Hand-Arm Vibration - HAVS - Assessment

Hand-arm vibration mythology is creating unnecessary financial and human costs...

The depressing evidence is that many HAVS risk management programmes are seriously flawed and that industry is not only wasting fortunes on ineffective risk reduction measures, but is also storing up future problems despite the best of intentions. There is a minefield of opportunities for vibration risk management mistakes based on misinformation and myth - very costly mistakes that are, unfortunately, actively encouraged by many suppliers in the vibration measurement industry.

View the video of the joint INVC/IOSH webinar that cuts through the myths and provides a definitive summary of what constitutes HAVS risk management best practice here >

The following are some of the most common areas for errors covered in the video:-

HAV mis-measurement – monitors measuring vibration to no standards whatsoever…

Misunderstanding HAV measurement and monitoring marketing material can put hands and safety policies at risk. Caveat emptor. Some claims made by some suppliers of the latest “HAV monitors”, “HAV dosimeters”, “vibration monitoring gloves” etc are disingenuous, misleading end-users as to the limitations inherent in these vibration monitors. None of these alternative HAV measurement techniques provide values that can be used for a reliable assessment of the vibration exposure of operators as required by BS EN ISO 5349-1 2001. Read the full details of why hand-arm vibration dosimeters, hand, glove or wrist-mounted transducer vibration measurement systems do not provide vibration values to the standard.

Manufacturers’ Hand-Arm Vibration Data – it’s data, but not necessarily assessment data

Manufacturers’ updated declared values (to BS EN ISO 8662; EN 60745; EN ISO 20643 - which they have to provide under the Supply of Machinery (Safety) Regulations 2008) are often used as the basis for "traffic light" risk ranking by hire companies. However, whilst useful as an initial estimate, you cannot use these figures for accurate risk assessment unless you can show that they are representative of your real-use tool vibration. Be particularly careful where the operator dose may be close to action or limit values as there can be serious consequences. Quoting the HSE guidance – “…you will still need to check with the manufacturer that the vibration emission declared in the equipment’s handbook is representative of your normal use of the equipment.” Consider the commercial pressure on suppliers not to go out of their way to publicise the higher vibration values often associated with real field use.

HAVBase can be used to aid optimum tool selection as part of a "Buy/Hire Smooth" policy to minimise HAVS risk.

Hand-Arm Vibration Measurement Accuracy – don’t measure unless you have to…

Accurate HAV measurement is time-consuming and expensive – and often unnecessary. In fact, you may never need to measure vibration again by heeding the HSE guidance that recommends using accurate published field vibration data wherever possible (e.g. HAV-Base). Incorrect transducer mounting and other technical mistakes have led to inaccurate field vibration measurements that can under-estimate vibration risk by factors of x2 to x20. We do measure, often, but take great care to ensure the data is valid.

Repeated Vibration Monitoring – and also repeated monitoring

Save your time and money. Once you have good data for your tools and operations, you never have to repeat the process unless you change tools or your operating procedures. Many companies spend a fortune on unnecessary repeat measurements, costly monitoring systems and procedures when it would better be spent on new, low vibration tools and other measures that actually reduce the risk.

Hand-Arm Vibration PPE – an oxymoron

There is no generally effective PPE for HAV, despite claims by some AV glove suppliers. In fact, it is often likely that so called “AV” gloves may actually increase the risk due to their effect on ergonomics.

HAVS Risk Management - learn what constitutes best practice

Our IOSH certified hand-arm vibration competency course covers the state of the art. Versions are also available as in-house and online management briefings or bespoke, industry-specific HAVS workshops.

Avoid the costs (time, training, instrumentation) and hassles associated with field HAV assessment by using our Virtual Assessment service based on our hand arm vibration database. Download and fill in our template tool register or email us your tool register for a rapid and very low-cost virtual assessment. Fill it in, email it to our office and we can then provide you with a low cost vibration risk assessment from our HAVBase HAV database that complies with the HSE guidance recommending the use of accurate published vibration data wherever possible to avoid wasting resources on measurement.

The data can also be combined with additional on-site field vibration measurements if required to reduce assessment costs by around 70-80% and the time (and hassle of getting all the plant together) involved by up to 95%.

More HAVBase details >>

Hiring low-vibration tools and plant is an important element of “best practice” in HAV risk management. The commonly used hire tool company HAV risk “traffic light” system is supposed to provide information to users about the relative risks from tools. Unfortunately, it can be dangerously misleading as it is based on manufacturers’ declared values that should not be used for risk assessment. Despite this fact, some hire company literature implies the data can be used for assessment. Relying on this data could leave employers open to claims as tools can be much higher risk than the colour coding suggests.

HAVBase aids selection of the best tools to buy or hire to minimise risk. It also provides you with the tools and information you need to implement “best practice” in risk management (statistics, combinations of tools, finger-on-trigger calculations, automatic risk recalculation to meet the regulations …) plus high quality, automated reporting and graphical representations of the data.

