LPG versus Petrol. What's your view - Page 5

Pilch · 31-08-2005, 12:26 PM

I don't think there is anything further to point out in the area of tank safety, the reality is the majority of tanks, regardless of what fuel they are designed for, will be rarely exposed to conditions which will lead to a dangerous situation. The safety measures in place seem adequate and there is always potential for human error.

Sourbastard, there are Monkeys in all professions, that expose the customer to different dangers in varying degrees. Unfortuanetly that is human nature, and Johnydep's attached article makes that point.

Well put post though Sourbastard, very objective. Maybe a LPG racing category could be created so than the greenies would have a motorsport to support in preference to others due to the lower emmisions produced

:

Heeno · 31-08-2005, 01:05 PM

i'd like to go lpg for the cost's but not to lose power doing it, my mechanic told me if i do convert i would notice the power loss and with my car being gutless as it is i don't want to lose anymore power.

MAD · 31-08-2005, 01:49 PM

Quote:

Originally Posted by sourbastard

With enough heat and time, ANY pressurized containment vessel will rupture. Thats just physics. Shouldnt, Wouldnt, Couldnt is something to be argued from a safe distance from the burning car.

And its not as if every LPG installation is done perfectly, with 100% of the knowledge required and installed in a safe manner.

Thats not the case with LPG tanks, they are made to vent off excess pressure. Which, for example, if the car is on fire it will vent like a big flame-thrower, but will never explode.

MAD · 31-08-2005, 01:52 PM

Johnydep:
In that letter it says the nissan patrol had 2 tanks but only one was affected.... did the other one explode due to the first exploding?

johnydep · 31-08-2005, 02:17 PM

Quote:

Originally Posted by MADXF

Johnydep:
In that letter it says the nissan patrol had 2 tanks but only one was affected.... did the other one explode due to the first exploding?

Don't know.

Read this; http://www.lpgaustralia.com.au/assoc...05final1%2Epdf

It mentions; "as the investigation outcomes indicate the autogas tank may have been overfilled, and the pressure relief valve may not have operated to protect the tank, causing it to fail."

This indicates either faulty workmanship and/or passing th buck. As all recent LPG systems are fitted eith a Automatic Fill Limiter, they should not be able to fill tank more than 80%, unless incorrectly adjusted.

Please do not ask me anymore questions, ask these people http://www.lpgaustralia.com.au/index2.cfm

Sourbastard · 31-08-2005, 02:22 PM

Quote:

Originally Posted by MADXF

Thats not the case with LPG tanks, they are made to vent off excess pressure. Which, for example, if the car is on fire it will vent like a big flame-thrower, but will never explode.

Please re read the thread. There are instances of faulty valves not opening, and more then enough systems that never get checked. If a car with an LPG cylinder is on fire, im not about to get close enough to check if the valve is operating correctly. I will assume it isnt and move the hell away from it.

And also keep in mind if after impact in a car accident, the LPG cylinder is hit with sufficient force to dismount it, that flamethrower will cease to become a flamethrower and will become a projectile.

pandaman · 31-08-2005, 02:52 PM

Quote:

Originally Posted by MADXF

Thats not the case with LPG tanks, they are made to vent off excess pressure. Which, for example, if the car is on fire it will vent like a big flame-thrower, but will never explode.

Not quite true, a couple of pages back someone mentioned an event called a BLEVE. This can occur if a tank is exposed to fire for a long period of time. Initially the pressure valve will allow gas to escape and some of the liquid in the tank will boil off as the gas pressure drops. This has a cooling effect on the cylinder, if the level of liquid in the tank gets low enough that the cooling effect as it boils off is not enough to reduce the temperature of the tank, an explosion may occur. This is not the best explanation, if you really wanna know the exact physics then I suggest you look it up, but it is possible for a tank with a fully functional relief valve to explode. This does take a long time to happen though and even knowing that it is possible I still drive an LPG vehicle. why? because if it is has been hot enough in the car for long enough to cause a bleve, then I am either no longer in the vehicle or I am dead.

pandaman · 31-08-2005, 02:56 PM

Quote:

Originally Posted by sourbastard

Please re read the thread. There are instances of faulty valves not opening, and more then enough systems that never get checked. If a car with an LPG cylinder is on fire, im not about to get close enough to check if the valve is operating correctly. I will assume it isnt and move the hell away from it.

