More and more companies trust in protection by ESD safety shoes. ESD is the only protecting feature of safety shoes which is not only designed for the safety of the wearer but also for the protection of your products.
What does ESD (electrostatic discharge) mean?
Each of us “gets a jolt“ from time to time when touching a doorknob, other people etc. The reason is that you were charged electrostatically, for example while walking on a carpet. But sometimes the “friction” of your body at the air is sufficient. If you come close to an uncharged or differently charged object, a spontaneous discharge takes place, comparable to a mini-lightning. Human beings feel those discharges starting at a voltage of about 2,000V. Each of us causes small discharges every day, but they are not perceptible because most of them are considerably below 2,000V.
But if you are in touch with an electronic element, it might even be damaged due to the non-perceptible discharges. Besides this damage, the of this element could decrease, and as a consequence, your claim rate might raise.
But also in areas with an increased danger of fire or explosion, electrostatic discharges have to be avoided. They could fan flames or spark explosive gases.
There are various possibilities to avoid uncontrolled electrostatic discharges. Probably the most practical and flexible one is to wear ESD shoes on a grounded floor. The target is to be charged with a voltage at a maximum of 100 volts (currently recommended limit). Of course, your clothing and your entire workplace should have ESD properties, too.
What do Baak ESD safety shoes offer?
During the last years, Baak has become an ESD specialist. We are in constant information exchange with producers of ESD (measurement) products, certification institutes and acknowledged ESD experts. We have reached our goal to be an ESD specialist due to hard detail work. Besides the regular safety properties, all Baak safety shoes have been optimized in detail regarding their ESD ability, e.g. by electrostatic boards and insocks. That is why the recommended discharge resistance is certainly always fulfilled, even if there is only a partial contact of the sole to the grounded floor.
Recommended discharge resistance of the unit human/shoe/floor (ESD):
100 kOhm – 35 MOhm = 105 – 3,5 x 107 Ohm
|103 Ohm = 0,001 MOhm = 1 kOhm|
|104 Ohm = 0,01 MOhm = 10 kOhm|
|105 Ohm = 0,1 MOhm = 100 kOhm|
|106 Ohm = 1 MOhm = 1.000 kOhm|
|107 Ohm = 10 MOhm|
|108 Ohm = 100 MOhm|
|109 Ohm = 1.000 MOhm = 1 GOhm|
With safety shoes from Baak, you don´t have to waste any more time thinking about ESD. Better keep an eye on other subjects, such as:
- Health keeping
- Outstanding full-surface damping
- Option for the use of orthopedic in socks
ESD and standards
Laboratory test according to DIN 61340 – 4 – 3
There is only one parameter in the norm which must be complied with. The discharge resistance of a shoe is determined using pebble beds; the resistance of one shoe must be between 100 KOhm and 100 MOhm.
Workplace test according to DIN 61340 – 5 – 1
But in practice it is the resistance of the unit human/shoe/floor which is relevant. This can be evaluated by different methods of measurement (single/parallel measurement), set to different, individual limits.
In the workplace test according to the standard, the recommended discharge resistance of the unit human/shoe/floor should not exceed 35 MOhm.
We would like to optimize our know-how for you, therefore we depend on your help. The more information we get from companies about their measuring methods and limit values, the better we can adapt our developments to the requirements in the practical use. If you want to support us, we would be delighted if you forward this questionnaire to us:
Baak GmbH & Co. KG
Hubertusstraße 3 · 47638 Straelen
Fax +49 (0) 2834 94241-69
Thank you very much.
Dependence on the climate
The electrostatic charge and discharge depend strongly on the air humidity and thus on the climate at the location. The lower the air humidity,the lower the discharge. At the same time, the charge increases strongly at a low level of air humidity.
The laboratory test (DIN 61340 – 4 – 3) is classified into 3 climate categories:
- Climate class 3 = 50% air humidity
- Climate class 2 = 25% air humidity
- Climate class 1 = 12% air humidity
In all 3 classes, the discharge resistance levels must be the same; the classes only differ in the air humidity.
|Produced charge at air humidity|
|Source||10–20 %||65–90 %|
|Walking on a carpet||35,000 volts||1,500 volts|
|Walking on linoleum||12,000 volts||250 volts|
|Work at a work bench||6,000 volts||100 volts|
|Paper in plastic bag||7,000 volts||600 volts|
|Kunststoffbeutel||20,000 volts||1,00 volts|
|Upholstered chair||18,000 volts||1,500 volts|
Advice for ESD safety shoes
- Put on your ESD safety shoes at least 15 minutes before your work starts. Thus, an optimum contact between the foot and the safety shoe can be established due to the natural foot humidity – so you will get the best protection from the first minute of your work.
- Keep the soles clean. Dirt can increase the discharge resistance.
- Only use original insocks which have been certified together with your safety shoe. Further information