David Vandyne, P.E., President IDC Engineering Lima, Ohio
Articles
Lighting and Lighting Controls March 1, 2003
Beyond Mission Critical – to Hypercritical
It was once thought that electrical reliability had reached its peak at "six nines." And for many facilities, it is still the standard. As a measure of electrical system availability, six nines means that the power supply is available 99.9999% of the time (see "Average System Availability Index below).
By David Vandyne, P.E., President IDC Engineering Lima, Ohio