NOISE DOSIMETER

Noise dosimeter
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A noise dosimeter (American) or noise dosemeter (British) is a specialised sound level meter intended specifically to measure the noise exposure of a person integrated over a period of time; usually to comply with Health and Safety regulations such as the EU Directive 2003/10/EC, or the equivalent American OSHA rules.
Contents
[hide]
• 1 History
• 2 Measuring industrial noise
• 3 Other differences in exposure description
• 4 Variations in legal requirements
• 5 International standards
• 6 The permitted levels reduced
• 7 The PSEM arrives
• 8 Use of dosimeters
• 9 The 21st century devices
• 10 References
• 11 External links

[edit] History
The first dosimeters were designed in about 1969 as a result of the American Walsh-Healey Act (50-204.10). The regulations resulting from this legislation set legal limits on the “amount” of noise to which a worker could be exposed. This act was followed by the OSHA – Occupational Safety and Health Act of 1970, which was passed by the U.S. Congress and became effective in April, 1971. The full text of this act can be seen in the Code of Federal Regulations, Title 29, Chapter XVII, Part 1910.
It was recognized that the cumulative effect of noise exposure is a prime cause of industrial hearing damage. While it was known that the damage was proportional to a combination of sound pressure and time, the precise relationship between noise level, exposure time and the resulting hearing damage was not then well understood.
The American OSHA noise exposure limits, with the benefit of hindsight, are now widely discredited outside the USA, but at the time they were the best that could be done and were the essential first step in protection against hearing damage risk due to noise. It was a revolutionary regulation and reflected the then best current acoustic knowledge.
The act and subsequent Occupational Safety and Health Administration (OSHA) regulations set the permitted noise dose by a trade-off of time and level following the data in table 1.
Exposure duration per day – in hours Sound level in dB(A)

