No. 2A201-519EN*A
67
(3) Suppression and prevention of static electricity (Antistatic measures for nonconductors)
1. Increasing relative humidity
As shown in tables A.1.2-2 and A.1.2-3, the generation of static electricity can be
prevented by increasing the relative humidity.
Table A.1.2-2 Dependence of generated static electricity voltage on relative
humidity
Static electricity voltage (V)
Static electricity generated by
10% to 20% PH
65% to 90% PH
Walking on a carpet
35,000
1,500
Walking on a vinyl floor
12,000
250
Working at a work table
6,000
100
Storing/removing work instructions in/from
a vinyl cover
7,000 600
Picking up an ordinary polyethylene bag
from a work table
20,000 1,200
Sitting on a work chair with a polyurethane
foam cushion
18,000 1,500
*: The voltage can be reduced to less than 1/10 by increasing the humidity.
Table A.1.2-3 Relationship between the humidity and the static electricity
voltage for various fibers
Static electricity voltage (kV)
Fiber
50% RH
65% RH
80% RH
Wool 4.9
2.0
0.8
Cotton 0.1
0.0
0.0
Viscose rayon
4.7
1.6
0.5
Acetate rayon
6.0
3.5
3.3
