Workers at the Braamfontein office park where a building caught alight on Tuesday afternoon thought it was all simply a fire drill.

Cindy-Louise White said she works at Forum Five‚ opposite the building which caught alight.

 “One of my colleagues said it seems like we are having a fire drill‚” said White.

 It was unclear what had caused the colleague to make that assumption as they had not heard any sirens going off.

“We weren’t in any hurry to leave so we just casually started packing up our work stations but then I walked to the fridge to get my lunch and saw from the window that the building next to us was on fire‚” White said.

 After alerting her colleagues‚ they rushed out of the building.

 “I got my car from the underground parking and left. There were lots of people who were trying to get their cars out so there was a long queue‚” she said.

 Once outside the building‚ they saw the extent of the damage.

 “There was even debris which was falling on our building‚” she said.

 Plumes of smoke had covered the area as the blaze continued to rage on the sixth floor of the building.

 Fire fighters had managed to contain the blaze before 3pm.

 Johannesburg emergency services spokesman Synock Matoboko said they would investigate the cause of the fire‚ including reports that the building’s fire alarms had not been working.

“We were forced to use fire hydrants in the street because we had problems with the building’s fire hydrants.”

The cause of the fire was still under investigation.