First, a little background. Since C3H8 has been active in the propane industry for very many years, I asked him if he could tell me about the origin of Annex G. As it has been so long ago, C3H8 has cautioned me that some of the details may not be entirely accurate:
I do not believe that automotive gasoline or diesel fuel tanks are required to survive any sort of crush test and I would fully expect them to rupture if similarly tested. I have asked Transport Canada why OEM fuel tanks are not held to this same level of safety and they gave me the following answer:C3H8 wrote:The issue that started annex G happened at least 10 to 15 years ago in Carseland, Alberta. On the highway outside Carseland some construction was taking place on a bridge. The construction was at the bottom of a long hill with a bend very close to the bottom. A mini school bus (Fords or Chevy's that carry about 15 to 20 passengers) had approached the construction zone and was stopped by a flagman. While the bus waited a fully loaded semi came down the hill too fast and saw the bus too late. He had no where to go as he approached the bus. He hit it in the rear and drove the LPG tank, mounted under the vehicle, into the differential which caused it to be driven up into the interior of the bus through the floor. The bus was driven off the road quite a distance. The tank leaked fuel into the bus and ignited, killing the driver and at least one or two children. The driver burned and I believe the child may have suffered some burning too.
The parents of the victims went public and demanded the Alberta Education Superintendent insist on propane conversion removal. Initially there was a ban on LPG conversions and school divisions were asked to remove the existing conversions. The school divisions refused saying the cost would be excessive and that this was a sever accident which no vehicle could have withstood. Eventually cooler heads prevailed until an investigation could be completed. The investigation into this took a long time (several years as I remember). It was believed that the victims died from the impact, not the burns.
The investigation revealed the tank was manufactured by A&R. The tank was a manifold tank and the broke where the crossover tubes connected the tanks. The tubes were driven inside the tanks breaking the welds. Discussions on this were controversial. Sleegers claimed that their design would have withstood the force of the collision better since they have curved crossover tubes that would have collapsed, not broken. Manchester disagrees, so does A&R. After the investigation was completed findings stated that the victims would have been killed no matter what the fuel was. Propane was absolved of any contribution to the deaths. The investigation stated the force of the collision was so extreme that it is unlikely anyone could have survived an accident of this nature. The committee did make recommendations that manifold tanks should undergo a crush test to ensure that the connecting tubes would not break in collisions.
Several things happened after this. The mounting on uni-body tanks in school buses are required to be mounted with specific distances between the bumper and the differential. Special bracket designs are required on uni body vehicles. Annex G was battled over, but passed requiring crush testing on all manifold tanks. At the last report Sleegers had the only approved manifold tanks. Manchester finally relented and began testing on their manifolds. A&R eventually quit making tanks, however this was not due to this accident but just a downturn in the industry.
As far as I know this is the only time a manifold tank has broken in an accident.
[In my enthusiasm to start a healthy debate on this topic, I made a controversial statement about Sleegers that was incorrect. I apologize for any misunderstanding that this may have caused.]Transport Canada wrote:Frank, the federal regulations are based primarily on performance crash testing requirements in a self certification environment. This puts the responsibility on the vehicle manufacturer to properly design and test the vehicle. Provincial requirements apply to a much broader range of users and thus their requirements are generally more prescriptive, with limited destructive testing so that one vehicle can be easily manufactured to meet the requirements. In the rare case of propane and natural gas, the federal government allows the alternative of prescriptive requirements to be followed so that one vehicle can be built without the need to crash test three or more vehicles.