Protecting people against electrical discharge: Anti-static or ESD?

The build-up of static energy is a common natural phenomenon. Discharge of this energy should be prevented at all costs. With protective clothing, workers in (petro)chemical industries are protected against statical build-up. However, anti-static clothing is often wrongfully confused with the term ElectroStatic Discharge (ESD). Although both terms associate with statical energy, their meaning is different. In this blog, we clear up the confusion and help you recognise the difference between anti-stat and ESD.

What is anti-stat?

When it comes to protective clothing, anti-stat is a term indicating that a fibre is not able to eliminate or control static-electricity. Static charging is caused by friction (between the clothing and another surface, like your body, other clothing or a chair) or occurs when two surfaces separate. In other words, friction can occur almost anywhere, and the same goes for static charging.

It is not the charging, but the potential discharge that is dangerous. Discharges often create sparks, which are life-threatening in explosion-prone areas:

Even the smallest spark could have disastrous consequences with static charging. That is why anti-stat clothing is crucial in many work environments. Anti-static protective clothing complies with EN 1149-5, which makes sure that electric charge will be neutralised rapidly and doesn’t pile up. 

While the terms are often mixed up, ESD is something very different.

What is ESD?

ESD, or ElectroStatic Discharge, is the discharge between charged objects, due to direct contact or the transfer of static energy. It occurs when high electrostatic power develops between two objects that are close to each other. When this happens to a machine with small, sensitive components, this can damage the equipment.

ESD and its corresponding standard that prevents electrostatic discharge - IEC 61340 - are very important for industries where people work with very sensitive equipment, for example microchips.

Just like anti-stat garments, ESD-proof material has to be able to scatter charges, opposing the build-up of static energy. However, the difference is that ESD is about the protection of products, equipment or the production process. Therefore, an ESD-product is not being classified as PPE(personal protective equipment).

Different terms, different standards

Anti-stat and ESD correspond to completely different standards.

EN 1149-5 is a standard that specifies the requirements of electrically conductive workwear, making it anti-static with the sole purpose of protecting its wearer. Anti-static material prevents sparks and explosions.

The standard for ESD is IEC 61340, which has the purpose to protect the production process or the equipment within the production process. Material that complies with the standard for ESD protects components against electric shocks. It contains recommendations for safety in relation to equipment, clothing and the environment, like the floor. 

My garment complies with IEC 61340 (ESD). Does this mean I am also covered for en 1149-5 (anti-stat)?

The answer is no. EN 1149-5 is meant to prevent the formation of sparks, which is why it is often applied in flame resistant clothing. ESD, on the other hand, is in most cases not flame resistant. 

Anti-static properties are implemented in the fabric with an anti-static thread. This thread is woven into the fabric every few yarns, which creates a grid or a thread in the full width and/or length of the fabric. These grids provide the function that prevents sparks from forming and make sure the fabric contains Static Control.

Because ESD has higher protection requirements to electrostatic discharge, the grids are placed closer to one another compared to garments with anti-static properties.

This seems to imply that ESD-proof clothing is automatically flame-retardant, but this is not the case. The smallest spark could set a garment on fire in case of an explosion. That’s why protection against heat and flame is often an extra requirement of ESD-proof clothing.

Assess your risk environment properly

When protecting your workers in environments with static build-up, these FR properties could be the difference between life and death. Make sure you assess the risks your workers can face properly. 

While ESD is not our specialty, anti-static and flame resistant clothing are. Our specialists can help you select the right protective clothing. Contact our experts and profit of their knowledge.

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