Accident Investigation
The purpose of an accident investigation is to ascertain its cause and take action to prevent such events from recurring. During the last 20 years GexCon (previously CMI/CMR) has solved many mysteries surrounding gas explosions under assignments for Norwegian and foreign industries and authorities.
Examples of famous accident investigations in which GexCon has been involved are:
Piper Alpha, TWA 800 and lately P-36 platform.
It is also very important to find causes of small explosion accidents in order to prevent larger events from occurring. There are several examples of companies that have gone bankrupt as a consequence of the physical damage and the resulting loss of production time after a major accidental explosion.
In order to find the cause of an accidental gas explosion it is important to be present at the scene of the explosion as soon as possible after it has occurred. By going through the debris after an incident we can often find traces of what caused the explosion. These traces often disappear quickly during the clearance work.
The TWA accident investigation
On the evening of July 17, 1996, a Boeing 747-131 operated by Trans World Airlines as flight 800 from New York to Paris crashed just off the coast of Long Island. All 230 persons aboard perished.
Reconstruction of the TWA 800 wreckage
The National Transportation Safety Board (NTSB), in charge of the investigation, recovered about 95% of the wreckage (in 9 months), and reconstructed a part of the fuselage. After intensive examination (including computer simulations with finite-element structural analyses), they concluded that the only way to explain all the observations was if there had been an explosion in the centre fuel tank.
The centre tank can carry 13,000 gallons of kerosene, but for this flight, it was not filled. However, 50 gallons of fuel were lying on the floor. After several experiments and measurements of pressure and temperature, they concluded that the gas emanating off this remainder was flammable, and that a gas explosion could have occurred. But one thing was still missing: what ignited the gas cloud?
To find the ignition location, the NTSB built a quarter-scale tank and started to produce gas explosions in this model, measuring pressures, temperatures and flame speeds. But such experiments cost a lot of time and money. So the best way to investigate could be to use additional computer simulations to re-create the explosion. At this point, GexCon assisted in the investigation by using our explosion code FLACS.
After reproducing the experiments with a good accuracy in the quarter-scale, FLACS was used to simulate many possible explosion scenarios in a full scale tank. Based on the simulation results and the observations made from the wreckage, a better understanding of what may have occured was established.
More information about the TWA accident investigation.
Contact
Ronan Abiven
Phone no: +47 415 04 229
Email: ronan(at)gexcon.com