8 90
6 92
4 95
3 97
2 100
1.5 102
1 105
1/2 110
1/4 or less 115
Table 1, the OSHA permitted noise exposure levels
When this regulation was introduced, measuring sound level was poorly understood and only a handful of manufacturers offered suitable equipment world wide. The act led to a huge expansion in suppliers of sound level meters and dosimeters, about 30 different brands being introduced, mostly in the United States, although a few United Kingdom and other companies were also started. Today, most of these have ceased trading, once again leaving just a handful of companies world-wide manufacturing noise dosimeters.
One of the classic meters from the early 1970s is shown in figure 1, the Dupont dosimeter. This stored the data on a chemical cell.
[edit] Measuring industrial noise
In many factory noise situations, a sound level meter is a perfectly suitable device to check compliance with OSHA or EU requirements. If a Class 2 sound level meter is used, or what used to be called a “Type 2,” with due allowance made for the measurement uncertainty, and in any part of particular premises there is no noise level above say 80 dB(A)S, (80 decibel A-frequency and S-time-weighted), it is clear that every worker will be below a limit set at say 85 dB(A) and there is no need to use more complex measurement devices. However, if it is suspected or known that sound levels above 85 dB(A)S are found, a dosimeter was traditionally the usual instrument required – at least in the USA and its sphere of influence.
Work mainly in the UK and Germany after about 1970, demonstrated that the ‘5 dB doubling’ rule in Table 1 above and used in the USA did not correspond very well with hearing damage risk and the International Organization for Standardization (ISO) recommended an ‘equal energy rule’, where a 3 dB increase in level halved the permitted exposure time; 3 dB being a doubling of the energy although a 6 dB increase is a doubling of the sound pressure. The ISO document started at the same point of 90 dB(A) for 8 hours as the criterion value, but then the exchange of time and level followed Table 2.
Permitted Exposure time Level in dB(A)
8 hr 90
4 hr 93
2 96
1 hr 99
30 min 102
15 min 105
7.5 min 108
225 sec 111
112.5 sec 114
As can be seen, a worker in the USA could be exposed to 110 dB for 30 minutes, whereas under International rules the maximum time was about 3.8 minutes – a very significant difference; the American worker being less protected .
[edit] Other differences in exposure description
There was also a difference in some countries how levels below the criterion level of 90 dB(A) were handled. Some authorities thought that there should be a threshold at 90 dB(A), so that a level of 87 dB(A) counted as zero and the exposure time for levels under 90 dB(A) could be infinite; others said that the 3 dB exchange should continue down, so that at 87 dB(A) the exposure should be limited to 16 hours. Even others suggested a threshold that was not the same as the criterion level having perhaps the criterion at 90 dB(A) but a threshold at say 87 dB(A).
Because the early regulations – both American and International – had 90 dB(A) for 8 hours as their criterion, this was counted as “100% dose” and as a result, many early dosimeters were scaled in terms of ‘percentage dose’. This while being simple to understand was very misleading indeed. Clearly ‘100% dose’ in the USA and the rest of the world was different, except in the special case of a steady level of 90 dB(A), but it took some time before it was realised that there was no way of converting a ‘%dose’ taken under OSHA rules to the ISO equal energy rules. Indeed as late as 1974, an American paper at the International Congress on Acoustics in London tried to show how to do a conversion, but it contained a significant error in the maths.
One further added complication was that the US Air Force, to try and improve their health protection, had yet another doubling rule where the time was halved for every 4 dB increase, but still starting at 90 dB(A).
The tables 1 and 2 show the permitted exposure times for different levels, both based on A-weighting, but there are other more complex differences. The OSHA rules assumed an exponentially averaging sound level meter with S-time-weighting (originally called Slow Time Constant) such as was given by the dc output of a classical sound level meter; while others based their rules on a linearly averaged pressure squared metric, for example the noise exposure in Pa2h. These two systems gave radically different outputs from the detector, the difference depending on the form of the noise and they are incompatible, although instrument tolerances may hide the difference in some cases.
Finally, the American ANSI standards demanded that the microphone be calibrated by a random incidence wave – that is sound coming from all directions, whereas the International standards called for a plane wave coming from a single direction; again these two systems are incompatible.
The one constant was that all regulations used A-frequency-weighting, even though even this was specified slightly differently in the USA.
[edit] Variations in legal requirements
This meant that the user had to specify under what legal regime he wanted to use his dosimeter, as each country could – and did have their own local laws for such measurements. In each region, sometimes down to regions with tiny populations such as Western Australia, only one combination was usually legally accepted and that could be very different to an adjoining region. While these decision may have seemed sensible at the time, users were in general not adequately informed of these problems and this resulted in many measurement errors.
The five main parameters that were commonly different in different political entities were:
• Threshold
• Criterion level
• Exchange rate
• Exponential or linear integration
• ‘Head-on’ or random incidence calibration
There were of course others, such as the single event maximum level, the peak value etc.
To reduce the variations of instrument required to be manufactured, some commercial companies made complex “Universal” units where all these things could be selected by the user. As measuring noise was not well understood, such complexity clearly militated against accurate results and many anecdotal stories give examples of huge errors resulting; as very few unqualified users understood the complex issues involved.
[edit] International standards
The international body that specifies the technical requirements of such instruments as sound level meters and dosimeters is the International Electro-technical Commission (IEC) based in Geneva; whereas the method of their use is normally given in an ISO publication. However, in any particular political region, local laws apply as the IEC and ISO publications only have the status of “recommendations” and so countries could – and did – have their own sets of rules – many of which were technically flawed and in some cases scientifically impossible. Every new regulation thus made the concept of “%dose” more meaningless. The “100%” dose was different in different countries, but many users did not understand this and would buy low cost USA built dosimeters where the American “100%” was not correct for their local regulations and usually very much under-estimated the noise exposure.
[edit] The permitted levels reduced
