1. Safety/Electrostatic Discharge (ESD) Computer Maintenance Copyright © Texas Education Agency, 2011. All rights reserved.1

2. IT: Computer Maintenance - Safety & Electrostatic Discharge2 Enabling Objectives What Is Electrostatic Discharge (ESD)? Why is ESD important? ESD Damage Preventing ESD Damage ESD Workstation Components ESD Wristband or Ankle Strap ESD Floor or Table Mat ESD Garments ESD Gloves or Finger Covering Increasing Humidity Anti-static Bags Copyright © Texas Education Agency, 2011. All rights reserved.

3. IT: Computer Maintenance - Safety & Electrostatic Discharge3 What Is Electrostatic Discharge (ESD)? Electrostatic Discharge (ESD) When two objects rub together they create friction. A by-product of friction is heat. The result of the increased molecular activity brought about by electrons moving back and forth between the two surfaces. Our bodies are constantly in motion. When we move against another material, like carpet, we create friction. This results in rapid movement of electrons, some of which remain in our bodies. This exchange of electrons builds up a charge within our bodies Copyright © Texas Education Agency, 2011. All rights reserved.

4. IT: Computer Maintenance - Safety & Electrostatic Discharge4 What Is Electrostatic Discharge (ESD)? (cont.) Electrostatic Discharge (ESD) Built-up electrons inside us are seeking an outlet: A way to flow through us to another electrically conductive material that isn’t quite as charged up as we are Such as a doorknob When we make contact with another electrically conductive material, the electrons jump from our bodies to the other material. So static electricity is the buildup of an electrical charge within an object, such as a person, the discharge of which is in the form of electricity. Copyright © Texas Education Agency, 2011. All rights reserved.

5. IT: Computer Maintenance - Safety & Electrostatic Discharge5 Why is ESD important? Our bodies constantly generate and release static electricity. Almost every time we touch something, we discharge some amount of static electricity. While you work on a computer, you can discharge static electricity to the components of the system just by touching them. The human body can only feel an electrostatic discharge of 3000 volts OR MORE. Less than 100 volts can damage or destroy the delicate circuitry found in computers. Copyright © Texas Education Agency, 2011. All rights reserved.

6. IT: Computer Maintenance - Safety & Electrostatic Discharge6 ESD Damage Discharge of high levels of electricity into wires and components not designed to accept such levels will result in damage. Damage is not always immediately apparent. Partial damage can result in intermittent errors in the computer because some pulses still flow properly while others don’t. Users will complain of errors and problems that are not always duplicable. Copyright © Texas Education Agency, 2011. All rights reserved.

7. IT: Computer Maintenance - Safety & Electrostatic Discharge7 Preventing ESD Damage Ensure that any electrostatic buildup in your body is discharged immediately to the ground. You must provide a direct ground path from your body. Use special electrostatic dissipative products. They slow the transference of electrostatic energy, allowing it to dissipate before damaging components. Copyright © Texas Education Agency, 2011. All rights reserved.

8. IT: Computer Maintenance - Safety & Electrostatic Discharge8 Preventing ESD Damage (cont.) As a computer technician it is your responsibility to ensure you don’t cause damage to the systems you are servicing. Create an ESD workstation or environment to reduce ESD damage. A good ESD workstation should incorporate the components shown on the next slide. Copyright © Texas Education Agency, 2011. All rights reserved.

9. IT: Computer Maintenance - Safety & Electrostatic Discharge9 ESD Workstation Components ESD wristband or ankle strap ESD floor or table mats ESD garments ESD gloves or finger coverings Increased humidity The presence of moisture allows electrons to better discharge safely into the air Anti-static bags Copyright © Texas Education Agency, 2011. All rights reserved.

10. IT: Computer Maintenance - Safety & Electrostatic Discharge10 ESD Wristband or Ankle Strap ESD wristband or ankle strap Attached to the wrist with a wire leading to a metal clip attached to the grounded object Can be grounded to various items: ESD mat ESD floor mat Metal table or chair leg Removed computer case Separated from any components you might touch Copyright © Texas Education Agency, 2011. All rights reserved.

