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Wrist mounted vibration transducers – not again!

Once more there are claims that wrist/glove mounted vibration transducers can be used to assess HAV risk in operators as per the British Standard (BS5349). No they can’t. Thank you for listening…

Vibration measurements: compare BS5349 with wrist-mounted transducersI would suggest that anyone considering using any of the wrist (or glove) mounted automated transducer measurement systems in an attempt to measure vibration (as against using them as tool timers linked to properly measured tool vibration levels) to assess operator exposure should consider the following before making a decision:-

  1. It is specifically deprecated by the HSE. Their recent guidance states: “There is currently no wrist or glove mounted device which measures vibration suitable for use in a vibration risk assessment”. Hence as wrist (or glove) mounted transducers do not measure according to ISO/BS5349, the data they produce is not related to the EAV or the ELV dose values and cannot be used for comparison with them in a risk assessment. Those are the facts. This could not be clearer…
  2. Carry out a simple experiment on a high vibration tool (impulsive tools in particular): measure on the tool handle as per BS5349. Measure on the wrist with the wristband loose, and again with it tight enough to cut off the blood supply to the hand. Compare with the measurement made to the standard. They are different – which means they are wrong by definition as all the risk statistics were based on tool handle measurements.
  3. How do you persuade the operator to move the wristband to the other hand as is necessary when using different tools/handles or when swapping the tool to the other hand? This doesn’t seem to be mentioned anywhere in the vibration monitoring system sales literature.
  4. The HSE specifically say that you should spend a minimum on monitoring and focus resources on risk reduction instead. This makes a lot of sense and is best practice.

A recent back-to-back vibration measurement test on 2 items of plant compared the results from BS5349 measurements (2 different personnel using 2 different meters) with those from a “leading” wrist-mounted transducer system (the latter carefully controlled in a way that probably does not reflect general use). Whilst all the BS values were within 5% of each other, the comparable wrist-mounted data varied by between 14% and 240%…


There is an IOM report that is purported to validate wrist measured vibration data. However, this is based on a statistical analysis of supplied data sets without knowledge of any potential exclusions, i.e. it is not an independent study of the validity of wrist mounted vibration monitoring. Validating alternative automated HAV monitoring wrist or glove techniques would require submission to ISO/BS committees, peer review and the extensive reevaluation of risk data, not just a limited statisical analysis carried out in isolation. Moreover, the problems associated with the laws of physics and human nature would still remain.

Defending claims
Now imagine you are the barrister for a HAV injury claimant. Based on the above, just how easy would you find it to drive a coach and horses through a risk management defence based on wrist-mounted vibration data capture? Potentially a very costly mistake…

The new HSE guidance on HAV measurement and management covering the increasing concerns over mis-measurement may well change the way you measure and monitor HAV risk – dramatically… We have developed a short HAV Master Class competency update workshop that covers these and other issues. Check availability and dates to ensure that you are up to date with best practice.

More on the HAV Master Class workshop and a copy of the new HSE guidance

There is considerable deliberately disingenuous disinformation put out by some suppliers taking advantage of the technical nature of the subject to promote sales of products that do not perform as advertised. Tool timers: fine if properly set-up. Vibration dosimeters: absolutely not. In addition, the whole thrust of the wrist/glove mounted automated vibration measurement system approach is that you should spend your resources on continuous, costly logging and measurement rather than on reducing the risk. This directly contradicts HSE advice and goes against current best practice.

In its place
This type of monitoring certainly has a place in risk management – provided that you can justify the high cost. Whether it is a good choice depends on the cost v benefit for your particular circumstances. If you have spent much of your budget on monitoring, there may little left to actually reduce the risk e.g. by buying better tools instead. These monitoring systems may be OK as sophisticated tool timers used to monitor likely exposures provided properly measured tool data is used in the calculation and not the wrist/glove measurements. They can also sometimes give an indication that a tool needs to be serviced – although the operator could do that for free…

Whilst hand-held transducers are not generally recommended, they can be used in circumstances where hard-mounting a transducer would be difficult – as long as you can make sure that the transducer is very firmly held against the tool. However, the results should be treated with care as they can be significantly different to hard-mounted transducer data.

