Anatomy of a Disaster
At a cost of $110million dollars and with a construction time of 3 years and 4 months, the Glass Tower broke more than just the world’s tallest structure record. With the estimated budget closer to $180million many were left stupefied when Duncan Enterprise released their final estimated construction total five days before the buildings inauguration. With the company eyeing up the lucrative national urban renewal contract, some in the industry questioned whether such frugality was aimed directly at the government body chosen to award the contract. Yet it was still mystery how the building came in so far under budget and seemingly completed to standard. On 14th December the naysayers got their answer.
The press conference at San Francisco City Hall on Wednesday morning gave a platform for Lead Fire Investigator Matthew Abbott to share his first report following two weeks of thorough inspections of the building and initial interviews with those caught up in the events on 14th December. What he told the gathered press merely confirmed the rumours that were already circulating; the fire was a result of faulty wiring throughout the Glass Tower. The Tower’s Chief Engineer John Callahan had confirmed to the San Francisco Chronicle just days after the disaster that both he, Principal Architect Doug Roberts and the Clerk of Works Will Giddings had discovered the defective wiring at around lunchtime on the 14th December. A junction box in the Tower’s basement power room had blown. Upon inspection Roberts discovered that the wiring inside was well below the standard he had requested in his original specifications.
Pic 1 - The location of the Glass Tower in the heart of the Union Square district
Roberts later confirmed that he and Giddings began working their way up the Tower inspecting key junction boxes as the dignitaries gathered on the Tower steps to begin the inauguration ceremony at 7.00pm. It was a security guard who spotted the fire that had begun in the storage room on floor 81. As Roberts and Giddings examined the junction box just along from the storage room, Giddings spotted the smoke coursing under the storage room door. Anticipating the backdraft that would follow if the door was opened, Giddings dove towards the security guard. He was just too late; Roberts reported that the guard was saved but Will Giddings took the full brunt of the fire that blew through the open doorway. Giddings was the first victim of the Glass Tower, succumbing to his injuries a short while after arriving at hospital.
Situated on the corner of Market Street and Geary Street, the Glass Tower was meant to kick start a financial revival in the city’s Union Square district. The Peerless Building, San Francisco’s previous tallest skyscraper, stands opposite the Glass Tower. Its fifty five per-cent occupancy level did not deter Duncan Enterprise or the investors they enticed to roll the dice on an even bigger high-rise in the shadow of Peerless. Pinning all their hopes on the title of ‘World’s Tallest Building’ and the potential business such a crown might create, financiers took a chance. The gauntlet had already been laid down on the opposite coast. The twin towers of the World Trade Centre were a few months ahead of Duncan Enterprise and details of their ambitions double construction had already been released. Construction Executive Jim Duncan now knew the challenge he faced and he set Principal Architect Doug Roberts to work on designing a structure to surpass the WTC.
Pic 2 - Photographs taken by Sarah Claflin of the Glass Tower lobby and front steps early on the morning of 14th December
With a reputation for the perfect combination of stylish yet safe constructions, Roberts set about planning the impossible. Placing the world’s tallest building in San Francisco immediately raised questions over earthquake safety. A unique friction pendulum system was incorporated in to the design to protect the Tower against anything the San Andreas Fault might throw at it. But it would ultimately be a man-made disaster that would test the building to its limits.
Roberts confirmed in his statement to the Chronicle that fire proofing had been of upmost importance in his design and that systems were included that went well beyond the current San Francisco Building Regulations Code. In his press conference statement however, Investigator Abbott revealed that not all the systems that featured in Roberts design were in place, or if they were they weren’t working. The exhaust system that should have removed much of the smoke from the Tower was non-operational, the sprinkler system was not functioning, and the stand pipe system did not provide the gallons-per-minute specified in the buildings directorate (GPM 1,500 ground floor to 68, GPM 1,000 floor 68 to 100, and GPM 500 floor 100 to 138). Abbott did praise the emergency operation of service elevators that allowed firefighters to gain quick access to the designated forward command post on floor 79, situated fittingly in Roberts’ own office. However, even these were disabled by numerous power outages as junction boxes across the Tower overloaded and exploded.
Pic 3 - Diagram showing the main geography of incidents during the night and the location of the helicopter crash that claimed the lives of two US Navy officers.
It was this element that proved so deadly on the night. Without carrying out a trial run of the Tower running on full power, the overload on the Towers generators proved too great, and the transference of that overload to substandard wiring caused overheating and electrical fires all over the structure. It was acknowledged by Abbott that it was bad luck that the first of these occurred in a storage room that contained industrial solvents such as paint and paint thinner. An inspection of the room by investigators found a number of accelerants which quickened the blaze and allowed it to spread vertically in to the ceiling space between floors. By the time the first fire department personnel arrived on floor 81 at around 7.25pm the blaze had already spread to floor 82 and the under-flooring of floor 83.
