Integrated Systems Testing (IST)

Integrated systems testing (IST) is the final commissioning test in which a data center's power, cooling and controls are run together under simulated failures before a customer moves in. Engineers load the halls with resistive load banks, then cut utility power, trip generators and fail UPS modules, cooling units and pumps to prove that redundancy works as designed. A full IST on a multi-megawatt hall typically takes several days and runs at 100 percent of design load. Tier certification of a Constructed Facility by Uptime Institute includes witnessing such demonstrations. Operators that skip or shorten IST tend to discover control-logic faults only during their first real outage, which is why hyperscale leases often make a passed IST a condition of delivery and rent commencement.