This question has been asked of many propane dealers and is also a topic discussed by people that are unfamiliarwith propane, propane tanks, propane accidents and explosions involving any type of container storing flammable orcombustible material. Propane tanks do not just explode if they fall over, are hit by the lawnmower or a car. In fact,it would be hard to say that a propane tank will explode if it were hit by an airplane or bullet. Many peoplemistakenly believe that propane tanks in any setting will explode if they are mishandled in some certain way. Let'sexplore and dispel this common myth.
Propane Explosions 101
Propane tanks do not explode. They do not implode and nor do they rupture or come apart on their own. In fact,bringing a propane tank to the point of "explosion" is a tremendously difficult and time consuming task that's not assimple as most people think. Many people believe that a propane tank "explosion" can occur with the slightest of ease.This is not the case whatsoever and people should understand that a propane tank, operating under normal circ*mstanceswill not explode or rupture. Safety devices and mechanisms are in place to prevent explosions, accidents and propanetank ruptures or breaches. Just like any other hazardous material or activity, human error is a primary factor inpreventing or contributing to any type of accident, however serious in nature.
BLEVE - Boiling Liquid Expanding Vapor Explosion
The term BLEVE is well known among firefighters and hazardous materials response teams and does not solely refer topropane tanks. A BLEVE occurs when the pressure in the tank exceeds that at which the safety relief valve can safelyvent the excess pressure into the outside atmosphere. Relief valves are designed to vent tank pressure at a certainflow rate to the outside atmosphere once the pressure inside the propane tank reaches a certain level and will closeonce the pressure in the tank falls below that level.
Let's look at a simple example involving something we're all familiar with, a plastic 3 liter soft drink bottle.The soft drink bottle has a 1/4" hole drilled in its side (about the same diameter as the cord on your mouse). Thishole functions as the safety relief valve. If you were to blow air into the bottle through the top after unscrewingthe cap, the excess pressure in the bottle would be relieved through the opening in the bottle's side causing nodamage to the bottle. Now, suppose you attached an air hose that screwed onto the bottle top forming a tight seal andthe air hose was supplied by a large air compressor. Turning the air compressor on starts the flow of air into thebottle which in turn creates more pressure than the small hole (relief valve) in the side of the bottle can keep upwith. The plastic bottle starts to expand and eventually ruptures. The reason the bottle ruptures is that the amountof increasing pressure inside the bottle is far greater and exceeds that at which the small hole allows to escape. Thepressure in the bottle is increasing faster than it can escape through the "relief valve".
Propane BLEVE
A propane tank BLEVE will occur when the container is subject to extreme heat, such as in a fire. While the tank isbeing heated, the liquid propane inside is being heated causing it to expand. The safety relief valve will openallowing pressure to vent to the outside atmosphere. If the pressure inside the tank grows to a level exceeding thatat which the safety relief valve can expel it from the tank, the propane tank may rupture. If flames or a source ofignition is present, the propane will ignite resulting in an explosion. It's important to know that a BLEVE will occuronly if the conditions are right, such as being subject to continuous flame impingement over a period of time. Thepossibility of a propane tank explosion (BLEVE) is extremely remote.
Pictured here is a tank that was involved in a grass fire. The fence caught fire and burned down around the tank.Although the tank is no longer serviceable, it is a testament to the strength propane tanks have as well as themanufacturing standards propane tanks are subject to. Many people believe that an LP Gas tank will explode easily iffire is present or near. This propane gas tank is an example of the rule, not the exception.
Propane Tank Strength
The pictures below are of propane bobtail tanks that were involved in accidents. Each of these 2,600 gallon tanks were involved in rollover accidents and were over 60% full. That means each tank contained over 1,500 gallons (~6,300 pounds) of propane. The tanks may be dented but the force of 10,000+ pounds coming down on the hard pavement is definitely a testament of strength in itself.
FAQs
A BLEVE can occur when fire impinges on the LP tank shell at a point or points above the liquid level of the contents of the LP tank. This impingement causes the metal to weaken and fail from the internal pressure. BLEVEs can result from mechanical damage to a tank, as well.
What would cause a propane tank to explode? ›
If sufficient pressure builds, the tank can explode launching fire, shrapnel, and other debris in all directions. Because propane tanks are regulated and include safety devices to prevent over-filling, the tanks should not be able to explode under typical use or under typical temperatures.
