Static

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Dealing With Static Electricity In the Workplace

“Static electricity” is an electrical phenomenon in which the positive and negative charges on nearby items are not in balance. It occurs when two dissimilar insulating materials touch one another and are then separated. Two things are especially important here:
 The first is that two surfaces need to be electrical insulators. If either is an electrical conductor, the imbalance corrects itself. In fact, that is what is happening when you get a shock from touching a metal surface.

Static Electricity in Lightning
The second is that touching is all that is needed. Rubbing or scuffing the two surfaces is not necessary. Chemical bonds are formed when the surfaces touch, and if the atoms in one surface tend to hold electrons more tightly, that surface will tend to steal electrons from the other upon contact, creating the imbalance. Note that if one of the materials is rough or fibrous and thus does not give a good contact area, then the process of rubbing one material against the other can increase the total contact area, and thereby increase the total imbalance. The rubbing, however, does not cause that imbalance; it results from the contact alone. Simply walking across certain types of carpeting, for example, is enough to create an imbalance between the flooring and the soles of one’s shoes. While walking, we leave behind either positively or negatively charged footprints on the carpet (depending on the materials in each), while our bodies become oppositely charged. Because the electrical imbalance of “Static electricity” seeks to correct itself, it creates an electrical voltage, or pressure, between an unbalanced object and any conductor. These voltages can be very large (usually between 1,000V, and 35,000V), which is why the sudden discharge we feel when we touch something conductive is painful. When you feel a static shock, you are experiencing a minimum of 3,000 volts of electricity.

To prevent static discharge shocks, we must prevent the charging process. This can be done in a variety ways:
     1. Raise the humidity, which causes shoes and rugs to become conductive so charges can flow back together. Keep relative humidity at 50 to 70%. If humidity is above 70%, morning coolness may cause condensation in equipment and the workplace can get uncomfortable.
     2. Spray the floor with antistatic treatment.
     3.Identify and avoid shoe sole types that are good insulators. Thick rubber soles and some types of composite materials can cause significant charging, while thin leather soles cause much less.
     4. Identify and avoid clothing materials which make the problem worse, such as wool sweaters and pants, nylon, etc.
     5. Mix up some anti-static solution and spray floors or upholstered furniture. Use a teaspoon of fabric softener mixed in one quart of water. The limitation to this technique is that it tends to work at first, but then wears off and need a re-coating. Commercial carpet service companies often offer more resilient treatments.
     6. Install “ionizing blowers” from an ESD-abatement company. These blowers emit large quantities of both positively and negatively charged air. This makes the air itself conductive, and the air then silently discharges any charged objects in the room, including people.

There are also several things individuals can do to minimize the effects of static charges that do build up:

     1. Touch doorknobs or other metal objects with your knuckles first. The shock is less painful to your knuckle than your fingertips.
     2. Develop the habit of holding your car keys as you move about the building, then gripping the keys firmly and touching a metal object with the tip of the key first. You can still watch the spark jump, but it will not be painful.
     3. A similar technique is to wear a metal thimble on your finger, then constantly touch grounded metal objects during your travels. Again, you will still see the sparks, but they will not be painful.
     4. If you just touch metal desks, filing cabinets, doorknobs, etc. as frequently as possible when you move around, you will experience many more shocks, but they will be much smaller

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