During the 1980s and 1990s many workers – led by Scandinavia – determined that the ’90dBA for 8 hours’ limit was far too high and an unacceptable number of workers would be damaged at these levels, so a level of 85 dB(A) for 8 hours was felt to be a better criterion. Even later the EU reduced the limits still further to the 80 dB(A) we have today, as given in the UK’s “The Control of Noise at Work Regulations 2005.”. These regulations follow closely the EU Directive 2003/10/EC, normally called the Physical Agents Directive.
A further complication for the sound level meter designer was that it was realised that a single very high noise peak could instantaneously damage hearing, so a limit was originally set by the then European Community so that no worker should ever be exposed to an rms acoustic pressure of more than 200 Pa – equating to 140 dB re 20 μPa – and that this should be measured using an instrument with no frequency weighting. This while a good idea, was patent nonsense as 200 Pa could be generated by trains going through tunnels, closing a door, in fact many everyday things could cause such a pressure wave below the frequencies that could be heard or could cause hearing damage. Accordingly C-frequency-weighting was specified to measure the peak level as this has a flat frequency response between 31 Hz and 8 kHz. However, this missed a significant amount of important energy and a new frequency weighting of ‘Z’ (zero) weighting was specified in IEC 61672 : 2003 that has a flat response from at least 20 Hz to10 kHz.
[edit] The PSEM arrives
To try and simplify the situation, in the 1980s Working Group 4 of IEC Technical Committee 1 started to write a new standard for a dosimeter, but decided that for many good reasons, a new name was called for and the long – but more correct name – of Personal Sound Exposure Meter (PSEM) was used. WG4 was mainly made up of design engineers from the International Sound Level meter companies together with scientists from various national acoustic laboratories and a few academics. The result of their efforts became IEC 61252 :1993, the current PSEM standard. This has tolerance limits based on a Class 2 – what was a Type 2 – sound level meter, but because it is intended to be worn on the body, it has relaxed directional characteristics.
The favoured metric for many scientists was simply the sound exposure in pressure-squared-time, for example Pa2h and this was used for the PSEM standard and at a stroke this removed all the various options for measurement. However for health and safety legislation in Europe for legal purposes the metric chosen was the daily personal noise exposure level, LEP,d, which corresponds to LEX,8h as defined in international standard ISO 1999: 1990 clause 3.6, and is expressed in decibels A-frequency-weighted [dB(A)]. In simple terms this is the normalised sound exposure expressed in decibels.
[edit] Use of dosimeters
The original dosimeters were designed to be belt worn with a microphone connected to the body of the dosimeter and mounted on the shoulder as near to the ear as practicable. These devices were worn for the full work shift and at the end would give a readout initially in percentage dose, or in some other exposure metric. These were the most common way of making measurements to meet legislation in the USA, but in Europe the conventional sound level meter was favoured. There were many reasons for this, but in general in Europe the dosimeter was distrusted for several reasons, some being.
• The cable was considered dangerous as it could catch on rotating machinery
• The dosimeter could tell you the level had been exceeded, but it did not say when this happened
• Workers could falsify the data very easily
• The device was big enough to affect the work pattern
In the USA – where most of the early devices were manufactured, these reasons did not seem to matter so much.
To remove these European objections, dosimeters became smaller and started to include a data store where the Time History of the noise, usually in the form of Short Leq was stored. This data could be transferred to a personal computer and the exact pattern of the noise exposure minute by minute plotted. The usual method used was to store data in the form of Short Leq, a French concept that helped to bring computers into acoustics. As well, dosimeters started to incorporate a second C-frequency-weighted channel that allowed the true peak to be indicated. By the time the PSEM standard was published, many major sound level meter companies – in both Europe and the USA had a dosimeter in their range. A typical noise dosimeter is shown in figure 2
[edit] The 21st century devices
The next technology breakthrough came when in the 1990s the United Kingdom Department of Trade and Industry awarded a SMART grant to Cirrus Research to design an ultra-miniature dosimeter. It was to be so small and light that it would not affect the worker and as well was to have no microphone cable. The resulting device (Fig. 3) – the first true dosebadge – was a twin channel device able to meet all the requirements of the European Directive and also the market need for data storage. An important design criteria was that the device had to have no internal display nor any controls, so workers would not be tempted to try to ‘modify’ or affect the readings; instead the acquired data was transmitted and the device was controlled by an infra-red link. Normally, the acquired exposure data from several badges is transferred to a reader unit where it can be read and stored. As well, most manufacturers offer software to transfer the reader’s data to a computer where it can be archived and as well put into a database to allow full and complete reports to be generated.
Today, such devices are available from several manufacturers – at least one with a full Intrinsic Safety certificate for use in hazardous atmospheres. Some sophisticated ones have extra channels to store data on the state of the battery, any ‘out of range’ signals and some units are able to be used on the USA OSHA as well as EU equal energy rules, although a different physical badge is usually needed. Others have a “Time History” store, where the exposure minute by minute is stored for the full working shift, allowing Health and Safety Officers to pinpoint the exact time of any high energy noise and assist in determining the cause.
A recent design of a noise dosimeter offers a multiple-point approach to assess workers daily noise exposure. This approach uses dosimeters that have wireless (Bluetooth) communication with a handheld device such as a PDA, but apart from their use of Bluetooth technology are basically similar in function to units using either infrared or cable connection.
These new devices are split into two groups. Those that have no display on the body-worn acquisition unit, and those that include such a display. While it would seem that a display may be advantageous, many professionals regard it as another potential error source as the user may be tempted to put the device near to a noise source. Their motivation is thought to be either to watch the display move or to try to modify the results, but in either case an additional uncertainty has been introduced into the measurement. An advantage of an internal display however, is that if only a single unit is in use, the exposure can be read without external devices.
[edit] References
• EU Directive 2003/10/EC, normally called the Physical Agents Directive.
• Occupational Safety and Health Act. Code of Federal Regs, Title 29, Chapter XVII, Part 1910.
• IEC 61252 :1993 – Acoustics – Personal Sound Exposure Meter
• Wallis A.D. & Krug R.W. “A data storing dosimeter” Proc IOA Vol 11 part 9 101-106 Nov 1989.
[edit] External links
http://en.wikipedia.org/wiki/Sound_dosimeters