And also keep in mind if after impact in a car accident, the LPG cylinder is hit with sufficient force to dismount it, that flamethrower will cease to become a flamethrower and will become a projectile.

If the car has been hit hard enough to break the cylinder mountings then chances are you're going to have bigger problems than a venting lpg cylinder. In an impact that hard I'd be more worried about the cylinder itself being damaged and not immediately catching alight, a cloud of unignited gas is a lot more dangerous than either this flamethrower or projectile you seem so concerned about.

Casper · 31-08-2005, 02:57 PM

Quote:

Originally Posted by pandaman

If the car has been hit hard enough to break the cylinder mountings then chances are you're going to have bigger problems than a venting lpg cylinder. In an impact that hard I'd be more worried about the cylinder itself being damaged and not immediately catching alight, a cloud of unignited gas is a lot more dangerous than either this flamethrower or projectile you seem so concerned about.

: and this is comforting to know?

Steffo · 31-08-2005, 02:59 PM

In an impact hard enough to damage or dislodge the LPG cylinder... chances are you won't be very alive anyway...

deankdx · 31-08-2005, 03:02 PM

heres my 2cents worth
i have seen 3 cars catch fire from petrol related faults(all were carby types)(one burnt to the ground) if they were on gas this particular fault would not have happened, needle and seat prob and fuel line

i can say i've owned gas cars for 10 years and at the moment if it wasnt for gas i could not afford to run a falcon, i'd have to buy a corrola and fit a1.6motor and 5 speed(not that theres anything wrong with that)(might do it anyway and fit gas also)

to me the less people who jump on the gas is cheap bandwagon and covert to gas the better, as with the rule of supply and demand gas should remain relatively cheap by comparison

look at the options and facts and make the decision yourself

Casper · 31-08-2005, 03:02 PM

Quote:

Originally Posted by Steffo

In an impact hard enough to damage or dislodge the LPG cylinder... chances are you won't be very alive anyway...

As a mod on this site I must contain my urge to ask the obvious.......

Stuff it... Can we see a demonstration with the Pintara???? :hihi:

pandaman · 31-08-2005, 03:04 PM

Quote:

Originally Posted by Casper

: and this is comforting to know?

It's comforting to know that it is actually very bloody difficult to deform a cylinder in a manner that will cause it to breach. Any impact hard enough to cause this sort of damage is likely to cause enough damage to any organic ocupants of the vehicle as to make them fairly unconcerned about whatever is happening to the rest of the vehicle.

Sourbastard · 31-08-2005, 03:07 PM

Quote:

Originally Posted by pandaman

If the car has been hit hard enough to break the cylinder mountings then chances are you're going to have bigger problems than a venting lpg cylinder. In an impact that hard I'd be more worried about the cylinder itself being damaged and not immediately catching alight, a cloud of unignited gas is a lot more dangerous than either this flamethrower or projectile you seem so concerned about.

Either is going to be a real bad end to the day wouldnt you agree?

pandaman · 31-08-2005, 03:23 PM

Quote:

Originally Posted by sourbastard

Either is going to be a real bad end to the day wouldnt you agree?

This is true. BUT being in a car crash with enough force/fire involved to produce either outcome is also going to suck quite badly anyway. I wouldn't like to be in such a crash in a petrol/diesel/coal/hippie powered vehicle.

Sourbastard · 31-08-2005, 03:34 PM

Quote:

Originally Posted by pandaman

This is true. BUT being in a car crash with enough force/fire involved to produce either outcome is also going to suck quite badly anyway. I wouldn't like to be in such a crash in a petrol/diesel/coal/hippie powered vehicle.

Theres usually more people then just the occupants of one vehicle involved in accidents though. Bystanders, other traffic behind the accident, emergency services etc, other vehicles involved in the incident that will be in close proximity.

pandaman · 31-08-2005, 03:46 PM

Quote:

Originally Posted by sourbastard

Theres usually more people then just the occupants of one vehicle involved in accidents though. Bystanders, other traffic behind the accident, emergency services etc, other vehicles involved in the incident that will be in close proximity.

And do you have any factual accounts of collateral damage resulting from a an automotive gas cylinder gone ballistic? I can remember a story a while back about a bloke in melbourne whose house got blown off its foundations but that was a freak accident by anyones standards.

