therefore, a fit test that can be comprehensively promoted shall have the characteristics of being easy to use, easily accessed, affordable, etc.
Respirator fit tests can be categorized as either qualitative or quantitative according to their method of implementation. Qualitative methods
(QLFTs) are non-numeric pass/fail tests that rely on the respirator wearer’s response to a test agent to determine respirator fit. To complete the test the respirator wearer generally stands in an enclosure and is subjected to a test agent such as Isoamyl Acetate, Saccharin, Bitrex or irritant smoke. If the respirator wearer can smell any of the test agents, or is irritated by the smoke during the test, the fit test is failed. Quantitative methods (QNFTs) provide an objective measure of the fit, generating a number referred to as a fit factor. A fit factor is the ratio of the test agent concentration outside the respirator to the test agent concentration inside the respirator. It may also be the ratio of total inhalation airflow to the airflow through faceseal leaks. A number of fit test methods exit. Currently in the U.S., OSHA (Occupational Safety and Health Administration) has accepted four QLFT and three QNFT methods [8]. However, the irritant smoke protocol is not recommended by NIOSH (National Institute for Occupational Safety and Health) due to health effects. Previous studies have explored and compared the pros and cons of each fit test in detail [11,12]. In general, QNFT is expensive, requiring costly instrumentation, (approximately 245,000-350,000 NTD), as well as expenditures for additional adapters or probed respirators. In addition, quantitative fit tests must be conducted by highly trained personnel. In contrast, qualitative fit tests are convenient and easy to perform. The equipment used is also much less expensive. Consequently, QLFT is more widely used [11].
Currently on the market, the FT-10 [13] made by 3M and Q-Fit [14] made by TSI are the two
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most common QLFT in use. Both of them utilize the pneumatic atomizing method to generate aerosol particles as test agents. The main difference is that the FT-10 generates the required air pressure for atomization by manually squeezing a rubber ball, while the Q-Fit utilizes an integral pump to disperse test solutions. Regarding cost, though the two aforementioned pieces of qualitative fit testing equipment are both relatively cheaper compared to the quantitative ones, their prices still range from a few thousand to tens of thousands NT dollars. Therefore, the promotion of fit testing would benefit from other alternative equipment that is more economical and easily accessible. Since the medical nebulizer is commonly used and has no difference in operating principles compared to the FT-10 or Q-Fit, and it has potential substitutability with the advantage of a cheaper price. Therefore, we measured the particle size distribution with regards to commercial nebulizers for qualitative fit testing (3M’s FT-10 and TSI’s Q-Fit) and pneumatic medical nebulizers, respectively, followed by incorporating a filtering facepiece and leaking pore combination of known aerosol penetration ratio, from which the fit factor of each type of nebulizer was calculated and compared with each other to determine whether they could be used interchangeably.
Materials and Methods
1. Size distribution measurement of droplets generated by nebulizers
The equilibrium size of a water droplet is quite sensitive to ambient relative humidity.
Therefore, in order to obtain the challenge particle size distribution, the relative humidity in the experimental chamber should be maintained with the same level as in the fit test hood. From the preliminary test results (shown in Figure 1 below), when the subject donned a fit test hood, the relative humidity inside the hood gradually increases from 70% to 90% over 5 minutes. Accordingly, the relative humidity in the experimental chamber is kept at 90% throughout the tests.
Fig 1 Change of relative humidity inside the hood
The particle size distribution measurement system is shown in Figure 2. The nebulizer is filled with test solution and sprayed toward a test chamber. The droplets are diluted by a clean air flow and sent to the instrument for particle size analysis. The relative humidity is about 10% when using complete-dry compressed air, and with the proper flow rate adjustment of dry and wet gas, respectively, the relative humidity in the test chamber can be stably controlled at 90%. The temperature and humidity inside the test chamber can be monitored with a thermo-humidity meter (Rotronic HygroPalm 22, Rotronic Instrument Corp, USA). The pressure generated
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by squeezing the nebulizer's rubber ball is measured by a pressure transducer (Omega Model No. PX176-015A5V), and signals are relayed to a data acquisition board (PCI-1710HGU DAS card & PCLD 8710 I/O Wiring Terminal Boards, Advantech Co., Ltd.) for data recording. This system is also capable of displaying the real time squeezing pressure on a screen. Then the person performing the study can more precisely control the squeezing force. The droplet size distribution is monitored in real time by the Electrical Low Pressure Impactor (ELPI, Dekati Ltd., Finland), which is a cascade impactor capable of measuring the number concentration of particles with sizes between 0.007~10 µm in 13 channels. The ELPI measures particle size distribution at 1 Hz interval. At the inlet of the ELPI, a corona charger imposes an electrical charging state on the particles composing the aerosol. At the charger’s outlet, the particles are classified according to their aerodynamic diameter using a low pressure cascade impactor. Currents induced by particles collected on impaction stages are measured using electrometers and are converted into particle number concentration. As the sampling flow rate of ELPI is 30 L/min, the flow rate in the experimental chamber is set at 32 L/min in order to minimize sample contamination by ambient air and collect almost all the particles that have been generated.
Since the ELPI sampling frequency is 1 Hz, we can measure the particle distribution with regard to each squeeze. A two-minute continuous sampling is done for each squeeze to ensure that most of the generated particles have been replaced, and by totaling the particle distribution of each
second, the result of the squeeze can be obtained. Each experimental condition is performed with 15 squeezes, and the average value is calculated and chosen as the representative. In order to increase the comparability between the nebulizers, all nebulizers are operated with 3M FT-10 rubber balls. As for the test solution, both 3M and TSI nebulizers use exclusive original test agents, while the medical nebulizer uses the original 3M test agent for testing. The flow rate of all instruments is calibrated by a soap bubble flow meter (Gilian Inc., West Caldwell, NJ, USA).
Furthermore, in order to evaluate the amount of solution consumed by each squeeze, the weight differences are obtained using a scale (Precisa 92SM-202A, Teopal, Switzerland) before and after each of the 50 of squeeze and averaged for the final value.
Fig 2 Diagram of the ELPI droplet particle size measurement system
The nebulizers used in this research for the evaluation and test include the 3M FT-10, TSI Q-Fit, and 13 other commercial nebulizers made by five different brands, with the prices ranging from 10 to 2,000 NTD.
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2. Fit factor simulative calculation
Using the filtering facepiece as an example (Figure 3), the air can flow into the inside of the mask when inhaling through the filtering material (QF) and the gap between the face and the mask (QL). Therefore, from a gas behavior point of view, the fit factor (FFA) is defined as:
FFA = QF+QL
QL
Since using aerosol particles for fit testing does not directly measure QF and QL, the aerosol particle concentration is used to calculate the air flow rate indirectly. Therefore, during the measurement, the efficiency of particles penetrating the filtering material and leaking gaps is expressed by the aerosol penetration, P, that is, PF and PL, respectively, which will interfere with the judgment of the fit factor. If the test particle concentration in the environment is C, then the ratio of particle quantity outside (NAM) and inside (NIN) the mask is as follows:
NAM
NIN =
C×(QF+QL)�C×QL×PL+C×QF×PF
= QF+QL
QL×PL+QF×PF
The calculated value from the above formula is conceptually equivalent to the protection factor, PF. While PF ≅ 0, PF represents the fit factor (FFP) measured by using the aerosol particles. Furthermore, while PF ≅ 0 and PL = 1, FFA = FFP; and while PF ≅ 0 and PL < 1, FFA < FFP. Therefore, we combine QF and QL in our designed calculation and define the penetration curve of different particle sizes versus filtering materials
and leakages under individual flow rate. Then, by importing the particle size distribution value of particles generated by nebulizers, FFP can be derived.
Fig 3 Illustration of air flow rate distribution when wearing a mask
In the research, the leakages were simulated by capillaries, and, the relationship between the air flow rate and resistance in the capillary can be calculated with the following formula [15].
Where, ∆p is the pressure drop inside the mask, Do is the diameter of the capillary, η is the viscosity coefficient of air, and L is the length of the capillary.
Larger particles flow through the capillary would lose due to the aspiration efficiency and gravitational settling. Regarding the aspiration efficiency (Easpiration), we only calculated the two extreme conditions in which the capillary is parallel (θ = 0°) or perpendicular (θ = 90°) to the external air flow rate (Uo). The Easpiration is as follows:
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When θ = 0° [16],
�
Stk is the stokes number. When θ = 90° [17],
The loss of particles in the capillary due to gravitational settling can be calculated with the following formula [18]:
Where, Vts is the terminal settling velocity, U is the air flow rate inside the capillary, and θ is the angle between the capillary and the horizontal direction. In conclusion, the overall penetration rate of the capillary can be expressed as:
With regard to the air resistance and particle penetration of the filtering facepieces, actual test data is used as the basis for additional simulative calculation. For resistance, a commercial N95 respirator was sealed in a holder and tested to air flow rates in the range of 0~85 L/min. The air flow rates are controlled by a mass flow controller (Hastings, HFC-303). The pressure difference in the upstream and downstream of the mask is obtained via an inclined manometer (model 400, Dwyer Instruments Inc.). After deriving the
regression equation between the mask resistance and air flow rate based on the experimental data, we can calculate the air flow rate distribution by using different sizes of capillaries under the same air resistance with regard to flowing through the mask filtering material and the capillary, respectively, thus obtaining the FFA under such conditions. Using Figure 4 as an example, the thick solid line denotes the air resistance of the N95 respirator under different flow rates, while the other two thin solid lines represent the relationship between air flow rate and air resistance of a capillary of 0.4 mm in diameter with the length of 10 mm and 20 mm, respectively. When inhaling, the negative pressure inside the mask is 2.2 mmH2O, and the air flow rate through the filtering material is 25 L/min, while it is 0.05 L/min when flowing through the capillary. Therefore, FFA is found to be 501([25+0.05]/0.05).
