In the same ITQ which I posted about yesterday, there is a section on acceptable Service Availability.
Again, the awarding party has done a good job defining what he is looking for:
The Supplier shall ensure during any one month period, hosting services availability shall be 99.5%, excluding scheduled maintenance. Services availability in a month is being calculated as follows in percentage:
Note that scheduled maintenance is excluded. Some customers do not think this should be the case. :)