Antistatic and ESD footwear are both capable of grounding electric charge. This means that they can protect electrical devices by diverting the electric charge in the ground and avoiding generating static electricity, a charge or a spark. Electrostatically dissipative footwear is used in industries where static electricity can cause a fire, explosion or damage sensitive equipment.
ESD VS ANTISTATIC FOOTWEAR
The technical terms ESD and antistatics can cause a lot of confusion and not only when talking about footwear. Although one includes the other the reverse is not true. Both refer to contact resistance but they are defined as follows:
Antistatic footwear has low electrical resistance between 0.1 and 1 000 MΩ. Using them will protect against generating static electricity in the body by diverting it to the ground and avoiding creating sudden electrical current between electrical devices used for work.
In comparison to antistatic footwear, ESD footwear has an even lower electrical resistance between 0.1 and 100 MΩ. Using them will protect against generating static electricity in the body by diverting it to the ground in a very safe and controlled manner. ESD footwear guarantees that no sudden electrical current is created between electrical devices used for work. 
ESD footwear used in different industries
ESD and antistatic footwear are used in many different fields of industry to protect sensitive equipment and their components from the effects of electrical charges. Footwear is used for example in the production of industrial, computer, telecommunication, even manufacturing spacecraft as well as used by medical workers and electrical engineers.
ESD helps avoid multiple kinds of harmful effects in the working environment. Uncontrolled discharge of static electricity can cause gas, fuel vapor or coal dust explosions. For people working in the mentioned fields we recommend the following ESD footwear:
ESD TESTING
ESD properties are tested in laboratory conditions. Two different methods of testing are used:
Standard EN 61340-5-1 measures resistance with the person-footwear-surface method. A person wearing the footwear undergoing tests will stand on a counter electrode and will place their finger on a metal plate serving as the second electrode. The electrical resistance between the metal plate and counter electrode is then measured. If the resistance is smaller than 35MΩ then the footwear has successfully passed the test and is ESD compliant as described in the EN 61340-5-1 standard.
Standard EN 61340-4-3 tests footwear in laboratory conditions. Footwear is kept in a chamber with a set relative air humidity and temperature (see graph). During testing the footwear is placed on a stainless steel plate which acts as the first electrode and the second electrode is placed on the inner sole of the protective footwear. Then a 12.5 kg (+/- 2.5 kg) weight is placed on the footwear. A special device will measure the resistance between the two electrodes. The test will be carried out in three different so-called climate classes. To be ESD certified for a specific climate class the resistance must be less than 100MΩ.
WHAT CAN AFFECT THE RESULTS OF AN ESD TEST?
Electrical resistance can be affected by a number of factors, for example temperature, humidity and dirt. The electrical resistance is higher at lower temperatures. Footwear taken from a trunk of a car in winter might not pass the control test and the same can happen with dirty footwear. The test results can be affected by time weared. While wearing the footwear it will become humid which in turn will decrease electrical resistance.
Hopefully we were able to bring some clarity to the subject of electrically grounding footwear. Nevertheless, since we’re dealing with highly specific footwear here, we recommend carefully checking out the product features. If you have additional questions you can always visit our store or contact us via phone or email and we will gladly help you make the best decision. 