Misunderstanding Hand Arm Vibration monitoring marketing material can put hands and safety policies at risk. Caveat emptor. We are regularly asked about new vibration measurement technology, particularly re the latest hand-held, glove or wrist mounted transducers that are presented as the latest assessment improvements. Whilst they may be useful tools, unfortunately some claims have been disingenuous and end users have misunderstood the limitations inherent in the vibration measurement techniques. Where
Best Practice in HAV Assessment and Risk Management – simpler than you think…
HAV measurements – usually an unnecessary expense…
Regulation: control vibration risk, don’t measure…
Beware manufacturers’ vibration data for risk assessment, and why not optimise tool maintenance?
We have a rare level of expertise in the field of hand-arm vibration (or vibration white finger – VWF) that has allowed us to develop a uniquely pragmatic approach to HAV risk management that dramatically reduces the costs and resources required to meet regulatory and moral responsibilities. Our reputation is such that we were invited to present on the HSE road-shows across the UK to launch the HAV regulations. Key innovations include the largest hand-arm vibration database of accurate field data available, HAV-Base, that can cut assessment costs by up to 90% and the development of HAV-Test, the only effective vibrating tool condition maintenance test system available. We also have the engineering skills to reduce vibration at source.
“If you are paying suppliers or consultants to measure the vibration on your tools every year or two, it’s very good business for them, but completely unnecessary…”
HAV Myth Management
The depressing evidence is that many HAV assessments are seriously flawed and that industry is storing up future problems despite the best of intentions. There is a minefield of opportunities for vibration risk management mistakes based on mis-information and myth. The most common areas for errors are:-
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 provide higher and more realistic vibration values than the old ISO8662 standard. However, whilst useful for an initial estimate, you still cannot use these figures for accurate risk assessment unless you can show that they are representative of your real-use tool vibration. This is particularly the case where the operator dose is likely to be close to the action or limit values as there can be substantial 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.” However, there is commercial pressure on suppliers not go out of their way to publicise the higher vibration values that are often associated with real field use….
Hand-Arm Vibration Measurement Accuracy – don’t measure unless you have to…
HAV measurements are time consuming and expensive – and often unnecessary (use an accurate database). When measurements are made, incorrect transducer mounting and other technical mistakes often lead to poor vibration measurement data that can under-estimate vibration risk by factors of x2 to x20.
Repeated 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 and 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 and 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.
Hand-Arm Vibration Management Programme – Best Practice Guide
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.
- Create a vibrating tool / plant register: this always takes much longer and turns up many more tools than you expect. Make sure you have sufficient information to define a tool and an operation – “blue drill” is not sufficient! As a minimum, you need 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 then forward a copy to us so that we can evaluate the assessment options for you (see below). Click here to download the free template HAV tool register
- Carry out a HAV risk assessment – don’t measure unless you absolutely must. Surely everyone has already done this? The key message from the HSE is: “Don’t measure vibration unless you absolutely must”. Instead, use your resources to reduce risk by contacting us for data from HAV-Base, our hand-arm vibration database, for low cost virtual assessment by email… Never measure vibration again?
- Implement an effective HAV risk management programme: this includes operational factors, working conditions, behaviour, ergonomics, symptom reporting systems etc. Note that this does not include PPE as there is no effective PPE for hand-arm vibration – although you might not get that impression from reading the technical literature from various suppliers.
- Reduce the levels of vibration via tool maintenance and vibration control measures: evaluate the sensitivity of tool and plant vibration to their mechanical condition so that maintenance can be prioritised. The level of vibration from tools can range from completely unaffected to very sensitive to tool condition. In some cases, retro-fit engineering modifications can substantially reduce vibration in some cases.
- Hire / Buy low vibration tools and plant: base your decision on field vibration data. Include operational, productivity and ergonomic factors as well as levels of hand-arm vibration in your selection criteria. Be aware, however, that the commonly used HAV data traffic light system based on manufacturers’ data often seriously underestimates the risks.
- Training: as operator risk can be very dependent on behaviour, training is a very important risk management element – toolbox talks, management briefings and full HAV competency as appropriate.
- Health Surveillance: introduce a health surveillance programme for all workers who are likely to be exposed above the current Exposure Action Value (A(8) of 2.5 m/s^2). This includes education, reporting system, health checks and communication.
- Audit the risk management programme: check that you are implementing current best practice for all of the above elements – in practice and not just on paper. We have often found that the audit will turn up disconnects between theory and practice and that risk management can be improved in parallel with significant cost savings.
Hand-Arm Vibration Database – Vibration Risk Assessment Best Practice
…never measure vibration again – virtual assessment from our vibration database
Our Hand-Arm Vibration Database contains accurate field data for a huge cross-section of tools and activities. The information can be used to reduce the time, costs and resources required to carry out high quality risk assessments by 80% or more. This approach is also in keeping with the current HSE recommendation to use reliable published data wherever possible. It is much better to invest your time and resources in risk management rather than re-inventing the wheel by repeating measurements that have already been made elsewhere.
