Evaluation Of Accident Frequency For Hydrogen Vehicles Engineering Essay

It is estimated that over 600 million rider autos travel the streets and roads of the universe today which is around 87 % of the entire vehicles in the universe ; this gives an thought that there are about 1.12 billion vehicles in the universe. It gives a ratio about 1:6 with the universe ‘s population which is approaching 7 billion [ 11 ] . Therefore they produce serious jeopardies to the common public worldwide. This jeopardy converts to put on the line with accidents on route.

Canadian Institute for Health Information ( CIHI ) reports that 48 % of the terrible hurts are due to drive vehicle hits [ 1 ] . As per informations available by National Highway Safety Traffic Administration ( NHTSA ) , in 2007, over 0.5 % of the entire vehicle clangs resulted in human death and over 28 % resulted in nonfatal hurts [ 2 ] . Transport Statistics – Great Britain: 2009 provinces from Department of Transport ( DFT ) 2,538 human deaths among 171,000 traffic accidents and 228,000 casualties in twelvemonth 2008 due to it [ 3 ] , while Australian Bureau of Statistics ( ABS ) in their study “ Measures of Australia ‘s Progress – conveyance ” writes 1,621 human deaths in twelvemonth 2003 [ 4 ] . These human deaths are chiefly due to crushed by, struck by, turn overing and fire and detonation. Fire and detonation in the vehicle after accident causes maximal figure of human deaths.

Introduction of new engineering in transit industry will hold a great impact on the safety of people. Thus attempts are made by many states and independent organisations to show safety of H engineering vehicles. Particular undertakings are undertaken all around the universe to carry through the demand of necessary criterions and statute laws for safe debut of H vehicles. For many old ages assorted pilot undertakings are carry throughing their undertakings to prove pros and cons of this clean engineering.

When it comes to utilize H in vehicles, it is of extreme importance to quantify hazard. Brief utile belongingss of hydrogen.. .. . . . . . .

There is a demand to happen out impact of engineering alteration to common public. To gauge this alteration accident badness and frequence is used as a tool and the undertaking was selected under supervising of DNV, Aberdeen.

This study briefs of import belongingss of H as vehicular fuel ; attempts to compare it with hydrocarbon fuels like Diesel, gasoline, CNG, LPG etc. and estimates the alteration in accident badness with H as vehicular fuel. I believe that this study will assist, to readers, to give initial cognition of H engineering and its impact on common populace.

This subdivision provides Jockey shortss about undertaking and describes lineation of thesis.


Accident frequence and badness rate have been treated as steps of safety public presentation. Almost all authorities and many non-government organic structures have dedicated staff to fix and keep these databases. They collect all the informations related to accidents and supply an input to assorted surveies for research.

This study uses informations from assorted beginnings, viz. Australian Bureau of Statistics ( ABS ) , Department for Transport ( DFT ) , National Highway Traffic Safety Administration ( NHTSA ) etc. , to happen present position of accidents in transit industry, by ciphering accident frequence and badness of accidents in vehicles. An attempt has been made to gauge accident frequence and badness for usage of H, as possible alternate fuel, with present car engineerings. This will give a safety public presentation step of H engineering in current scenario. It is expected that it will supply a baseline step for farther betterments to utilize H as vehicular fuel.

Aims and Scope of work


Undertaking will seek to province and look into issues with H stored as vehicular fuel alternatively of conventional fuels ( Diesel, Petrol, CNG, LPG etc. ) . Aims are:

To cipher and analyze accident frequence for bing conventional fuelled vehicles.

To analyze badness of impact when utilizing Hydrogen as fuel.

To analyze effects of fire/explosion ensuing from Hydrogen leak due to impact, and comparison with conventional fuelled vehicles.

To quantify the addition for Hydrogen as a vehicular fuel.

Scope of Work

The range of this undertaking is as follows:

Calculation of current vehicular accident frequence

This involves computation of accident frequence and badness rate for light motor vehicles ( e.g. Car, Matador, public route conveyance vehicles etc. ) . Collision of mentioned vehicles is considered. Individual escape incidents are non considered for computations.

