What caused the hotel fire in the Turkish ski resort?

The fire, which killed at least 76 people at the Grand Kartal Hotel in the early hours of Monday, is one of the deadliest disasters of its kind in Turkey's history.

Some survivors said they had not heard an alarm, and experts told the BBC they would not have expected such a high death toll in a hotel where fire-fighting systems were working properly.

The 12-storey hotel in the popular Turkish ski resort of Kartalkaya hosts tens of thousands of visitors every year, so Turks understandably want to know how such a terrible tragedy could have happened at the start of a two-week school holiday.

The interior minister said the fire started at 03:27 (00:27 GMT) in the restaurant on the fourth floor and firefighters arrived within 45 minutes.

Some survivors described smelling smoke as much as an hour earlier.

Culture and Tourism Mehmet Nuri Ersoy said the hotel has a certificate of fire competence “issued by the fire service”.

But this was disputed by local mayor Tanju Ozcan, who said the fire department had not issued a positive report since 2007.

Some survivors say they did not hear an alarm while there are claims of inadequacy of the hotel's fire suppression systems.

“My wife smelled the fire,” said Atakan Yelkovan, who said he was staying on the third floor of the hotel.

“We came down earlier than the others. The alarm didn't go off… It took about an hour to an hour and a half for the fire department to come. Meanwhile, the fourth and fifth floors were burning. People upstairs were screaming.”

Some guests on higher floors tried to escape with their mats and some jumped to their deaths.

Aylem Senturk said the fire alarm didn't go off until she left the building. Her husband had to jump off the hotel veranda because of the smoke: “We are very lucky to have survived.”

The BBC tried to contact the hotel's managers about the allegations, but has so far not heard back.

Nine people, including the hotel owner, have been detained as part of the Turkish investigation.

Hotel managers issued a statement saying they were grieving the loss and were cooperating fully with authorities.

In such a large building where fire protection systems are fully operational, experts say fire detectors are expected to respond to a fire within seconds and send a signal to the fire control panel.

“A good business should have someone in charge of this panel 24 hours a day, seven days a week,” Kazim Becheren, president of the Turkish Fire Protection and Education Foundation, told the BBC.

The death toll is also extremely high, raising further questions.

“There will always be fires, but we wouldn't expect so many people to die in these types of buildings,” said Prof. Sevket Ozgur Atayalmaz, Head of the Department of Mechanical Engineering at Yildiz Technical University, who worked on fire safety planning.

“If the structure is designed correctly for fire, if there are escape routes and if the smoke is evacuated properly, it is possible to overcome the fire without loss of life.”

The Home Secretary said there were two fire escapes but there were signs they were not up to scratch.

An official from the Union of Chambers of Turkish Engineers and Architects (TMMOB) in Bolu, Erol Percin, said the way the fire spread suggested that fire warning, detection and extinguishing systems may not have been available.

He said the building's exterior wooden facade was supposed to be 100 percent fireproof, but that doesn't appear to be the case.

The head of the Turkish Foundation for Fire Protection and Education told the BBC that the size of the fire suggested that “the fire protection system either does not exist or is not designed according to standards”.

There were 238 people in the “Grand Kartal” hotel at that time.

Kazim Beseren said fire safety systems are designed to take three minutes to evacuate each floor — and a facility with more than 200 people can be evacuated in 15 to 30 minutes under ideal conditions.

When an alarm is triggered, the person in charge of the fire control panel is expected to check the location, according to the head of the Turkish Fire Protection and Education Foundation.

If there is no indication of a false alarm, or if a second detector sends an alert, fire alarms are usually activated throughout the building.

With a properly installed system, people are then directed by message to the nearest fire exits with flashing lights for the hearing impaired or audible warnings for those sleeping.

As fires can spread very quickly, sprinkler systems are considered extremely important for early intervention.

It is also a backup power source. According to fire protection regulations, signs indicating emergency exits and lights indicating the paths to those exits must work for one to three hours, even if there is a power failure.

The Bolu Union of Engineers and Architects said in a statement that “an automatic sprinkler system is mandatory” in buildings of this size.

“The pictures on the hotel's website show that the automatic sprinkler system that was supposed to be installed in 2008 has not been installed. Because of this damage, the fire grew rapidly and there were casualties.'

BBC Turkish was unable to independently confirm the claims about either the building's timber cladding or the hotel's fire-fighting system.

One of the big questions is whether the hotel's fire protection systems have been checked properly.

Bolu Mayor Tanju Ozcan said the tourism ministry was responsible because the hotel was outside his city limits. Errol Persin agreed.

The mayor said the last time Bolu municipality issued a report stating the hotel was fireproof was in 2007. and since then there have been no such inspections.

However, Mehmet Nuri Ersoy of Culture and Tourism said the hotel had a certificate of fire competence “issued by the fire department” and that the checks were down to them.

There were also calls for relatively old structures to be inspected due to a change in legislation.

“Places should stop working if they do not meet current standards in crowded places such as hotels, residences, nursing homes or kindergartens,” says Prof. Atayilmaz from Yildiz Technical University.