Obtaining reliable and accurate field data requires costly instrumentation, a high level of practical training, considerable organisation (of both tools and operators) and is a very time consuming and boring pass-time. Fortunately, it is now largely unnecessary. Purchasing or using our HAV Database is by far the simplest, quickest and most cost effective approach to HAV risk assessment and management.
Produce automated HAV risk assessments for a set of tools used on a project within minutes, print to pdf and email; decide on the best tools to hire; generate tool vibration statistics to aid maintenance decisions; assess operator exposures for multi-tool use; add new tool data….
NOISE-base adds occupational noise data to the HAV tool information. This simplifies noise and HAV management by keeping all the data on the same, easily accessed system. NOISE-Base also includes automated PPE selection against a comprehensive database of available hearing protection and the calculation of the “safe” working distance within which PPE is mandatory. This is best practice in risk management for mobile plant made simple.
Virtual / Field Measurement HAV Assessment – by email
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. We provide you with a template tool register, you fill it in, email it to our office and we can then provide you with a low cost vibration risk assessment from the HAV database. Combined with any additional field vibration measurements required, this can reduce your assessment costs by around 70-80% and the time (and hassle – getting all the plant together) involved by up to 95%.
Optimising Vibrating Tool Maintenance Systems – HAV tool condition, testing and maintenance pitfalls…
How to focus your maintenance on the right tools
The costs associated with managing the risks from Hand-Arm Vibration can be reduced very substantially by introducing an effective condition based maintenance programme. We have collated the field vibration values for thousands of tools to generate statistics that show how maintenance affects vibration. For example, for standard breakers or rivet guns, the vibration from an “as new” tool is little different from an old, worn tool. In contrast, a poorly maintained angle grinder or leaf blower will generate several times the vibration of a well maintained unit as shown in this graphic of the statistical spread of vibration levels. It shows that as the vibration from rivet guns changes very little with condition, maintenance is not important with respect to reducing the risk of HAVS.
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. Contact us if you like to discuss the options to optimise your tool maintenance programme.
Optimising vibrating tool maintenance contracts – beware maintenance contract HAV meter measurements
Increasingly, post-maintenance vibration checks are included in tool maintenance contracts. Unfortunately, as they are usually carried out under no load using a HAV meter, this provides no useful information about tool condition. HAV meter measurements cannot be compared with the manufacturers’ (ISO 28927) declared values as the test conditions are completely different, nor do they provide any useful information about the mechanical condition of the tool (except gross issues that are obvious). They could be used to provide risk assessment values, but only if the tool is tested under simulated conditions that accurately reflect those in the final workplace.
HAV meter measurements do not detect most tool faults as they filter out much of the vibration associated with component and assembly faults. Consequently, a newly fitted damaged bearing will not be detected – despite the fact that it will quickly lead to much higher levels of operator HAV exposure in normal tool use.
The only way to evaluate HAV tool condition accurately is to use the HAV-Test tool vibration signature analysis system. This takes a few seconds to assess the mechanical condition of tools pre-overhaul. As around 50% of tools are typically in perfect condition, they need not be overhauled, cutting maintenance costs and increasing tool availability. A post-overhaul test ensures that the maintenance procedure has returned each tool to “as new” condition within the manufacturers’ specification. This corresponds to the lowest vibration – and lowest HAV risk – possible for each tool. View more information on HAV-Test.
HAV Management Audit – dramatically reduce HAV risk management costs
The Audit is the fastest and most effective way to ensure compliance with current best practice in HAV assessment and risk management. It benchmarks your policy and procedures and generates a detailed Action Plan with full technical support based on innovations that can reduce costs by up to 80%.
Contact us for more information on the HAV Management Audit
Hiring and Buying Low Vibration Plant – Buy “Smooth”
Hire Company HAV Data Traffic Lights, Hirer beware!
This is a very 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 cannot be used for risk assessment. Despite this fact, some of the hire company literature implies that the data can be used for this purpose. Consequently, relying on this data could well leave employers open to potential liability claims as many tools are much more dangerous than the colour coding would suggest. The hand-arm vibration database provides you with the means to specify preferred tool types for any job quickly and easily. The HAV database 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.
Vibration Control Engineering Development
Whilst it is often not practical to reduce vibration from tools and plant, in some cases retro-fit engineering modifications can be developed that not only significantly reduce vibration exposure, but that often increase productivity. The following are a few examples.
Manufacturers are under increasing commercial pressure from their customers to develop low vibration plant. The innovative low vibration handle developed by the INVC for Dennis Mowers 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.
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.
Concrete Ramming Tool
A hand-held Ingersol Rand sand rammer packing concrete lintel moulds generated 28m/s^2 with a maximum trigger time of only 15 minutes/day before reaching the 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.
Riveting Aluminium Panels
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.
Impact Wrench Bolt Tightening
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 factor of three. On a similar operation, simply ensuring the grinding bit was pushed fully into the chuck up 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.
Hand-Arm Vibration training: options include management briefings, HAV competency training (IOSH), supervisor and vibration toolbox talks plus briefings developed specifically for tool suppliers . Material can also be made available for in-house use by your own trainers. The INVC is the major provider of noise and HAV training in the UK and Ireland and is the IOSH approved training organisation for both noise and vibration.Download HAV information