To HAV and to hold

Major contractors are aiming to improve the management of hand-arm vibration health risks for construction workers by expecting supply chain members to train operatives about the dangers and look for alternative methods. This is being driven through the pre-qualification process.

This decision affects all m&e contractors, who must now be compliant with the new legislation. So the key question is, how does the m&e market react to this new demand?

The challenge for tool suppliers

The HSE website states that all tool testing must be done in accordance with BS EN ISO 5349-2 (2001): practical guidance for measurement at the work place. This ensures that the final vibration figures are based on real life working conditions.

The challenge for the power tool industry is not only based on the lowering of vibration figures, but also on increasing performance and thus the amount of work that can be carried out each day.

What is vibration exposure?

There are two legally defined exposure values in an eight hour working day – Exposure Action Value A(8) of 2·5 m/s2 and Exposure Limit Value A(8) of 5 m/s2.

At any level of exposure, the risk must be eliminated or reduced to the lowest possible reasonable level. However, if exposure is above the Exposure Action Value, an employer must have a programme of actions to control risk.

For example, an operative carrying out an operation using a tool that has a vibration level of 2.5 m/s² can work with the tool for eight hours before reaching Exposure Action Value A(8). If the vibration level of the tool is higher, work time must be reduced to get an equivalent exposure.

A tool that has a vibration level of 5 m/s2 can be used for a period of eight hours in a day before reaching Exposure Limit Value A(8). Here again, if the tool has higher vibration level then the working time must be reduced to get an equivalent exposure. The employer must take actions such as health surveillance and control measures or look for alternative methods.

The Exposure Limit Value A(8) is set as a maximum and must not be exceeded. Therefore, a tool with a vibration level of 13.5 m/s² can only be used for 71 minutes per day providing the aforementioned measures have been arranged.

Up to 2006, the generic standard BS EN ISO 5349 was used to measure vibration because no product standard was available. In the meantime, tri-axial vibration test codes were developed under the safety standard EN 60745 for electric power tools. This standard is listed under the EC Machinery Directive and is the legal basis for the manufacturers of electric power tools on safety and physical agents. EN 60745 values can be used for the vibration risk assessment employers have to conduct. This is also in line with HSE's Control of Vibration at Work Regulations (2005).

What can be done?

Over the past five years, Hilti has been working closely with major m&e contractors to create individual solutions that comply with all regulations, while being simple and commercially viable.

Haden Young, Balfour Kilpatrick, Crown House, Emcor and Interserve are just five of the companies that have produced m&e-specific tool selectors which, following application testing with Hilti, express the findings as the amount of work done rather than impractically stating recommended exposure times in hours of daily use.

The process succeeds in matching the correct machine and consumable to the task and accurately identifies the amount of work that can be safely carried out before both Exposure Action Value and Exposure Limit Value are reached.

The solution covers all applicable m&e tasks for each company and shows work done as holes drilled or how many pipes can be cut or bevelled. Crown House’s selector, for example, includes figures for reciprocating saws, cordless drills/drivers, jigsaws and, where Hilti tools are not applicable, other manufacturers’ products.

More information can be found in Hilti’s booklet, Reduce HAVS health risks. This also provides details of how companies can comply with all required legislation and explains the tool selector, whilst ensuring their employees are protected.

Is there another way?

The short answer is yes. Most m&e companies have a set way of achieving specific tasks and these are based on tried and trusted techniques. However, with all the product developments in recent years, there are alternative methods that can remove the HAVS risk almost in its entirety. The key is to eliminate the risk at source during the design stage.

Two of the main advancements have come in the fields of shot-firing systems, which are powder-actuated to reduce the vibration element and diamond drilling, where the tool is placed on a rig before being manually operated. In both cases, there is little risk of HAVS exposure and productivity can actually be improved.

M&E companies must meet the legislative requirements if they are to retain a good reputation. Although legislation may seem confusing at first glance, there are simple solutions that are practical and profitable.

Companies that have not been aware of the requirements of main contractors must get up to speed. Others must make sure they are using the right products to design out risk at source. Failure to do so may result in them being removed from the main contractors supply chain altogether.

Derek Gow is head of building services at Hilti (GB).