Page 177 - Lean six sigma demystified

5
UCL
4.5

4

3.5 3 Cellular-free G UCL
Number of false fire alarms 2.5 2 countermeasure O +2 Sigma

O
+1 Sigma
implemented here.
Average
D
–1 Sigma
–2 Sigma
1.5 LCL
CL Printer dust
After 0.95
1
Before
0.5 Countermeasure eliminated false fire alarms
0.08
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun July Aug Sep
1990–1991
FIGURE 5-5 • Control chart of reduction in false fire alarms.

Causes of false fire alarms 91% 100%
Number of false fire alarms 8 6 4 2 7 64% 2 82% 1 1 70%
10
90%
80%
60%
50%
40%
30%
20%
0
0%
Faulty Cell phone Water leak Printer dust 10%
detector demonstration
Before

Causes of false fire alarms

Number of false fire alarms 1 1 100% 0 100% 0 100% 0 100%

0
0%
Printer dust
Faulty
Cell phone
demonstration Water leak detectors 50%
After
FIGURE 5-6 • Comparison Pareto charts showing improvement.
156