June 24, 2009 at 10:05 pm Leave a comment

Noise Evaluation Versi OSHA

Section I: What is considered “noise” and what are the potential health effects?
________________________________________

TOP

Physics of Sound
Sound is the physical phenomenon that stimulates our sense of hearing. It is an acoustic wave that results when a vibrating source, such as machinery, disturbs an elastic medium, such as air.
• In air, sound is usually described as variations of pressure above and below atmospheric pressure. These fluctuations, commonly called sound pressure, develop when a vibrating surface forms areas of high and low pressure, which transmit from the source as sound.
Additional information (App I:A) on the physics of sound, including basic qualities, sound fields, sound propagation, filtering, loudness, and sound pressure weighting is also available.

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Anatomy and Physiology of the Ear
The ear is the organ that makes hearing possible. It can be divided into three sections:
• External outer ear
• Air-filled middle ear
• Fluid-filled inner ear
The function of the ear is to gather, transmit, and perceive sounds from the environment.

This involves three stages:
1. Modification of the acoustic wave by the outer ear, which receives the wave and directs it to the eardrum.
2. Conversion and amplification of the modified acoustic wave to a vibration of the eardrum (transmitted through the middle ear to the inner ear).
3. Transformation of the mechanical movement of the wave into nerve impulses that will travel to the brain, which then perceives and interprets the impulse as sound.
Additional information (App I:B) on outer ear, middle ear and inner ear is also available.

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Effects of Excessive Exposure
Although noise-induced hearing loss is one of the most common occupational illnesses, it is often ignored because there are no visible effects, it usually develops over a long period of time, and, except in very rare cases, there is no pain. What does occur is a progressive loss of communication, socialization, and responsiveness to the environment. In its early stages (when hearing loss is above 2,000 Hertz (Hz)) it affects the ability to understand or discriminate speech. As it progresses to the lower frequencies, it begins to affect the ability to hear sounds in general.

The three main types of hearing loss are conductive (App I:C-1), sensorineural (App I:C-2), or a combination of the two.

The effects of noise can be simplified into three general categories:
• Primary Effects, which includes noise-induced temporary threshold shift, noise-induced permanent threshold shift, acoustic trauma, and tinnitus.
• Effects on Communication and Performance, which may include isolation, annoyance, difficulty concentrating, absenteeism, and accidents.
• Other Effects, which may include stress, muscle tension, ulcers, increased blood pressure, and hypertension.
In some cases, the effects of hearing loss may be classified by cause.

Additional information (App I:C) about the effects of excessive noise exposure is also available.

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Ultrasonics
Ultrasound is high-frequency sound that is inaudible, or cannot be heard, by the human ear. However, it may still affect hearing and produce other health effects.

Factors to consider regarding ultrasonics include:
• The upper frequency of audibility of the human ear is approximately 15-20 kilo-Hertz (kHz).
o This is not a set limit and some individuals may have higher or lower (usually lower) limits.
o The frequency limit normally declines with age.
• Most of the audible noise associated with ultrasonic sources, such as ultrasonic welders or ultrasonic cleaners, consists of subharmonics of the machine’s major ultrasonic frequencies.
o Example: Many ultrasonic welders have a fundamental operating frequency of 20 kHz, a sound that is at the upper frequency of audibility of the human ear. However, a good deal of noise may be present at 10 kHz, the first subharmonic frequency of the 20 kHz operating frequency, and is therefore audible to most persons.
Additional information (App I:D) on ultrasonics and the applicability of OSHA’s Occupational Noise Exposure standard, 1910.95, health effects and the American Conference of Governmental Industrial Hygienists’ (ACGIH) Threshold Limit Values (TLVs) is also available.

Section III: How do I evaluate noise exposure?
________________________________________
The first step toward solving any noise problem is to define it. To understand what requirements must be implemented according to OSHA’s noise standard [29 CFR 1910.95, it is necessary to determine exposure levels. The following sections provide information about evaluating noise exposure levels:
• Indications of a Problem
• Walkaround Survey
• Workshift Sampling
• Instruments Used to Conduct a Noise Survey (App III:A)

Checking for noise source
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Indications of a Problem
There are various factors that may indicate noise is a problem in the workplace. While people react differently to noise, subjective responses should not be ignored because they may provide warnings that noise may be at unacceptable levels.
• Noisy conditions can make normal conversation difficult.
o When noise levels are above 80 decibels (dB), people have to speak very loudly.
o When noise levels are between 85 and 90 dB, people have to shout.
o When noise levels are greater than 95 dB, people have to move close together to hear each other at all.
• High noise levels can cause adverse reactions or behaviors. See more information about effects on communication and performance (App I:C).

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Walkaround Survey
A walkaround survey should be performed to screen for noise exposures and to determine if additional monitoring is necessary. When screening for noise exposures, sound level meter measurements and estimates of the duration of exposure are sufficient. The resulting spot readings can be used to determine the need for a more complete evaluation. The following general approach may be followed:
1. Tour the facility and develop a detailed understanding of facility operations and potential noise sources. Take the tour with someone who is familiar with plant operations. Speak with knowledgeable personnel about operations and maintenance requirements. Make notes on a diagram of the floor plan if possible. Look for indications that noise may be a problem.
2. Use a sound level meter (App III:A) to take spot readings of operations that are in question. It may be useful to mark the sound levels on a diagram of the floor plan. Make notes regarding what equipment is on or off.
3. Estimate exposures by identifying workers and their locations and estimate the length of time they spend in different areas or how long they operate particular equipment or tools.
If the results of the walkaround survey indicate time-weighted average (TWA) exposures of 80 dBA or more, then additional noise monitoring should be performed. Remember to take into account the accuracy of the sound level meter when making this estimation. For example, a Type 2 sound level meter has an accuracy of ±2 dBA.

