All due respect Neil, but there are three kinds of untruths in the world: lies, damn lies, and statistics. 18,000 ER visits does not equate to any exploded LP tanks. That picture you posted...I'm pretty sure it's a training excercise. Regardless, I never said that it was impossible, just not as prevelant as was proclaimed....and don't forget, I did say that safety precautions should be put to use. I doubt every one who uses a gas oven is sober and well rested. Just sayin....
dmp
I miss our debates Rance...:becky:
The National Fire Protection Association claims that “more than 6,100 accidental fires and explosions occur [each year] due to the improper use of grills, resulting in 20,000 emergency room visits and $29.1 million of estimated damage.”
Furthermore, approximately 20 deaths each year are attributed to propane fires and explosions associated with gas grills.
There are two reasons why there are so many injuries and deaths caused by propane gas grills: “venting” and “odor fade.”
First, the mechanics of a common household propane tank need to be understood. When propane tanks are exposed to excessive heat, the gas itself expands. If there is not enough room in the tank to accommodate the expanded gas, a pressure release valve will open in order to allow propane gas to be emitted from the tank. This is called “venting.” It typically occurs when the internal tank pressure exceeds 375 PSI and prevents the tank from exploding.
When venting occurs, a pungent odor should be present. Propane is an odorless gas; the “rotten eggs” smell most people associate with propane is actually provided by ethyl mercaptan, an additive which is mixed with propane gas to alert users of a leak. The problem arises when gas is released from the tank during venting, but there is no odor. This is known as “odor fade.”
Once the ethyl mercaptan becomes undetectable, propane leaks can place users in grave danger. There have been several cases against propane gas grill manufacturers where consumers have been injured or killed while transporting propane tanks, or when operating gas grills in areas that were not properly ventilated, because of leaks they did not detect.
Problems with odor fade have plagued the propane industry for decades, because the odor of ethyl mercaptan dissipates over time. The length of time varies, depending on such factors as the age and condition of the tank, but studies have shown that ethyl mercaptan can significantly dissipate within five to seven days after a propane tank has been filled and may become undetectable within just three weeks.
BLEVE - Boiling Liquid Expanding Vapor Explosion
The term BLEVE is well known among firefighters and hazardous materials response teams and does not solely refer to propane tanks. A BLEVE occurs when the pressure in the tank exceeds that at which the safety relief valve can safely vent the excess pressure into the outside atmosphere. Relief valves are designed to vent tank pressure at a certain flow rate to the outside atmosphere once the pressure inside the propane tank reaches a certain level and will close once 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). This hole functions as the safety relief valve. If you were to blow air into the bottle through the top after unscrewing the cap, the excess pressure in the bottle would be relieved through the opening in the bottle's side causing no damage to the bottle. Now, suppose you attached an air hose that screwed onto the bottle top forming a tight seal and the air hose was supplied by a large air compressor. Turning the air compressor on starts the flow of air into the bottle which in turn creates more pressure than the small hole (relief valve) in the side of the bottle can keep up with. The plastic bottle starts to expand and eventually ruptures. The reason the bottle ruptures is that the amount of increasing pressure inside the bottle is far greater and exceeds that at which the small hole allows to escape. The pressure 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 is being heated, the liquid propane inside is being heated causing it to expand. The safety relief valve will open allowing pressure to vent to the outside atmosphere. If the pressure inside the tank grows to a level exceeding that at which the safety relief valve can expel it from the tank, the propane tank may rupture. If flames or a source of ignition is present, the propane will ignite resulting in an explosion. It's important to know that a BLEVE will occur only if the conditions are right, such as being subject to continuous flame impingement over a period of time. The possibility of a propane tank explosion (BLEVE) is extremely remote but not unheard of.
So a safety valve vents a heated tank next to a smoker into the outside air...air with the open flames of BBQ Pits all around??? Possible gas with no odor due to "odor fade" sure its a long shot I'm talking about
but will charcoal and wood explode?
I count 6 people in this conversation that have seen a propane accident...
Thats about 15% of us in this thread. Now apply that to 5200 teams and hundreds of contests...
Just my 2 cents