Fig 4 The relationship between pressure drop and air flow rate for a 0.4 mm capillary and an N95 respirator
As for the particle penetration simulation of the filter, some important basic parameters have been measured or estimated based on past
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studies [19, 20], including fiber diameter (df), filter thickness (t), packing density (α) and charge density (δ) Accordingly, the filter penetration curve as a function of particle sizes under different face velocities can be derived by introducing the single fiber theoretical model. The filter thickness is measured by using a vernier caliper. The packing density can be calculated based on the density of the fiber material and the weight of a known volume of filter sample. Based on the air resistance of the filtering facepiece at different air flow rates, the equivalent fiber diameter can be calculated using Darcy’s law. Since there is no reliable way to directly measure the charge amount of fiber, is the value can be deduced based on the particle penetration rate data. For example, the following figure shows the test result of the particle penetration rate (solid points) of an N95 respirator at 85 L/min (U = 8.0 cm/s), and by using the above method, t, α and df are derived as 0.97 mm, 0.051, and 3.81 µm, respectively. Therefore, with Microsoft Excel sheets created based on the single fiber theory and by adjusting the theoretical value of fiber's charge amount (dotted line) to fit to the experimental data, we can derive δ=8.5×10-5C/m2, which enables us to set the known air flow rate within the operable condition range and use the above method to calculate FFP for particles with any size distribution.
Fig 5 The fil tering efficiency of an N95 respirator filter
Results and Discussion
1. The particle size distribution measurement of droplet particles generated by nebulizers
The generated pressure wave is subject to the squeezing frequency of the rubber ball. After testing, the normal pressure of operation is 2~15 psi; therefore, we divided the atomization pressure into low (<7 psi), middle (7-9 psi), and high (>9 psi) to evaluate the influence on the generation of particle size distribution characteristics. Figure 6 shows the average particle size distributions of saccharin droplets generated by the 3M FT-10 under different pressures. In general, the output concentration of droplets increases as the atomization pressure increases. As for the particle
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size distribution, except for a smaller MMD at the minimum pressure, no significant difference is found between the other pressure values.
Fig 6 The weighted distribution of the mass of saccharin particles generated by nebulizers under different pressures
The 3M FT-10 nebulizer's nozzle and test solution are separate. The test solution is added into
the nebulizer each time before use. In contrast, the solution and nozzle of the TSI A-Fit are integrally formed, so each test requires a new combination of solution and nozzle. We used two 3M FT-10 nebulizers (A, B) and a TSI Q-Fit nebulizer to measure the average droplet size distribution generated under 90% relative humidity, three different atomization pressures, and four kinds of test reagent, as shown in Table 1 below. In general, the different conditions had no significant influence on the distribution of droplet particles, as the MMD is consistently 2~3 µm and GSD is around 2.
R e g a r d i n g t h e c o m m e r c i a l m e d i c a l nebulizers, the test was carried out at 90% relative humidity and middle atomization pressure to determine the droplet distribution characteristics of the generated saccharin fit testing solution. The results are provided in Table 2.
Table 1 The particle size distribution of droplets generated by 3M FT-10 and TSI Q-Fit
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Table 2 The particle size distribution of the droplets generated by the commercial medical nebulizers
Due to the original design, some nebulizers would suck the solution back as the rubber balls restored, so no data could be retrieved; such instances are represented in the table with "--". For the nebulizers with a miner pump-back situation, as the particle size distribution measurement is based on each squeeze and the solution inside the rubber ball has no influence on the next generation, the particle size distribution data is still obtainable but includes the interference of loss on the estimation of output amount of each squeeze. These nebulizers (7 models) should be excluded from being used in fit tests (7 of 13); while the droplet particle size of the remaining six nebulizers fell within 2~3 µm for MMD except for Par_1 which is a bit larger, and their GSD is all around 2. Under the same conditions, each squeeze (at middle atomization pressure) of the 3M FT-10 and TSI Q-Fit outputs
a solution amount around 1.134 and 0.586 mg, respectively; as for the medical nebulizers, the output amounts are all less than 3M FT-10 except for BB_4, which is slightly bigger. However, this situation did not have a big impact on its application in qualitative fit testing because the nebulizers with different output amounts would be adjusted according to each subject’s sensitivity when doing the threshold value test (the squeeze times of the one with a larger output amount should be fewer; while ones with a smaller output amount should be squeezed more times). Using the 3M FT-10 and TSI Q-Fit nebulizers as examples (assuming that both are operated by manual squeezing), as the solution output amount of the Q-Fit is half of that of the FT-10, the squeeze times of the Q-Fit shall be twice those of the FT-10. However, the amount of squeezes is limited to 30; anything over that would
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mean that the nebulizer is not usable.
2. The simulative evaluation of FFA and FFP of masks
We u s e d t h e c o m b i n a t i o n o f t h e aforementioned N95 respirator with a capillary of 1.1 mm in diameter and 10 mm in length. When the air flow rate through the filter was 5 L/min, the air flow rate inside the capillary became 0.05 L/min, and thus, FFA is 101. When using aerosol particles to evaluate the fitness of mask wearing, assuming the efficiency of the filter is nearly 100% and has no loss of particles in the capillary, the concentration ratio of particles inside to outside the mask is around 0.99% when calculated with FFA=101. However, as shown in Figure 7, since the aspiration efficiency of the capillary worsens as the particle size gets larger, the particle concentration inside the mask decreases as the particle size increases, thus obtaining a higher FFp value; furthermore, the particle loss gets worse in the horizontal direction of the capillary due to gravitational settling, resulting in an even higher FFp value. Conversely, as the intake efficiency of small-sized particles is high and the terminal settling velocity is small, the loss due to the settlement inside the capillary is insignificant. However, as the N95 filter cannot completely filter out smaller-sized particles, the total particle penetration rate is greater than 0.99%, i.e. FFp<101.
Fig 7 The curve of particle penetration rate at 5 L/min combining an N95 respirator and capillaries.
According to the results shown in Figure 7, we can deduce a series of particles with MMD and GSD combinations in log normal distribution, which can be used to determine the influence of different particle size distributions on the test results of mask fitness. The results are shown in Figure 8. If the particle size is too small, parts of the particles will penetrate through the filter into the mask, causing FFp < FFA; on the contrary, if the particles are too big, parts of the particles will be lost due to the limitation of the capillary's aspiration efficiency, causing FFp > FFA. If the gravitational settling loss of particles in the capillary is further considered (Figure 8B), the usable particles are subjected to a smaller upper limitation of particle size.
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Fig 8 The fitness of different particle size distribution combining an N95 respirator and capillaries at 5 L/min
By adding the particle size distribution data of Table 1 and 2 into Figure 8A, the results of the simulative tests of the 3M FT-10 and TSI Q-Fit nebulizers show reasonable agreement. With a low flow rate, the deviation between FFp and FFA is less than 10%, while most of the other medical nebulizers also achieve the same result.
Conclusions and Recommendations
1. Under a 90% relative humidity, the 3M FT-10 and TSK Q-Fit generate droplet particle distribution with MMD between 2~3 µm and GSD about 2, regardless of the type of test solution used.
2. The medical nebulizers used in this research are able to generate droplet sizes similar to those of the 3M FT-10 and TSI Q-Fit. Ultimately, six of the tested nebulizers can be used as alternative options, one of which costs only 29 NTD, which can drastically reduce the cost of qualitative fit testing. Even so, the cognition and operation techniques of
the operator that conducts the test (especially for the force and frequency of squeezing the rubber ball) are important factors that would affect the test results. Therefore, methods for enhancing operation training is a direction that should be considered in the future.
Acknowledgements
This research is supported by the 2013 research fund of the Institute of Labor, Occupational Safety, and Health, MOL (ILOSH102-H502). We hereby express our appreciation.
References
[1] Rengasamy S, King WP, Eimer BC, Shaffer RE. Filtration performance of NIOSH-approved N95 and P100 filtering facepiece respirators against 4 to 30 nanometer-size nanoparticles. Journal of Occupational and Environmental Hygiene 2008; 5: 556-64.
A Study on the Feasibility of Conducting Qualitative Fit Test by Using Pneumatic Medical Nebulizers
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filter efficiency under high constant and cyclic flow. Journal of Occupational and Environmental Hygiene 2009; 6: 52-61.
[3] He X, Grinshpun SA, Reponen T, Yermakov M, McKay R , Haru ta H , Kimura K .
Laboratory evaluation of the particle size effect on the performance of an elastomeric half-mask respirator against ultrafine combustion particles. The Annals of Occupational Hygience 2013; 57: 884-97.
[4] Coffey CC, Campbell DL, Zhuang Z. Simulated workplace performance of N95 respirators. American Industrial Hygiene Association Journal 1999; 60: 618-24.
