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- Jonsson, Per, et al.
(författare)
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Anti-vibration gloves - in theory and practice
- 2016
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Ingår i: Arbete och hälsa. - 0346-7821. ; 49:5, s. 1-31
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Tidskriftsartikel (refereegranskat)abstract
- Are anti-vibration gloves the solution to the problem of hand-arm vibration?Vibrations from hand-held machinery are a major problem in the Swedish labour force. In 2009, 14% of men and 3% of women of employed in Sweden reported exposure to hand-arm vibration at least a quarter of their working time according to the Swedish Work Environment Authority (Arbetsmiljöverket 2010). It is tempting to imagine a protective glove that could reduce or even eliminate this problem.Research can validate the quality of labour protection gear available on the market and then make recommendations and suggestions for improvements. This report from the Department of Occupational and Environmental Medicine in Lund and Gothenburg describes how anti-vibration gloves (AVGs) are experienced, and how they work and affect the exposure from hand-held machines.BackgroundToday, gloves labelled “anti-vibration” (AV) are advertised as “reducing vibration by 40%”. To be marketed as “AVG”, a glove must be CE-certified and thereby comply with the requirements of International Organization for Standardization standard ISO 10819. The requirements apply only to the suppression of vibration in the palm of the hand, while in many work situations, vibration is transmitted to the fingers. However, in the ISO standard it is pointed out that AVGs provide inadequate damping of vibrations of low frequencies. Such vibrations are common in many hand-held tools and machines in industry and crafts, such as different types of grinders. Some regular protective gloves can even provide amplification of low frequencies but cannot be approved in accordance with this standard.Generally, all protective equipment disrupts work to a greater or lesser degree. Working without a helmet, protective mask, hearing protection and protective clothing is preferred in most situations. Furthermore, the availability of gloves which are supposedly AV may give rise to an ethical dilemma: the user may handle the machines more intensely and for a longer time in the belief that the hand is protected from vibration damage. But are those AV claims true and how do these gloves perform in practice? Is the experience regarding the gloves that they dampen the vibrations? To what extent do the gloves disturb the worker and interfere with the work? How much damping can be expected when using low-speed and high-speed grinders, respectively? These issues will be discussed in the following report. ImplementationNine subjects, whose work task was to deburr and grind aircraft engine components, were given the opportunity to test a specific AVG for 3 months. They all worked with a variety of rotating air-powered and vibrating machines. All had extensive experience in this work. Usage times for the individual machines varied between ½ hour and 4 hours/day. The total usage times sometimes exceeded 4 hours/day. The most commonly used rotating machines rotate at high speeds, 100 000 revolutions per minute (rpm), but other machines with low speed, 500 rpm, were also used.Only one model of AVG was tested. The back of the glove was made of porous polyester and the palm of a denser, elastic synthetic material. Approximately 7 mm thick, foam-like materials were built into the palm, thumb and fingers grip side of the glove. The glove was CE-marked and was claimed to comply with standard ISO 10819:1996.The test subjects tried the glove for 3 months. After this period they answered a questionnaire containing 14 questions including questions on hand temperature, grip, dexterity and self-reported vibration damping.To assess the usefulness of the AVG, the vibration level and vibration frequency spectrum were measured on the machines used by the subjects. During the measurements a skilled operator performed a typical deburring task. Results and DiscussionThe comfort in terms of hand temperature was rated mediocre. Grip was rated good while finger sensitivity was rated low. At a so-called “pencil grip”, required for handling small machinery, the gloves were uncomfortable; however, they worked well with larger machines.The majority, eight of the nine individuals, responded that the glove offered good vibration damping. As the hand’s ability to perceive vibrations varies with the frequency of vibration the possibility to self-assess whether a glove is vibration-damping or not largely depends on how well the person can perceive the frequency of the machine in question. With a high-revving machine of, say, 50 000 rpm, the vibration tactility is fairly low, and so is therefore the ability to self-assess the glove’s damping properties. In addition, the vibratory sense in the hand does not reflect the hand-arm weighted vibration level which needs to be measured according to the Swedish Work Environment Authority’s regulations (AFS 2005:15). With regard to the vibrations, large differences between the various machines were measured; hand-arm weighted levels according to the regulations were between 0.8 and 8.3 m/s2. High-revving, ≥55 000 rpm, machines gave the lowest weighted vibration levels. A machine’s rotation speed was found to cause the dominant vibration frequency; however, high frequencies from high-speed machines do not increase the hand-arm weighted exposure levels.ConclusionThe vibrations from many of the machines in this study, which are used over long periods for deburring, will be damped to some extent. But it is not obvious that this damping neither can be experienced, nor give reduced daily vibration exposure in accordance with the regulations, or reduce the risk of vibration injury in the hands. So-called “AVGs” generally give insufficient reduction in vibration exposure. This is demonstrated already by the standard for CE certification of AVGs. For a glove to protect against normal, low-frequency vibrations, it would have to be too heavy and thick to be practical. Despite the limitations of the protection that the CE-marked protective gloves offer against vibrations, we still recommend the use of gloves because:1) High-frequency vibrations, which are presumed to be harmful, will be damped.2) The gloves will ensure that vibrations will not be amplified.3) Gloves keep the hands warm, which is believed to reduce vibration-related disorders.
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| 3. |
- Kuklane, Kalev, et al.
(författare)
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Systematisk kunskapsöversikt 10. Occupational Heat Stress
- 2017
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Ingår i: Arbete och hälsa. - 0346-7821. ; 51:7
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Forskningsöversikt (refereegranskat)abstract
- The present review covers a wide scope of occupational heat stress related issues. The problematics related to climate change have placed heat exposure on the agenda. As a result, the research on heat effects has increased in recent years and a considerable amount of new material has become available. The literature includes general and specific reviews that focus on various heat-related aspects in detail. The aim of the current review is to compile the most relevant information, both past and present, that primarily covers knowledge on how one can carry out simple evaluations of heat stress in occupational settings. Very specialised information is described in full in the specific papers. The present review covers basic information on exposure to heat, descriptions of climatic factors and how they are measured. The review takes up human thermoregulation, heat exchange with the environment, and responses to heat. Several common hot environment evaluation methods along with heat assessment and management strategies are discussed. Sample industries are described.
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