Impact analysis for storage armored combat vehicles incorporating Hydrogen.

Focus is to happen the conditions ( velocity and weight of vehicle ) of hit between two vehicles sufficient to damage fuel armored combat vehicle incorporating Hydrogen fuel

To happen possible H release rate from fuel armored combat vehicle in instance of hit and frequence of release.

To analyze incident scenario for fuel release and

To cipher badness and frequence of fire/explosion in H vehicle accidents.

Restrictions and premises of survey

To accomplish realistic consequences handiness of primary informations is of import. Approachability to detailed databases that can supply critical inside informations of accident is hard. Bing a new industry informations available publically for H vehicle is negligible. Collision analysis informations is besides really hard to obtain.

The H database is based on accident frequence for bing petrol/ Diesel vehicles. . . . . .


Presentation of safety facets of systems is really of import. Accident badness is a negative index of safety public presentation. Positive indexs give an estimation of public presentation that can be achieved with certain safety steps, while accident frequence and badness rate gives existent position of how that peculiar system has performed in the yesteryear. It indirectly includes safety oversights, system failure, and human errors.

In this study based on informations, for UK and US route traffic accidents, collected from [ 2 ] and [ 3 ] accident frequence of light motor vehicle is calculated. Serious and little hurt rate is besides calculated for the same. It is assumed that little hurt rate is tantamount to little accident rate and used as little and serious accident. This accident frequence and badness rate is used as a baseline and it is expected that this deliberate frequence and badness rate can be achieved with H vehicles if all of the light motor vehicle on route today are replaced. Then an estimation of hit impact energy is made. “ Accident Impact Calculator ” [ 16 ] is used to cipher the impact force and debauched impact energy. Based on velocity and weight of vehicle impact energies are sorted to stand for serious and little hurts. Scenarios with higher impact energy so needed to damage H fuel storage armored combat vehicle are sorted. Based on hurt rates frequence of fuel armored combat vehicle harm is calculated and so scene is escalated to fire and detonation. Based on these computations and H belongingss expected fire and detonation frequence is estimated.

Outline ( 0.5 ) chapters described

Chapter 1 gives debut to the topic under survey

Chapter 2 reviews some literature related to the job that chiefly includes H hydrocarbon fires in vehicles, QRA for assorted accident scenarios ( PhD Thesis ) ,

Reappraisal of Literature ( 1-2 )

CNG and Hydrogen Cylinder demands

Recent Undertakings

In 1981, Peter Hoffman, in his book, The Forever Fuel, the narrative of Hydrogen, stated that, serious work on H vehicles began in 1930s. Rudolph Erren converted over 1000 vehicles to hydrogen and hydrogen/gasoline in England and Germany [ 12 ] . Now there are many development plans in Europe, UK, USA, Canada, Japan and Russia.

In Europe under European Union ( EU ) Framework Programme 5 and 6 ( FP5 and FP6 ) many of the undertakings were aimed on H engineering. These programmes were aimed to beef up the scientific engineerings and technological bases of Industry [ 23 ] .

Based on recommendations from Vision study of the High Level Group on H fuel cells European Commission ( EC ) established the European Hydrogen and Fuel Cell Technology Platform. Its purpose was to speed up the development and deployment of H and fuel cell engineerings in Europe. These engineerings will be cost-competitive and universe category and develop fuel cell based energy systems and component engineerings for applications in conveyance, stationary and portable power [ 23 ] . Some of them are briefed below.


Safety of Hydrogen as an Energy Carrier is one of the undertakings lending to the safe passage to the more sustainable H engineering and its application. The undertaking is to develop methodological analysiss and roll uping informations for hazard direction of H substructure [ 9 ] .

For successful public credence of a new engineering a trust worthy presentation of safety is required. This presentation has to be based on widely known facts and aggregation of informations incorporating accident and incident information. This information can be utilised for hazard appraisal of H applications [ 9 ] .