White paper: HAV mis-measurement – to no standards whatsoever… New HSE guidance
Contact us if you’d like to discuss the issues surrounding current HAV risk management best practice. More information about this white paper and a summary of the latest HSE guidance on the topic is available here>.

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Radical update to noise risk management best practice launched at BOHS OH2017 conference

How to update the current (failing) noise risk management process to make it much more effective – and self-financing

Noise Induced Hearing Loss claims of £400,000,000 per annum show that thousands of people are suffering hearing damage, most of which could be avoided by changing the way risk management is is carried out.

A simple, innovative approach that dramatically improves the effectiveness of noise risk management was described at the BOHS OH2017 conference in Harrowgate by our technical director, Peter Wilson. The key elements are:-

  • current risk management processes are demonstrably not working
  • applying simple best practice re PPE and noise control would reduce risks by c 90%.

Make this happen by:-

  • making this best practice instantly available to anyone on the shop floor (no noise expertise required) so that it gets used
  • use a real-world performance algorithm to evaluate and improve actual PPE performance
  • track performance and provide feedback
  • taking advantage of the fact that this approach is self-financing – it saves money and time compared with current practice

Click the link below to acquire a copy of the presentation.

Please send me a copy of the OH2017 presentation

You can learn more about the new best practice approach and how to apply it within your own organisation on the one day Noise Risk Management Master Class workshop (Jume 15th, Slough). This also functions as an update to noise competency training and includes the revised HSE draft guidance and the radical new otoacoustic emission hearing damage screening test technology that allows you to track annual changes in the hearing damage of personnel.

Please send me information on the Noise Master Class

Noise competency update + risk management Master Class

The current noise risk management process has failed. This is how we fix it to reduce risk by c 90%…

Noise Induced Hearing Loss (NIHL) claims currently running at about £400,000,000 per annum is unsustainable and demonstrates that current risk management processes have been ineffective and must be changed. Thousands of people are suffering hearing damage needlessly due to a lack of knowledge. Did you know that:-

  • PPE – muffs: lose 70% of their performance after 1 month; 90% due to glasses etc; 40% of PPE users get zero protection
  • PPE – plugs: most not fitted correctly; as low as 3dB attenuation; women get up to 9dB less attenuation than men
  • Audiometry: the damage criteria used include frequencies that do not reflect hearing loss; no threshold shift is necessarily detected despite substantial damage and reported symptoms

Please send me information on the Master Class

Noise Master Class – one day workshop

Book your place to find out how to implement a risk management revolution that can reduce hearing damage risk by c 90% and that can dramatically reduce costs

This one day workshop provides details of the key innovative changes in best practice that should be introduced to reduce the risks of future hearing damage by around 90% at a fraction of the cost of the current conventional (top-down) risk assessment processes. The day is suitable for anyone with responsibilities for risk management who needs to keep up to date with the latest developments and expectations or for people who have previously attended accredited noise competency training. It includes:-

  • New HSE guidance: puts the emphasis on action, not placebo documentation and processes
  • New approach to risk management: brings together all the simple, effective “low hanging fruit” risk reduction elements, making them easily available to non-specialists. This replaces the current typical “top-down” process, giving anyone the means and responsibility to reduce risk – at negligible cost. The process is initially available by email, covering:  PPE tool: hearing protection database and real-world performance algorithm. Noise control tool: database providing instant access to detailed, low cost engineering solutions to common problems
  • oae hearing test screeningNew OAE hearing screening test: audiometry does not detect the early stages of hearing damage. Otoacoustic Emission (OAE) does. It can assess and track  the actual performance of risk reduction programmes, detecting shortcomings before significant damage is done. OAE will soon be available as a fast, objective, low-cost test by a technician in a quiet office that assesses noise-induced damage to the inner ear structures at an early stage, removing the guesswork as to your risk reduction programme noise measurement appperformance.
  • Digital Noise Assessment (DNA) App beta: currently under development, this will make the new best practice available to anyone, anywhere on smartphone or tablet with automated action reporting and noise measurement.

