Approximately 08:20 pm, there was a fire alarm from Level 15. Fire Brigade was on site. Fire Rescue Staff went up to level 15 and checked the level. There was not any fire so it looked like a false alarm. One of cleaning staff member was there with cleaning trolley. She did not know how to evacuate. Fire man said she might have used some cleaning spray which might have turned the alarm on. They also advised her to get evacuation training