âº EVC System. A disabled refuge is a relatively safe area within a building or exit staircase for mobility impaired occupants, allowing building management and emergency services to safely assist these people from the building.
Standard deviation is a number used to tell how measurements for a group are spread out from the average (mean), or expected value. A low standard deviation means that most of the numbers are very close to the average. A high standard deviation means that the numbers are spread out.
Purpose. Short-term standard deviation estimates the standard deviation within a data set subgroup, and is a measure of how widely values are dispersed from the average value (the mean) due only to the effect of common-cause variation. It is used to calculate Short-term Process Capability (i.e.: Cp and Cpk).