Please send me information on the Master Class

HAV mis-measurement – to no standards whatsoever… New HSE guidance

Misunderstanding Hand Arm Vibration monitoring marketing material can put hands and safety policies at risk. Caveat emptor.

Stop Press: 27/02/17: HSE has just issued new guidance on HAV measurement and management covering similar concerns. These may well change the way you measure and monitor HAV risk – dramatically… A one-day HAV Master Class and competency update workshop covering these topics is now available. Book a place to ensure that you are up to date with best practice – places are limited.

More on the HAV Master Class workshop and a copy of the new HSE guidance

HAV measurement techniquesWe 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 these techniques do not conform to measurement standards, the results cannot be compared with the regulatory action and limit values. If these values are mistakenly used, then operator risks could be seriously underestimated. Put simply, none of these alternative measurement techniques provide values that can be used for a reliable assessment of the levels of vibration to which operators are exposed as per BS5349.


The following is a summary explaining why alternative HAV measurement techniques may not provide correct values. Click below to acquire the definitive white paper guide.

Acquire a copy of the full HAV measurement white paper

Why is poor vibration measurement technique such a recurring issue?

Correct measurement technique is a regular issue because the British Standard (BS EN ISO 5349-1:2001 2:2002) technique is time consuming. Common problems include:-

  • Service providers taking short cuts: e.g. using hand-held transducers because it is quicker, despite that fact it is inaccurate; HAV -hand arm meter for vibration measurement strapping accelerometers to tool handles with tape etc…
  • New instruments and measurement techniques: many end users have been left with the impression that hand, glove and wrist mounted transducers can be used to carry out vibration measurements to BS5349 – they cannot. Some of the wording used in the descriptions of some systems and services has caused confusion.

Note the statistics used to estimate the relationship between the level and duration of vibration (dose) and the damage risk were based on values from transducers hard-mounted to tool handles. If a new measurement method gives a different value, it is incorrect by definition. Moreover, the HSE guidance recommends spending a minimum on measurement, investing in risk reduction instead. In keeping with this recommendation, for example, most of our HAV risk assessments are taken from our extensive HAV-Base database of accurate field vibration values. This can dramatically reduce (or even eliminate) measurement via virtual assessments by email (contact us for details).

Why non-standard vibration measurement techniques are not accurate

The reasons why alternative measurement systems do not provide vibration values comparable with the regulations are down to the simple dynamics discussed below.


BSEN ISO5349-1:2001/2:2002 measurements:BS5349 vibration measurement the standard measurement where the transducer is hard mounted to the handle. This can be modeled by a stiff spring with low damping which does not vary. This provides the most reliable and repeatable data which can be compared directly with the regulatory action and limit values.


glove or hand-held vibration transducerHand-held or glove mounted transducer: the transducer is gripped between hand and handle or is mounted in a glove as illustrated. This introduces a set of soft, variable springs with high damping between the handle and the accelerometer. Consequently, higher frequencies are progressively filtered out. In addition, the handle shape and grip strength can seriously affect the measured level of vibration (for a constant vibration source). It is not difficult to measure levels that are less than half the correct value.


wrist mounted vibration transducer measurementWrist mounted transducer: wrist mounted “watch” based transducer are very effectively  vibration isolated from the source. Only low frequency vibration is transmitted into the accelerometer. Consequently, the measured value can bear even less relationship to the actual vibration in the handle than for hand-held transducers. It is also highly variable – how tight do you wear your watch-strap?

HAV tool vibration measurement – the hard (and only correct) way…

The BS5349 measurement technique minimises the number of variables involved in hand-arm vibration measurements and provides the only accurate levels that can be compared with the risk statistics (the basis for the action values in the regulations). That is not to say it is not possible to devise better measurement techniques, but many years of work would be required to relate any vibration values to operator risk.

