Fire crews were called to a vent manufacturer’s electrical testing facility in Manor Royal.
West Sussex Fire and Rescue Service was called to Vent-Axia, Fleming Way, at 5.03pm yesterday (Thursday March 5).
A spokesman said an electrical product caught fire accidentally in the outbuilding.
Firefighters used two hose reels and breathing apparatus to put out the small fire.
The spokesman said the whole one floor facility was damaged by smoke.
They ventilated the building and left at 5.55pm.