Vibration exposure from handheld and hand-operated tools is the cause of hand-arm vibration injuries (damage to nerves, blood vessels, and joints in the hand and arm), also called HAVS. These injuries manifest as, among other things, sensory disturbances and reduced blood circulation in the fingers (“white fingers”) and muscle/joint pain in the hands.
According to the Factbook on Working Environments and Health 2021, approximately 136,000 Norwegian employees are exposed to hand-arm vibration for more than 1/4 of their working time. The resulting health effects contributes significantly to departure from occupations involving such exposure, as well as permanent reduction in hand function and disability for those affected.
STAMI has investigated associations between occupational exposure to vibrations and potential effects on neurosensory function in three integrated projects.
HAVS in road maintenance workers
First, we investigated the association between sensory outcomes and reduced hand function in the hands of specialized road workers following occupational exposure to vibrations from handheld tools. Methodological challenges related to exposure assessments were also highlighted by comparing two different measurement approaches.
A comprehensive exposure assessment of hand-arm vibrations was conducted during rock slope stabilisation and guardrail installation. Subsequently, clinical indicators of health effects present in the early stages of Hand-Arm Vibration Syndrome (HAVS) development were measured repeatedly over a 5-year period among rock securing and guardrail installation workers in a construction company. We used vibrometry, strength tests, tremor tests, and nerve conduction velocity tests to identify early signs of vibration-induced injury in the hands and arms of these occupational groups.
This was done in collaboration between Mesta Occupational Health Services and Oslo University Hospital (OUS), and partially funded by the Fund for Regional Safety Delegates in the construction industry.
Modification with new technology
The next objective was to acquire knowledge about the magnitude of vibration exposure when using existing tools before and after the modification/production of machines with new vibration damping technology.
The measurement technology employed in this project provided a better understanding of the exposure compared to previously used risk assessment tools, both in terms of prevention and knowledge development. This enabled the design more precise preventive measures against vibration-related injuries.
Identifying reduced levels of hand-arm vibration exposure serves as a valuable metric for the preventive potential to reduce the occurrence of hand-arm vibration injuries and is presumed to impact the incidence of such injuries over time by informing builders and contractors about the possibility of using tools with lower vibration levels and creating greater awareness among occupational groups using such tools.
IA in BNL (Inclusive Workplace in the Norwegian Construction Industry) contributed financially to this part of the project, which also had a reference group where participating companies (Mesta, Skanska, Peab, Caverion, Vestfold fjellboring, Gjerden Fjellsikring, and Visinor) were represented.
Substantial potential for prevention
In a follow-up study, we included several additional tool categories and activities compared to the preceding intervention project. We incorporated testing and impact measurement of exposure-reducing measures for both larger and smaller handheld vibrating tools, some of which also generate a significant amount of dust.
There is substantial potential for prevention associated with the use of tools with reduced vibration transmissions. The implementation of technical solutions to decrease vibration in the tool and transmission via control handles, among other things, provides the opportunity to perform tasks with vibrating tools, exposing workers to reduced or eliminated risk of these injuries, which are only minimally reversible.
Outcomes
Identification of exposure levels and association with neurological HAVS and nerve compression in hand and elbow. Identification and evaluation of engineering activities to reduce exposure to hand-arm vibration from hand-held and hand-steered vibrating tools. One PhD degree including three scientific papers. Additionally, two papers out of three in another PhD degree. A report on the exposure reduction effects of means to reduce transmission from hand-held vibrating tools.