Datacenter owner/operator and retired engineering contractor here. 

They are not talking about “mechanical” systems such as HVAC, they are instead describing a “Mechanically attached roofing system”.  That’s a specific term, and covers metal roofs of a specific type and construction.   

See: https://msrs.com/new-construction/fully-adhered-vs-mechanically-attached/

Concrete is a superior substitute.  Concrete deck your datacenter and you’re done.   It’s considered pretty bulletproof.  Figuratively and literally.

Our DCs have concrete floors walls and ceilings. 



-Ben

On Sep 14, 2018, at 8:34 AM, Andrew Latham <lathama@gmail.com> wrote:

I would have to go check for sure but I believe it applies to screws or bolts that could pierce the membrane. A well sealed roof is all they are looking for.

On Fri, Sep 14, 2018 at 10:03 AM Valeriu Vraciu <valeriu@roedu.net> wrote:
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



--
- Andrew "lathama" Latham -