One of the key differences between UTI:TST and ANSI/TIA-942 is the scope. For the TST topology guideline of UTI the scope is very clear as it only covers the mechanical and electrical infrastructure. This is often seen as inadequate by data centers owners. As one of a data centre consultant once said to me “you could build a data centre in a wooden hut next to the railroad track and nuclear power plant with no fire suppression and the doors wide open and still be a Tier-IV data centre based on UTI:TST. As ridiculous as it might sound, the reality is that nobody could argue with this consultant as the UTI:TST only covers electrical and mechanical, full stop. Although electrical and mechanical systems are very important, it doesn’t make any sense to ignore all other aspects that would contribute to a reliable, secure and safe data centre.
For ANSI/TIA-942 the situation is slightly more complicated. Officially the standard is called “Telecommunications Infrastructure Standard for Data Centers”. There are a number of annexes in the ANSI/TIA-942 which describe additional criterion such as site location, building construction, electrical and mechanical infrastructure, physical security, safety, fire detection and suppression etc. So, one could easily figure out that ANSI/TIA-942 is clearly covering all aspects of a data center. So what is the issue?
There is a theoretical and practical side to this. Let’s start with the theoretical side first. The standard indicates in the introduction that the 8 annexes are not part of the requirements of the standard and as such the annexes start with the term ‘informative’. However, a few sentences later it states “It is intended for use by designers who need a comprehensive understanding of the data center design, including the facility planning, the cabling system, and the network design”. This indicates that the Technical Committee who put the standard together has a clear intent to cover the whole data centre and not just the network infrastructure alone. Furthermore, the standard also states that “Failsafe power, environmental controls and fire suppression, and system redundancy and security are also common requirements to facilities that serve both the private and public domain’. In addition to this, in Annex-F it states “This Standard includes four ratings relating to various levels of resiliency of the data center facility infrastructure”. It is hard to ignore by the continues reference to the relation between telecommunications and facilities infrastructure that this should be taken as an overall design standard and not just for telecommunications alone.
Then we have the practical side of the matter which is that any data centre which is taking the ANSI/TIA-942 as their refence point does so by referring to Tier/Rating levels. I have never seen any data centre declaring conformity to the ANSI/TIA-942 which ignored all the annexes as by right one could then just pull the approved network cables in the right way and forget about all other aspects such as electrical and mechanical systems etc. The reality is that data centre operator/owners who are using the ANSI/TIA-942 standard as their reference point are using its full content, including the annexes and rating systems.
So, the conclusion is very simple. No matter how much confusion some parties try to throw into the mix, the reality is that data centre designers/operators/owners take the full document as their reference for designing and building a reliable, secure, efficient and safe data centre. Anybody who says that ANSI/TIA-942 is only used for telecommunications is either ignoring what is happening in the real world or is just oblivious to the facts of how ANSI/TIA-942 is being written and/or used.