Watch out for data operator claims of Tier 4. Has the facility actually gone through the certification process? If they are a facility worthy of certification then they would not mind spending the extra $30,000 for the blessing of their design. Tier 4 certification for a data center or having a Tier 4 design is not easy to achieve. The link above is a list of Tier certified facilites globally.
Data centers are incorporating this certification into their marketing even though even though the Uptime Institute has not certified them. All the facilities that are Tier 4 certified are corporate data centers not open to public colocation. There is only one facility that is tiered certified (Tier 3) that offers public colocation in North America.
Another point to consider is that Tier certification only pertains to the four walls of the data center outside factors are not taken into consideration, like weather , earthquakes ect....
How does the power, coper and fiber come into the facility? Aerials? Encased in concrete?
How many Generators? Diesel or Natural Gas?