Siam Commercial Bank has yet to determine the cause of the fire that broke out on the 10th floor of its head office on Saturday but said it was unlikely arson.
The blaze damaged only Zone A of the floor at SCB Park Plaza 1 on Ratchadaphisek Road, which also houses the bank's Ratchayothin branch, the bank said in a statement on Monday.
"Police found the fire had burned at a normal rate and there was no trace of fuel that indicates arson," the bank said in a statement on Monday.
The cause of the blaze will likely be known in a week, the statement said.
The fire began at 9.45pm on Saturday on the floor, which is used to keep documents on mortgage loans. Firefighters, assisted by aerial trucks, took about two hours to bring the blaze under control and put it out.
The blaze killed Decha Duangchana, a 35-year-old firefighter volunteer for the Bangkok Fire and Rescue Department based in Lak Si district, as he and other fighters tried to contain the fire. He was believed to have died of suffocation due to lack of oxygen.
Although the fire damage was limited to Zone A, the automated sprinkling system triggered in the entire zone and firefighting efforts had forced the bank to seal the area, the statement said.
Karoon Chandarangsu, a structural engineer of the 135-metre building, said after his initial inspection that the damage was not severe and would not affect the structure. He already reported the findings to Bangkok Metropolitan Administration on Monday.
The Engineering Institute of Thailand (EIT) also said on Monday no crack was found in the columns during initial inspection.
Firefighters put our the fire at SCB Park Plaza on Saturday. (Photo by Krit Promsaka na Sakolnakorn)
Lifts were functioning normally at the time but stairways located in the centre and in a triangular shape might have confused people and were considered a weakness of the building, a state-of-the-art structure when it was completed in 1996.
An EIT team, led by president Suvachvee Suwansawat, held a press conference on Monday after inspecting the site.
On the 10th floor, almost all of the documents and equipment were destroyed.
While no cracks are visible in the columns, they will be tested thoroughly to determine whether they can support at least 85% of the weight.
"The EIT will finish the inspection in 30 days as instructed by BMA. We hope to come up with a safety report in two weeks," said EIT secretary-general Siriwat Chaichana.
Bussakorn Saensuk, chairwoman of the EIT's engineering safety committee, said the building had a fire safety system capable of putting out a fire in 20 minutes.
"It took two hours to contain the fire. We found the system could not function efficiently because it had not been set to automatic mode. Besides, fumigation earlier in that day might have triggered false alarms, causing people to take it for granted," she said.
"A large number of documents on the floor also fuelled the fire beyond the capability of the installed equipment," she said.
Smoke also spread to fire exits and the security system did not unlock them when the fire broke out, making it hard for firefighters to do their jobs and delay the efforts.
All SCB branches are operating normally but the Ratchayothin branch's operation has been temporarily moved to the Bang Khen branch. Customers who need to contact the head office can do so at the RCP Building at SCB Park Plaza. More information at 02-777-6600 or 02-777-777.