Sourbastard · 31-08-2005, 04:25 PM

Quote:

Originally Posted by pandaman

And do you have any factual accounts of collateral damage resulting from a an automotive gas cylinder gone ballistic? I can remember a story a while back about a bloke in melbourne whose house got blown off its foundations but that was a freak accident by anyones standards.

Not on hand. But theres more then enough evidence of collateral damage from the failure of pressurized vessels, of which many are designed along the exact same principals as an LPG Cylinder.

This part of the thread was not an argument of what has occured, rather it was looking at the potential hazards of petrol tanks vs LPG cylinders. As a potential hazard any pressurized vehicle has more destructive power in the event of a catastrophic failure then a petrol tank, simply because of what each contains, and how they are stored. Its point was also to highlight the concept that an LPG cylinder cannot explode is incorrect.

Wether by design fault, lack of maintainence or simple chance, its does absolutely have the potential to explode and has done so on documented occasions as Johnny Dep posted.

MAD · 31-08-2005, 08:04 PM

From http://www.legco.gov.hk/yr97-98/engl...ry/967rp05.pdf - pages 9 and 10.

Quote:

8. Safety

Fire and Explosion

8.1 LPG tends to be more inflammable than both petrol and diesel because it has a wider flammability limit2.

8.2 Accidents involving LPG sometimes result in fire or in explosion. Explosion happens when there are sufficient amounts of both air and LPG and they are ignited to generate a large amount of heat and rapid air movements in a very short period of time. If heat is released gradually, the burning of the fuel tends to lead to fire rather than explosion. This means that ventilation or air movement is important in safety in storage and transport of LPG.

8.3 Examples of explosions involving LPG vehicles were found in Japan where two explosions happened in 1962 and another two in 1963. An explosion involving an illegally-converted LPG vehicle took place in June 1992 in Taiwan3.

8.4 The characteristics of LPG have implications on the design of fuel tanks, storage tanks and refuelling stations. One example is Japan’s requirement on LPG tanks to be fixed permanently into position after the explosions in 1962 and 1963.

Human Factor

8.7 There is no conclusive evidence to show that LPG is more dangerous or less dangerous than petrol or diesel. Human factor plays an important role in affecting the safety in using LPG. For example, Japan has not have any explosion or serious accidents in the past 30 years since it introduced various safety measures regulating the use of LPG.

8.8 A study in Canada showed that human error was the major cause of accidents involving LPG vehicles (Table 8). The information on 80 accidents was gathered by Transport Canada’s investigation office and the Ontario Ministry of Consumer and Commercial Relations from August 1981 to May 1986.

Yes LPG expolsions can happen, but so can car accidents and plane crashes, and even space shuttles can burn up on re-entry to earth's atmosphere.

Faults in manufacturing happen all the time, some with more potential for serious injury than others, but they still happen.
I watched a program just recently where a heap of people were having major pain after having a hip repacement due to the fact some mineral oil was left on the surface of the cup, that is insterted into the pelvis, from the machining process.

You can never entirely avoid the possiblility of a failure, but the best way to reduce the risks with LPG is to use a licenced fitter and make sure your system is maintained correctly. Simple really, if you watch your own back you will have a lot less to worry about.

Everything that has been laid out against LPG so far (with exception of the faulty pressure valves) has all been to do with human factors. So why point the finger at LPG?

Racecraft · 31-08-2005, 08:08 PM

I signed off this debate ages ago, it turned into a two way war about the safety of the tanks.. That lost me folks :(

MAD · 31-08-2005, 08:38 PM

Nothing really to do with the topic, but interesting none the less, I was just doing a bit of searching and came across this homegrown aussie invention to eliminate BLEVE's.....

http://www.scienceinpublic.com/fresh...colinyoung.htm

I hope it works

Sourbastard · 31-08-2005, 08:41 PM

Quote:

Originally Posted by Racecraft

I signed off this debate ages ago, it turned into a two way war about the safety of the tanks.. That lost me folks :(

Sorry mate, prolly my bad when I said LPG was an explosive and pressurized gas. But obviously its not explosive, it ignites from the addition of fairy dust :P

Casper · 31-08-2005, 08:52 PM

Well, given this thread is called "Whats your Views" and some have shown a clear case that the explosive nature of a stored gas is a major concern... I think the "safety" aspect of the view has been clearly covered. Yes, all fuels have a POTENTIAL to combust and LPG, as a gas, has a very low flash point, I think its been covered enough.