[5] Campbell DL, Coffey CC, Lenhart SW. Respiratory Protection as a Function of Respirator Fitting Characteristics and Fit-Test Accuracy. AIHAJ - American Industrial Hygiene Association 2001; 62: 36-44.
[6] Coffey CC, Lawrence RB, Campbell DL, Zhuang Z, Calvert CA, Jensen PA. Fitting characteristics of eighteen N95 filtering-facepiece respirators. Journal of Occupational and Environmental Hygiene 2004; 1: 262-71.
[7] Lawrence RB, Duling MG, Calvert CA, Coffey CC. Comparison of performance of three different types of respiratory protection devices. Journal of Occupational and Environmental Hygiene 2006; 3: 465-74.
[8] OSHA. Respiratory Protection Standard (29 CFR 1910.134), 1998, Washington, DC: US Government Printing Office, Office of the Federal Register; 1998.
[9] NIOSH. Framework for Setting the NIOSH PPT Program Action Plan for Healthcare
Worker Personal Protective Equipment: 2013-2018, draft, Version 7 June 2013.
[10] IOM. Preparing for an Influenza Pandemic: Personal Protective Equipment for Healthcare Workers. Washington, DC: The National Academies Press; 2008.
[11] Mullins HE, Danisch SG, Johnston AR. Development of a new qualitative test for fit testing respirators. American Industrial Hygiene Association Journal 1995; 56: 1068-73.
[12] Han DH, Willeke K, Colton CE. Quantitative fit testing techniques and regulations for tight-fitting respirators: current methods measuring aerosol or air leakage, and new developments. American Industrial Hygiene Association Journal 1997; 58: 219-28.
[13] 3M. Qualitative Fit Test Apparatus FT-10 (Sweet) and FT-30 (Bitter). 2005. (Accessed June 1, 2016)(http://multimedia.3m.com/mws/mediawebserver?6666660Zjcf6lVs6EV s666qg9COrrrrQ-).
[14] TSI. Respirator Fit Testers. 2012. (Accessed June 1, 2016)(http://www.tsi.com/uploadedFiles/_Site_Root/Products/Literature/Manu als/Q-Fit-Manual.pdf).
[15] Young DF, Munson BR, Okiishi TH. A brief introduction to fluid mechanics. 2nd ed. New York: John Wiley & Sons; 1997.
[16] Belyaev SP, Levin LM. Techniques for collection of representative aerosol samples. Journal of Aerosol Science 1974; 5: 325-38.
[17] Hangal S, Willeke K. Overall efficiency of tubular inlets sampling at 0-90 degrees from horizontal aerosol flows. Atmospheric Environment. Part A. General Topics 1990;
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24: 2379-86.[18] Pich J. Theory of gravitational deposition
of particles from laminar flows in channels. Journal of Aerosol Science 1972; 3: 351-61.
[19] Chen CC, Huang SH. The Effects of Particle Charge on the Performance of a Filtering Facepiece. American Industrial Hygiene Association Journal, 1998; 59: 227-33.
[20] Huang SH, Chen CW, Chang CP, Lai CY, Chen CC. Penetration of 4.5 nm to aerosol
particles through fibrous filters. Journal of Aerosol Science 2007; 38: 719-27.
[21] Huang SH, Chen CW, Kuo YM, Lai CY, McKay R, Chen CC. Factors Affecting Filter Penetration and Quality Factor of Particulate Respirators Aerosol and Air Quality Research 2013; 13: 162-71.
國立成功大學碩士論文;2004。[6] Sen RN, Ganguli AK, Ray GG, De A,
Chakrabarti D. Tea-leaf plucking: workloads and environmental studies. Ergonomics 1983; 26: 887-93.
[7] Zuskin E, Skuric Z. Respiratory function in tea workers. British Journal of Industrial Medicine 1984; 41: 88-93.
[8] Kuman Priya . Challenges that Indian Tea Industry faces, 2008. http://www.commodityonline.com, 5/11/2012
[9] Barthakur R, Kripalini D. Vision 2020 Reinventing the Indian Tea Industry to Achieve Sustainable Global Competitiveness and Sustainable Livelihood. Global Managed Service. http://www.gmsworldnet.com/images/vision_reinventing_indian_tea_industry.pdf, 5/11/2012
[10] 行政院勞工委員會勞工安全衛生研究所。本土性人因工程指引探討。勞工安全衛生
研究所;1992。
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Research Articles
Investigation of Physical and Ergonomic Hazards in Tea Manufacturing Industries
Mei-Hui Chung1 Chih-Ta Wang1
Liwen Liu2
1 Department of Environmental and Safety Engineering, Chung Hwa University of Medical Technology
2 Institute of Labor, Occupational Safety and Health, Ministry of Labor
Abstract
Tea is one of the most popular three beverages all over the world. The total production quantity or the average personal consumption of tea increases gradually nowadays, according to the international statistics from the United Nations. In Taiwan, there exist statistically about 6,000 tea manufacturing factories, resulting in over 50,000 workers of the total labor population in the tea manufacturing industry. However, most of the tea workers do not have only the concept of occupational health and safety, but also the knowledge of self-protection in the work.
All the tea manufacturing processes, including tea plantation, tea plucking, tea processing procedures and so on are subjected to the Taiwan Labor Safety and Health Act. Workers in the tea manufacturing industry are likely exposed to a variety of occupational health and safety hazards, including pesticides exposure, hand plucking, high-temperature and mechanical cutting and vibration injuries, ergonomic hazards, muscle skeleton disorder, and so on. Therefore, investigation of the occupational hazards for the tea manufacturing worker is important and valuable.
We have basically investigated the potential physical and ergonomic hazards factors and analyze the severity in the tea manufacturing processes by finishing 32 spot coverage and 346 questionnaire surveys.
The finding indicates that the percentages of tiredness, muscle skeleton ache and disorder, hot harzard are 53.5%, 52.04% and 49.5%, respectively. The top three disorders of muscle skeleton follow the order: malleolus (80.64%)> buttocks (78.9%)> upper dorsum (73.41%).
Accepted 29 April, 2016 Correspondence to: Chih-Ta Wang, Safety Health & Environmental Engineering, Chung Hwa University of Medical Technology, No.89, Wenhwa 1st St., Rende Shiang, Tainan County 71703, Taiwan(R.O.C), Email address: [email protected]
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Introduction
Tea is one of the three most common beverages in the world. According to statistics, tea production was over 1 million (1.02 million) tons in 1963, over 2 million (2.06) tons in 1983, and over 3 million (3.059) tons in 2001, and recently reached 4.162 million tons in 2010. Tea in Taiwan is divided into three major categories: green tea, oolong tea, and black tea. Semi-fermented tea is the most common variety [1]. Estimated by the Tea Research and Extension Station of the Council of Agriculture, the total area of tea farms is currently 21,554 hectares. Tea Research and Extension Stations are mainly located in central Taiwan. About 6,000 tea farms and more than 50,000 tea-picking/tea-processing workers are involved in the tea-processing industry, and they have become a huge workforce [2]. The “tea-processing employee” referred to in our research includes both tea-picking workers and tea-processing workers.
Figure 1 shows the current methods of tea processing in Taiwan, including all necessary procedures, from receiving fresh tea leaves to final packaging. Methods vary according to the category of tea, such as green tea, black tea, and pouchong/oolong. The green tea process is easier since it does not need fermentation. After fresh tea leaves arrive, they directly begin the panning procedure and then drying. As for semi-oxidized teas, like pouchong and oolong, the process is more complicated since they require wilting and ball rolling. Therefore, the whole production is more laborious and time-consuming.
Figure 1 Processing procedures of all types of teas [2,3].
Green Tea Pouchong/Oolong Black Tea
Fresh Tea Leaf
Sunned Wilting
Indoor Wilting
Wilting (standing and stirring)
Panning
Rolling
Ball Rolling Oxidation/
Fermentation
Drying
Special Packaging
Bulk Packaging
Industries related to tea processing are standard labor-intensive processing industries. Starting from the tea plucking, this industry requires large amounts of labor. Each year, there are six to seven months of plucking, so many plucking events are needed. After the plucking, other procedures, such as the primary process and the refining process, take place. The primary process includes wilting, stirring, panning, rolling, and drying to oxidize fragrant tea leaves and to
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dry them for storage. The refining process further oxidizes and dries tea leaves for export sales. Labor costs account for more than 50% of tea processing costs, from the primary process to the refining process. Many jobs derived from tea processing are can be divided into two categories: tea-processing workers and tea-plucking workers. Current tea processing procedures include sunned wilting, standing, stirring, and rolling. Among these, rolling is the most difficult because this procedure takes considerable effort to form tea leaves into strips. The plucking procedure can be completed either by hand or by machine. In general, teas with better quality are processed by hand, but take much more effort [4].
