Compaq N150 manual Typical Electrostatic Voltage Levels, Static-Shielding Materials

Removal and Replacement Preliminaries

Non-conductive plastic bags, tubes, or boxes

Metal tote boxes

￿Electrostatic voltage levels and protective materials

Table 4-1 shows how humidity affects the electrostatic voltage levels generated by different activities.

Table 4-1

Typical Electrostatic Voltage Levels

					Relative Humidity
	Event			10%		40%		55%
Walking across carpet				35,000	V	15,000	V	7,500	V
Walking across vinyl floor				12,000	V	5,000	V	3,000	V
Motions of bench worker				6,000	V	800	V	400	V
Removing DIPS from plastic tube				2,000	V	700	V	400	V
Removing DIPS from vinyl tray				11,500	V	4,000	V	2,000	V
Removing DIPS from Styrofoam				14,500	V	5,000	V	3.500	V
Removing bubble pack from PCB				26,500	V	20,000	V	7,000	V
Packing PCBs in foam-lined box				21,000	V	11,000	V	5,000	V
	A product can be degraded by as little as 700 volts.
￿	Table 4-2 lists the shielding protection provided by antistatic bags
	and floor mats.
			Table 4-2
		Static-Shielding Materials
Material			Use	Voltage Protection Level
Antistatic plastic			Bags	1,500 V
Carbon-loaded plastic			Floor mats	7,500 V
Metallized laminate			Floor mats	5,000 V

Maintenance and Service Guide 4–7