As it relates to hydrocarbon gases, blue flame is indicative of complete combustion whilst a yellow flame indicates incomplete combustion. The flame colour changes to orange, yellow or red flame and the flame wavers. Natural gas flame color orange indicates incomplete combustion. See the flame color temperature chart below:. Propane gas furnace flame color is the same as propane flame color. A gas fireplace flame color is yellow or red flames and is the exception to the rule.
Gas fireplace flame color is typically designed to burn with red flames, not blue flame, for a more natural look. Wood logs do not burn with a blue flame colour, so a gas fireplace needs yellow or red flames for a realistic look and feel. It is also engineered to operate safely with yellow or red flames. This means that the gas fireplace flame colour breaks the rule of having a blue flame.
They are also flued so there are no indoor emissions issues, should they produce some CO from the red flames. Propane fireplace flame colour is typically yellow, as propane fireplace flame colour is designed to burn with a more natural look. As wood logs do not burn with a blue flame colour, neither should a simulated wood fire. A propane fireplace needs yellow or red flames for a realistic look and feel.
It is also engineered to operate safely with yellow or red flames, with a flue to eliminate indoor emissions. A gas cooker yellow flame indicates a combustion problem. A gas cooker or stove should have a blue flame. Propane torch flame temperature colour would also be blue flame. See the flame color temperature chart above. The amount of oxygen supplied with the gas is the most important factor in determining the colour of the flame. The air to gas ratio for natural gas is around The air to gas ratio for LPG gases is higher.
The air to gas ratio for propane gas is approximately The air to gas ratio for butane gas is approximately To achieve this difference, LPG is typically provided in a smaller quantity but at a higher pressure, drawing more oxygen with it into the combustion process, giving LPG a higher air to gas ratio than for natural gas. A yellow or red flames on gas stove is dangerous, as it is indicative of incomplete combustion and carbon monoxide CO generation.
A gas cooker yellow flame is a dangerous safety problem, if it occurs with an indoor appliance like a gas stove. You could also be wasting gas. A blue flame means complete combustion is taking place. A key warning sign that you require gas appliance servicing are yellow or red flames or a gas flame colour with a yellow burning tip.
The exceptions to this are gas fireplaces and gas log fires that are designed to have a yellow or red flames. Burners blocked with dirt can result in improper combustion, leading to soot build up inside the appliance. Flames in a gas oven should burn with a blue flame colour, meaning complete combustion, as with other gas appliances. Blue flame in gas oven applies to the flame color of propane or natural gas cooktops, as well.
So, as a question for you, will food cook more quickly over a roaring orange campfire or a quiet blue gas jet? Hope that helps. A flame is a region of strong chemical reaction. For example, a fuel, like say propane gas, a hydrocarbon can react with diatomic oxygen to produce carbon dioxide plus water vapor and lots of heat and some light also.
Blackbody radiation is the emission of light from a hot body; higher the temperature larger the frequency of light emitted light emitted will shift from infrared, red, green, blue towards UV as temperature increases. This is what the answer on science line points to: more complete the combustion process, more the heat released, and higher the temperature, which makes it look blue.
Although the above reasoning of the answer and the physics is correct, this is not typically what happens in gas flames. This is a quantum mechanical phenomena, where the molecule gets into an excited state with the energy supplied by the combustion process and subsequently relaxes to a lower energy state by releasing the extra energy in the form of light.
The color of the light emitted in this process is characteristic of the molecule excited. Both, blackbody radiation and molecular excitation should be discussed in the context of color of the flame.
Orange flame is due to blackbody radiation coming out from an incomplete combustion or slightly cooler area, where the released energy is not enough to excite the molecules. When the combustion process is complete and produces enough heat to excite molecules, the molecular excitation produces a distinct bluish-green spectrum. A simple and beautiful experiment to see molecular excitation in play is to hold a salt in flame and see the color emitted.
This is often used to identify a salt, since the color is characteristic of the molecule. A properly adjusted gas stove burner burns with a blue flame.
But if the burner is out of adjustment, the gas flame will be yellow. Gas burners burn blue if the ratio of fuel to air is correct. A yellow burner flame is a symptom that the burner is not getting enough air for complete combustion of the gas.
If you want to fix the problem of a yellow flame yourself, allow the stove to cool, remove the top grates and lift up the stovetop to expose the burner piping.
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