Some marketing literature surrounding the use of hand-held, glove or wrist mounted transducer measurement systems can be misleading if it gives the impression that the vibration values can be used directly in operator risk calculations. If incorrectly used in this way, these values can dramatically underestimate the risks to operators which could lead to avoidable heath issues and potentially serious repercussions should there be a claim.


If you need to carry out full HAV risk assessments (as well as measurements), there is a best practice guide checklist and open source template tool register available for download. We can also provide a full range of HAV training courses and workshops (up to full competency).

Contact us for a copy of the full HAV measurement guide white paper

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New test, new best practice to reduce hearing damage risk

The availability of this new test will have a dramatic effect on the management of hearing loss prevention programmes…

New technology has become available that provides companies with data that they can use to check the real world performance of their hearing conservation programmes very quickly and very easily. It is a development of otoacoustic emission (OAE) screening technology that, unlike conventional audiometry, can be used to detect the very early stages of damage to the outer hair cells in the cochlea. Coupled with the latest hardware, it is a fast, objective, accurate and low cost test that can be used to assess the difference between the theoretical and the actual protection afforded by PPE programmes.

Please send me more information

Applying OAE in practice

OAE has been used as standard practice to evaluate the hearing of babies for many years, but is relatively new in the industrial arena. However, AkzoNobel in the Netherlands, for example, has been using OAE to track changes in the condition of staff hearing to inform risk management procedures and as a motivational tool. OAE is an objective test that does not require special soundproof facilities (a quiet office will do) and the results, (in the form of % damage) are easily understood and tracked. An HSE report on the usefulness of OAE testing in occupational health surveillance (in 2011) concluded, that, even then, it was useful for the early detection of at risk groups and commented on the value that it can bring to preventative risk management of noise health risks.

Noise competency training update

As OAE will become an important element of best practice, we will soon be updating our IOSH competency training courses to reflect this fact. These one-day refresher Master Classes will be run in conjunction with Rob Shepheard, Consultant Audiologist and a leading expert on the subject in the UK. Contact us if you’d like advanced information on the dates and venues.

Would you like to test the technology on your site at no cost?
Rob would like to run some additional field trials of the technology as part of a fully funded project (via Acton Plan on Hearing Loss – NHS). This would involve testing a small number of noise exposed personnel and collating the results – at no cost to the host company. You would get the results and be able to test the approach in advance of its imminent adoption as part of best practice.

Please contact us if you would like to discuss the changes we foresee in best practice and the potential benefits to your company. If you would like to take part in the study, contact us or contact Rob directly at +44-1603-208419.

Please send me more information

Noise recording and analysis workshop

This is one of a number of highly rated, interactive and practical noise related workshops developed for Environmental Health Officers. They are held locally by a host authority, saving on travel, time – and at a fraction of the cost of conventional training. It can even be a profitable exercise…

Noise Workshop Content and Objectives

Make the best use of your equipment and speed-up the processing of recordings
Northampton Borough Council: Thursday 27th October

smartphone noise meterThe ability to record sound files is increasingly common – noise nuisance recorders, sound level meters or smartphones.  This workshop covers the practical techniques that make recording and subsequent analysis much faster and more efficient, including procedures for accurate and reliable calibrated recording using complainant operated noise nuisance or any other type of recorder. It also covers subjective and objective analysis of recordings (particularly on PCs) and the use of frequency analysis related both to BS4142 and to noise source diagnosis.

The workshop is an opportunity to acquire practical techniques, short cuts and “tricks-of-the-trade” that reduce dramatically the time required to solve intractable noise problems. The workshop carries 2 CPD points and includes:-

  • Noise Recording Best Practice
    Sound level meters and noise nuisance recorders – complainant issues – £100 on the web converts any old SLM into a sound recording meter, or use a smartphone…
  • Best Practice in Processing Recordings
    Techniques that speed-up both subjective and objective analysis, from ears to PCs
  • Interpretation and Source Diagnosis
    Is it a fan – or a pump? Does it exist? Low frequency issues…
  • Remote Control of Noise
    Free evaluation of what constitutes BPM with costs typically 80% lower than conventional mitigation
  • Free audio playback analysis software

Contact us to book a place or to run your own workshop locally.

