ESD knowledge: guides and terms

ESD knowledge that helps in everyday work: this section arranges five guides and a glossary so that purchasing, production and quality assurance quickly find the right answer. You learn how charging arises, how people and workstations are grounded, what ESD clothing achieves and which terms appear in datasheets and standards.

How to use this knowledge

ESD protection is a system of many parts. Anyone who buys just one product without knowing the set-up rarely gets the hoped-for effect. The guides help you understand the overall context before you buy or set up a workstation anew.

A sensible starting point is the basics page. It explains why components are damaged and which three pillars support protection. After that it is worth looking at the distinction between antistatic and ESD, because it determines selection in purchasing. Then come the topics of personnel grounding and workstation, which cause the most errors in everyday use.

For buyers and specialists, the datasheet is the most important yardstick. It states standard, dissipative resistance, material details and care instructions. The guides explain how to read this information but do not replace the datasheet.

Who this knowledge is for

The guides are aimed at buyers, occupational safety officers, quality assurance and production managers. They also help employees who work in the ESD area and want to know why certain rules apply. The language stays factual; technical terms are explained when they first appear.

Frequently asked questions

Is one piece of ESD clothing enough for protection?

No. The clothing is part of the system. It must be connected to ground via the body, and the workstation must be grounded. Without grounding the protective effect remains limited.

How do I recognise an ESD-suitable product?

Check the details in the datasheet: standard, dissipative resistance, material and test conditions. A colour or a note on the label is not sufficient as proof.

Do I have to measure regularly?

Yes, if you operate an ESD area. How often to measure depends on risk, staff and product. Measurements before the start of a shift and after modifications are usual.

What does an error cost?

The costs rarely arise immediately. A damaged component often only comes to light at the customer. Complaints, replacement and loss of trust are the price that testing avoids in advance.

The guides

The guides are structured so that you can read them individually. Each starts with the basic principle, explains the practice and ends with typical mistakes. Where details depend on standards or datasheets, we say so explicitly.

Terms from A to Z

The following terms appear in datasheets, standards and conversations with manufacturers. The explanations are kept short. The exact definition is in the respective standard.

Dissipative

A material is dissipative if it carries electrical charge away through a defined resistance. Dissipative materials are the basis of ESD protection. They differ from conductive materials, which release charge very quickly, and from insulating materials, which hold charge.

Dissipative resistance

Dissipative resistance describes the electrical resistance through which charge flows away. It is stated in ohms and measured under defined test conditions. Many details in the shop give a range, for example from 10 to the power of 5 to 10 to the power of 7 ohm. The datasheet of the respective product is decisive.

Grounding wrist strap

The grounding wrist strap is worn on the wrist and connects the body to a grounding point via a cord. It usually contains a protective resistor that limits the current in the event of a fault.

Grounding point

The grounding point is the connection where grounded parts of the workstation come together. It is connected to the protective earth conductor. Installation is carried out by a qualified electrician.

Grounding plug

The grounding plug offers several connections for snaps or cords. It connects mat, wrist strap or tool to the grounding point.

ESD

ESD stands for electrostatic discharge. In everyday usage ESD also means the protection against it, that is, the system of grounding, material, staff and process.

ESD area

The ESD area is a delimited work area in which measures against electrostatic discharge apply. It is marked and checked regularly.

ESD clothing

ESD clothing is made of dissipative fabric that carries charge away via conductive fibres, provided the clothing is grounded via the body. It is part of the system and no substitute for personnel grounding.

Heel grounder

The heel grounder is worn over the shoe and grounds the person when walking. It needs a dissipative floor. There are disposable versions to stick on and reusable versions with a fastener.

Human Body Model

The Human Body Model is a test method that simulates the discharge of a human body. It is used to classify the sensitivity of components to discharges. The class is given in the manufacturer's datasheet.

Insulative

An insulating material holds charge for a long time and barely dissipates it. Plastics, glass and many textiles made of pure synthetic fibres belong here. Insulators are undesirable in the ESD area where they are not needed.

Mat, table mat, floor mat

Mats form a grounded work surface or a grounded floor covering. Table mats lie on the work table, floor mats on the floor. The choice depends on size, surface and load.

Surface resistance

Surface resistance describes the resistance between two points on a surface. It helps determine how a material is classified. Classification into classes follows the standard.

Cleanroom

A cleanroom is an area with a controlled particle count. Classification follows ISO 14644-1. Cleanroom and ESD complement each other when both requirements apply. Clothing and accessories must then meet both specifications.

Service kit

The service kit is a set of mat, grounding cord and clamp for repair and maintenance. The clamp grounds the device or assembly being worked on.

Coiled cord

The coiled cord connects the wrist strap or heel grounder to the grounding point. The figure 1 MOhm or 2 MOhm in the name refers to the resistance of the cord. The total resistance of the grounding circuit is higher and can be found in the datasheet of the system.

Nonwoven

Nonwoven is a fibre fleece used for disposable products such as caps, gowns and overshoes. Antistatic nonwoven contains conductive components. It is light and inexpensive but loses its effect with wear.