According to the statistics that the Taiwan Union of Tea has received from tea farmers, nine people were injured due to tea plucking and processing in 2009, 16 people in 2010, and 13 people in 2013, for a total of 38 injured individuals over three years. However, the above statistics are not complete since many processing employees did not report their injury incidents. The actual number of injured people is most likely more than what is reflected in the statistics, making it a subject worthy of attention and research. After visiting and interviewing employees related to the tea process, we found that the potential hazards that could occur during tea processing are as follows:
1. Musculoskeletal Disorder (Ergonomic Hazards)
From plucking, fixation, and drying to packaging, all these procedures require large amounts of labor. Even though many kinds of
machines are widely used in tea-processing procedures, many procedures cannot be replaced by machines and still require manual labor. Some tasks have to be repeatedly performed with the hands or wrists. Therefore, tea-processing workers may suffer from a variety of musculoskeletal disorders that are considered to be related to the properties of this industry, such as carpal tunnel syndrome, lower back pain, shoulder and neck pain, and numbness and muscle weakness in the hands.
2. Health Hazards of Pesticides (Chemical Hazards)
In general, people can be exposed to pesticides through three major pathways: dermal exposure, inhalation, and ingestion. Occupational pesticide exposure is usually dermal exposure. However, for some pesticides, such as fumigants, inhalation is the most likely exposure pathway. During the tea-processing industry, workers exposed to pesticides include not only those who actually spray pesticides and production, moving, shipping, and packaging employees, but also plucking workers and people in the greenhouse, storage area, house, and yard where the pesticides are sprayed.
3. Inhalation and Allergy Hazards (Biological Hazards)[5]
During tea processing, significant amounts of tea dust and microparticles will be produced due to shaking sifting, rotary sifting, and wind sifting. When these microparticles enter the respiratory tract, they will affect the respiratory tract through nonspecific stimulation or immune mechanisms [5].
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4. Hazard of Equipment Operation (Physical Hazards)
Due to the use of heavy equipment on the tea farm, certain hazards may occur during tea processing, such as thermal burns, mechanical entanglement, and so on. Due to the high temperatures surrounding the equipment, appropriate measures are required to prevent people from getting burns [4].
Currently, many studies regarding the effects of tea dust on the respiratory system and allergies have been carried out both in Taiwan and overseas[5-9]. However, other research about potential occupational hazards that may occur on site are seldom investigated and analyzed, such as ergonomic hazards of musculoskeletal disorders, hazards of equipment operation, etc. Therefore, occupational safety and health guidance cannot properly be introduced to tea processing employees to improve the knowledge of occupational safety and health in the tea-processing industry. Furthermore, most tea-processing employees are not well educated and are middle-aged/elderly and thus do not understand much about preventing occupational hazards. Therefore, our study mainly analyzes the ergonomic occupational hazards that may occur during tea-processing work by using a large scale of investigation and interview with tea-processing employees in order to reduce the risks to tea-processing employees.
Methods
1. Subjects
The subjects of this study were mainly employees related to tea processing, including the
two major categories of tea-plucking workers and tea-processing workers. Research subjects were recruited with purposive sampling. According to the distribution of tea farms and the percentage of tea farms and tea processing workers in each county, we carried out a questionnaire investigation and sampling interview. The samples came from tea farms in Hualian County, Nantou County, Chiayi County, New Taipei City, and Miaoli County. Our study collected a total of 362 questionnaires on site, and 346 of them were valid.
2. Questionnaire Design
The questionnaire used in our study consisted of three parts. The first part was personal information such as gender, marital status, occupation, age, height, weight, working hours, and so on. The second part was job description, including the recognition of hazards, safety protection, and risks of postures or movement during work. The third part addressed musculoskeletal discomfort and was revised based on the Nordic Musculoskeletal Questionnaire translated and published by the Institute of Labor, Occupational Safety, and Health [10]. This questionnaire used the “human body figure” with all parts of the body labeled (including neck, shoulders, upper back, lower back/waist, elbows, hands/wrists, hip/legs, knees, and ankles/feet) to ask interviewees about the parts that have discomfort and asked them to evaluate the frequency, time, effects, and level of discomfort.
3. Questionnaire Investigation
We used on-site interviews for the questionnaire investigation. Interviewers gave the questions and options on site and recorded the results. All
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interviewers were trained before the interviews in order to ensure that their interview and recording methods were consistent.
4. Analysis
Data collected from the questionnaire were analyzed based on the intentions of this study with SPSS (Ver. 20) to carry out the general description statistics in order to investigate the hazardous factors on all body parts of tea-processing workers.
Results and Discussion
1. Age and Gender Ratio in Employees
In this study, we interviewed 346 tea-processing employees, of which 114 employees (32.90%) were male and 242 employees (67.10%) were female. As shown in the Table 1, the percentage of female workers was twice that of male workers. Dividing job into tea-plucking workers and tea-processing workers, we interviewed 235 tea-plucking workers (67.92%) and 111 tea-processing workers (32.08%). Tea-plucking workers accounted for a significantly larger percentage of the total interviewees, with nearly twice as many tea pluckers and tea processors. The major reason was that tea plucking and tea processing can be viewed as a continuous process. During our research, we found that more laborers were required for tea plucking, more than 20 workers at a time regardless of the area of the tea farms. However, the number of tea-processing workers was limited by the scale of the tea-processing factories. In general, tea-processing factories with a small scale, like a family-based factory, usually have 3-5 laborers.
For those with a larger scale, factories usually have 10 laborers per shift, so tea-processing workers accounted for less percentage of total employees. Regarding the gender ratio of tea-plucking workers, there were 38 males and 197 females. Therefore, the majority of tea-plucking workers were female. This fits the general impression. The gender ratio in tea-processing workers was opposite, 76 males and 35 females. Most of the females were responsible for the sunned wilting and indoor wilting procedures since these two require relatively less physical loading. Other procedures that require more physical loading were done by the male tea-processing workers. We inferred that tea-processing workers need more physical strength to do such works as moving tea leaves, loading tea leaves, rolling tea leaves, and so on. The physical load of these works is much more than tea plucking, so it is more appropriate to have men be responsible for the tea-processing job.
According to the composite of this sample, 25 employees (7.31%) were under the age of 30; 34 employees (9.94%) were aged between 31 and 40; 70 employees (20.47%) were aged between 41 and 50; 103 employees (30.1%) were aged between 51 and 60; and 110 employees (32.16%) were older than 60. The missing value was 4 (1.16%). Using the age of 50 as the critical line, 62.3% of tea-processing workers were older than the age of 50. We found that the age of tea-processing workers was higher, thus showing the current difficulties of the tea industry and agriculture. Younger people would rather work in factories or offices. Therefore, a smaller percentage of young people have entered the agriculture field. A gap was revealed when
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passing down the technology. Categorized by job, the age distribution of tea-processing workers was more even, with most employees aged between 41 and 60. Most tea-plucking workers were older than the age of 50, accounting for 67.09%. Most of the tea-plucking workers were from tea-plucking teams in villages. A leader, who might be the worker from a tea farm or tea factory, would contact and organize the entire team. Other members were composed of housewives or seniors who did not have regular work in daily life. Most of them were old enough to be grandparents. Of the tea-processing workers, 14 employees were under the age of 30; 12 employees were aged between 31 and 40; 54 employees (50.0%) were aged between 41 and 60; and 18 employees were older than age of 60. Comparing to tea-plucking workers, the percentage of the elderly was lower in tea-processing workers, which might be due to the larger physical labor required during the tea processing. Furthermore, these workers usually worked at night. Since their continuous working hours were longer, seniors are not suitable for this job.
Table 1 Characteristics of Basic InformationVariables
Total (346) Tea-Plucking Tea-ProcessingN (%) N (%) N (%)
2. Investigation of Work Environment Hazards and Status
Table 2 shows the potential hazards of tea-processing employees. From the data of this sample of the 346 interviewed employees, 31.8%, 30.1%, and 27.5% experienced very severe muscle soreness, heat stress, and fatigue, respectively, accounting for one-third of interviewees. Meanwhile, 20.24%, 29.4%, and 26.0% of employees suffered severe muscle soreness, heat stress, and fatigue, respectively. Combining the very severe group with the severe group, the top three risks were fatigue (53.5%), muscle soreness (52.04%), and heat stress (49%). This shows that half of the people suffered the above hazards with at least a severe level. These results are significant, and proposing related solutions should be our first priority in the future.
Dividing our data into tea-plucking workers and tea-processing workers based on job type, we found that hazard recognition varied with the different job types. With regard to heat stress in tea-processing employees, 92 (39.15%) tea-plucking workers had very severe heat stress, and 43 (18.3%) workers had severe syndromes. Therefore, heat stress in tea-plucking workers is the problem that should be addressed first. For tea-processing workers, 12 (10.81%) workers had very severe syndromes, and 24 (21.62%) had severe syndromes. Therefore, one-third of employees also thought that heat stress was a serious issue in the workplace. From the above data, heat-related problems are unclear for both tea-plucking workers and tea-processing workers and should be
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improved in the future. As for muscle soreness, 90 tea-plucking
workers (38.30%) had very severe muscle soreness and 42 workers (17.87%) had severe muscle soreness. These results were almost the same as those of the heat stress investigation. Therefore, the muscle soreness risk also has to be resolved. Among tea-processing workers, 20 (18.02%) had very severe muscle soreness, and 28 (25.23%) had severe muscle soreness. These results were significantly higher than those of heat stress. Therefore, tea-processing workers consider sore muscles a very serious hazard in the workplace. From the above data, muscle soreness is a common problem in both tea-plucking workers and tea-processing workers, so we should aim to improve this issue in the future.
