As a facilities manager for over 20 years and not knowing your business requirements, structures or political structures, the first issue is that I think facilities need a kick in the bum for two reasons. A not providing a environment that allows you system to run in the required redundant mode (if critically required) either due to sufficient capacity and the required short term repairs. The second is that from your description the computer room air conditioning design is not efficient and not the required system for a modern (or the last 10 years) data centre. The fact you have both under floor supplied air and on ceiling supplied air (Unless it is a Liebert type or similar correctly designed & constructed hot/cold isle system) the air flow from the systems are competing with each other and creating a mixed air flow temperature, instead of a correct cold supply to the servers and the correct hot air return to the A/C units, with the minimum amount of hot & cold air mixing. While the air mixing may be removing the total heat from the room the actual air to the servers is hotter than possible and the efficiency drops and when you have A/C unit failures you have less ability to manage the higher temperatures as the mixed air into the servers is hotter than if correctly separated. E.g less redundant ability to handle failures. In relation to the server temperatures it is really the operating temperature of the electronic components on the cards in the servers. Once theses reach about 60degC or 140degF they are fried. The ability of the server to remove the heat from the components is the server design and the amount of air flow its fans provide. (heat removal) In practice I have found that nearly all servers are ok until the air into the server reaches 32degC or 89degF. A lot of servers now specify supply temperatures up to 38 to 40degC (100 to 104degF) One way to help slightly may be to try and increase the air blown thought he server.

As a facilities manager for over 20 years and not knowing your business requirements, structures or political structures, the first issue is that I think facilities need a kick in the bum for two reasons. A not providing a environment that allows you system to run in the required redundant mode (if critically required) either due to sufficient capacity and the required short term repairs. The second is that from your description the computer room air conditioning design is not efficient and not the required system for a modern (or the last 10 years) data centre. The fact you have both under floor supplied air and on ceiling supplied air (Unless it is a Liebert type or similar correctly designed & constructed hot/cold isle system) the air flow from the systems are competing with each other and creating a mixed air flow temperature, instead of a correct cold supply to the servers and the correct hot air return to the A/C units, with the minimum amount of hot & cold air mixing. While the air mixing may be removing the total heat from the room the actual air to the servers is hotter than possible and the efficiency drops and when you have A/C unit failures you have less ability to manage the higher temperatures as the mixed air into the servers is hotter than if correctly separated. E.g less redundant ability to handle failures. In relation to the server temperatures it is really the operating temperature of the electronic components on the cards in the servers. Once theses reach about 60degC or 140degF they are fried. The ability of the server to remove the heat from the components is the server design and the amount of air flow its fans provide. (heat removal) In practice I have found that nearly all servers are ok until the air into the server reaches 32degC or 89degF. A lot of servers now specify supply temperatures up to 38 to 40degC (100 to 104degF) One way to help slightly may be to try and increase the air blown thought he server.