With over 30 years of experience in the field of noise and vibration, and as a former employee of the HSE working in their research facilities, Sue Hewitt gives her expert opinion on the use of anti-vibration gloves.
In recent months we have no doubt all become very familiar with the term PPE (Personal Protective Equipment). For hazardous agents, PPE is the last line of defence, to be resorted to only when all other efforts to control the hazard have resulted in there still being a level of risk that needs to be managed.
Anti-vibration gloves can be legitimately sold in Great Britain as PPE for protection against exposure to hand arm vibration. The unsuspecting purchaser or potential user could therefore be forgiven for thinking that if they have purchased a glove described as ‘anti-vibration’ and bearing a CE mark, there is a guarantee that the glove will provide effective protection against vibration. Yet HSE, in its guidance to the Control of Vibration at Work Regulations 2005, advises employers that anti-vibration gloves cannot be relied upon to provide protection from vibration. So, what should employers think? The following paragraphs outline some of the reasons why, in most situations, anti-vibration gloves are not effective and should not be relied upon to provide any benefit to the wearer; in fact their use may cause more harm than good.
In civil claims for vibration-related personal injury (Hand Arm Vibration Syndrome), it is common, in my experience, for claimants to allege that the defendant employer was negligent in that it did not provide antivibration gloves. Given HSE guidance however, an employer should not be criticised for not supplying gloves as PPE against vibration. Some defendants cite gloves as a control measure and this might suggest other problems. For example, an employer relying on gloves and believing the problem of vibration has been solved may well neglect to look at those control measures that could and should be employed to reduce vibration exposure and risk.
In the current standard test for an anti-vibration glove (ISO 10819:2013+A1:2019) the vibration transmitted by the glove to the wearer is tested in compression at the palm of the hand. The amount of vibration transmitted through the glove in a single direction is measured and the results are used to calculate the vibration transmission in two ranges of frequencies, both of which must be sufficiently low for the glove to bear the CE mark and be sold as an anti-vibration glove.
Without going into technical details regarding the test, the approach for assessing an anti-vibration glove raises a number of simpler wider issues. The first is that for an operator using a power tool, vibration is likely to be transmitted to all areas of the hand in contact with the vibrating surface, not just the palm. Research has shown not only that the gloved hand responds differently to vibration at the fingers compared with at the palm, but also that, rather than reducing vibration, a glove often amplifies vibration at the fingertips[1],[2]. In some circumstances, vibration may also be amplified at some frequencies at the palm of the hand. Furthermore, the transmission to, and dynamic response of, the hand arm system is different if the glove material is tested in shear, i.e. with the vibration running parallel to the glove surface through a gripped hand. But the shear direction is not considered at all in the test, even though the standard method for assessment of vibration exposure (BS EN ISO 5349-1:2001) considers the vibration in all directions.
When a glove is used, factors such as the physical characteristics of the wearer, their different postures and varying grip and push forces will affect how much vibration is transmitted through the glove material. The transmission can be very different for different types of power tool, depending on factors such as the speed of rotation of rotary tools such as grinders, or the number of impacts per second for impulsive tools such as demolition hammers. These factors affect the main frequencies of the vibration coming from the tool and they can change depending on how the tool is used. In general, an anti-vibration glove is more likely to reduce transmission of higher frequencies than lower frequencies. The many variables affecting how a glove responds mean that it is practically impossible to predict how a glove will perform, but they also mean that there is ample opportunity for the conditions under which the glove amplifies, rather than reduces the vibration, to be met.
To improve a glove’s ability to reduce transmission of the lower frequencies[3] to the palm of the hand, the thickness and/or softness of the glove material needs to be increased. However, increasing the thickness of the glove may lead to additional problems for the wearer. For example, a thicker glove may affect manual dexterity and this may have safety implications. A thicker glove may also mean that the wearer has to exert more force to be able to carry out the usual work and this may in turn lead to increased fatigue. Any increase in the thickness or softness of the glove material would, however, be likely to have a negative effect in terms of transmission to the fingers[4].
It is easy to criticise the current standard test for an anti-vibration glove. However, it is important to acknowledge the difficulty associated with development of such a test. The techniques that must be applied to make an adequate assessment of glove performance are complicated and costly, and the benefits of specifying a more thorough test are largely outweighed by the lack of any discernible benefits of wearing an anti-vibration glove. Consequently, further development or improvement of the test of glove transmissibility may be unlikely. The most recent version of the standard test for an antivibration glove contains normative Annex B, added in 2019, which includes requirements to make it clear that gloves are, for the most part, unlikely to provide any real protection against vibration. Paragraph B.2 b) requires that the information supplied by the manufacturer of the glove shall include:
“A warning that the use of a protective glove does not imply a sufficient protection against health risks due to vibration or other factors. In addition, the measured vibration attenuation results cannot be used to calculate daily vibration exposure values within a risk assessment, e.g. according to ISO 5349‑1”.
This requirement makes it clear that the glove should not be relied upon to protect the wearer and that data from the test cannot be used to estimate a ‘protected level’ in the way that for example data for hearing protectors can be used. In terms of legal requirements, the Control of Vibration at Work Regulations 2005 do not mention anti-vibration gloves. The only mention of PPE is a reference to the provision of clothing to protect against cold and damp. The PPE at Work Regulations 1992, however, require that the employer assesses and selects PPE according to its suitability. So, while the supply side law allows the marketing and sale of anti-vibration gloves, the workplace law requires that their suitability is assessed and, at present, any reasonable assessment would not only be difficult to achieve, but could only conclude that they were not suitable.
As a result of the multitude of issues surrounding their assessment and performance, some of which are described above, and also because there is a lack of scientific evidence to show that anti-vibration gloves can significantly reduce the risk of vibration exposure, the simplest advice, as given by HSE, is that gloves cannot be relied upon to provide any benefit, and that they may in some situations, have adverse effects. Gloves can, of course, be used to keep the wearer’s hands warm and dry, which is beneficial for maintaining good circulation, but anti-vibration gloves may not be the most suitable gloves for this purpose. Other means of controlling exposure to vibration, such as eliminating the vibration altogether using alternative work techniques, buying and using low-vibration machinery, carrying out routine preventative maintenance and controlling exposure durations are far more likely to reduce vibration exposures and should all be considered and or implemented first.
For more technical details regarding the issues raised in this article, please read my commentary from 2015 [5], co-authored with experts from NIOSH and published online.
[1] Resali & Griffin, 2014. The transmission of vibration through gloves to the hand and to the fingers: Effects of material Dynamic stiffness. Applied Mechanics and Materials Vol. 564 (2014) pp 149-154
[2] Welcome DE et al. 2014 The effects of vibration-reducing gloves on finger vibration. Int J Ind Ergon; 44: 45–59.
[3] Lower frequencies contribute the most to the overall vibration magnitude assessed according to BS EN ISO 5349:2001 although there is some uncertainty about the validity of the frequency weighting which is applied.
[4] Resali & Griffin, 2015. Transmission of vibration through gloves: effects of material thickness. Ergonomics. http://dx.doi.org/10.1080/00140139.2015.1102334 accessed 13/05/2020.
[5] Hewitt et al, 2015. Antivibration gloves? (https://academic.oup.com/annweh/article/59/2/127/2740610 accessed 13/05/2020).
