Vibration is classified as one of the physical occupational hygiene hazards in the workplace.  It is separated into two sub categories; Hand-Arm vibration (HAV) (usually associated with the use of vibrating hand tools), and Whole-Body Vibration (WBV) which is experienced when the operator or driver sits on or in a vibrating machine, usually a vehicle such as a forklift, or one of the numerous kinds of vehicles used in agriculture, transport, materials handling, mining and forestry.

Vibration as a hazard has not received the recognition or attention that it deserves when compared to other occupational hazards for a number of reasons.

1) WBV does not have a specific target organ which it affects, making it a hazard with non specific health outcomes which are not easy to clearly discern.
2) It is usually a costly, technical and relatively difficult hazard to measure and evaluate.
3) It is one of the least recognised and most misunderstood of the occupational hazards with fairly limited research carried out in the area compared to other hazards
4) It is often difficult and costly to control, and especially in developing countries there are many other more visible occupational hazards that exist and are given a higher priority.

We will focus on the whole-body-vibration.

Whole-body vibration relates to mechanical vibration which is transmitted into the body, when seated or standing, through a supporting surface (usually a seat or the floor) during or in connection with work activity. Whole-body vibration is typically associated with driving or riding in certain types of vehicles, for example driving or riding on a vehicle along an unsurfaced road, operating earth moving machines or standing on a structure attached to a large, powerful, fixed machine which is impacting or vibrating.

The body being much the same as a machine can tolerate certain levels of vibrational energy but eventually starts to deteriorate and fail as long-term damage is done and natural processes and systems of the body are disrupted. High levels of whole body vibration may be experienced by operators and drivers of off- road machinery such as construction, mining and quarrying machines, for example scrapers, bulldozers and building site dumpers, and tractors and other agricultural and forestry machinery. High exposures to whole-body vibration may also occur where vehicles designed for operation on smooth surfaces are driven on poor surfaces e.g. when lift trucks with no wheel suspension or with solid tyres are used on a cracked or uneven yard. High exposures also occur in small, fast boats.

As a consequence of the abovementioned legislation, employers are required to make an assessment of the risks to employees' health created by vibration in the workplace.

The legislation also introduces restrictions on the quantity of mechanical vibration to which a worker shall be exposed during a working day (referred to as the daily exposure level and denoted in the legislation by the term A(8)) which takes account of the magnitude and duration of the vibration. The exposure action value set out in the legislation defines a daily exposure level which if exceeded requires specific action to be taken to reduce the associated risk. The daily exposure level must not exceed the exposure limit value as set out in the legislation.

These restrictions on the quantity of mechanical vibration to which a worker is exposed during a working day increase the need to monitor vibration exposure levels in the workplace.

Whole-body vibration exposure measurements and monitoring is now easy!

In order to help to comply with the 2002/44/CE european directive a whole-body wireless vibration dosimeter (EVEC) has been developed in partnership with INRS (research center for safety, France). Based on an innovative concept, the EVEC dosimeter automatically measures drivers' daily vibration exposure and evaluates the results making it easy to determine whether a person works within the limits set by the directive.

Unique features of EVEC

• User-friendly operation (can be used by non-experts)
• Automatic measurement and computation of the exposure levels as defined in the 2002/44/CE european directive.
• Automatic measurement of exposure time
• Wireless, monitors without cables
• Automatic identification and removal of unrelated events.
• Direct access to measurement results using a laptop or PocketPC
• Very short training
• Reasonnable cost
• Developed in partnership with INRS (French Research Center for Safety)

THE EVEC MONITOR IS DESIGNED ACCORDING TO ISO10326 AND HAS INTERGRATED :

• A 3-axis accelerometer
• A microcontroller performing the accelerometer signals weighting, according to ISO2631
• An algorithm for the detection of unwanted effects
• A sensor detecting the presence of the driver
• A wireless communication link allowing the transmission of the measurements to the host PC/Pocket PC
• A battery for autonomous operations (>20hours)

EVEC Operation

Although EVEC exhibits advanced functions, it has been designed to be used by non-experts. The EVEC sensor is placed on the driver’s seat, without mechanical or electrical connection. A few clicks are enough to prepare the measurements campaign and retrieve the results. This is done by the EVEC software which can be installed on the user laptop or a Pocket PC, both equipped with a Bluetooth connection. No user data sorting, handling or computing is required. Thanks to the presence of the detection device integrated into the EVEC monitor, the vibration exposure, as well as the A(8) value as defined in directive 2002/44/CE, are computed immediately from the signals of the 3-axis vibration accelerometer. The EVEC software also shows how the vibration levels measured compare to the action level and exposure limits specified in the directive.

The standard EVEC set is delivered in a plastic casing that includes:

• The monitor, a semi-rigid interface to be placed on the worker seat
• A charger for the sensor
• A user manual
• A CD-ROM including the software to be installed on a laptop (requires Windows XP or VISTA and a Bluetooth interface) or on a Pocket PC (requires Windows Mobile 5.0 and a Bluetooth interface)

Configuration of typical measurement set - Sensor(s) used

Seated operator exposure Set
The Seated operator exposure Set is a dosimeter for measuring vibrations transmitted to the whole-body. It allows measurement of the vibration levels experienced by seated operators in accordance with European Directive 2002/44/EC. The sensor is a semi-rigid interface to be placed on the driver’s seat.