Muscle soreness and fatigue are often caused by repetitive tasks. We will now discuss tea-plucking workers and tea-processing workers from two separate aspects. Tea-plucking workers usually start tea plucking at 6 am and perform their task three to four times in the morning and twice in the afternoon. Therefore, workers pluck five to six times a day. When plucking tea leaves, workers have to stand up for a long time and bend over or lower their heads. They carry baskets that can weigh as much as 10 kg when full for a long time on their backs. This may be the main cause of their sore muscles and fatigue. For tea-processing workers, sore muscle and fatigue may be caused by inappropriate methods of applying force or adopting wrong postures. The rolling procedure requires considerable effort since workers need to rub the cloth tight with strength. If workers
improperly apply force, they can develop sore muscle or get hurt.
Furthermore, the results showed that 21.7% employees, one-fifth of all interviewees, thought that slip and fall hazards were serious or even very serious. The opinions of both tea-plucking workers and tea-processing workers were the same. Therefore, we should also pay attention to the risk of slips and falls. For tea-plucking workers, tea farms are mainly located on steep slopes, so workers easily slip due to environmental factors when walking uphill or downhill. Meanwhile, for tea-processing workers, tea dust is often on the floor and makes the floor slippery. Furthermore, tea-processing workers walk around frequently during their work, thus increasing the risk of falls. These issues should be addressed through labor education in order to prevent slipping accidents in the future.
Regarding mechanical injury, 27.24% tea-plucking workers thought that the risk of cutting injury was severe, which is worthy of further attention. As we observed, cutting injuries mainly occurred when tea-plucking workers used sharp knives during the plucking. This kind of cutting injury is usually not very serious, but we still need to prevent it.
As for the noise, we found that 20.73% of tea-processing workers thought that workplace noise hazards were serious and worth special note. According to our observation, the noise was caused by operating machines in the tea-processing factories. The risk becomes much more serious when more machines are operating at a single time and smaller workplace or in a closed space during
Investigation of Physical and Ergonomic Hazards in Tea Manufacturing Industries
Process 1(0.90%) 7(6.31%) 48(43.24%) 6(5.41%) 49(44.14%)
3. Investigation of Implementation of Safety Intervention of Occupational Accidents
According to our data, among the 346 tea-processing employees, 175 employees (50.6%) thought that safety intervention was properly implemented while 22 employees (3.36%) thought that such intervention was poorly implemented (please see Table 3). Although the results showed that most tea-processing employees thought safety intervention was well implemented, we found that safety intervention was not actually implemented in most workplaces.
For example, the tea farms in our study that had steep slopes did not provide such protection as railings, handrails, or anti-slip steps to prevent slips and falls. Furthermore, the safety of vehicles
was poor. No personal protective equipment, such as respiratory protection, was used for spraying pesticides. Using the tea-processing factories as an example, we did not see any protections, such as good ventilation, prevention of inhaling tea dust, prevention of entanglement when operating machines, or any safety protection, during out visit. With regard to transportation, no attention was paid to traffic safety. A small truck with 20-30 people was often seen on the farm. The truck was overcrowded and not equipped with seat belts. It would be very dangerous if an accident occurred. From our research, we could see that the recognition of workplace safety was not sufficient, and more education and intervention are needed in the future.
Table 3 Implementation of Occupational Safety Prevention
4. Investigation of Discomfort of Working Postures and Movements
We investigated ten working postures and movements . We found that the most uncomfortable one was standing for too long, which was reported by 172 employees, accounting for 49.7%. The second most uncomfortable movement was repeated tasks with hands, reported
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by 122 employees, accounting for 35.4%. Then, 114 employees had poor posture, accounting for 33.0%. The three aforementioned items of discomfort were reported by more than one-third of all employees. Other discomforts, such as when moving heavy loads, was reported by 81 employees, accounting for 23.4%. We should propose improvement methods for these four items to relieve the discomfort of employees. Please see Table 4 for more details.
Table 4 Discomfort of Working Postures or MovementsBody Part
DiscomfortN % 百分比
Whole Body Vibration 24 6.9%Use Tools Causing Hands Vibration 23 6.6%Hands with Repeated Movements 122 35.4%Use Heavy Tools in Hands 27 7.8%Moving & Shipping Heavy Loads 81 23.4%Unnatural Posture 114 33.0%Standing Up or Walking for a Long Time 172 49.7%Contact with Skin 50 15.0%Working Speed 10 2.9%Unfit Chair or Working Platform Height 48 13.9%
5. Investigation of Musculoskeletal Disorders
Our study investigated nine body parts, and the collected data is shown in Table 5. The highest percentage of employees, 80.64%, reported discomfort of their ankles/feet, followed by their hips/legs (78.90%), upper back (73.41%), elbows (71.64%), knees (63.85%), neck (60.9%), hands/wrists (60.08%), shoulders (53.47%), and lower back/waist (45.09%). The uncomfortable parts of the tea-plucking workers differed from those of the tea-processing workers. For tea-plucking workers,
feet/ankles accounted for the highest percentage, while hips/legs, upper back, and hands/wrists were also commonly reported. For tea-processing workers, the order was hips/legs, followed by hands/wrists, and then knees. From the above data, we inferred that tea-plucking workers standing or bending over for a long period of time might be the reason for soreness in the lower limbs. Furthermore, the sore upper back in tea-plucking workers may be the result of carrying baskets for a long time. On the other hand, moving heavy packages may cause soreness of hands/wrists and knees in tea-processing workers.
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6. Problems and Solutions to Labor Shortages in the Tea-Processing Industry
Tea growers in Taiwan are all small farmers. Currently, due to precarious employment, economy insecurity, and hard workloads, most employees in the tea-processing industry belong to a minority, such as elder temporary workers, foreign spouses, or foreign workers. These populations lack a recognition of safety and health in the workplace, as well as professional training, and become occupational safety concerns. Furthermore, younger populations are not willing to work in tea-related industries. Tea processing will face difficulties in the future as experienced workers gradually retire. Therefore, the government should develop policies to assist the cultivation of talents and pass down experience. Our study suggests that the government could establish professional teams specifically for tea-plucking workers and tea-processing workers in order to solve long-term problems regarding the lack of laborers and professionals. For example, the government could offer government subsidies or professional training and establish a virtual information platform for interaction, communication, integration, and matching in order to train people who are willing to work in the tea-processing industry to equip them with various gardening skills (farming, caring, harvesting, and manufacturing). Furthermore, the government could develop professional harvest teams to promote professional contract work, such as a professional team for rice machinery harvest. With these approaches, releasing and enlarging economic incentives can
attract younger people to enter tea-processing related industries.
Conclusions and Suggestions
Our study used questionnaires to investigate the occupational hazards that tea-processing employees may face in the workplace. We received 346 valid questionnaires, and the results could be used to make future improvements. Based on our results and in-depth interviews, our conclusions are as follows:1. Tea is one of Taiwan’s top four exported
agricultural products and plays an important role in the country. However, young people do not want to enter this industry, so current tea-processing employees are elderly and less educated. The tea-processing industry will face difficulties caused by a labor shortage and the question of passing down experience once these experienced workers retire. All related units in the government should develop strategies as quickly as possible for the sustainable development of Taiwan’s tea industry.
2. We suggest that the government set up professional teams with inter-departmental resources to solve issues related to tea plucking and tea processing. For example, the Council of Agriculture can cooperate with the Ministry of Labor to hold professional technique training courses in order to train people who are willing to work in the tea-processing industry and equip them with various gardening skills (farming, caring, harvesting, and manufacturing). Furthermore,
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the government could develop professional harvest teams to promote professional contract work. Finally, an information platform should be set up to help tea farmers cooperate and match up. The Ministry of Labor should also be involved in order to promote and educate employees about recognizing occupational safety and health in order to prevent occupational accidents.
3. The working hours of tea-processing jobs are long. Tea processing requires continuous working, so employees sometimes work more than 10 hours and even at night. Working such long hours can cause both physical and mental illnesses.
4. Of the 346 tea-processing employees interviewed, 31.8%, 30.1%, and 27.5% suffered from very severe muscle soreness, heat stress, and fatigue, respectively, a c c o u n t i n g f o r a l m o s t o n e - t h i r d o f interviewees. Adding up the people with very severe discomfort and severe discomfort, the top th ree were fa t igue (53 .5%) , muscle soreness (52.04%), and heat stress (49.5%). The result showed that half of the interviewees thought that the above hazards were serious, and we have to pay attention to these hazards in the future.
5. Our research found tha t the h ighes t percentage of discomfort was caused by standing for a long time, which was reported by 172 employees, accounting for 49.7%. This was followed by repeated hand movements in 122 cases, accounting for 35.4%, and unnatural posture in 114
cases, accounting for 33.0%. More than one-third of the interviewees stated that they experienced one or a combination of the three aforementioned discomfort items at work, and these results are worthy of noting. Other discomforts, like moving heavy loads, had 81 cases, accounting for 23.4%.
6. Of the 346 in te rv iewees , 84 .64% of employees experienced discomfort in their ankles/feet, accounting for the highest percentage. This was followed by hips/legs (78.90%), upper back (73.41%), elbows (71.64%), knees (63.85%), neck (60.9%), hands/wrists (60.08%), shoulders (53.47%), and lower back/waist (45.09%).
