Selecting Proper K-Rating

[Kuku]

I have a small office building with one 112.5 kVA dry type transformer, which at the time of design wasn't specified to be k-rated to handle harmonics. There are quite a few computers and other pieces of equipment that may add harmonics. How can I go about determining which k-rating to use? I've figured about 76 kVA of connected load on this transformer to be receptacles that could have computers, printers, etc. on them.

Thanks for the help.

 

[Kuku]

I found what I needed, but for the sake of anyone else who needs this info, the following table should be helpful:

Harmonic Producing Equipment (kVA versus total kVA on xfmr)

< 5% => K-1

< 35% => K-4

< 50% => K-7

< 75% => K-13

< 100% => K-20

These are some recommended values that I found, but are in no way standard that I know of.