Can a propane tank explode in a car accident? ›
In addition to the tanks themselves, the vehicle that is transporting the tanks should be in good working order. A faulty vehicle can lead to an accident, and the force and heat that is generated in a motor vehicle accident could cause a propane tank to explode.
What was the largest BLEVE explosion? ›
19 November 1984, San Juan Ixhuatepec, Mexico – The San Juanico disaster: In the worst ever BLEVE accident, as well as one the deadliest industrial disasters ever occurred, more than 500 people died when a series of BLEVEs hit a Pemex LPG storage terminal.
What is a propane BLEVE? ›
(Boiling Liquid Expanding Vapor Explosion) - a BLEVE occurs when a vessel containing liquid under pressure, such as a liquid propane tank, is subjected to a temperature above the liquid's boiling point.
How common are propane tank explosions? ›
While not common, the short answer is, yes, a propane tank can explode. The Consumer Product Safety Commission estimates roughly 600 propane tank explosions occur each year.
How explosive is propane? ›
On its own, propane isn't explosive - requiring external ignition sources to ignite the gas. Nevertheless, there are safety measures that can help provide additional levels of protection against accidental combustion or explosion. Keep your tank away from ignition sources.
What is it called when a propane tank explodes? ›
During propane tank fires, the potential always exists for an explosion known as boiling liquid expanding vapor explosion (BLEVE).
What are the dangers of propane tanks? ›
Propane tanks must always be kept upright and secure. If a tank's relief valve opens while the tank is on its side, liquid propane may escape and convert into a dangerous gaseous form. Dangers can also arise when propane tanks run low. If gas lines are left open once the gas runs out, then refills can leak out.
Can an empty propane tank still explode? ›
An empty tank still contains a small amount of propane gas. A propane tank may explode in a garbage truck or when the garbage is processed. Propane tanks in garbage are a safety hazard to people and can damage equipment.
Class B fires involve flammable or combustible liquids and gases such as gasoline, diesel fuel, paint, paint thinners, and propane. (Class B fires generally involve materials that Boil or Bubble.)
Can propane tanks explode in cold weather? ›
No, propane tanks cannot freeze and explode. While propane tank explosions are possible, they cannot be caused by freezing. However, you can run into other issues with your propane in extremely low temperatures.
What causes BLEVE explosion? ›
A BLEVE occurs when a vessel containing liquid above its normal boiling point and under pressure fails catastrophically. When the vessel fails, the pressure immediately drops to atmospheric, and the hot liquid rapidly boils, generating a large quantity of vapor.
What happens when a BLEVE occurs? ›
A BLEVE is a boiling liquid expanding vapor explosion, which occurs when pressurized liquid inside of a vessel, such as a propane tank, reaches temperatures higher than that liquid's boiling point.
How do you prevent Bleves? ›
There are a few things you can do to help prevent a BLEVE:
- Keep flammable liquids in closed containers: This will help to prevent the liquid from being exposed to a sudden change in temperature.
- Store flammable liquids away from heat sources: This will help to prevent the liquid from being exposed to a fire.
Abbasi and Abbasi (2007a)The term BLEVE is the acronym for “Boiling Liquid Expanding Vapor Explosion” and is associated with one of the worst accidents that can occur in the chemical industry or in the transport of dangerous goods (Casal et al., 2001).
Can water cause a BLEVE? ›
A BLEVE can occur with many types of fluids and is not an exclusive phenomenon for flammable liquefied gases such as propane or butane. Other superheated liquids suffering a fast depressurization at high temperature may entail a BLEVE, such as water in steam generation systems.
What are common causes of explosions? ›
Fires and explosive atmospheres can be caused by work which involves storage, use or creation of flammable substances including gases, mists, or vapours or by combustible dusts. If there is enough of a substance, mixed with air, then all it needs is a source of ignition to cause an explosion.
What is an example of a BLEVE? ›
Examples of BLEVE can happen after the abrupt breaking of containers containing LPG, methane, ethylene, propane, ammonia, chlorine, sulphur dioxide, oxygen and liquefied nitrogen under pressure, or liquefied and maintained at low atmospheric pressure at low temperature.
