ESD is the result of electron transfer when two materials make contact and then separate or what is known as triboelectric charging. The level at which static electricity can build up is determined by several factors such as area of contact, the speed of separation, relative humidity, and chemistry of the materials. Some common examples of static generation are walking across carpet or picking up a poly bag from a work bench. These types of events can generate charges from thousands of volts to tens of thousands of volts in a normal environment.