Zhuhair,

Every building is different, so its best if you check with your landlord and they will usually send someone out to inspect what you want to put in. I know that several building I worked in would do this free of charge, but you might want to ask first just to be sure.

If you are installing anything large, like a UPS / AC unit you deffinatly need to check with your building and / or get permits to put these things in most places.

Good luck.