Hydrocarbons are the simplest organic compounds, consisting entirely of hydrogen and carbon atoms. They can be straight-chain, branched chain, or cyclic molecules. Carbon tends to form four bonds in a tetrahedral geometry. Hydrocarbons have been utilised for there propensity for controlled combustion in oxygen. They are a suitable for many purposes such as heating, cooking, vehicular fuel and as a refrigerant. Commonly used today are Natural Gas (mostly methane) and Liquid Petroleum Gas (propane and butane).
Natural Gas and LPG
Natural Gas and LPG are hydrocarbon gas mixtures mined from fossil fuel deposits. Natural Gas is composed of 95% methane and 3.2% ethane, LPG is composed of propane and butane in varying ratios. They are a good source of relatively clean burning fuel that when ignited in oxygen results in a combustion reaction producing heat. They are today one of the primary energy sources used the world over. Whether plumbed directly from a municipal system or a decentralised system such as individual bottle or pressure vessel we need to be careful of leaks, and here’s why…
Gas is stored under pressure, because of this leaks are fairly common. On its own the key component methane is a colourless, odourless gas, that is relatively invisible and undetectable. So how can we detect a gas leak then? Well a fouling agent is added to the mixture so that the gas is easily detectable, recognisable and strongly detestable by human smell.
The specific gravity of methane relative to air is approximately 0.6 but published values of natural gas range from about 0.554 to about 0.87. This means that a gas leak will disperse fairly quickly rising up into the atmosphere, rather than settling lower.
That’s a good thing, helping to keep us safe as it generally stops a gas leak concentrating to dangerous levels. But this doesn’t help us too much if the leak is internal and the dwelling is sealed. In the case that the leak occurs in a small enclosed space then the concentration of natural gas in the air can quickly become dangerously high, where explosion and inhalation become real risks.
So lets investigate these two hazards a little bit more shall we:
Being highly combustible and easily ignited from a spark or other source, an unvented gas leak runs the risk of becoming a high explosion risk. There are many examples of fatal explosions resulting from gas leaks. In the case of a suspected leak make certain not to cause ignition from heat sources, electrical sources or electromagnetic sources. Immediately vent the enclosed space to outside ambient air, this reduces the pressure and concentration of the combustible gas.
Incomplete combustion of natural gas can produce carbon monoxide, this gas mixture in high concentrations is considered to act as an asphyxiant, which means it displaces oxygen from the air. A lack of oxygen in the air causes hypoxia, symptoms include headache, decreased vision, fatigue, shortness of breath and loss of consciousness.
Losing consciousness while being exposed to a natural gas leak is dangerous. The carbon monoxide in the natural gas prevents oxygen from being absorbed into the bloodstream. This not only damages internal organs and tissues, but can cause death. In the event of sudden or severe exposure to natural gas, try to move the victim out of the home and into fresh air as quickly as possible.
What you can do about it
What if your sense of smell is degraded? Well like the smoke detectors we use to warn of house fires, gas detectors are readily available and can be installed in your home to warn of gas leaks.
For more information on this subject see the following page, it contains handy tips on how to detect a gas leak, and what to do if you find one.
We recommend the 24 Hour Emergency Plumbers Melbourne they are experts in gas plumbing. They can help with installation of gas burning appliances and detectors, they do professional repair (including welding and fitting), they can even help during the design phase of a new house or apartment block.