Hazard appraisal has been an of import tool in many industries for decennaries. Introduction of hazard appraisal engineerings for development of new industries is really of import. It provides sound footing for making consciousness about bing possible jeopardies and hazards to do determination for betterment and decrease in hazard in the new engineering. It is really of import to show that all safety facets related to new engineering are controlled to avoid unacceptable hazard to society. This requires acceptance of bing methods and criterions to the specific applications [ 9 ] .

DNV has worked as a lead participant in Work Package 12 ( WP 12 ) of the FP 6 that surveies risk analysis methodological analysis and credence standards. The survey concluded with harmonisation of finding of risky zones. It suggests that “ ATEX 199/92/EC ” should be the footing for this and “ EN 60070-10 ” shall be used to develop methodological analysis which is another undertaking under WP12. It besides suggests that Seveso II 1996/82 will be a footing related to legal frame work for determination of safety distances [ 24 ] .

Hydrogen Incident and Accident Database

Under the EU ‘s 6th model programme, a Network of Excellence undertaking “ HySafe ” was established and defined. In this undertaking, a specific Work Package was devoted to database development, viz. WP5 – Hydrogen Incident and Accident Database ( HIAD ) [ 9 ] .

This information base is aimed to function as a information beginning for making hazard appraisal and revel tendencies. The information base is non limited to accidents and incidents, but besides includes risky state of affairss and near-misses. It is expected that it should incorporate all H releases irrespective of size/volume even if non ignited [ 9 ] .

HIAD is planned to function as a common format for informations aggregation, high quality information about accidents in H industry. When to the full operable, it will be an of import beginning for jeopardy designation, appraisal of chances, effects and to suggest hazard decrease steps [ 9 ] .

European Integrated Hydrogen Project

It is one of the most of import undertakings for edifice criterions and ordinances and database of bing codifications of pattern applicable to utilize of H in vehicles.

The undertaking ( EIHP – Phase I ) has worked in eight stages. The stages were:

Phase 1: Survey/ analysis of regulations, ordinances and licensing processs in all participating states

Phase 2: Analysis of bing and planned Hydrogen safety constructs and engineerings

Phase 3: Designation of regulations and ordinances ready for harmonisation

Phase 4: Designation of lacks in regulations and ordinances

Phase 5: Designation of lacks in safety constructs and engineerings

Phase 6: Proposal for probes to make a footing for standardisation

Phase 7: Proposal for safety constructs

Phase 8: Proposal of pre-normative regulations

The undertaking was conducted over two old ages ( 1998 to 2000 ) . The cardinal consequences of this undertaking are:

Two bill of exchange ordinances for the blessing of H fuelled route vehicles were finalised. These bill of exchanges were under treatment within ECE. Besides promoted these bill of exchanges as building codifications and to better them with proficient development of LH2 systems.

It gave guidelines for measure by measure development of ordinances for H substructure.

The European thematic web on H energy ( HyNet )

HyNet was founded under the fifth Framework programme of the European Commission. A major undertaking of this web was to develop roadmap for European Hydrogen Energy substructure. An appraisal of socio-economic and political issues associated with development towards H based energy hereafter was carried out. It proposed big presentation activities and joint undertakings to move in response to the concerns of committee for roll uping the European attempts on H energy [ 19 ] .

The European thematic web on H energy ( HyNet ) was active from 2001 – 2004. Subsequently many of the HyNet activities were continued under European Hydrogen and Fuel Cell Technology Platform knows as The Fuel Cell and Hydrogen Joint Undertaking ( FCH JU ) [ 19 ] .

Undertaking ‘s attack was to confer with Europe ‘s cardinal stakeholders over one twelvemonth period through a H reappraisal work store and garner their positions. In the chief workshop cardinal informations on H engineerings was cod and harmonised. This information was green goodss as a matrix which is published in the referred article [ 25 ] .