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Workshift Sampling
When the results of the walkaround survey indicate that noise levels may exceed those outlined in OSHA’s noise standard 29 CFR 1910.95, additional monitoring is necessary.
• Establish a sampling protocol for your workplace. A general protocol (App III:B) is provided as an example.
• In addition to the general information collected during all health inspections, OSHA may collect certain information where it is pertinent to evaluate compliance with OSHA standards (29 CFR 1910.95, 29 CFR 1926.52, or 29 CFR 1926.101). Additional information (App III:C) on inspection data is also available.
• Sample the noise exposures of representative employees from each job classification that may be potentially overexposed.
• Use a dosimeter with a threshold of 80 dBA (A-weighted sound pressure level) and 90 dBA to measure noise exposures. Most modern dosimeters use simultaneous 80 and 90 dBA thresholds and may be used accordingly. Additional information (App III:A) on dosimeters is also available.
o A dosimeter with a threshold of 80 dBA is used to measure the noise dose of those employees identified during the walkaround survey as having noise exposures that are in compliance with Table G-16 of OSHA’s noise standard 1910.95, but whose exposure may exceed the levels specified in Table G-16a [29 CFR 1910.95 Appenix A: Noise Expsoure Computation]. In other words, the 80-dBA threshold is used to determine compliance with the 85 dBA time-weighted average (TWA) action level under OSHA’s noise standard.
o The dosimeter with a threshold of 90 dBA is used to measure the noise dose of those employees identified during the walkaround survey as having potential noise exposures that exceed the sound levels in Table G-16 [29 CFR 1910.95] or Table D-2 [29 CFR 1926.52]. In other words, the 90 dBA threshold is used to determine compliance with the permissible exposure limit (PEL).
• As a minimum, sampling should be conducted for a length of time necessary to establish whether exposures are above the limits permitted by Table G-16, Table G-16a, or Table D-2 (for general industry or construction workplaces, respectively). Instrument accuracy must be taken into account.
• Consider the following with respect to the monitoring results:
o TWA exposures at or above the action level of 85 dBA require a hearing conservation program [29 CFR 1910.95 (c-n)] (results obtained from the 80 dBA threshold).
o TWA exposures exceeding the PEL (Table G-16) require feasible engineering or administrative controls to be implemented [29 CFR 1910.95(b)] (results obtained from the 90 dBA threshold). Refer to the OSHA Field Operations Manual (FOM) for additional information.
• There is also information specific to evaluating noise exposure of employees wearing sound-generating headsets (App III:D).

June 24, 2009 at 10:02 pm Leave a comment

Supremasi Ekonomi Indonesia! Untuk Indonesia yang Lebih Baik

JAKARTA, KOMPAS.com – Presiden Susilo Bambang Yudhoyono menyatakan, perlakuan yang dialami oleh tenaga kerja Indonesia di Malaysia, Siti Hajar, sudah di luar batas kemanusiaan. Presiden Yudhoyono meminta agar mantan majikan Siti mendapat ganjaran hukum yang setimpal.

”Hal yang dialami Siti Hajar merupakan sesuatu yang di luar batas kemanusiaan. Saya sungguh prihatin. Oleh karena itu, saya sudah menginstruksikan sesuatu kepada duta besar kita di Malaysia, Da’i Bachtiar,” kata Presiden Yudhoyono dalam keterangan persnya di Kantor Presiden, Kompleks Istana, Jakarta, Kamis (11/6).

Menurut Presiden, ia juga sudah menugasi Kepala Badan Nasional Penempatan dan Perlindungan Tenaga Kerja Indonesia (BNP2TKI) Jumhur Hidayat untuk mengambil langkah-langkah yang semestinya agar hukum dan keadilan dapat ditegakkan.

Presiden juga sudah mendapatkan informasi tentang sikap dan perlakuan Kepolisian Malaysia soal nasib yang menimpa Siti dari Da’i Bachtiar. ”Mereka dinilai cukup responsif dan kooperatif menangani kasus Siti Hajar itu. Media di Malaysia juga mengangkat berita yang memprihatinkan ini dengan sudut pandang yang positif,” kata Presiden.

Untuk menenangkan hati Siti, Presiden Yudhoyono mengaku sudah berbicara langsung dengannya melalui telepon. ”Saya beri tahu, kita semua, saudara-saudara di Indonesia, ingin Siti dan semua saudara-saudara kita yang bekerja di luar negeri mendapatkan bantuan-bantuan dan perlindungan semestinya,” tutur Presiden.

