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 -