In normal conditions, static electricity and electrostatic discharges (ESDs) aren’t anything to worry about. Children often play with static electricity, and ESDs, though a little painful, are generally not strong enough to cause any issues or injuries. However, static is a potential problem in some industries. From pharmaceutical through biotech and food processing to electronics, even small static charges can cause a number of serious issues.
As static is a natural phenomenon, it can’t be eradicated altogether. Instead, companies need to control levels of static in order to prevent problems and protect products and equipment. Humans are major generators of static – a person can create an incredible 35,000 volts just by walking across a carpet. So the best way to stop a build up of static is to wear specially designed ESD clothing.
What is ESD Clothing?
The same static discharge that makes a balloon attract hair or gives you a shock after walking on a certain surface can cause real issues in other settings. An electrostatic discharge can ignite flammable mixtures and damage electronic components. This damage isn’t always immediately obvious, but can eventually cause products to fail. Static electricity can also attract contaminants in clean environments and cause products to stick together.
The cost of repairing and replacing products damaged by static can be significant. Way back in 1984, researchers estimated losses in the electronics industry directly attributed to ESD amounted to $18 billion. Today’s figure is likely to be significantly higher.
Static is caused by a large number of materials. This can make it virtually impossible to prevent static build up, even in tightly controlled conditions. Materials that cause static include:
- Human skin
- Human hair
- Nylon
- Wool
- Fur
- Silk
- Paper
- Cotton
- Wood
- Rubber
- Rayon
- Polyester
- Polyethylene
- PVC (Vinyl)
- Silicon
- Teflon
ESD clothing is specifically designed to prevent static charges passing from a person, or their clothing, into the surrounding environment. They are worn whenever static damage is a concern and are common practice in a number of industries. Some of the most common types of ESD clothing you’ll find are boots, coveralls and smocks.
How Does ESD Clothing Work?
Most everyday clothing is electrically insulated or isolated from the body. This means that static charges that build up on the fabric won’t necessarily pass to the skin and then to the ground. ESD clothing is specifically designed to stop the static that builds up on fabric from generating an electrostatic discharge or creating other issues associated with static.
Most ESD clothing is made from cotton or polyester and then imbedded with a grid of carbon fiber. These fibers effectively create a Faraday Cage around the body of the wearer. This shields any charges generated from the clothing that could otherwise damage devices that are sensitive to static electricity.
ESD clothing is generally manufactured from manmade fabrics as, unlike natural materials, their fibers won’t break down. This helps to minimise static and make the space even safer. Standards for ESD clothing are set by the ESD Association. All ESD clothing must meet these standards in order to properly protect the wearer and the surrounding environment.
Groundable Static Control Garment Systems
If the fabric of ESD clothing is conductive enough, it can also be used as a groundable static control garment. This means the wearer can be grounded through their ESD clothing. In order to achieve this, a coil cord needs to be fitted to the garment and be touching the ground. In order for an ESD garment to be used in this way, it needs to provide a resistance of less than 35 megohms from the person to the groundable point of the garment.
How is ESD clothing classified?
ESD clothing is often made in order to meet ‘cleanroom’ standards. Often used in manufacturing and scientific research, cleanrooms are controlled spaces with low levels of pollutants like dust, airborne microbes, aerosol particles and chemical vapours. Cleanrooms have a controlled level of contamination that is specified by the number of particles per cubic meter.
Cleanrooms are assigned an ISO value depending on their level of contamination. ISO 1 is the cleanest and most sterile space while ISO 9 is normal room air. Spaces with an ISO 3 classification are also rated as Class 1 spaces. ISO 4 is equivalent to Class 10, ISO 5 to Class 100 and ISO 6 to Class 1,000.
ESD clothing will generally list the ISO and Class value it’s designed for. So if you need boots, a smock or coveralls that will be suitable for an ISO 4/Class 10 space, it should be easy to find the right work wear.
Find out more about the importance or ESD clothing, and explore our high quality range of products, by checking out our online store and the All Seasons Uniforms blog today.