Deteksi dini

Agar kasus penganiayaan terhadap tenaga kerja Indonesia tidak terulang lagi di Malaysia, Presiden Yudhoyono juga telah menginstruksikan Da’i Bachtiar dan Jumhur Hidayat untuk segera membangun satu sistem yang bisa secara efektif dan cepat mengetahui kasus-kasus seperti yang dialami oleh Siti Hajar untuk ditindaklanjuti.

”Tidak baik situasi jika seperti itu terus berulang-ulang dan kejadiannya baru ketahuan setelah sekian lama. Diperlukan ketekunan dan kerja sama yang baik antara pihak Indonesia dan negara tuan rumah berkaitan dengan penegakan hukum. Saya akan mengecek sejauh mana upaya kita bisa membentuk semacam deteksi dini itu atas kejadian yang menimpa para tenaga kerja kita,” papar Presiden.

Wakil Duta Besar RI untuk Malaysia Tatang B Razak yang dihubungi dari Jakarta mengatakan, pihak KBRI di Malaysia sudah menyiapkan penasihat hukum lokal untuk mendampingi Siti Hajar.

”Kami juga sudah mengambil gaji Siti sebesar Rp 51 juta yang selama ini tidak dibayar majikan. Kami tetap memantau pemulihan fisik dan psikis Siti,” ujar Tatang. (har/ham)

Sumber : Kompas Cetak

Marilah sejenak kita renungi artikel mengenai kasus Siti Hajar tersebut. Bagaimana penderitaan yang dialami oleh Siti Hajar, dan jutaan TKI lainnya di seantero dunia ini yang mungkin mengalami nasib yang tidak mengenakan (penyiksaan, kekerasan fisik, perlakuan yang tidak manusiawi, atau paling tidak apa yang mereka alami jauh di bawah ekspektasi mereka). Saat ini media menyoroti perlakuan semena-mena warga negara Malaysia terhadap TKI asal Indonesia, dan bagaimana TKI dieksploitasi sebagai karakter yang tertindas.Mengapa saya bilang dieksploitasi, karena tidak ada langkah proaktif (preventif) yang cukup efektif apalagi efisien untuk mencegah perlakuan buruk terhadap TKI kita. Dan kita hanya mempermasalahkan symptom yang terjadi, penyiksaan terhadap TKI kita. Lantas Kita menebar simpati, dan kepedulian ala kadarnya.

Kepedulian ala kadarnya? Intinya semua simpati kita, apakah mengubah nasib para TKI tersebut. Hmmm… nampaknya tidak ada perbedaan signifikan nasib para TKI yang lebih baik. Ada gula ada semut, hal ini nampak berlaku pula pada konteks ketenagakerjaan. Dimana ada suatu lapangan kerja yang menjanjikan “kesejahteraan ekonomi” maka di situ akan bayak semut tenaga kerja di situ. Lantas satu PR yang penting , apakah tidak cukup gula itu ada di negara kita, atau gula itu juga bukan untuk tenaga kerja lokal.

Saya ingin mengajak segenap bangsa Indonesia untuk bangun… Kalau kita harus ditampar, maka tamparan itu lah yang membuat semangat kita terlecut.  Kita bodoh, saatnya kita belajar, Kita miskin, saatnya kerja keras dan kerja cerdas. Saatnya kita membuat gula itu untuk bangsa kita, dan harapan saya,  no more Siti Hajar! Kembalikan martabat bangsa kita….

Untuk Indonesia Jaya


June 24, 2009 at 12:22 am Leave a comment

Dari Blog HSE Indonesia

Kebisingan dan Nilai Ambang Dengar

PENDAHULUAN
Berdasarkan KepMenKes No. 1405 Tahun 2002, kebisingan diartikan sebagai terjadinya bunyi yang tidak dikehendaki sehingga mengganggu atau membahayakan kesehatan. Kebisingan merupakan faktor fisika di tempat kerja dimana pemajanan faktor fisika ini dapat mempengaruhi dan atau membahayakan kesehatan. Akibat dari kebisingan ini penyakit akibat kerja berupa kecacatan yang ditimbulkan biasanya ketulian oleh jenis pekerjaan pada suatu industri.

Berdasarkan International Statistical Classification of Diseases and Related Health Problems (ICD-X) in Occupational Health mempunyai kode H83.3 (noise effects on inner ear). Tingkat cacat ditentukan dengan mengukur nilai ambang dengar (Hearing Treshold Level, HTL) yaitu angka rata-rata penurunan ambang dengar dalam dB pada frekuensi 500Hz, 1000Hz dan 2000Hz. Penurunan nilai ambang dengar dilakukan pada kedua telinga.

