Вибрации на дланите

Фон

The EC – Directive 2002/44/EC lays down minimum requirements for the protection of workers from risk to their health and safety arising or likely to arise from exposure to mechanical vibration.

The assessment of the vibration exposure is calculated in relation to a standardised 8h daily exposure value A(8). After establishing the A(8) value, this should be compared with the exposure action- and limit-values. As the Directive lays down minimum requirements, it is also vital to check legislation in each individual Member State of interest to find out if this legislation has stricter exposure values.

Depending on the daily Exposure Action Value (EAV) and the daily Exposure Limit Value (ELV), the employer has an obligation to take appropriate action in order to control the vibration exposure.

Действителни нива на вибрации

Когато операторът е подложен на вибрации A(8) надхвърлящи установените, работодателят е длъжен да вземе мерки и да създаде нормални условия за работа. За повече информация вижте Директива 2002/44/EC и законодателство на държавите–членки на ЕС.

Допустими нива на вибрации

В никакъв случай операторът не трябва да бъде подлаган на вибрации, надхвърлящи (5.0 m/s²).

Мерки за намаляване нивата на вибрациите

Use only low vibrating power tools. This recommendation could be regarded as the most important one. Vibration data can often be found in the manufacturer’s technical information.

Shorten the usage time of the tool. As the A(8) value is a function of both vibration value and exposure time, one alternative is always to cut down on the working time.

Service and maintenance of the machine. Follow the manufacturer’s recommendations. It is especially important to maintain the cutting equipment and the rotating elements that can become unbalanced due to wear.

Калкулатор на вибрациите в ръцете

This calculator was developed as an aid to perform calculation of vibration exposure and was carried out under the following conditions:

Equivalent vibration value, a_hv,eq. Measured according to ISO 5349-1 or according to relevant measuring standard based on ISO 5349-1 for the specific power tool.

Typical daily exposure time, T_exp. The exposure time is always less than the daily working time. For most power tools, the estimation of T_exp comes from an international study (CEN Technical Report - “Guideline for the assessment of exposure to hand-transmitted vibration based on information provided by manufacturers of machinery”). For machine types not included in this report, the T_exp has been estimated from time studies. See table 1.

The assessment of A(8) is thereby only valid for these conditions. If a machine is used in a non-standard working application or if the exposure time is not relevant, the assessment of A(8) should be made taking these factors into consideration.

Инструкции за експлоатация

The calculator is divided into two sections of which the left section immediately produces each power tool’s individual A(8) exposure value, based on 8 hours usage time.

The right section is the actual calculator, which calculates each tool’s partial exposure to any usage time if other than 8 hours. If the worker chooses to use multiple tools over the working day, the calculator produces their total A(8) exposure values as well.

Choose model of power tool. The chosen model's A(8) value and the model's equivalent vibration value a_hv,eq will show next to the left section’s model field. The model field adds one row for each model.

To calculate a new A(8) exposure value when using multiple power tools or for various user times, simply enter the specified tools’ estimated daily working times into the white fields. Read the result for each tool from the column partial daily exposure. If you use multiple tools, the calculator will produce the tools’ accumulated A(8) exposure value during the full working day in the cell below the partial daily exposure column.

The lights at the bottom will change with the A(8) value.
Green - The daily vibration exposure is below 2.5 m/s².
Yellow - The daily vibration exposure is above the exposure action value at 2.5 m/s².
Red - The daily vibration exposure is above the exposure limit value at 5 m/s².

To clear all cells and start again, click the "Reset form" button.

Изчисляване за машини, нефигуриращи в списъка.

Нивото на вибрациите A(8) е известно

The calculator has two options to include other hand-arm vibrating power tools as well. The simplest option is when the tools’ rated A(8) exposure values are known.

Choose “other” from the model list. By selecting “other” the calculator automatically uses the typical vibration exposure time for that specified tool group. See table 1.

Edit the name in the model field (not necessary).

Enter the A(8) exposure value into the third column in the left section. Then use the calculator as described in section “Instructions for use”.

Нивото на вибрациите A(8) е неизвестно

Ако нивото на вибрации A(8) е неизвестно,трябва да бъде определено алтернативното ниво на вибрации за всяка ръкохватка ahv,eq .За да го определите ahv,eq са необходими нивата на вибрации при ускорение ahv за всяка ръкохватка и работен режим. Това е ahv квадратният корен на сумата от квадратите на нивата на вибрации ahw измерени в три оси на ръкохватката, предоставени от производителя.

Еквивалентното ниво на вибрации ahv,eq е сумата от вибрациите на различни модели. Тук калкулаторът използва ahv във връзка с продължитеността на работата във всеки работен режим in conjunction with each operating mode’s time sequences ti за да изчисли ahv,eq. ahv,eq трябва да бъде изчислено за всяка ръкохватка поотделно.Тъй като,се използва нивото на вибрация само на най-лошата ръкохватка,то е нивото,което следва да бъде въведено в калкулатора.Сега калкулаторът изчислява дневното ниво на вибрация A(8),което ще се появи в лявата секция на калкулатора.Калкулаторът използва третото уравнение (3),за да определи дневното излагане на вибрации A(8) нормализирано до 8 часа,използвайки еквивалентното ниво на вибрации ahv,eq и типичното дневно илзагане на вибрации Texp за съответния уред.Виж таблица 1.

Choose “other” from the model list. By selecting other the calculator will automatically use the typical vibration exposure time for the specified tool group. See table 1.

Edit the name in the model field (not necessary).

Enter the worst (maximum) handle’s a_hv,eq value into the second column in the left section of the calculator. Now the calculator determines the daily exposure value A(8), which is shown in the third column in the left section of the calculator.

Таблица 1 - Типично време за излагане на вибрации

Typical daily exposure times for the use of single power tools during an 8-h working day. From CEN-Technical report “Guideline for the assessment of exposure to hand-transmitted vibration based on information from manufacturers of machinery”.

Важно! Дадените типични времена за излагане на вибрации са определни от полеви тестове, проведени при реални условия. В 90% от всички проучени приложения типичното време за излагане на вибрации е по-кратко от даденото в таблицата. Установено е, че само 10% от проучените приложения имат по–продължително излагане на вибрации от даденото. В този смисъл, от голяма важност е времето за изпълнение на конкретната задача да бъде внимателно анализирано, за да се определи дали не предполага по-продължително излагане.

Таблица 2 – Продължителност на работата

Time sequences of the operating modes for chain saws and other power tools as described in CEN-Technical report “Guideline for the assessment of exposure to hand-transmitted vibration based on information from manufacturers of machinery”.