They were called to the scene in Hector Street just before 9.30pm on Wednesday.
When they arrived the whole building was smoke logged and it was not clear whether any people were inside.
Extra resources were called, and at the height of the operation there were six fire engines, two special appliances and up to 50 firefighters tackling the blaze.
Crews wearing breathing apparatus and using thermal imaging cameras searched the premises - it was later confirmed there had been no-one inside.
The cause of the fire is still under investigation.