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Noise and HAV risk management – on site simplification

A simple way to cope with mobile plant and tools

A question about a common problem that came up when giving a presentation at a recent IOSH meeting has a really simple answer. What struck me was the enthusiasm for a solution that we developed and been advocating as best practice for years in our training courses. Whilst the talk was on noise and noise control, the approach is equally applicable to Hand-Arm Vibration – in fact, combining the two (where appropriate) saves resources.

Q: “How do you assess noise risks from mobile plant in practice when tools and locations change all the time?”

A: “Put labels on the plant showing the distance within which PPE is mandatory.”PPE hearing protection advice

The very mobility and variations in the tools or mobile plant in factories or on construction sites, at first glance would seem to make it difficult to manage and police likely exposures. For noise, the risks for a “quiet” operator may suddenly escalate when a jack hammer starts up nearby. For HAVS, the degree of risk from a particular tool use may not be obvious (unless you can do the calculation in your head).

Combining Noise and HAV Data

We advocate creating a spreadsheet database of the items of plant which lists noise levels at the ear and also calculates the “safe” working distance within which PPEHAV risk trigger time
is mandatory i.e. the distance at which the noise falls to below 85dB(A). This figure should be calculated for the worst case i.e. when there are reflecting surfaces nearby (which can increase the local noise level by several dB). The same spreadsheet should also include the levels of vibration (where appropriate) and the calculated “safe” working time to reach the Exposure Limit Value (ELV) of 5m^2 (single tool use finger-on-trigger time). Our free template HAV spreadsheet is available via this page.

Practical Policing

Print labels for the plant and tools. To check risk management on site, you don’t need a sound level meter or a HAV exposure calculator, you just look at the stickers. A glance at a tool label not only tells you how risky the noise is (it also informs the operator – very simply and with no noise knowledge required), but also who should be wearing PPE. The HAVS version is a very simple way to inform about relative risk (albeit, for single tool use) and is the basis for questions for operators about how long they have been using the tools.

Not perfect, but very simple and very effective…

We already have a huge database of both noise and HAV data for mobile plant and tools that we use to implement this approach. Instant virtual noise and HAV assessment by email…

I’d like more information or to discuss the practicalities

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Your email:
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Environmental Impact Award for INVC

INVC recognised at the UK Energy Innovation AwardsINVC environmental noise award

This annual event is organised by the Energy Innovation Centre to celebrate the most successful innovations arising from collaborations between SMEs and the energy networks. In our case, we were awarded the “Environmental Impact Award” for our work in collaboration with Echo Barrier to develop innovative new ways to minimise the noise impact of gas pipe replacement work in built-up areas.street work noise screens

High levels of noise from the equipment used (breakers, saws etc) to dig holes and trenches in roads is a perennial problem, both to pedestrians and to local residents who often overlook the work. There are also the practical problems associated with working in confined areas (increased noise due to multiple sound reflections) with mobile plant that has to be moved quickly and easily with a minimum of staff.

The solution was to develop custom versions of the acoustic tent (with wheels) plus additional mobile acoustic screens gas street works screens webmaking use of the advanced Echo Barrier technology. This means that high noise attenuation can be achieved using low weight components (including a patented waterproof acoustic absorbent layer) which aids with the high degree of mobility and practicality required for this type of project. The typical noise reductions from the INVC designed system are 13dB – 18dB in very confined built-up areas, rising to around 20dB – 25dB when used in the open.

The award is recognition, of our ability to blend practical experience (in this case in construction, demolition and infrastructure noise projects) with innovative engineering to generate new best practice in noise control.