PERHITUNGAN Hearing Treshold Level (HTL)
Cacat pendengaran dibagi berdasarkan cacat monoaural, cacat biaural dan presbiakusis (cacat pendengaran pada orang lanjut usia, lansia). Untuk penentuan cacat pendengaraan monoaural yaitu dengan menentukan nilai ambang dengar pada frekuensi 500Hz, 1000Hz dan 2000Hz. Contohnya dapat dilihat pada tabel berikut:

Telinga Kanan
500Hz = 35dB
1000Hz = 40dB
2000Hz = 60dB
Telinga Kiri
500Hz = 40dB
1000Hz = 50dB
2000Hz = 60dB
Jumlah = 135dB
Jumlah = 150dB
Rerata telinga kanan = 45dB
Rerata telinga kiri = 50dB

Dari rerata tersebut maka telah didapatkan nilai ambang dengar rata-rata (Average Hearing Treshold Level, HTLrerata)

Pada usia muda yaitu usia di bawah 40 tahun maka HTLrerata dikurangi 25dB, sehingga pada telinga kanan yaitu 45dB-25dB = 20dB dan pada telinga kiri 50dB-25dB = 25dB. Dari hasil pengurangan tersebut HTLrerata yang melebihi 25dB dikonversikan kedalam persentase daya dengar dengan mengkalikan 1.5%.
– Telinga kanan : 20 x 1.5% = 30% (penurunan pendengaran monoaural)
– Telinga kiri : 25 x 1.5% = 37.5% (penurunan pendengaran monoaural)

Untuk perhitungan cacat pendengaran biaural yaitu 5 kali penurunan pendengaran monoaural terkecil ditambah 1 kali penurunan pendengaran monoaural terbesar dibagi 6.
Hasil konservasi kedalam persentase penurunan pendengaran monoaural kemudian dikonversikan kedalam persentase biaural yaitu :
– Telinga kanan (lebih baik) : 30% x 5 = 150%
– Telinga kiri (lebih buruk) : 37.5% x 1 = 37.5%
– Jumlah (150% + 37.5%) = 187.5%
Jumlah tersebut di atas kemudian dibagi 6, maka didapatkan nilai penurunan pendengaran biaural 31.25%.

Jadi nilai presentase penurunan pendengaran biaural total yaitu 31.25% x 40% = 12.5%

PRESBIAKUSIS
Presbiakusis yaitu kenaikan ambang dengar 0.5dB setiap tahun dihitung dari usia 40 tahun. Apabila seorang pekerja berumur 45 tahun maka kenaikan ambang dengar karena faktor usia ialah (45tahun – 40tahun) x 0.5dB = 2.5dB.

Dari kenaikan ambang dengar tersebut di atas HTLrerata dikurangi 25dB dan dikurangi lagi dengan ambang dengar oleh prebiakusis (nilai di atas 2.5dB), maka :
– Telinga kanan : 45 – 25 – 2.5 = 17.5dB
– Telinga kiri : 50 – 25 – 2.5 = 22.5dB

Dari nilai tersebut di atas maka konversikan HTLrerata ke dalam presentase penurunan daya dengar dengan mengkalikan 1.5%, sehingga :
– Telinga kanan : 17.5 x 1.5% = 26.25% (penurunan pendengaran monoaural)
– Telinga kiri : 22.5 x 1.5% = 33.75% (penurunan pendengaran monoaural)
Sehingga penurunan pendengaran biaural dapat diketahui yaitu :
– Telinga kanan (lebih baik) = 26.25% x 5 = 131.25%
– Telinga kiri (lebih buruk) = 33.75% x 1 = 33.75%
– Jumlah (131.25% = 33.75%) = 165%
-Jumlah tersebut kemudian dibagi 6, maka didapatkan 27.5%.

Jadi nilai penurunan pendengaran biaural total yaitu 27.5% x 40% = 11%.

Oleh:
Yogi Sasongko. Occupational Health Section Head, Safety & Industrial Health Department.
PT Freeport Indonesia
Arif Susanto. Environmental & Health, Public Health Department. PT Freeport Indonesia

Posted by HSE Club Indonesia on May 15, 2006 at 9:33 AM | Permalink

May 27, 2009 at 1:29 am Leave a comment

Theos & Sophia = Berkhidmat kepada Tuhan

Tasawuf, hal yang amat sering didengar sebagai salah satu atribut agama Islam. Sepintas, tasawuf nampak seperti suatu kata dala bahasa Arab. Namun ternyata Tasawuf sebenarnya bukan dari Bahasa Arab. Tasawuf sebenarnya berasal dari bahasa Yunani yaitu Theo Sophia yang berasal dari kata Theos yang artinya Dewa atau Tuhan, dan Sophia yang berarti khidmat. Jadi tasawuf dapat diartikan sebagai

berkhidmat kepadaTuhan atau Theo atau Deo atau Dewa.

