Posted on: May 9, 2018
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 (BS ISO 5349). No they can’t. Thank you for listening…
I 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:-
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 statistical analysis carried out in isolation. Moreover, the problems associated with the laws of physics and human nature would still remain.
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.
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 >