7. Our study showed that muscle soreness, heat stress, fatigue, falls, and cutting wounds were more severe hazards among tea-processing employees. We suggest developing plans and solutions to these hazards in order to improve the workplace of tea-processing employees.
8. Resul ts f rom our invest igat ion show that employees are eager to take courses and receive training in order to prevent occupational accidents. We suggest that the government should increase its budget for labor safety education and encourage all industries to apply for intervention seminars in which industries invite specialists to have a discussion with employees in order to propose feasible strategies.
Acknowledgement
Our study was supported by the 2012 annual budget from the Institute of Labor, Occupational
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Safety, and Health of the Ministry of Labor (IOSH 101-3014). We hereby express our sincere appreciation.
國立成功大學碩士論文;2004。[6] Sen RN, Ganguli AK, Ray GG, De A,
Chakrabarti D. Tea-leaf plucking: workloads and environmental studies. Ergonomics 1983; 26: 887-93.
[7] Zuskin E, Skuric Z. Respiratory function in tea workers. British Journal of Industrial Medicine 1984; 41: 88-93.
[8] Kuman Priya. Challenges that Indian Tea Industry faces, 2008. http://www.commodityonline.com, 5/11/2012
[9] Barthakur R, Kripalini D. Vision 2020 Reinventing the Indian Tea Industry to Achieve Sustainable Global Competitiveness and Sustainable Livelihood. Global Managed Service. http://www.gmsworldnet.com/images/vision_reinventing_indian_tea_industry.pdf, 5/11/2012
Nagarajan L, Vasundhra MK. An enquiry into work environmental status and health of workers involved in production of incense sticks in city of Bangalore. Indian journal of public health 1991; 36: 38-44.
[4] Lion SH, Yang JL, Cheng SY, Lai FM. Respiratory symptoms and pulmonary function among wood dust-exposed joss stick workers. International archives of occupational and environmental health 1996; 68: 154-60.
Borjan M, Robson M. Incense and Joss Stick Making in Small Household Factories, Thailand. The international journal of occupational and environmental medicine 2014; 5: 137-45.
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Research Articles
The Characteristics of Aerosols and Heavy Metal Distribution in Incense Industry Operating Environments
Ying-Fang Hsu1 Shinhao Yang2
Hsiao-Chien Huang2 Po-Chen Hung3
Chin-Hsiang Luo4 Shu-Hsien Lin4
Kuan-Chun Lin2
1 Center for General Education, CTBC Financial Management college2 Center for General Education, Toko University, Toko University3 Institute of Occupational Safety and Health, Occupational Hygiene
Division4 Department of Safety, Health and Environmental Engineering,
Hungkuang University
Abstract
This work aims to investigate the characteristics of aerosols and heavy metal distribution in incense industry operating environments. The environmental factors, particulate matter concentrations, and heavy metal components would also be conducted in this work. Five incense plants have been selected as the test subjects. The total particulate concentration, respirable particulate concentration, and heavy metals components in the sampled dust would be measured by the suggesting methods of Institute of Occupational Safety and Health, Occupational Hygiene Division, Taiwan (CLA4002, CLA4001, and CLA3011).
Experimental results showed that the average total particulate concentration and respirable particulate concentration were around 1.96~2.32 mg/m3 and 1.23~1.96 mg/m3. According to the data, the higher particulate concentrations were sampled in pre-operating area and incense-producing area. The ratios (respirable particulate concentration/total particulate concentration) in the most incense operating environments were greater than 60%. This finding indicated that operating workers
were affected by the respirable-particulate exposure. Moreover, the heavy metals components in the sampled particulates and selected incenses were also measured, and the highest concentration of detected heavy metal were both Zn and Ba.
Keywords: Incense industry, Total suspended particulate, Respirable particulate, Heavy metal, Distribution
Accepted 9 May , 2016 Correspondence to: Shinhao Yang, Center for General Education, Toko University, No.51, Sec. 2, Xuefu Rd., Puzi City, Chiayi County 61363, Taiwan(R.O.C), Email address: [email protected]
置依次分別置於p1(13,15,13)cm、p2(54,15,13)cm、p3(94,15,13)cm、p4(135,15,13)cm、p5(13,15,37)cm、p6(54,15,37)cm、p7(94,15,37) cm 及 p8(135,15,37) cm。氣體釋放流量穩定維持在2l/min。九支濃度取樣探頭成九宮格陣列排列,探頭中心點與探頭中心點相距10cm,每根探頭由內徑1cm、長度10cm的不鏽鋼管製成。九支探頭由等長的管子連接至一圓形匯整
[3] Huang RF, Chen JK, Tang KC. Development and Characterization of an Inclined Air-Curtain (IAC) Fume Hood. The Annals of Occupational Hygiene 2015; 59: 655-67.
[5] Huang RF, Chen JK, Hung WL. Flow and Containment Characteristics of a Sash-less Variable Height Inclined Air-Curtain Fume Hood. Annals of Occupational Hygiene 2013;57. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.
[6] Saunders T. Laboratory fume hoods. A user’s manual. 1st ed. New York: John Willy & Sons, Ine; 1993.
[7] EN. Fume Cupboards-Parts 3: Type test method (prEN14175-3). European Committee for Standardization; 2003.
[8] Head of testing station:B. Konrath; 2013. Type testing of bench-type fume cupboard Zystm Zafe 81,W=900mm, with VAV-system LabVent LV-VAV/LVVI 250 according to EN 14175-6:2006. Hochschule Aachen test report, report no.: 1/FC-Z81/P6/06/13.
Performance Evaluation of an Inclined Air-Curtain Walk-in Fume Hood
281
Research Articles
Performance Evaluation of an Inclined Air-Curtain Walk-in Fume Hood
Chien-Hung Lee1 Chuen-Jinn Tsai1
1 Institute of Environmental Engineering ,National Chiao Tung University
Abstract
The inclined air-curtain (IAC) fume hood employed in the present work was constructed with the cross-flow fan at the bottom, deflection plate along the side walls, and a suction slot at the top of the cabinet. The containment in the cabinet was controlled effectively by using the two-dimension blow velocity and suction velocity.
A research of an IAC walk-in fume hood performance was operated in several methods. Face velocity was measured at different sash opening to know the distribution and it’s average face velocity. The mean leakage SF6 concentration is less than 0.005 ppm at p1~p8 block by inner test method based on EN14175-3. The peak concentrations are 0.027 ppm. The tracer gas concentrations are less than 0.005 ppm in 10 cm,15 cm, 20 cm and 25 cm sash opening by self-develop method. The average concentration are less than 0.005 ppm, peak concentration are 0.011 ppm and 0.010 ppm at 30 cm and 35 cm sash opening.
The average concentration of SF6 is 0.093 ppm, peak concentration is 0.280 ppm at Hej=60 cm, H=20 cm~100 cm sash movement test. The tracer gas test results in different blow jet velocity were as below: Vb=1.7 m/s, Cavg=0.056 ppm; Vb=0.7 m/s, Cavg= 0.115 ppm; Vb=0.2 m/s, Cavg=0.179 ppm. Robustness test results were: The average concentration is 0.041 ppm when Vb is 1.7 m/s. The average concentration is 0.155 ppm when Vb is 0.7 m/s. When the blow jet velocity (Vb) decreased, the containment efficiency also reduced at sash movement test and robustness test. This result showed that an adequate blow jet velocity would provide a higher containment performance.
Keywords: Fume hood, Face velocity, Tracer gas technique, Walk-in fume hood
Accepted 19 June, 2016 Correspondence to: Chien-Hung Lee, 3F. No.104, Guoguang St, North Dist, Hsinchy city 300, Taiwan(R.O.C), Email address: [email protected]
[2] AISC Manual of Steel Construction. Allowable Stress Design: 9th ed. Chicago, IL. American
Institute of Steel Construction; 1989.[3] 鋼構造建築物鋼結構設計技術規範。鋼結
構容許應力設計法規範及解說。中華民國
鋼結構協會印行;2008。[4] 行政院勞動部職業安全衛生署。營造安全
衛生設施標準;2010。[5] Peng JL. Stability Analyses and Design
Recommendations for Practical Shoring Systems during Construction. Journal of Construction Engineering and Management ASCE 2002; 128: 536-44.
[6] Peng JL. Structural Modeling and Design Considerations for Double-layer Shoring Systems. Journal of Construction Engineering and Management ASCE 2004; 130: 368-77.
[7] Peng JL, Wang PL, Chan SL, Huang CH. Load Capacities of Single-Layer Shoring Systems – an Experimental Study. Advances in Structural Engineering 2012; 15: 1389-410.
[8] Peng JL, Wu CW, Shih MH, Yang YB. Experimental Study of Load Capacities of Tubular Steel Adjustable Shores Used in Construction. International Journal of Structural Stability and Dynamics 2013; 13: 1250063-1~32.
[9] Peng JL, Wang PL, Huang YH, Tsai TC. Experimental Studies of Load Capacities of Double-layer Shoring Systems. Advanced Steel Construction 2010; 6: 698-721.
[11] Mosallam KH, Chen WF. Determining shoring loads for reinforced concrete construction. ACI Structural Journal, American Concrete Institute 1991; 88: 340-50.