Ajaran Suffi sendiri berkembang di daerah Mediteran dan Persia, ciri khas yang menonjol adalah hidup menjauh dari kenikmatan dunia. Kaum Suffi pantang memakan daging, menggunakan pakaian dari bulu domba, dan selalu berpuasa.

February 27, 2009 at 2:28 pm Leave a comment

TUGAS ELEKTRONIKA INDUSTRI-13405153

Apa Definisi Setrum?

setrum padanan katanya adalah arus listrik atau  electric current. Electric current didefinisikan sebagai perpindahan muatan negatif (elektron). Karena sifat elektron yang cenderung menyukai muatan positif, maka perpindahan elektron yang  terjadi adalah perpindahan dari daerah yang bermuatan lebih negatif (katoda) menuju ke daerah yang lebih bermuatan positif (anoda).

Apa Definisi Kesetrum?

Kesetrum memiliki padanan kata electric shock. Electric shock secara fisikawi terjadi karena adanya perbedaan potensial yang tinggi antara sumber listrik dan tubuh manusia. Secara alamiah, hal ini mengakibatkan arus listrik mengalir ke tubuh manusia. Dalam taraf tertentu, tubuh manusia memiliki sifat dapat menetralisir kelebihan muatan (sama seperti bumi). Saat tubuh tidak bisa menetralisir, maka media lain yaitu bumi yang akan menetralisir kelebihan muatan tadi. Saat itu, tubuh menjadi penghantar listrik (pada tegangan tinggi tubuh manusia yang termasuk isolator dapat berubah menjadi konduktor). Karena  sifat listrik yang dapat berubah menjadi energi panas, dan perbedaan potensial yang besar tadi, kesetrum dapat mengakibatkan kerusakan (kebakaran) jaringan tubuh yang fatal.

Apa  Syarat Terjadinya Kesetrum?

Ada batasan-batasan di mana tubuh dapat merasakan arus listrik. Arus listrik minimal yang dapat dirasakan tubuh manusia pada frekuensi sebesar 60 Hz sebesar 1 mA ( 1 mili Ampere) pada arus AC (arus bolak – balik) dan minimal sebesar 5 mA pada arus DC (arus satu arah) dan mulai mematikan pada tingkat arus 100 mA. Selain itu tegangan yang dimiliki oleh sumber harus cukup tinggi.

Apa Bahaya Kesetrum?

  • Pada arus rendah untuk listrik komersial (DC sampai 150Hz), kontak langsung dengan tubuh dapat menyebabkan depolarisasi jaringan permiable tubuh, akibatnya adalah kerusakan lokal pada jaringan otot.
  • Pada arus 14-16 mA, dapat berakibat pada kerusakan jaringan otot rangka dan saraf tepi, akibatnya adalah kelumpuhan pada daerah yang terkena setrum tadi.
  • Pada arus di atas 50 mA, dapat mengakibatkan repolarisasi myocardial (otot jantung). Akibatnya disfungsi jantung, akibat lebih parahnya adalah kematian.

Referensi :

www.shvoong.com/books/408905-electric-shock-mechanism-effects

id.wikipedia.org/setrum

February 19, 2009 at 4:47 am Leave a comment

Tebak2 Berhadiah menarik lo! hehehehe…

Hmmm.. Bingung mau ngapain hahahaa.. inget ama becandaan-becandaan pas zaman SD dulu gak?

hahahaha.. refresh deh.. Merasa tertantang silakan comment di sini ato email ke hadian_ti05@yahoo.co.id! Ada hadiahnya lho..!

Pertanyaan pertama

Apa bedanya pacar, cileuh ama bis kota? ps: cileuh adalah kotoran mata, terutama dapat terlihat ketika orang belum mandi. Heheheh.. ayo siapa yang belum mandi?).

Pertanyaan kedua

Amir, Joko, dan Budi adalah 3 sekawan yang selalu memiliki rasa ingin tahu yang sangat tinggi. Si Amir dkk. mencoba eksperimen gaya berat. Lalu muncul hipotesa sederhana anak SD. Hipotesanya adalah benda yang lebih berat (bermassa lebih besar) akan lebih terasa sakit bila dijatuhkan ke kaki manusia. Asumsikan hipotesa mereka adalah benar. Pertanyaannya adalah bila amir dkk. memiliki satu karung kapas seberat 5 kg dan besi blok seberat 5 kg mana yang paling sakit bila dijatuhkan ke kaki?

Ps : pertanyaan logika bayi alias naluriah .. gak perlu dipikir pake logika tingkat tinggi

Pertanyaan ketiga

Tebak Angka. Jika diketahui 0 bernilai 1 dan 1 bernilai 0, berpakah

  1. 2400
  2. BABI
  3. 115
  4. KACA

Ps : gunakan imaginasi grafis anda!

Rasanya sudah cukup.. hehehe.. coba berfikir dengan cara yang berbeda dari biasanya!

Bravo….

June 21, 2008 at 8:11 am Leave a comment

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