Rotating abrasive products are subject to high mechanical stresses during the operation. Peripheral speeds of 80 m/s have today become the standard on hand-held machines (e. g angle grinders). But there are also numerous applications where cut-off wheels run at a speed of 100 m/s, equivalent to 225 mph. It is easy to understand that even in case of an experienced user considerable forces are exerted on the welded segments. How much higher will the stresses be if the abrasive is used in a way for which it was not designed? Misuse is a major cause for product breakage, combined with a substantial risk of injury.
Unsafe abrasive products – a danger to life and limb
The European Safety Standards specify the safety factors that must be designed into the abrasive products. Possible misuse is also taken into account.
For example the EN 12413 Safety Requirements for Bonded Abrasives stipulates that cut-off wheels for use on hand-held machines running at maximum operating speed must have a safety factor against breakage by centrifugal forces of S = 3.5. If the abrasive is constructed for 80 m/s, it must have a bursting speed of at least 1.87 times the operating speed (burst speed factor = √S).
With an oSa® labeled abrasive you can be assured that the manufacturer has thoroughly tested his products in accordance with the requirements of the standards before the authorisation is granted for serial production. Moreover, oSa-members have to carry out regular on-going destructive tests.
As a user of abrasives you should therefore demand abrasives which bear the oSa®-trademark. It provides an indication of a safe product.
Accidents with abrasives unfortunately occur each day. In the professional sector, accidents are recorded by insurance companies. The respective statistics are confidential. We as oSa know in Germany alone, about 6.000 reportable accidents occur per year, some even fatal. This is where those using abrasive products need to be properly trained. How much higher is the risk to untrained DIY enthusiasts, who snap up a bargain and put their health at risk and sometimes even their lives? Here an example from oSa practice:
In the autumn of 2003 a woman came to the offices of the oSa and asked for help. Her brother-in-law had bought, segmented and sintered a diamond saw wheel with a diameter of 230 mm from a renowned DIY store. A quite normal, everyday product. However, on the receipt only the term "tool" was printed, and no mention is made of a diamond cutter. This very general designation later proved to be fatal.
At home the DIY enthusiast fitted the wheel onto the machine. He switched it on and a split second later lost an eye. Four segments were only loosely attached and not sintered onto the blade.
This incident already occurred in October 2000. This was three years before his sister-in-law asked the oSa for help. Three years in which it was not possible to find out who imported or sold this dangerous product. An old test number on the label points to a Chinese manufacturer, but the importer remains untraceable. With reference to the receipt the store declines any responsibility. No-one can be held responsible for this serious accident. The injured man is left out in the cold. To help the woman a survey was started among oSa members. Perhaps someone had bought some of the diamond saws from this particular store to check their safety. Competitors sometimes do this, and this is an element of the mutual monitoring practised within the oSa. However, in this case it didn't prove to be of any help. With a product of an oSa member this would not have happened this way.Although no-one can guarantee one hundred percent safety in technical applicaions, the "oSa" system minimises the risk for users, as manufacturers are fully committed to making safe products. This is verified onsite by oSa using independent inspectors, without prior notification if this should be necessary. A cutting wheel marked with the oSa® label can be traced back to the manufacturer and also to the time of its production. We guarantee this! As a result anyone suffering injury knows where damages can be applied for.
The trademark oSa® – The sign of safety
Behind the oSa®-trademark stands a stringent system of admission and monitoring for all members of the organisation in order to determine that the risk of injury for the user remains as low as possible. Mandatory factory inspections by independent inspectors and the operation of a certified quality management system are mandatory requirements for membership. Independent destructive testing must be carried out where requested by the inspector. Each member is obliged to monitor the whole production process and carry out ongoing production controls according to the EN-standards. Moreover, products manufactured by oSa-members must always bear a proven traceability code.
Do not take any unnecessary risks, choose the right safety sign. The oSa®-trademark on abrasives offers you a maximum in safety when grinding:
- Maximum user safety
- Minimisation of the accident risk; protection of life and limb
- Clear orientation and safety in your purchasing decision
Correct marking of abrasives
There are numerous tools that are simple to use and have neither markings nor are supplied with safety instructions. Among these are hammers and screwdrivers.The situation is quite different for abrasive products. A wrongly selected abrasive or its improper use carries a high risk of injury.
The range of sizes, shapes and specifications therefore requires clear rules of marking. These are stipulated in the European Safety Standards for abrasives. Unfortunately, many products do not fulfill these requirements and thus pose a high risk of safety. The oSa’s clear message is: “Avoid using products that are insufficiently marked or not marked at all.”