Experimental Study on Load Capacities and Failure Models of Tubular Steel Adjustable Shores
299
Research Articles
Experimental Study on Load Capacities and Failure Models of Tubular Steel Adjustable Shores
Jui-Lin Peng1 Chen-Chung Lin2
Chong-Yang Kao2 Tsung Yen3
How-Ji Chen3 Chung-Ho Huang4
Shu-Ken Lin3
1 Department of Civil and Construction Engieering, National Yunlin University
2 Institute for Occupational Safety & Health, Ministry of Labor3 Department of Civil Engineering, National Chung Hsing University4 Department of Civil Engineering, National Taipei University of
Technology
Abstract
The falsework of tubular steel adjustable shore (TSAS) is typically adopted in reinforced concrete
buildings which have a low headroom and insignificant slab loads. The TSAS is easily setup and
conveniently conveyed, so contractors commonly use it in construction sites in spite of the low bearing
capacity of TSAS. However, the structural design information of TSAS is insufficient. Thus, the TSAS
usually collapses on construction sites. This study mainly focuses on the bearing capacities and failure
models of TSAS based on experimental tests. The research result shows that the failure of TSAS has
two types. The connecting tube-lock of TSAS fails when the shore length is less than four meters. The
TSAS is typically buckling when the shore length is greater than four meters and the the compressive
strength of TSAS reduces with the increase of the shore length. It is found that the reinforcing
steel of number 3 is not appropriate for using as a connecting tube lock due to its low strength. The
compressive strengths of TSAS systems of 3.4-meter height based on four, nine, sixteen, twenty-
five shores with and without horizontal braces in tests were close to the compressive strength of an
isolated shore times the total shore numbers. However, the compressive strength of TSAS systems of
3.4- meter height based on twenty-five shores without horizontal braces in test was less than that of
an isolated shore times the total shore numbers. The engineers need to pay attention to this specific
Accepted 19 April, 2016 Correspondence to: Chen-Chung Lin, Institute of Labor, Occupational Safety and Health, Ministry of Labor, No.99, Lane 407, Hengke Rd., Sijhih District, New Taipei City 22143, Taiwan(R.O.C.), Email address: [email protected]
Journal of Labor, Occupational Safety and Health 24: 282-300 (2016)
300
issue in shoring structural design. Based on horizontal braces setup on shoring systems on actual
construction sites, the compressive strength of the TSAS system with the shore length of 3.4 meters
increases insignificantly. However, the compressive strength of the TSAS system with the shore length
of greater than 3.4 meters tied by horizontal braces increases about 20% ~ 50%. However, frame-
type scaffolds or system scaffolds are apporpriate for substituting the TSAS in the same headroom of
buildings. The horizontal braces can provide the TSAS from the failure induced by the lateral forces
50~150V 3.0 m (10 ft 0 in.) 1.0 m (3 ft 6 in.) 避免接近
151~750 3.0 m (10 ft 0 in.) 1.00 m (3 ft 6 in.) 0.3 m(1 ft 0 in.) 751~15kV 3.0 m (10 ft 0 in.) 1.5 m (5 ft 0 in.) 0.7 m(2 ft 2 in.)15.1~36kV 3.0 m (10 ft 0 in.) 1.8 m (6 ft 0 in.) 0.8 m(2 ft 7 in.)36.1~46kV 3.0 m (10 ft 0 in.) 2.5 m (8 ft 0 in.) 0.8 m(2 ft 9 in.)
46.1~72.5kV 3.0 m (10 ft 0 in.) 2.5 m (8 ft 0 in.) 1.0 m(3 ft 3 in.)72.6~121kV 3.3 m (10 ft 8 in.) 2.5 m (8 ft 0 in.) 1.0 m(3 ft 4 in.)138~145kV 3.4 m (11 ft 0 in.) 3.0 m (10 ft 0 in.) 1.2 m(3 ft 10 in.)161~169kV 3.6 m (11 ft 8 in.) 3.6 m (11 ft 8 in.) 1.3 m(4 ft 3 in.)230~242kV 4.0 m (13 ft 0 in.) 4.0 m (13 ft 0 in.) 1.7 m(5 ft 8 in.)345~362kV 4.7 m (15 ft 4 in.) 4.7 m (15 ft 4 in.) 2.8 m(9 ft 2 in.)500~550kV 5.8 m (19 ft 0 in.) 5.8 m (19 ft 0 in.) 3.6 m(11 ft 10 in.)765~800kV 7.2 m (23 ft 9 in.) 7.2 m (23 ft 9 in.) 4.9 m(15 ft 11 in.)
個人防護具選用
NFPA 70E提供能量分析方法及電弧閃光個人防護具等級兩種方法,以選用個人防護具。
1. 能量分析方法
透過IEEE 1584或NFPA 70E公式計算可得弧光能量,並以1.2cal/cm2
及12cal/cm2為基準,
簡單分為3個能量等級,在個人防護具的選擇上,只需依據計算所得之及弧光能量,選用足
夠承受該能量之個人防護具即可,如表5弧光
勞動及職業安全衛生研究季刊 民國105年9月 第24卷第3期 第301-310頁
306
危險等級與個人防護具選用。
表5 弧光危險等級與個人防護具選用[2]弧光能量 防護衣物 其他個人防護具
小於1.2 cal/cm2
不會融化(符合 ASTM F 1506)或未經處理之天然纖維的長袖上衣與長褲或衣褲相連工作服(coverall)
[1] Institute of Electrical and Electronics Engineers. IEEE 1584: IEEE Guide for Performing Arc Flash Hazard Calculations; 2002.
[2] National Fire Protection Association. NFPA 70E: Standard for Electrical Safety in the Workplace. Ma, U.S.A.; 2015.
[3] National Fire Protection Association. NFPA 70E: Standard for Electrical Safety in the Workplace. Ma, U.S.A.; 2012.
Journal of Labor, Occupational Safety and Health 24: 301-310 (2016)
310
Research Articles
Hazard Analysis of Electric Arc Flash Burns from Panelboards
Wen-Yuan Su1 Jyh-Cherng Gu2
Hao-Fong Lai2
1 Institute of Labor, Occupational Safety and Health, Ministry of Labor2 National Taiwan University of Science and Technology
Abstract
Aside from electric shocks, burns from electric arc flash are the most common injury suffered
by electricians operating on panelboards. However, Taiwan is lacking in standards and technical
documents on electric arc flash burns. Therefore, most of the companies or electric technicians have
not performed the hazard analysis caused by electric arc flash from panelboards.
We discuss the IEEE 1584 analysis methods of burns from electric arc flash, and the NFPA 70E
selection of personal protective equipment and the warning label of hazard. Finally, to establish an
example of panelboard arc flash analysis, the IEEE 1584 base program is applied to an electronic plant
which the electric system including 22.8kV, 380V and 220V.
Keywords: Electric arc flash, Personal protective equipment, Panelboard
Accepted 19 April, 2016 Correspondence to: Wen-Yuan Su, Institute of Labor, Occupational Safety and Health, Ministry of Labor, No.99, Lane 407, Hengke Rd., Sijhih District, New Taipei City 22143, Taiwan(R.O.C.), Email address: [email protected]
備」(Wet Bench或Wet Chemical Equipment)來進行顯影製程、蝕刻製程、去光阻製程、洗
淨製程、光罩清洗製程。而上述製程中會使用
濕式化學品如過氧化氫、濃硫酸、濃鹽酸與異
丙醇(IPA)等酸性溶劑,甚至在半導體與面板產業製程設備零組件清洗與表面處理亦是使
用類似方法以過氧化氫、氨水、氫氟酸來清洗
設備,以提升產品良率及提高製造設備的稼動
率。為了提高清洗製程的效果,化學清洗設備
(Wet Bench)常採用加熱製程,但是因所使用的化學溶劑不僅具有易燃特性,且清洗槽大多
採用耐酸鹼卻易燃的塑膠材質,使得化學清洗
設備發生火災爆炸事故的頻率大幅提高。
根據[2]及[3],美國FMRC(Factory Mutual Research Corporation)的統計資料,1977 至1997 年20年間全球半導體工廠發生的407件有紀錄之工安事故。以區域而言,北美地區
267起工安事故,台灣發生7起工安事故,其中『華邦』及『聯瑞』兩起工安事故造成台
幣近200億元損失。以發生原因而言:火災佔
47%,流體外洩佔22%,爆炸佔5%,其中造成火災事件中以易燃易爆氣體佔32%,電子元件佔30%,製程流體加熱器佔27%。以製程使用的機台而言,濕式化學設備有70多起工安事故,並以濕式化學清洗製程(Wet Chemical Cleaning Processes)為火災事故率最高,而加熱器故障為主要火災發生因素。
根據文獻[3]及[4],日本半導體產業協會(Electronic Industry Association of Japan, EIAJ)針對日本半導體業從1980年至2000年間由氣體引起的83件製程意外事件的統計資料發現:設備引發之意外事故頻率仍以溼式清洗機台為最
Journal of Labor, Occupational Safety and Health 24: 311-329 (2016)
328
Research Articles
The Study of Safety Survey for Wet Bench inLED Process
Yuan-Pin Shih1 Tzu-Chi Wang2
Cheng-Ming Chang3 Tsung-Chi Chuang3
1 Department of Mechanical Engineering, Taoyuan Innovation Institute of Technology
2 Department of Chemical Engineering and Materials Engineering, Chinese Culture University
3 Institute of Labor, Occupational Safety and Health, Ministry of Labor
Abstract
In terms of procurement requirements, operation, and maintenance, the wet benches used in
domestic LED industry are very different from those used in the semiconductor and optoelectronic
industries. This study conducted hazard analysis and safety investigation on wet benches in LED
industry with the aim of providing LED industry with checking standards for wet bench procurement
and maintenance.