The following is a step-by-step check list of the components of any effective HAV risk management programme that should be included in any risk assessment report. Contact us for more on any of the element(s) for which you need more information.

1. Create a vibrating tool/plant register: always takes much longer and turns up many more tools than expected. Ensure there is sufficient information to define a tool and operation (“blue drill” is not sufficient!). At least make, model, accessory, the operation for which it is used and the material (metal, plastic, grass, scrub etc). Download and fill in our open-source HAV tool register and email to us to evaluate the assessment options for you (see below).
2. HAV risk assess – don’t measure unless you absolutely must. Surely everyone has already done this? The key HSE message is: “Don’t measure vibration unless you absolutely must”. Get a fast, very low-cost virtual assessment by from our online HAVS database by email and use your resources to reduce risk instead.
3. Implement an effective HAV risk management programme: include operational factors, working conditions, behaviour, ergonomics, symptom reporting systems etc. It does not include PPE as there is none.
4. Reduce vibration via tool maintenance and vibration control measures: use HAVBase stats to evaluate which tools pose an increased risk as they wear to prioritise maintenance schedules. Increases in tool vibration from range from completely unaffected to very sensitive to tool condition. Retro-fit engineering modifications can substantially reduce vibration in some cases.
5. Hire / Buy low vibration tools: base decisions on operational, productivity and ergonomic factors as well as levels of hand-arm vibration. Note: the common HAV traffic light system is based on manufacturers’ data that will often seriously underestimate risk.
6. Training: as operator risk is very dependent on behaviour, training is an important risk management element – toolbox talks, management briefings and full HAV competency training as appropriate.
7. Health Surveillance: introduce a programme for all workers likely to be exposed above the Exposure Action Value (A(8) of 2.5 m/s^2). This includes education, reporting system, health checks and communication.
8. Audit the programme: check you are implementing best practice for all the elements above, in practice, not just on paper. We often find the audit will show disconnects between theory and practice and risk management can be improved in parallel with significant cost savings.

Manufacturers are under increasing commercial pressure from their customers to develop low vibration plant. The innovative low-vibration handle developed by the INVC for a Dennis Mowers lawn-mower reduced operator exposure from 6m/s^2 down to 2m/s^2 – without compromising mower control. This is a dramatic improvement that would allow operators to use the mower all day without reaching the 2.5m/s^2 Exposure Action Value.

This was developed and tested in prototype form within around 4 hours of arriving on site...

A hand-held Ingersoll Rand sand rammer packing concrete lintel moulds generated 28m/s^2 with a maximum trigger time of only 15 minutes/day before reaching the ramming tool vibration control Exposure Limit Value, seriously limiting production. We designed a mass / sprung balance system that reduced the vibration to 11.5m/s^2, extending the “safe” trigger time to 90 minutes/day. Combined with substantial ergonomic improvements, operator HAVS risk was virtually eliminated and there were large productivity gains. As the whole project was completed within days (no site visit) via information (data, video) forwarded by email, the total cost was a few £hundred, making it self-financing over a few days.

Vibration from riveting on a bench jig posed a very high risk of HAVS. Our redesigned, stiffer jig reduced the riveting time by 50% and the vibration by 25%. This cut the overall operator dose by nearly 90% – improving productivity as a side effect.

Flash removal from hand-held aluminium components generated 32m/s^2 – the Exposure Limit Value (ELV) would be reached in 12 minutes, severely limiting production. Detailed analysis revealed dominant vibration was caused by a pedestal grinder component rest resonance. It was replaced by a floor mounted version that improved the ergonomics and reduced the vibration to 1m/s^2, allowing unlimited use without risk of HAVs.

The operator used a spanner on one side of conveyor frames and an impact wrench on the other, producing significant HAVS risk in both hands. We recommended a larger, more ergonomic spanner and a more powerful wrench. These measures halved the vibration dose and significantly improved productivity.

High-speed bits were used to trim aluminium panels, but the tool speed was far too low. Changing the die grinder for a high speed unit to match the bit left the vibration unchanged, but the improved efficiency cut working time from 20 minutes to 2 minutes, reducing the risk by a factor of three. On a similar operation, simply ensuring the grinding bit was pushed fully into the chuck reduced the level of vibration by a factor of x4.

Designing a shorter stirrer bar and reducing the speed  of a hand held paint stirrer reduced the 30m/s^2 vibration level to 8m/s^2 without affecting performance.

The costs of managing Hand-Arm Vibration risks can be reduced very substantially by introducing an effective "likely condition based" maintenance programme. We have used field vibration values for thousands of tools to generate statistics showing maintenance affects vibration. Standard breakers or rivet guns, for example, show little difference between the vibration from “as new” tools and that from old, worn tools. In contrast, poorly maintained angle grinders or leaf blowers generate several times the vibration of well maintained units (see graphic of the statistical spread of vibration levels).

This information can be used to improve your tool maintenance programme by concentrating resources only on those tools that pose the greatest risk if they are not well maintained to reduce the risk of HAVS.