The Fuel Cell and Hydrogen Joint Undertaking ( FCH JU )

It is a public-private partnership back uping research, development and other presentation activities in fuel cell and H energy engineerings in Europe. It aims to present, a low/negligible C emanation engineering, H engineering. In this three members pool resources and program activities for commercial deployment of H engineerings. Its aims are to cut down clip to present these engineerings, to present robust H supply and fuel cell engineerings developed. In automotive sector it aims to enable industry to take the big scale commercialization determination to significant growing in the clip frame 2015-20 [ 20 ]

An integrated undertaking to develop the European H energy roadmap

HyWays was co-funded by research institutes, industry and by European Commission ( EC ) under the 6th Framework Programme. The undertaking started in 2004 and completed in 2007. In this the members stated specific consequences for green house emanations, mark H production and substructure engineerings. Further supply engineerings and end-use engineerings are integrated into proposal for EU Hydrogen Energy Roadmap. These consequences were given for the timeframes 2020, 2030, and 2050.


This undertaking was besides supported by EC. It is set up to look into possibilities of bringing of H by utilizing the bing natural gas web. This involved feasibleness surveies and the effects and benefit analysis of utilizing natural gas web for conveyance of H safely and expeditiously. The undertaking demonstrated capablenesss of NG web for H bringing, which may be a major part towards development of H economic system [ 26 ] .

The undertaking stated that depending of the type of steel to build high force per unit area grapevines, a mixture of up to 50 % H can be used. It suggests that a mixture of up to 20 % H in natural gas will non significantly affect the safety during conveyance, and for 50 % concentration feasibleness must be assessed instance by instance [ 26 ] .


It is a partnership of 29 organisations supported by EC ‘s FP 6. It studied proficient and socio-economical facets associated with fuel cell and H energy economic system. This undertaking provided support information and feedback to EC and HFP, and assorted other H programmes. The survey facets include –

Word picture and function of European engineering developers.

Creation of an on-line encyclopedia uniting numeral informations of cardinal engineering prosodies with recent progresss.

Analyzing proficient feedback from public presentation undertakings,

Analysis and projection of future public presentation of engineering applications, commercial viability analysis against a background of lifting energy and natural stuff monetary values

Deducing strategic recommendations for the research docket etc

The concluding study says “ Road conveyance is the most technically ambitious application, but the latest coevals vehicles are gaining the efficiencies that the fuel cell has ever promised. Sustained research attempt on cost decrease, lastingness and on-board H storage remains critical to gain the great economic and environmental potency in this sector. “ [ 27 ]

Clean Urban Transport for Europe ( CUTE )

It was a European undertaking aimed to show feasibleness of clean urban public conveyance. It was sponsored by EC FP6 an besides involved several industrial, authorities and academic spouses and conveyance operators. This conveyance is advanced and extremely efficient. It used H as vehicle fuel to run 27 public conveyance fuel cell coachs in nine metropoliss across Europe. Different H production and refuelling substructure was established in each of the metropoliss. It observed the practical application of renewable energy beginnings to transit system.

It is expected that this transit system will lend to cut down overall CO2 emanations. It will besides lend for riddance of NOx SO2 and particulate emanations. It greatly improved public credence of H fuel cell conveyance system and contribute to diversifying vouching more unafraid energy supply.

This undertaking was officially closed on March 2006 with HyFLEET: CUTE as a on-going undertaking. Both undertakings have objective of developing and showing H based public conveyance system.

Evaluation of impact on accident badness

Vehicles have an of import topographic point in our twenty-four hours to twenty-four hours life. One can non conceive of an easy life without them. Right from the innovation of wheel and so vehicles we are utilizing them for transit. Since the age of bullock carts worlds are developing vehicles for easy and fast transit. Internal Combustion engines ( ICE ) played an of import function in our development. However, every coin has two sides, on one side we developed and progressed ; on the other side this development and race to come on created jeopardies and hazards. Inventions gave us velocity and comfort to travel. However, accidents can non be prevented wholly. Accident causes belongings harm, hurts and human deaths.

Safety Performance Indicators play an of import function to place lacks in the degree of safety. They are the result of analysis of safety activities or safety breechings. They can steer advancement of engineering towards a safe system [ 5 ] .

