Unlike previous directives on machine sound levels and engine transmissions, effective control of vibration exposure is not just a function of the manufacturer's machine.

Simply, Vibration = Machine + Terrain + Operator, and we have a responsibility to influence all three.

The directive places responsibility on employers to:

Assess the levels and decide if employees are likely to be exposed to limits
Where necessary, take steps to reduce exposure
Provide employees with information and training on how to operate machines to reduce exposure
Keep records of risk assessments and control actions
Review and update assessments regularly

There are basically two ways in which exposure to vibration takes place

Whole body vibration, or WBV
Hand arm vibration, or HAV

HAV levels generally are below legal thresholds where action is required.

Manufacturers have responsibilities to make their machines as safe as possible and provide us with adequate information to help us use them safely. CE labels and certificates of conformities will demonstrate compliance.

Different tasks will produce different levels of vibration and the manufacturers have a duty to point out activities likely to create higher levels and advise on ways of minimising.

Practical steps which can be taken to reduce WBV are as follows:

Ensure machines are adequately maintained, particularly the suspension
Choose the right machine for the job
Ensure correct tyres, inflation pressure for the ground surface
Check the operators seat is in good repair and gives good support
Use a suspension seat that meets ISO 7096, and ensure it is set correctly according to the operators weight
Ensure cab equipment is set to suit operator
Identify machines and activities which create highest levels and arrange rotation to reduce individuals exposure
Plan work site routes over smoothest terrain
Improve road conditions, fill pot holes, clear debris and level surfaces

Employee training is also identified and should include

Sitting and posture
Seat adjustment
Correct type pressures
Keeping low speeds on uneven terrain
Varying work patterns
Reporting machine defects which effect comfort

Caterpillar have been driving down vibration since the 1940's with the Tandem rear axle arrangements fitted to motor graders which reduced bump input by 50%.
1955 Scraper cab suspension systems tested
1963 Air/Oil strut suspension for dumptrucks
1968 Cushion hitch suspension on scrapers
1978 Suspended undercarriage for tracked machines
1987 CAT dedicate team to vibration
1991 Lift arm suspension on FEL's
1999 Lift arm suspension fitted to backhoe loaders
2000+ Seat, Cab and Frame suspension system developments

Assessment of vibration exposure levels has historically been difficult to measure. CAT have developed vibration exposure tables which are derived from years of extensive testing and site measurements to give indicative values that one could expect of on various machine types used in various applications by all types of drivers.

It allows the assessor the ability to estimate a level which would be experienced by an operator in foreseeable conditions in most operations. Following from this determination of actions required can then be carried out.

To conclude the evening a vote of thanks was given by Steve Cole and our appreciation was given in the normal way.

Andy Shakeshaft (West of England Branch Committee member)