IOSH magazine recently ran a webinar on the complex health risk of Hand-Arm Vibration Syndrome (HAVS). Chris Steel, specialist inspector (noise and vibration) at the Health and Safety Executive (HSE), and Theo Simon, a global application engineer specialist in abrasives at 3M, answer your questions with the goal of simplifying its complexities and outlining strategies to help minimise and control vibration exposure in metalworking processes.
Q. DOES THE HAVS CALCULATOR PRESCRIBED EMISSION VALUES TAKE ACCOUNT OF UNCERTAINTY (K)?
You don’t need to add a K-value to the magnitudes given in the HSE calculator. K values are used to put a value on the uncertainty associated with laboratory emission tests. The HSE values, given in the calculator drop-down menus, have been calculated statistically from a wide range of measurements and already include a margin for uncertainty”.
Q. DOES USING A HAMMER IN A METAL FABRICATION WORKSHOP FALL UNDER THE SCOPE OF HAVS?
Hand-arm vibration is associated with powered hand tools and not with hand-held manual tools. The HSE would not expect the use of manual hammers in metal fabrication or any other work, to be included in a hand-arm vibration exposure assessment. However, you may still need to assess the use of hammers as part of your other risk assessment responsibilities, for example if there is a repetitive strain injury risk.
Q. SOME OF OUR EMPLOYEES HAVE THEIR OWN TOOLS AS THEY HAVE A TRADE. HOW MIGHT THAT WORK IN TERMS OF VIBRATION LEVEL CALCULATION ETC?
You would have to first show there is no reasonably practicable way you can supply power tools yourself. Also, all the duties regarding the provision of tools expected under the other health and safety regulations still apply (e.g. PUWER, CNWR etc). If you must let workers, use their own power tools, use the vibration magnitude values given in the HSE calculator or in the guidance document (L140). Duty holders who allow their employees to supply their own power tools, because there is no reasonably practicable alternative, have used the following methods to help them control exposure:
- Provide employees with a list of power-tools accepted by you as being vibration efficient.
- Introduce a permit to work system for power-tools you know to be high vibration.
- Supply a stock of power-tools for jobs or tasks you know to be high vibration.
Q. HOW EFFECTIVE ARE ANTI-VIBRATION HAND GLOVES WHEN WE TALK ABOUT USING THEM FOR GRINDING POWER TOOLS?
The HSE does not advocate the use of anti-vibration gloves. If you want to use anti-vibration gloves to control exposure you would have to test each combination of glove, operator, tool, and process to demonstrate that a reduction was achieved. If you want to find out more, look at Appendix 4 of the HSE guidance document for hand-arm vibration (L140). HSE has found that the use of anti-vibration gloves can reduce dexterity and increase grip force for the wearer.
HSE does advocate the use of normal work gloves to keep workers warm.
Q. ON THE NEW VERSION OF THE EXPOSURE CALCULATOR THE HSE HAS ADDED A DROP-DOWN BOX WITH TOOL TYPES. IS THERE AN ISSUE WITH USING THE OLDER VERSION WHERE YOU ARE FREE TO INPUT YOUR TOOL AND VIBRATION MAGNITUDE (AS DEFINED BY MANUFACTURER OR ANNUAL MONITORING BY AN EXTERNAL COMPANY)?
There is no issue with using an older version of the hand-arm vibration calculator. The only adjustment made to the new calculator is the introduction of the drop-down menu and the removal of some macros, to make it easier to use on a mobile device. It is still possible to put your own data into the new calculator.
Q. CAN WE REALLY RELY ON VIBRATION DATA FROM THE MANUFACTURER WHEN THEY DON’T OUTLINE HOW THEY MEASURE VIBRATION LEVELS? ARE THEY DONE IN A CONTROLLED LAB ENVIRONMENT OR IN ACTUAL USE IN THE WORK ENVIRONMENT?
The manufacturers of power tools test their tools to agreed standards often these are carried out by third parties and the manufacturer will declare the standard tested against. For example, declared vibration levels in accordance with EN12096; measurements carried out in accordance with standard EN ISO 8662-8: 1997. The values are from laboratory testing in conformity with stated codes and standards and are not sufficient risk evaluation. Best practice states you should carry out your own tests in the actual work environment for your risk assessment. If this is not possible an assessment can be made using available data on the HSE website.
Q. DO FIBRE DISCS PRESENT OTHER HAZARDS THAT NEED ENHANCED EXTRACTION, RPE OR NOISE PROTECTION?
Fibre discs are much lighter and generate a much lower vibration magnitude. They wear less than other forms of abrasive and so the abrasive itself produces less airborne particles. Furthermore, they are ‘softer’ so will be the quietest form of abrasive. In short fibre discs reduce many risks improving the working environment. PPE would still be required.
Q. WHAT IS COST DIFFERENCE WHEN COMPARING FIBRE DISCS AND CERAMIC DISCS?
Fibre discs will be cheaper and often much cheaper than their equivalent bonded ceramic wheel. Purchasing price aside the value these new technologies bring for example Cubitron™ 3, will significantly outweigh the cost differential in terms of total material removal, cut rate and long-term hazard mitigation. Having a huge impact on productivity and safety.
Q. WHAT IS THE PERMISSIBLE EXPOSURE LIMIT FOR THE WORKER IN OPERATING THE GRINDING TOOLS AND HOW IT IS RELATED TO ANSI?
The European Directive 2002/44/EC requests that employers carry out a risk assessment of the vibration exposure of their employees with the aim of reducing the health risks. The European Union passed this into law in 2005. The Exposure Limit Value (ELV) for HAV is 5 m/s2 A(8), and the Exposure Action Value EAV is 2.5 m/s2 A(8). Employers must take action to reduce exposure when it reaches the EAV. In 2006 ANSI revised its 1986 HAV exposure standard S3.34 with a new HAV standard S2.70-2006. ANSI use many of the same values as EN.
Q. ARE THE FIBRE DISCS COMPATIBLE WITH COMMERCIALLY AVAILABLE GRINDING TOOLS?
Yes, they are fully compatible with angle grinders, and it is advised you look for those abrasives bearing the declaration EN13743-2017 safety requirements for coated abrasive products and that are marked Organisation for the safety of abrasives (oSa). You will need a suitable good quality back-up pad and a retaining nut to run them in place of bonded wheel or flap discs.