The investigation showed that a second major fire started on floor 99 at around 8.15pm. This was followed by a third on floor 69 at around 8.40pm. It wasn’t until then that instructions finally reached the generator room to lower the power serving the Tower, highlighted as one of the key errors on the night. This mistake was compounded when a message was mistakenly given to the generator room staff to bring the power back up in order to return power to the upper elevator system. Faulty junction boxes and sub-generators subsequently reached a critical level and the overheating caused a number of explosions from 9.00pm onwards, the most powerful of which destroyed both stairwells serving the upper half of the Tower.
Pic 4 - A dramatic aerial photograph captured by the WYS news helicopter at 11.18pm shows the extent of the fires in the Glass Tower.
A smaller explosion dislodged one of the scenic elevators that Doug Roberts had fixed using a gravity break to lower it to street level. The unfortunate timing of the explosion and the elevator cars descent displaced the elevator from its moorings and left it hanging by a single cable. An audacious rescue was mounted by Chief Mike O’Hallorhan who was lowered and swung in to place by a Navy helicopter. A cable was then fixed to the car roof and the elevator cable cut through with an acetylene torch. The jolt of the helicopter taking the cars weight almost cost firefighter Mark Powers his life as O’Hallorhan held on to Powers hands during the descent.
Pic 5 - A photograph taken by Naval Officer Ethan Creswell shows the terrifying moment the scenic elevator was stranded on the side of the Tower by an electrical explosion; in the foreground the breeches buoy ferries another escapee to the Peerless Building.
As was reported by live television coverage during the night, the breeches buoy set up between the Peerless Building and the Glass Tower saved the lives of a number of the dignitaries stranded in the Tower’s Promenade Room. But as was quickly becoming clear the fires within the Tower were now too numerous and uncontrolled to fight effectively, and certainly not in time to reach those still trapped. Abbott reported that the decision was taken by the Battalion Chiefs following advice from their consulting architect Olan Johnson to destroy the water tanks on floors 136 and 137 in the hope that the deluge would at least subdue the fires on the upper floors in the building.
Pic 6 - A blueprint discovered in the debris around the Tower front steps shows the design of the Glass Tower lower floors.
If it wasn’t known to those involved at the time, it was clear to any building specialist watching the story unfold via live television news coverage; a series of explosions that extensive in a building is the death knell for the structures life. As Abbott went on to explain, there is simply no way to guarantee the Tower’s integrity after sustaining a blast of that magnitude, even more so following on from the smaller explosions earlier and fire. Investigator Abbott confirmed that the explosion and torrent provided by the Tower’s water tanks proved even more effective than was anticipated. The combination of blast wave in the Towers main conduits and elevator shafts, combined with the water flow, blanketed the fires as far down as floor 85. Continuing efforts were still required from the firefighters on site and it took another six hours for the fire to officially be declared ‘out’ at 6.00am on the morning of the 15th December.
The true cost of the tragedy was all too clear the following morning. By then fire had claimed 140 lives. That number climbed steadily during the following week as a rescue and recovery mission was mounted. Those that had succumbed to smoke or the fire were recovered as every one of the 138 floors were searched by specialist rescue teams from the fire department. Progress was slow at times, in particular between floors 87 to 100 where the stairwells bore the brunt of the sub-generator explosions. Some victims succumbed to their injuries despite hospital treatment, and this past week the Tower claimed its two hundredth victim, firefighter Ross Coleman.
Pic 7 - A photograph from 2.00am on 15th December shows the fires on the upper floors extinguished and smouldering. Fires on the lower floors continued to burn for another four hours.
Investigator Abbott didn’t apportion specific blame for the events of 14th December. That wasn’t his job, but in reality he didn’t have to; the story was all too clear. The man who appears to be drawing the most culpability, the late Roger Simmons, was Duncan Enterprise Contracts Director in charge of overseeing the electrical sub-contracting for the project. Whether corners were cut at this high level or further down the construction food chain, it isn’t currently clear. But if the feeling the flowed from Wednesday’s press conference is anything to go by, a court hearing to uncover the truth, and even a criminal prosecution, might not be too far away. At the very least it will renew the call for a national building code, one that follows prescribed model codes, and dispenses with municipality coding and local jurisdiction. It is at least one step towards preventing a repeat of the terrible tragedy that befell the Glass Tower.
Story by Richard Scortia