“It would have taken us longer to douse the flames had we stuck to spraying water from one side. We created an opening on a wall on the unaffected side of the fifth floor to fight the flames from another front,” said an officer of Calcutta police’s disaster management group, which assisted the fire brigade in the operation.

Several office workers said they came to know of the fire after the automated alarm system was triggered. Security guards got them to evacuate the building without any delay.

“Apeejay House has a trained in-house quick response team that can evacuate all people from the building within eight minutes,” a spokesperson for the Apeejay Surrendra Group said.

The building also has an underground reservoir that stores water for firefighting. The capacity of the tank is four lakh litres.

Apeejay House is a four-decade-old structure that has had a proper firefighting system for a decade, an official said.

Several well-known buildings in Calcutta that caught fire in the past decade were found to have flouted fire-safety norms. Most of them didn’t have basic firefighting equipment, let alone an alarm system.

Around 200 metres from Apeejay House, a blaze in the landmark Stephen Court building in 2010 killed 43 people. More than eight years later, the building that houses apartments and some popular restaurants on the ground floor still does not have a fire-safety certificate because not all the occupants have implemented the fire services department’s recommendations.

Mayor and fire services minister Sovan Chatterjee said he was glad that the firefighting system at Apeejay House stood up to the

challenge on Monday morning. “The sprinklers worked and their water pumping system was used by the fire brigade.”

Fire drills are held once every two or three months, employees of several offices in the building said.

The gutted Kotak Securities office at Apeejay House at 12.50pm on Monday. Sanjoy Chattopadhyaya

A fire at Apeejay House on Monday morning destroyed an office of Kotak Securities on the fifth floor but a functional firefighting system in the building ensured the flames couldn’t ravage more of the upper floors.

As flames leapt out of a fifth-floor office window along with black smoke, a crowd of anxious faces watched from the ground while the in-house firefighting team got to work and the building was evacuated.

Nobody was harmed, police said.

Park Street had been closed to traffic for 10 minutes from 11.27am to enable fire engines to reach Apeejay House quickly. After traffic resumed, the flow of vehicles was slow for a while, a police officer said.

Offices across the building had started filling when the fire started around 11am in the southeast corner office of Kotak Securities. The server room of the office is suspected to be the seat of the fire.

Apeejay House, owned by the Apeejay Surrendra Group that owns The Park Hotels among other businesses, has about 35 offices belonging to various companies. Around 4,500 people work there.

“We were in the middle of a meeting in my office when the smell of something burning wafted in. We didn’t give it much thought at first. A little later, a gush of smoke entered our office and we rushed out to find the windowpanes of the Kotak Securities office cracking in the heat,” said Supriyo Roy Chowdhury, an official of the pharmaceutical company Sanofi that has an office on the fifth floor.

According to Supriyo, the smoke possibly reached the Sanofi office through a tunnel connecting it with that of Kotak Securities.

He said most employees didn’t pick up even their laptops before running down the emergency staircase. “There was so much smoke within probably 10 minutes of the fire starting that nobody thought about anything else.”

The fire brigade control room said the blaze was reported at 11.10am and put out by 1pm. Eleven fire engines had been deployed.

Employees of companies that have offices at Apeejay House gather outside the building. Sanjoy Chattopadhyaya