Accident frequence and badness rate are the two of import safety public presentation indexs. They are the indexs of existent lacks in the system. These lacks may be related to human factors, environmental conditions, unity of system or escalation of accident.

Vehicle accidents and badness

Accident frequence is frequently calculated as figure of accidents per million adult male hours worked. While in conveyance industry it is calculate as figure of accidents per kilometer of vehicle travel. Badness rate can be calculated based on badness of hurts ( break up / little hurt ) per vehicle kilometer. Following expression is used to cipher the accident frequence and badness rate.

As stated earlier, information was collected from DFT, UK about accidents over a scope of 12 old ages ( 1997 to 2008 ) . This information is reproduced in the undermentioned tabular array.


Number of Accidents

Number of Fatalities

Number of Serious Injuries

Number of Slight


Number of casualties

Entire vehicle kilometer





















































































Table: Reported Road Accidents,

DFT, UK ( reproduced from [ 3 ] )

It can be considered that, break up the accident serious will be the hurts hence it can be assumed that human death and serious hurts corresponds to break up accidents. Similarly, little hurts will match to little accidents.

Graph: Accident and Injury Rate

The above graph shows that little hurt rate is more than the corresponding accident rate. It is because an accident may bring forth more than one little hurt. It should be noted that although little hurt rate is more than accident rate, the ratio of rebuff to entire accident rate is about changeless. Therefore, for computations and to happen chance of sever accidents little hurt rate can be used.

Above information suggests an accident frequence of 4.4E-07 accidents per vehicle kilometer over the period of 12 old ages. It is found that ratio of sever to little accidents ranges in between 1:7 to 1:8. It can be said that chance of sever accident is 0.13 when an accident takes topographic point.

Now as the accidents mostly depend on route conditions, traffic denseness, and driving wonts, while, type of vehicle has really undistinguished consequence for accident to take topographic point. Thus it can be assumed that, for the same scenario, H vehicles will besides hold the same accident frequence for the baseline. However, type of fuel used will besides hold an consequence on badness of accidents. This consequence is discussed in subdivision 4.3.

( Mention usage of accident frequence in PhD Thesis. Give tabular arraies, computations, graphs, reference and comparison frequence calculated by you 2-3 pages )

Analysis of impact on fuel armored combat vehicle after accident

Impact to fuel armored combat vehicle may happen when a vehicle accident takes topographic point. In this subdivision different scenarios of vehicle hit are studied. A hit can take topographic point in two ways.

Vehicle hits a stationary object

Two vehicles collide

In both the instances vehicle will acquire damaged. However, chance of harm to fuel armored combat vehicle is really low in instance ( a ) . This is because, in most of the vehicles, fuel armored combat vehicle is designed to be positioned on the rear side. A vehicle – stationary object hit should be strong plenty to damage the vehicle frame and than the fuel armored combat vehicle. Practically, in this scenario, an accident with energy of impact sufficient to damage fuel armored combat vehicle, can merely go on when vehicle is traveling really fast towards a stationary object. Probability of fuel armored combat vehicle harm will be more if a traveling vehicle hits a stationary vehicle in rear.

Two vehicles can clash in three possible ways

Front – Front ( Head on ) hit

In this instance the two vehicles collides front on forepart. The vehicles must be traveling in opposite way. It increases their comparative velocity and gives higher hit energy for a given set of mass and velocities. These type of hits are extremely destructive

Front – Rear Collision

Front – side on hit

The undermentioned figure shows the clang zones of a BMW 7 series auto as shown by Vernier [ 28 ] .

Primary_Crash_Zones [ 1 ] .jpg

Figure: Primary Crash Zones

Taken from [ 28 ]


Figure: Fuel Tank Position in BMW 7 Series

Taken from [ 29 ]

In figure 1 and 2 show the possible clang zones with their chance and the place of fuel armored combat vehicle as in BMW 7 series H autos. These armored combat vehicles store liquid H. It is really much clear that the said fuel armored combat vehicle is placed in a 1 % to 5 % zone. This suggests that chance of fuel armored combat vehicle harm and hence hydrogen leak can be taken as 0.05.

