The Importance of ESD and creating a safe work environment.
ESD is a huge area of study, it’s a concern for many and of very high importance. There’s lots to cover and this blog will only be the tip of the iceberg. First, let’s look at a definition of ESD or Electrostatic discharge:
Electrostatic discharge (ESD)
The sudden flow of electricity between two electrically charged objects caused by contact, and electrical short, or dielectric breakdown. […] The ESD occurs when differently-charged objects are bought close together or when the dielectric between them breaks down, often creating a visible spark.
Real life examples of ESD include:
- The static electricity you can feel after drying clothes in a tumble dryer
- Walking across carpet and then touching a metal door handle
- Coming into contact with another person
- Holding the banister of an escalator
The science behind ESD
Static builds when you rub two materials together (in scientific terms this is when electrons on the surface of one object pass to another object). This caused the object to become positively charged. This charge will then pass through your body and escape when it is able to. Hence why we experience what we refer to as ‘electric shocks’. This is actually an ESD event.
The ‘electric shocks’ we experience in our day to day lives do not have a large voltage, so you are unlikely to see the electricity pass. However, on particular occasions you can see large jolts of ESD. In these instances, it can create a spark visible to the naked eye. An example of this is lightening which is a large scale ESD event.
The Importance of ESD in the manufacturing industry
It is the heat from ESD which is the greatest threat to electrical components. If an ESD event occurs this can cause immediate or delayed damage. The delayed damage we often refer to as a ‘latent defect’. This can cause a device to malfunction at any moment of its lifespan. For example, a charge of just 30 volts is enough to damage the most sensitive electrical components. However, most components are at risk from charges at 100 – 200 volts.
Electrical components, particularly microchips, are at the greatest risk of damage by ESD. It is essential that you protect sensitive components during the manufacturing, assembly and shipping process. Furthermore, the work area should be grounded for effective anti-static control. This area is often referred to as an Electrostatic Discharge Protected Area (EPA). An EPA could be one small workbench or an entire manufacturing plant.
In an EPA all industrial equipment such as flooring, workbenches, chairs, trolleys, shelving storage and small parts storage should all be grounded to safely disperse static electricity. There are also a static dissipative workwear items that can be worn by employees, which we discuss in more detail below.
A technician walking to their workbench can generate enough static electricity to damage an electrical component.
How do you prevent electrostatic discharge?
ESD workbenches are suitable for static controlled areas and have worktops which are grounded for the safe discharge of static electricity. If the application involves the use of electrical components, then an anti-static workbench is an essential piece of equipment to help limit damage caused to these components during the work process.
Neostat worktop – has a dual-layer surface covering made from rubber. It has a dissipative top layer and a conductive bottom layer, it is this that creates a safe path to ground. Surface resistivity of Neostat is 105 – 107 ohms.
Lamstat worktop – has a plastic laminate static dissipative surface. This surface is also suitable for work involving soldering, heat and chemicals. Surface resistivity of the Lamstat is of 106 – 108 ohms.
Sometime an ESD workbench if not enough to prevent an ESD event. Therefore, numerous accessories have been developed to help assist in preventing and ESD event. These accessories include items such as:
- Wrist straps (help to disperse static electricity generated from a person)
- Insulting strips (required if you fit a worktop service duct to a workbench)
- Double Data Sockets and RCB Circuit Breakers
- Earth / Ground Leads
Training on how to use these accessories correctly is essential for total protection.
ESD matting is beneficial in many ways. As we mentioned above walking alone can create static electricity. However, ESD matting can help to disperse this electricity. These mats have electrically conductive carbon fibres throughout. Consequently, the ESD flows at a slower rate across the surface of the mat which in turn neutralises it.
What’s more, you don’t have to think of matting as just a product for the floor. There is also matting available which is appropriate to use on workbenches, trolleys and other surfaces.
For very sensitive EPAs you may require employees to wear anti-static clothing. Such items may include:
- Sole grounders
- Conductive shoes
- ESD protective overalls
- T-Shirts, sweatshirts & Polo shirts
- High Visibility Jackets
If when reading this it has made you question your current ESD procedures, or you believe that you may require putting such procedures in place the first place to start is a EPA assessment. A little like a Health & Safety assessment, you will need to note all areas that potentially pose a ESD threat. Consequently, you can work out what equipment or procedures you require to create or improve your EPA.
This process is as important as health and safety in the workplace. Ensuring that sound procedures are in place and that re-assessments are undertaken on a timely basis will help to guarantee a safe working environment for your employees. Not only will your employees benefit. Naturally, there will be an improvement in productivity because the waste of components or goods damage by ESD should decline.
In conclusion, the time spend creating an effective EPA should not be an inconvenience. Eventually, it will be an intrinsic and vital part of your business.
- Wikipedia (2017) Electrostatic Discharge
- Business Dictionary (2017) Latent Defect
- Health and Safety Executive (2013) Safety in Electrical Testing at Work. Available at: http://www.hse.gov.uk/pubns/indg354.pdf
- G&B Electronic Designs Ltd (2007) The Importance of Electro Static Discharge (ESD) Control in the Supply Chain. Available at: http://documents.rs-components.com/EITC/UK/electronics/article072_esd_control.pdf