tier 4 datacenter requirement "translation"

Fri Sep 14 05:03:07 UTC 2018

Hello,

It may be somehow offtopic, but maybe someone can help understand the
meaning of a requirement for Tier 4 DC.

We have a project to build a Tier 4 datacenter. One of the requirements
specified in TIA942 and related to roof of the building sounds like this:

"double redundant with concrete deck (no mechanically attached systems)"

For my understanding (being not a native English speaker) what exactly
does this mean ?
1. no mechanically attached to the roof systems (gear, equipment) like
air-conditioning, generators etc.

or

2. the roof (double) is made from components that are not mechanically
attached with bolts and such.

Thanks in advance.

-- 
Valeriu Vraciu
RoEduNet

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