Standing Operator exposure
The Standing Operator exposure Set (option) is an external and autonomous presence detector (for use in combination with the Seat or Floor sensor) that allows the calculation of the vibration level experienced by standing operators in accordance with European Directive 2002/44/EC.

S.E.A.T. Factor
The S.E.A.T. Factor set (option) is a dosimeter for measuring floor vibrations. Used in combination with the Seat sensor, it allows the calculation of seat efficiency factors, also called S.E.A.T. factors.

These sensors communicate with the EvecSensorDuo software installed on your PC through a wireless connection. No wires are needed..

EvecSensorDuo Software

This software allows users :
to select the required measurement configuration (seated operator exposure, standing operator exposure or seat efficiency measurement, S.E.A.T factors).
to switch ON the sensor(s) according to the selected measurement.
to access – through a wireless connection – measurements made by the sensor(s).
to automatically and easily calculate and display the final results of the vibration measurements (such as daily vibration exposure A(8) and/or the S.E.A.T. factors for example).

EvecViewerDuo Software (Option)

This software allows users :
display time related history of acceleration levels acquired with Seat, Floor and Detect sensors during vibration exposure measurements.
interact with acceleration graph to edit ranges, zoom, pan.
define exclusions ranges, beside the ones that are automatically created by the sensors, and activate or deactivate them in order to compute their impact on daily vibration exposures.
define groups of exclusions, which allows activating or deactivating all exclusions in a group simultaneously.
highlight peaks in acceleration measurements.
annotate measurement ranges of interest.
import voice records (which have been taken during the vibration measurements) into EvecViewerDuo, where you can play them and hence figure out the impact of particular driving or operating events on vibration measurement results.
simulate different utilization times of the vehicle or machine.
export results in 3 differents formats (evc, spreadsheet, text).
copy graphs and measurement results to the clipboard to paste them into a work processor for reporting purposes.

WBCheck (Option)
Vib@Work WBCheck, check bench for “whole body” dosimeters allows the acceleration measurement of “seat” or “floor” sensors to be validated along the 3 measurement axes X, Y and Z.

Hand-Arm Work Vibrations Monitoring

Description
Our innovative measurement system allows taking vibration measurements on handheld tools thanks to autonomous sensors that does not need to be wired during measurements.

Stored data is downloaded from the sensor(s) at the end of the working period using a docking station connected to a PC.

Software allows automatic computation and display of workers’ exposure to hand arm vibration, and indicates how it compares with limit and action values defined in the vibration Directive.

In order to cover the full range of existing handheld tools two sensors have been developed: one for usual vibrating tools while another one is dedicated to highly percussive tools exhibiting high level of shocks (Up to 50 000 m/s2).

Our measuring device, that can be attached to any kind of tools, is currently the only one capable of taking accurate vibration measurement without disturbing worker’s tasks with annoying and fragile cabling. A special version of the sensor is specifically dedicated to measurement on highly percussive tools.

Sensors Description
The sensing device is made of a miniature case to be fixed on the tool and includes :
a 3-axis accelerometer .
an electronic circuit acquiring , processing (weighting filters), and storing the acceleration values.
a compact battery.
a communication circuit to access stored values (not used during measurement).
an indication of operation (LED).

The available range includes two sensors looking the same and operating identically, but exhibiting different characteristics :
the first sensor allows taking measurements on most common handheld tools.
 the second sensor is dedicated to highly percussive tools (e.g. rammers, rock-drills, …).

(1)Sensor range (including internal mechanical filters)

Main Features

• Self contained miniature sensor.
• Wireless, monitors without cables
• Accurate measurement on all kind of handheld tools, including highly percussive tools (up to 5000 G).
• Automatic computation of standardized exposure values .
• Fully compliant with the European Vibration Directive.
• User friendly implementation and use.
• Includes means of avoiding common measurement errors.
• Non intrusive.
• Reasonable cost.

Operation
The sensors are plugged in the docking station, which is connected to a PC. These are then made ready to measure.
As soon as they are unplugged from the docking station, they can be attached to the tool(s) within a given period of time (user parameters).
At the end of the measurement period sensors are plugged again in the docking station. Measurements are downloaded from each sensor and worker’s exposure to hand-arm vibration is computed, eventually taking into account the different tools he has been using.
Measurement errors avoidance

Unwanted effects can lead to inaccurate results. Hand-arm vibration is prone to measurement errors such as those generated by high shocks encountered on percussive tools (e.g. DC Shift, …).

In order to avoid those phenomena, special provisions have been implemented (i.e. integrated 3-axis mechanical filter). Those provisions allows any user - being an expert in vibration or not - to get to accurate and consistent measurement results.

Compliance
Fully compliant with the european Vibration Directive 2002/44/EC and related standards ISO 5349-1 and 5349-2.
Compliant with the ISO 8041 : 2005 standard (Human response to vibration – Measuring instrumentation).
Weighting filters according to ISO 5349-1.
The sensors are supplied with coupling devices for firm and stiff attachment to the tools as per ISO 5349-2.
Developed in partnership with INRS (Research Center for Safety, France).

Supplied in the set
In its basic version, the Hand-Arm monitoring set is supplied in a carrying case with a capacity of 4 sensors including :
a vibration sensor (standard sensor or sensor for highly percussive tools).
sensor fixing means.
a docking station (4 sensors capacity) for charging and communication between the sensors and the software.
a communication cable between docking station and PC (USB port).
a charger.
a user manual.
the dose computation software on CD.