Contact us for more information

Fan Noise Control Master Class: Leicester and Slough

Learn how to cut fan noise attenuation project costs by 50% – 110%*

Fans are the most common of all occupational and environmental noise sources (NPL figures suggest that two thirds of complaints about noise from industrial premises are related to fans). However, most typical fan noise control projects still only consider high cost antediluvian palliative techniques that haven’t changed since Victorian times. Conventionally, the only techniques used are:-

  • silencers / attenuators (can reduce efficiency)environmental-noise-industry
  • enclosures (reduced access, heat build-up)
  • lagging (corrosion problems)
  • barriers (very often ineffective)
  • building modifications (seriously expensive)

However, there is a host of alternative techniques that should be considered before falling back on these palliatives. These include:-

The Fan Noise Control Master Class is designed to address this failing. It provides a definitive guide to all the fan noise attenuation options that are available with current technology. Delegates find out how to assess what constitutes “best practice” in assessing and controlling the noise from any type of fan, from take-away kitchen units to massive industrial fans. It also includes practical advice on the best measurement and analysis techniques and on the specification of noise limits. You also gain access to a free advice service to give you a second opinion to avoid potentially expensive mistakes…

“..the best lecturer I have ever had with relevant case studies.” Jon Tofts: PPC officer Environment Agency

Topics covered include:-

  • Fan noise reduction options
    Instant, low cost, retro-fit attenuation techniques for many common fan noise problems; material specifications; installation geometries; conventional smartphone websilencer types; setting fan noise specifications;  review of innovative aerodynamic source control and improved efficiency technology (silencing without attenuators). Many innovative noise control projects can improve system efficiency, making them self-financing
  • Diagnostic techniques – smartphone recording and analysis
    Problems with BS4142; BAT / BPM evaluation techniques; convert old sound level meters to calibrated sound recorders for £100; fan noise analysis – from ears to computers…
  • Remote control of noise – speeds up projects and complaint resolution
    The information needed to get a free evaluation of the fan noise control options and costs by email (smartphone recordings and photos)

Free FrequencyMaster noise analysis software (usually £900)low-frequency-noise-control
All delegates are provided with a free personal copy of our FrequencyMaster Noise Analysis Software. This provides easy to use access to 1/1 – 1/3 octave and tonal noise analyses from recorded data. We use this software ourselves on a daily basis to evaluate and diagnose fan noise problems.
*where increased system efficiency saves power or increases productivity

Contact us for more information or to book a place

How to Recommend Self Financing Noise Control Instead of Ineffective PPE

International Occupational Hygiene Association (IOHA) Conference Paper: 27th April 2015

Peter Wilson: INVC Technical Director

HSE Research – PPE is generally ineffective…

HSE sfi-controlresearch proving that hearing protection is not effective across most industrial applications (our summary of the PPE research is available here) provides a gold plated opportunity for the legal profession to drive a coach and horses through hearing damage claim defences based on PPE use. Consequently, as real-world PPE performance is so compromised, the best way to guarantee low levels of risk at low cost is to reduce the noise levels. This workshop paper demonstrates how occupational health and other professionals can add value to noise risk assessments by linking to best practice in engineering noise control to reduce the risks of hearing damage dramatically.

How to Add Quiet to Noise Assessments

Whilst noise control is not always practical, occupational health specialists are generally unaware of the technology that is now available. This can not only reduce hearing damage risk at a fraction of the cost of conventional measures, but, oxymoronically, it is self-financing surprisingly often as it reduces the requirement for PPE and can actually improve plant operation and productivity.

The paper provides a detailed guide as to how to modify the noise risk assessment process so that professionals without engineering expertise can generate the information required for a preliminary evaluation of the noise control options, costs and benefits. It also provides supporting material in the form of a host of multimedia case studies.

The Conference Paper Presentation

peter presenting ioha 2015 b webThe International Occupational Hygiene Association (IOHA) 2015 Conference was organised by the British Occupational Hygiene Society (BOHS). See for more information. The presentation? “I attended your noise control workshop and had a great time, I found it both engaging and thought provoking.”  Trevor Laurent: Air Surveys Ltd.

We also have a White Paper version of this presentation with more detailed content. I’d like a copy of the IOHA White Paper please >