Brief diffusion, and other related belongingss. Consider serious accident ration Probability of fuel armored combat vehicle escape from way of impact. . . . . . . .. )

Calculation of ignition chances

( Mention ignition, flammability bounds belongingss of H. )

Hydrogen – Air mixture is flammable over a broad scope ( 4 % to 75 % by volume ) of H concentration. Besides H Burnss with no seeable fire in twenty-four hours visible radiation. Hydrogen fire can take to deflagration and explosion as it nears stoichiometric mixture. Ignition energy of H near its stoichiometric mixture can be every bit low as 0.017 mJ while at lower concentrations it will be higher 10 mJ for 4 % [ 9 ] .

The chance ( PI ) of ignition of gas is dependent on the chance ( Q ) of a sufficiently strong ignition beginning being present and the chance ( Pv ) of this ignition beginning being exposed to the gas concentration within the flammable bounds in the country of leak. Now the chance of ignition of gas can be given by:

An analysis of 72 H leaks reported in EIGA database showed that 49 % of the reported leaks were ignited and 43 % of enkindled leaks ( 21 % of entire leaks ) resulted in detonation organizing a blast moving ridge [ 9 ] . A survey by Rosyid, 2006 says that 30.7 % of the accidents under survey resulted in fire. 20 % resulted in detonation. 4 % resulted in both fire and detonation, remainder of 45.3 % accidents include un-ignited H release [ 17 ] .

( USE Minimum Ignition energy standard to happen out ignition chances. Mention to Mathurkar ‘s Thesis and elaborate ) .

The above given chances are used for computations in the thesis.

Result ( accident frequence and badness for usage of H as vehicle fuel )

Hydrogen Accidents

The 1983 Stockholm H accident ( Stockholmpaper.pdf )

On 3rd March 1983 a H detonation occurred about 0900 hour in Brahegatan, Stockholm, Sweden. An unfastened backed truck was presenting

A H gas detonation occurred merely earlier 9:00 a.m. on Thursday, 3 March 1983 in Brahegatan, a street located in the A-stermalm territory of cardinal Stockholm, Sweden [ 10 ] . An unfastened backed truck was presenting assorted industrial gases to sites in the Stockholm country. At the site of the detonation a rack of Ar gas bottles was being delivered to a research lab in the edifice adjacent to the truck ( see Fig. 1 ) . The little lifting arm at the dorsum of the truck was being used to offload the Ar gas bottles when the operator ( truck driver ) heard a hushing sound. The operator stopped what he was making and went to look into the beginning of the sound at which point an detonation took topographic point. Approximately 180Nm3 of H was stored in a rack of 18 interrelated 50 fifty industrial force per unit area vass ( 200 saloon working force per unit area ) being carried on the dorsum of the bringing truck ( Figs. 1 and 2 ) . The official accident probe found that the releasewas the consequence of two broken connexions between force per unit area vass adjacent to 6mmdiameter T-connection mercantile establishments from the cylinders. Shut-off valves were non used to procure the single cylinders in the rack. The official study stated that one connexion was broken, though exposure in the same study clearly show two broken connexions ( ensuing in four release beginnings ) . Fig. 2. Hydrogen beginning, after the accident, comprised of 18 interrelated 50 cubic decimeter steel bottles at 200 saloon storage force per unit area ( image taken from accident study, with permission ) . The false jet waies of the four jets ensuing from the two line interruptions in the present simulation are shown with pointers. Three of the jets are parallel to the Y-axis and one to the Z-axis. A.G. Venetsanos et Al. / Journal of Hazardous Materials A105 ( 2003 ) 1-25 5 The edifices in the country of the accident are chiefly residential, typical of interior metropolis Stockholm, with about 5-6 floors. The closest edifice to the detonation was an office block of similar tallness to the neighbouring edifices. The cross-sectional dimensions of Brahegatan are about 2.0m broad pavings on either side of a 10m broad carriageway. Parking was permitted on both sides of the street. The official accident probe listed the undermentioned effects ensuing from the accident: 16 people injured ; 10 vehicles damaged ; frontage of the nearest edifice ( office block lodging a research lab ) was to a great extent damaged ; broken Windowss within a radius of about 90 m. A simple analysis of the accident contained in the official accident study estimates that an overpressure of 5 kPa ( 50 mbar ) was experienced at a distance of 90m from the Centre of the detonation, from the harm caused by the detonation. The study estimated that such a daze moving ridge would necessitate 18Nm3 ( 1.5 kilogram ) of H in a deflagration doing a free spherical shockwave and that 10 % of the flammable mixture was burned in the detonation, which is consistent with a release of 180Nm3. The method used to deduce this appraisal is non stated, though it is likely to be a simple TNT equality type method.