Personally, safety of LPG is a small issue in my mind but not the major one. Personally, I think the lack of power compared to petrol and its dry fuel compound killing engines not set up for it correctly is more of an issue to me.
$2500 for an LPGas set up is great... better add at least another $1000 if you want your engine to last the distance though.

deesun · 31-08-2005, 09:57 PM

Availability is also an issue,not every servo has it and if traveling away you need to plan your trip though it is getting better.You need a specialist mechanic also,not as easy to find. The explosion issue is nowdays not worth thinking about as it is almost non exixtant,when was the last time anyone heard of it happening even in an accident,but there is still a perception. Cars nowdays are far more capable of accepting it but very few conversions would cost $1000. More like $2000-2500,this being even more if there is finance involved thus increasing the length for a return. Average km per year is 20000 so there are lots of cars doing less. Threr are more involved reasons for some hipo cars v normal road cars but to average Joe in the street any small inconveniance is hard to overcome from the norm. The gas/oil companies obviously dont care otherwise more education/advertising would be used to entice people away from petrol.

bindi · 01-09-2005, 08:39 AM

Quote:

Originally Posted by deesun

Availability is also an issue,not every servo has it and if traveling away you need to plan your trip though it is getting better.

We travelled nearly 10 years ago in our first LPG car (XD wagon) from here to Adelaide. We had no issues filling up with LPG at any stage along the way, and we went through some real one-horse towns

Also the lack of power issue... it's not a major difference. It isn't as bad as all those who haven't driven any or many LPG cars make out. My EA is toeier on petrol but you feel a little thrown around, whereas LPG may not be quite as quick to respond to the foot-down but it is a much smoother ride. And you get to a stage in your life where you start driving like a grandpa anyway lol. As the Maddestman said to me yesterday, he enjoys driving off the lights like a grandpa and watching the hoons waste all that fuel, then meet up with them at the next red light.

To be honest, I am not sure exactly what it does to the internals of an engine. I know years ago the issues were with non-alloy heads, and needing to get hardened valve seats and heads specifically designed to cope with LPG.

Can someone please explain the exact process between LPG and petrol inside an engine, and why LPG apparently "wrecks" it?

Also I think the benefits to the environment through cleaner emissions plus the fuel savings outweigh the costs of another engine over time due to apparent LPG problems.

And what about cars that are designed with LPG in mind?

OzJavelin · 01-09-2005, 09:09 AM

After getting my Javelin back on LPG again I've come to the conclusion that in old carb'd cars I personally prefer LPG. When its working properly, provides smooth power delivery and on old V8s gives them fuel running costs equal to modern cars (ie. LPG cost 1/3 as much, but they still use three times as much of it as my EFI V8). An added benefit is that although LPG smells, the car appears to run much cleaner and doesn't smell anywhere near as bad as on petrol .. (unburnt fuel). I also persoanlly prefer the sound of the engine running on LPG. When running on petrol the engine note is deeper, but not as nice and smooth as on LPG.

My Javelin has been running on LPG for 10years without the engine being opened up. Supposedly this is the very high nickel content in AMC blocks/heads which means they ran on ULP in the seventies/eighties without valve seat inserts .. i.e. head material so hard they didn't need it??. Anyway, it still sounds/runs fine and I think the valves/seats are holding up fine. The only problems I've had are the LPG system gunking up from poor maintenance (Doh!)

BTW: Can someone explain what the problems are with valves/seats on ULP engines running LPG? I'd have thought nothing 'cos of the hardened seats? Is this correct??

pandaman · 01-09-2005, 11:22 AM

Quote:

Originally Posted by OzJavelin

BTW: Can someone explain what the problems are with valves/seats on ULP engines running LPG? I'd have thought nothing 'cos of the hardened seats? Is this correct??

My understanding is that the valve seats on the ULP engines are fine, the leaded engines can have problems if the valve seats aren't replaced though. The problem is that LPG is a "dry" fuel compared to petrol and does not provide lubrication to the valvetrain as it enters the chamber hence causing premature wear. I don't believe it's that much of a problem, I've never seen an LPG vehicle die from this although maybe I'm just lucky.