Use these guidelines to minimize static electricity buildup
in your data center.
Floor covering material can contribute to buildup of high static
electrical charges as a result of the motion of people, carts, and
furniture in contact with the floor material. Abrupt discharge of
the static charges causes discomfort to personnel and might cause
malfunction of electronic equipment.
Static buildup and discharge can be minimized by:
- Maintaining the relative humidity of the room within the system
operating limits. Choose a control point that normally keeps the humidity
between 35 percent and 60 percent. See the Air conditioning
determination for further guidance.
- Providing a conductive path to ground from a metallic raised floor
structure including the metal panels.
- Grounding the raised floor metallic support structure (stringer,
pedestals) to building steel at several places within the room. The
number of ground points is based on the size of the room. The larger
the room, the more ground points are required.
- Ensuring the maximum resistance for the flooring system is 2 x
1010 ohms, measured between the floor surface and the building
(or an applicable ground reference). Flooring material with a lower
resistance will further decrease static buildup and discharge. For
safety, the floor covering and flooring system should provide a resistance
of no less than 150 kilohms when measured between any two points on
the floor space 1 m (3 ft) apart.
- Maintenance of antistatic floor coverings (carpet and tile) should
be in agreement with the individual supplier's recommendations. Carpeted
floor coverings must meet electrical conductivity requirements. Use
only antistatic materials with low-propensity ratings.
- Using ESD-resistant furniture with conductive casters to prevent
static buildup.
Measuring floor resistance
The following
equipment is required for measuring floor resistance:
- A test instrument similar to an AEMC-1000 megohmmeter is required
for measuring floor conductivity.
The following figure shows the typical test connection to
measure floor conductivity.
Figure 1. Typical test
connection to measure floor conductivity