( Status of Handling and Storage techniques for liquid H in motor vehicles.pdf )

The DFVLR experimental BMW 520 vehicle was involved in two clangs. One of them occurred in 1982 in Pasadena during the WHEC4. The LH2 armored combat vehicle was filled to capacity with about 1201 of liquid H when one rainy flushing while the vehicle was stopped at a ruddy traffic light a big limousine crashed into the bole. The vehicle was pushed by about 7 m into the intersection. Although the tube of the fuel system was damaged by warps, no H leak was observed. A new rear bumper, rear bole wall, left rear wing and new rear tail lamps were required. The driveshaft tunnel was damaged by some clefts. No harm nor irregular force per unit area addition in the armored combat vehicle was observed

( Status of Handling and Storage techniques for liquid H in motor vehicles.pdf )

One of them, the UCLA vehicle, AMC-Jeep, as described in [ 10 ] was involved in an accident in 1975. Liquid H was stored onboard this-eehicle in a spherical fuel armored combat vehicle ( VLH-50G-dewar, provided by Minnesota Valley Engineering ) . This was the first liquid H Dewar vas designed and built specifically for automotive application. The outer and interior domains were made of 3003 aluminum ( 98.8 % A1, 1.2 % Mn ) . The inner domain was suspended from the outer sphere by a cervix made of Gll glassfiber epoxy. At the underside it was supported by two homocentric G11 cylinders, one attached to the inner sphere, the other one to the outer sphere. They were designed to reach merely when the Dewar vas was subjected to horizontal burden. These supports were designed to defy about 18-20 g in any way. The manner of failure for horizontal burden is a chapped cervix support and for perpendicular lading a sinking of the inner shell at the cervix fond regard. The vehicle was loaded on a tandem-axle dawdler and chained in topographic point. When the accident happened, the Dewar vas was filled to capacity with about 190 1 of liquid H at about 2 saloon force per unit area [ 20 } . It was caused by a runaway in one of the towing vehicle ‘s tyres, dawdler and towing vehicle coming out of stage at 55 miles per hour. At about 20 miles per hour the dawdler turned on its side, interrupting the dawdler lingua. Towing vehicle, dawdler and LH2 auto came to rest upside down. None of the residents were injured: no evident harm to the fuel system could be observed. Liquid H now came into contact with the warm top portion of the Dewar vas, doing a rapid force per unit area addition. The force per unit area in the Dewar vas was repeatedly lowered by opening the manual fill/vent valve. After the dawdler was unchained from the liquid H auto and pulled off, the liquid-hydrogen auto was turned upright. Then the Dewar vas was manually vented for 30-45 s to cut down the force per unit area to ambient degree. After review, the determination was made to drive the vehicle back to UCLA on H. No major harm to the H Dewar vas was found. The organic structure of the auto was damaged in legion topographic points. A new roof, right forepart wing, right door and left backup lens were required. This first clang of a liquid-hydrogen-fueled vehicle obviously was no more unsafe, nor did it do any more harm than a clang with its gasolene fueled opposite number would hold.

Discussion ( Comparison of H and hydrocarbon vehicle accident badness )