Annex G of CSA B51S1-05

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Frank
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Annex G of CSA B51S1-05

Post by Frank » Tue Mar 27, 2007 10:43 am

Further to Greg J's topic entitled Potential new propane tank requirements, I am interested to learn about the efficacy of Annex G of CSA B51S1-05 in protecting the public and its effect on the propane conversion industry.

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:
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.
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:
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.
[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.]


Frank
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Post by Frank » Tue Jun 12, 2007 12:18 pm

I had the opportunity yesterday to attend a CSA B149.5 committee meeting. One of the topics discussed were fatalities arising from propane tank failures. In one case, a fuel tank ruptured from the extreme load placed on the tank brackets by the severe impact caused by a truck rear-ending the vehicle. The severity of the impact caused the brackets to tear holes in the shell of the tank. If the tank in that vehicle were built to Annex G, this fatality would likely have never happened because of the additional bracket reinforcements mandated by the standard.

In another case, an old fuel tank (apparently already reinstalled several times) ruptured by the relatively minor collision of another vehicle that was rear-ended. The impact cause the valve guard to penetrate the tank which caused the tank to leak. A broken lamp likely ignited the fuel. The valve guard, according to Annex G, is designed to break away on impact to prevent this type of failure. Any valves damaged with type of impact would still prevent a fire because of excess flow protection installed within the shell of the tank.

Too often, fleets reuse older tanks in an effort to save pennies from their operating costs. They also sometimes only comply with the letter of law even if were wiser to also comply with the spirit of the law.

If you are considering a propane conversion, please consider using new tanks built to modern Canadian standards rather than reusing older non-compliant tanks. Americans, please also consider using Canadian tanks built to Annex G. Even though this is not a requirement for you, there is a great deal of extra safety built into these tanks. While fuel tank failures are extremely infrequent, no-one needs to be one of the statistics just to save a few dollars.

At this time, I believe only Sleegers manufactures tanks to Annex G.
Last edited by Frank on Tue Jun 12, 2007 2:53 pm, edited 1 time in total.

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Mattelderca
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The final nail

Post by Mattelderca » Tue Jun 12, 2007 2:47 pm

I have been considering this (a new tank) as part of my conversion. I fear it is the final nail in the LPG coffin! I just cannot justify that kind of expense for this car. :cry: I wish there was more of an incentive to make the change.

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