11. IT: Computer Maintenance - Safety & Electrostatic Discharge11 ESD Floor or Table Mat A floor mat placed where you stand The underside has contacts that provide an outlet for ESD to the ground beneath The floor and underneath the mat should be kept free of dirt and debris The table mat is placed on your work surface Provides a route to ground through: Contacts underneath to metal table or The grounding strap that runs from the mat to a grounding source Copyright © Texas Education Agency, 2011. All rights reserved.

12. IT: Computer Maintenance - Safety & Electrostatic Discharge12 ESD Garments Worn over your clothing and provide a ground wire that can be attached to an ESD floor or table mat Made of a static dissipative material that slows ESD to give it time to discharge to the ground through the ground wire Copyright © Texas Education Agency, 2011. All rights reserved.

13. IT: Computer Maintenance - Safety & Electrostatic Discharge13 ESD Gloves or Finger Covering Worn on the hands or fingers that will come into contact with sensitive components. Can be made of one of the following materials: Vinyl Good for anti-ESD work Special substances to dissipate or prevent ESD transference. Copyright © Texas Education Agency, 2011. All rights reserved.

14. IT: Computer Maintenance - Safety & Electrostatic Discharge14 Increasing Humidity ESD buildup is greatly reduced in a humid environment. As the presence of moisture in the air is increased, electrons are better able to discharge safely into the air instead of onto another object. Using a humidifier to increase the air moisture in your work area can greatly reduce ESD buildup. Too much humidity can cause condensation that can damage components. Copyright © Texas Education Agency, 2011. All rights reserved.

15. IT: Computer Maintenance - Safety & Electrostatic Discharge15 Increasing Humidity The Difference in ESD Generation Based on Relative Humidity (RH) Activity10% RH65% RH Walking across carpet35,000 volts1,500 volts Walking across vinyl flooring12,000 volts250 volts Working on a computer6,000 volts700 volts Paper and plastic moving7,000 volts600 volts Lifting a component poly bag20,000 volts1,200 volts Sitting in a padded foam chair18,000 volts1,500 volts Copyright © Texas Education Agency, 2011. All rights reserved.

16. IT: Computer Maintenance - Safety & Electrostatic Discharge16 Anti-static Bags Computer components are shipped in special plastic bags. These bags protect the components inside from ESD They should be saved and used to store the components that you work with Storing components in these bags will reduce the risk of ESD damage to the component Copyright © Texas Education Agency, 2011. All rights reserved.

17. IT: Computer Maintenance - Safety & Electrostatic Discharge17 Types Of Anti-static Bags Electrically conductive bags Usually black or gray, coated with a metallic or carbon layer, or with a metallic weave Metal helps conduct ESD across the surface of the bag to the ground very quickly Carbon slows ESD transference, routing the charge to the ground Bags can be used over long periods of time without losing effectiveness Copyright © Texas Education Agency, 2011. All rights reserved.

18. IT: Computer Maintenance - Safety & Electrostatic Discharge18 Types of Anti-Static Bags (continued) Electrically Dissipative Bags Usually pink, coated with a substance that slows the transference of ESD long enough for it to be conducted safely to the ground Very little protection might actually be afforded to the components inside Anti-static properties of the bag degrade over time Copyright © Texas Education Agency, 2011. All rights reserved.

19. IT: Computer Maintenance - Safety & Electrostatic Discharge19 Summary What Is Electrostatic Discharge (ESD)? Why is ESD important? ESD Damage Preventing ESD Damage ESD Workstation Components ESD Wristband or Ankle Strap ESD Floor or Table Mat ESD Garments ESD Gloves or Finger Covering Increasing Humidity Anti-static Bags Copyright © Texas Education Agency, 2011. All rights reserved.