There is one significant difference between home fumigation and commercial fumigation. You usually cannot fumigate a large commercial building yourself, even if you own it. Due to various state laws in the US, most commercial, farming or industrial pesticide solutions are governed by established standards, and do require licensing. So if you were to get a license for fumigation with dangerous chemicals, you could do so. However, you cannot simply fumigate your own commercial or industrial property – tent or no tent. The risk of releasing toxic chemicals (at much higher levels than home fumigation) is simply too risky for your family and for the environment to be ungoverned.
Most states have detailed licensing requirements for all areas of pest control, from “right of way” wild life laws, public health buildings, to regulatory pest control to sewer systems, and so on.
In larger buildings, this process is tricky, since you obviously can’t “tent up” a downtown skyscraper! Bug bombs, a common selection among DIYers are only as effective as the volume of space you have. The larger the building, the more gas will be needed. For larger buildings, less powerful pesticides may be required, if tenting or sealing is not available.