The TIA-942 standard indicates that the floor loading capacity for superimposed live load for a Rated-3 data center should be 12kPa (250 lb/ft2).

What was the intent of the technical committee when writing this requirement? The overall premise was that Rated-3 and 4 data centers are commonly used for high-availability applications and therefore, in general, have larger/heavier loads due to rack and equipment density. 

However, there are also Rated-3 & 4 data centres which are very critical but do not have such high rack/equipment density and therefore can easily be handled within buildings with a lower floor loading capability. Hence, auditors will then work on the principle of fit for purpose and appropriate.

This means that it will be acceptable that the floor loading capacity is lower than indicate BUT the data center operator/owner need to show that it has a process in place ensuring that the floor will not be at risk of overloading and therefore having a potential risk of collapsing/sinking.

So what would an auditor be looking for when potentially accepting a lower floor loading capacity? There are a few key elements for which evidence shall be submitted to the auditor.

1. Evidence indicating what the floor loading capacity is. This can be submitted in the form of a declaration letter, issued by the AHJ or a certified structural engineer.
2. Evidence such as a declaration letter from a certified structural engineer, indicating what the maximum load is which can be placed in a rack taking into account safety factors.  Where non-rack equipment is used, appropriate calculations should be provided.
3. Evidence showing the current full weight of each rack and other non-rack equipment in the computer room by means of an asset management system/process
4. Evidence of a process showing how rack loadings will be managed taking into account equipment moves.
5. Evidence of a process showing how new racks and other equipment are assessed for weight loading factors on the floor before moving them into the computer room.

As long as the data center operator/owner, with the evidence as listed above, can show that they have full management control over the process ensuring that the floor will not be at risk of being overloaded, then the auditor will be satisfied and can accept conformance.

Questions?