Multi-Vehicle Motorway Accident Involving Hydrogen Gas Tube Trailer and Jet Fire
Motorway accident which involved a large quantity of vehicles and a gaseous tube trailer which transported gas hydrogen in pressure. Some cars were burning under the back part of the gaseous tube trailer. (for details see source). The fire brigade team used a thermo-camera to assess the situation, finding that in proximity of the valves of the lowest containers there was flame, and there was an hydrogen release which was burning (jet-fire). One of cylinder was deformed in correspondence of tractors wheels. To reduce explosion risk the fire brigade team decide to cooling deformation point with maximum priority.By monitoring the flame evolution with the thermo-camera, and identifying when the jet-fire was reduced, it has been finally decided to proceed to the definitive turning off of the releasing valve. The operation of turning off has been effected with the aid of two throws of water crossed and through use of thermo camera has been verify the definitive extinction of the flame.
Event Date
March 1, 2003
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
Root cause is the development of a fire due to a road accident.This damage of one or more cylinders of the hydrogen trailer, and the release of hydrogen from the a valve and from a crack on the cylindrical side of one cylinder.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
tube trailer, Compressed hydrogen cylinders, multiple vehicles
Storage/Process Medium
Actual Pressure
14
Location Type
Location description
Countryside Road Or Highway
Operational Condition
Pre-event Summary
A road accident causing the abnormal behavior of the trailer cylinders.
Currency
Lessons Learned
Lessons Learned
The accident has identified the following direct or indirect source of hazard in need of attention:1. Lack of equipment to evaluate pressure inside the cylinder gaseous tube trailer.The knowledge of the pressure inside the cylinders is critical in case of accident, to assess the gas quantities involved and the filling of the storage system. The present gaseous tube trailer design does not allow for, due to the fact that the manometers installed on the cylinders heads are the most fragile elements and therefore are the first equipment that break. Even when still functioning, they are difficult to be read at a certain distance, and are often shadowed by other components. 2. Lack of protection in the back part of the tube trailer. All the valves for the load/unload of the gas are installed at the back of the trailer. They consist of connecting pipes, collector final valves of a pneumatic valve for Th remote control of all manometers. These components are not well protected in case of road accident. There is only a steel plate protecting the components from meteorological phenomena. Mechanical accidents at the rear can cause damage to the valves with consequent possible release and prevention of their confinement function. Fires can further damage the functioning of these components. 3. Lack of a mechanical system allowing the simultaneous closing of all the valves. Every cylinder has with a manual closing system by means of a proportional valve with bolt in brass and joint elements in Teflon. All the valves are connected via piping to two manual valves. According to the ADR normative all the valves during the transport must be in closing position. There is however no control system which allows to check automatically that the valves are really closed. 4. Lack of protection among the trailer wheels in rubber and the cylinders. The trailer components with the greater fire potential are the tires and the fuel. In case of road accident with fire, the heat develops quicker and more heavily around the anterior parts of the cylinders of tube trailer. This causes the pressure increase in the cylinders beyond their burst pressure value.
Event Nature
Emergency Action
The level of risk has been rather elevated for rescue team. There was an explosion risks for cylinder involved in fire. Pressure inside cylinder was unknown and there wasnt possibility to evaluate it remotely. In fact, a jet fire was originated from a leak in one of the tube and a second tube was deformed. Fire brigades team has been water-cooled the tube to prevent an explosion and than turn off the jet-fire when it was reduced due to pressure reduction inside the tube.
Emergency Evaluation
A thermo camera was used to evaluate the presence of hydrogen fires and the temperature and the shape of the tubes. This has allowed to identify the presence and nature of the hydrogen flame, and to follow the evolution of the flame.
Release Type
Release Substance
Hydrogen Release Concentration (%)
100.00
Hole Shape
Hole Length (mm)
10
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Article presented at the Int. Conference on Hydrogen Safety ICHS 2005.
Available at http://conference.ing.unipi.it/ichs2005/Papers/230001.pdf
(accessed June 2020)