The results are as follows: 1. Fifteen occupational incidents in domestic LED industry were
collected and analyzed; 2. Safety investigations on wet benches were conducted in six LED plants,
and statistical analysis was completed; 3. Wet benches used by domestic LED industry were
classified into 27 types according to their functions, and FTA/FMEA risk assessment were carried out
through different types of equipment in reference to domestic and foreign regulations and standards,
occupational incident cases collected, and the results of safety investigations; 4. The results of
FTA/FMEA risk assessment can be used by LED industry as the checking standards for wet bench
procurement, operation, and maintenance.
The recommendations resulting from this study are as follows: 1. Domestic LED industry usually
purchase customized wet bench equipment, it is recommended that more attention should be paid to
electrical safety in the process of wet bench procurement, operation, and maintenance; 2. In regard
to management and safety measures of wet bench system operation, it is recommended that standard
Accepted 13 April, 2016 Correspondence to: Cheng-Ming Chang, Institute of Labor, Occupational Safety and Health, Ministry of Labor, No.99, Lane 407, Hengke Rd., Sijhih District, New Taipei City 22143, Taiwan(R.O.C.), Email address: [email protected]
The Study of Safety Survey for Wet Bench in LED Process
329
operating procedures for assessing the incompatibility of chemicals and the process for authorizing
operators to set operation conditions are established, and the interlock function is assured during
maintenance and troubleshooting abnormal situations.
(Organization for Economic Co-operation and Development, 簡稱OECD)在2006年設立了工程奈米物質工作小組(Working Party on Manufactured Nanomaterials, 簡稱WPMN)。在2011年2月份,OECD發表了「奈米安全報告書」,整理了WPMN五年的重大成果,包括奈米材料資料庫建
米材料對環境健康與安全(environment, health and safety, EHS)之風險,提高奈米科技產品的社會接受度。此架構包含
六個步驟: ( 1 )描述材料與它的應用性(Describe material and its applications)。(2)建立奈米材料的盛衰過程(life-cycle)(包括: 原料來源、原料處理、製造合成、應用、廢棄 處理)中它們的物化特性、危害與曝露影響的輪廓資料。(3)評估奈米材料的風險性。(4)製定風險管理方法。(5)組成跨領域決策小 組建立相關法條。(6)建立審閱團隊確認相關資訊保持更新。(參考http://www.nano-riskframework.com)。國際標準組織( Internat ional Organization for Standardization, 簡稱 ISO)制定了奈米技術的工作定義,並且發佈了奈米技術相關詞彙的標準。於
奈米材料危害特性的評估[16]。美國國家職業安全及健康研究院(National Institute of Occupational Safetyand Health, 簡稱NIOSH)於2004年設立奈米技術研究中心(Nanotechnology Research Center, 簡稱NTRC),以整合NIOSH內部對安全奈米技術的研究;NIOSH在2005年提出「奈米物質操作安全指引」,以針對職業奈米曝
露之毒性與危害風險,提出了跨領域的研
究計畫;在2012年6月份,NIOSH又發表另一份指南,名為「研究工程奈米材料之
335
奈米微粒危害測試技術與生物毒性指標之探討
實驗室通用安全準則」,提出工程控管與
安全措施之建議,以供實驗室或小規模實
驗操作人員處理奈米材料之參考。美國職
業安全與健康管理局(Occupational Safety and Health Administration, 簡稱OSHA)近日發表「奈米物質安全使用概要
(Working Safety with Nanomaterials)」,希望藉此報告提供工作人員關於目前奈米
[1] Klasen HJ. Historical review of the use of silver in the treatment of burns. I. Early uses. Burns: Journal of the International Society for Burn Injuries 2000; 26: 117-30.
[2] Singh N, et al. NanoGenotoxicology: the DNA damaging potential of engineered nanomaterials. Biomaterials 2009; 30: 3891-914.
[3] Kroll A, et al. Current in vitro methods in nanoparticle risk assessment: limitations and
341
奈米微粒危害測試技術與生物毒性指標之探討
challenges. European Journal Pharmaceutical and Biopharmaceutics 2009; 72: 370-7.
[4] Horie M, et al. Protein adsorption of ultrafine metal oxide and its influence on cytotoxicity toward cultured cells. Chemical Research Toxicology 2009; 22: 543-53.
[5] Monteiro-Riviere NA, Inman AO, Zhang LW. Limitations and relative utility of screening assays to assess engineered nanoparticle toxicity in a human cell line. Toxicology and
Applied Pharmacology 2009; 234: 222-35.[6] Murdock RC, et al. Characterization of
nanomaterial dispersion in solution prior to in vitro exposure using dynamic light scattering technique. Toxicology Sciences 2008; 101: 239-53.
[7] Oberdorster G. Safety assessment for nanotechnology and nanomedicine: concepts of nanotoxicology. Journal of International Medicine 2010; 267: 89-105.
[8] L a i D Y. To w a r d t o x i c i t y t e s t i n g o f nanomaterials in the 21st century: a paradigm for moving forward. Wiley Interdisciplinary Nanomed Nanobiotechnol 2012; 4: 1-15.
[9] Brunner TJ, et al. In vitro cytotoxicity of oxide nanoparticles: comparison to asbestos, silica, and the effect of particle solubility. Environmental Science & Technology 2006; 40: 4374-81.
[10] Limbach LK, et al. Exposure of engineered nanoparticles to human lung epithelial
cells: influence of chemical composition and catalytic activity on oxidative stress. Environmental Science & Technology 2007; 41: 4158-63.
[11] Chargui A, et al. Cadmium-induced autophagy in rat kidney: an early biomarker of subtoxic exposure. Toxicological Sciences 2011; 121: 31-42.
[12] Zabirnyk O, Yezhelyev M, Seleverstov O. Nanoparticles as a novel class of autophagy activators. Autophagy 2007; 3: 278-81.
[13] Kang SJ, et al. Role of the Nrf2-heme oxygenase-1 pathway in silver nanoparticle-mediated cytotoxicity. Toxicology and Applied Pharmacology 2012; 258: 89-98.
[14] Fisichella M, et al. Mesoporous silica nanoparticles enhance MTT formazan exocytosis in HeLa cells and astrocytes. Toxicology In Vitro 2009; 23: 697-703.
[15] Fotakis G, et al. Cadmium hloride-induced DNA and lysosomal damage in a hepatoma cell line. Toxicology In Vitro 2005; 19: 481-9.
[16] Nel A, et al. Nanomaterial toxicity testing in the 21st century: use of a predictive toxicological approach and high-throughput screening. Accounts of Chemical Research 2013; 46: 607-21.
[17] Bakand S, Hayes A, Dechsakulthorn F. Nanoparticles: a review of particle toxicology following inhalation exposure. Inhalation Toxicology 2012; 24: 125-35.
Journal of Labor, Occupational Safety and Health 24: 330-342 (2016)
342
Commentary
A Study on the Approaches for Hazard Ranking and Identifying the Biomarkers of the Adverse Effects of
Nanoparticles
Yu-Hsuan Lee1 Chun-Yong Fang1
Chun-Wan Chen2 Ying-Jan Wang1
1 Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University
2 Institute of Labor, Occupational Safety and Health, Ministry of Labor,
Abstract
Advancement and improvement of nanotechnology, nanomaterials (NMs) have been comprehensively applied in our modern society and greatly influenced our daily life. However, the toxicity and hazardous impacts of nano-scale particles on organisms is still unclear. The different physico-chemical characteristics are identified in the nanofied particles, which may contribute to their toxic effects on the target cells. Currently, there are numerous approaches to carry out toxicity tests but there is a lack of common and reasonable/sensible biomarkers and detection systems for toxicity evaluation as well as a risk management platform for offering the reference database. In this study, we determined to select silver nanoparticles (AgNPs), which have been commonly used in industry, as the candidate toxicants and tend to demonstrate in vitro toxicity to a certain extent. We characterized the physico-chemical properties of the synthetic nanoparticles. We used human bronchial epithelial cells (BEAS-2B cell line) to evaluate the cytotoxic effects by using MTS and Live/Dead cell viability assays. Our results found that AgNPs led to elicit of reactive oxygen species (ROS), up-regulated expression of the Heme oxygenase 1 (HO-1) gene and occurrence of autophagy, which could be the bio-indicators for nanotoxicity. Therefore, the results from the preliminary data shows that MTS and Live/Dead cell viability assays could be used for cell line -based nanotoxicity screening and assessment. To conclusion, the outcome of the present work on AgNPs adverse effects might be implicated to other nanomaterials.
Accepted 8 June, 2015 Correspondence to: Ying-Jan Wang, Occupational Health Medical College National Chen Kung University, No.1, University Rd., Tainan City 701, Taiwan(R.O.C), Email address: [email protected]