Hand-arm trilling

Achtergrond

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.

Actiewaarde voor blootstelling (EAV)

Wanneer een medewerker trillingen ervaart die de EAV van 2,5 m/s² te boven gaan, moet de werkgever een risico-inventarisatie maken van de werkzaamheden en beheersmaatregelen invoeren. Zie voor meer informatie Richtlijn 2002/44/EC en wetgeving van de lidstaten.

Grenswaarde voor blootstelling (ELV)

Een werknemer mag niet worden blootgesteld aan trillingen die de ELV (5,0 m/s²) overschrijden.

Aanbevolen acties om de blootstelling aan trillingen te verminderen

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.

Blootstellingsberekening hand-arm trillingen

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

Equivalent vibration value, ahv,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, Texp. The exposure time is always less than the daily working time. For most power tools, the estimation of Texp 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 Texp 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.

Gebruiksinstructies

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 ahv,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.

Berekening voor gereedschappen die niet in de lijst voorkomen

De A(8) waarde is bekend

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”.

De A(8) waarde is niet bekend

Indien de A(8) waarde onbekend is, moet de equivalente trillingswaarde ahv,eq voor ieder handvat worden bepaald Om de ahv,eq te bepalen, zijn de trillingsversnellingen ahv van ieder handvat en de werkwijze nodig. De ahv is de vierkantswortel van de som van de kwadraten van de trillingswaarden ahw gemeten langs drie assen van het handvat en moet door de fabrikant worden verstrekt.

vergelijking 1: ahw = vierkantwortel van de som ( a²hwx + a²hwy + a²hwz ) (1)

De equivalente trillingswaarde ahv,eq is de som van de vibraties bij de verschillende werkzaamheden. Hier gebruikt de berekening ahv samen met de iedere gebruiksduur ti om ahv,eq te berekenen. De ahv,eq moet voor ieder handvat afzonderlijk worden berekend. Maar omdat alleen de waarde van het ergste handvat wordt gebruikt, moet deze in de berekening worden ingevoerd. Nu bepaalt de berekening de dagelijks blootstellingswaarde A(8), die in de linkersectie van de berekening wordt getoond. De berekening gebruikt een derde vergelijking (3) om de dagelijkse genormaliseerde waarde voor een 8-uurs periode –A(8)– te bepalen door de equivalente trillingswaarde ahv,eq en de kenmerkende dagelijkse blootstellingsduur Texp voor het specifieke gereedschap te gebruiken. Zie tabel 1.

vergelijking 2: ahveq = square root of the sum of 1 divided by T deriva of n by i=1 multipied by a²hvi multiplied by ti (2)
Vergelijking 3: A(8) = ahveq multiplied by square root of Texp divided by 8 (3)

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 ahv,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.

Tabel 1 – Kenmerkende dagelijkse blootstellingsperiodes

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”.

Machinetype Toepassing Kenmerkende blootstellingsduur
Top handle kettingzagen Boomonderhoud 2,4 uur
Prof. kettingzagen <80 cm³ Logging farming, Landscaping 3,7 uur
Prof. kettingzagen> 80 cm³ Intensieve bosbouw 3,7 uur
Grastrimmers Hovenierswerkzaamheden 4,0 uur
Bosmaaiers Wegonderhoud, hovenierswerkzaamheden 3,5 uur
Heggenscharen Hovenierswerkzaamheden 3,5 uur
Bladblazers Gemeentes 3,0 uur
Kantensnijders Hovenierswerkzaamheden 3,0 uur
Doorslijpmachines (hand) Bouw 1,0 uur
Doorslijpmachines (trolly) Bouw 2,5 uur

Let op! De opgegeven kenmerkende dagelijkse blootstellingsperiodes zijn in life-tests onder representatieve omstandigheden bepaald. In 90 % van alle onderzochte toepassingen was de dagelijkse blootstellingsduur korter dan de waardes in de tabel. De schatting is dat 10 % van de onderzochte toepassingen een langere blootstellingsduur heeft. Daarom is het belangrijk dat de specifieke werkzaamheid zorgvuldig wordt geanalyseerd om vast te stellen of de blootstellingsduur langer is.

Tabel 2 - Gebruiksduur

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”.

Machinetype Stationair Nominale snelheid Max. snelheid
Top handle kettingzaag 1/3 T 1/3 T 1/3 T
Prof. kettingzagen <80 cm³ 1/3 T 1/3 T 1/3 T
Prof. kettingzagen> 80 cm³ 1/2 T 1/2 T
Grastrimmers 1/2 T 1/2 T
Bosmaaiers 1/2 T 1/2 T
Heggenscharen 1/5 T 4/5 T
Bladblazers 1/7 T 6/7 T
Kantensnijders 1/2 T 1/2 T
Doorslijpmachines (hand) 1/7 T 6/7 T
Doorslijpmachines (trolly) 1/7 T 6/7 T