COOKING GAS: THE DANGER WE CAN LIVE WITH.
Liquefied Petroleum Gas (LPG) popularly referred to as ‘Cooking Gas’ is one of the lightest fractions of oil and it burns very clean, with extremely low levels of pollutant emissions.
Because of these characteristics, it can be used in closed environments like the kitchen, other enclosures that are sensitive to pollutants, and to manufacture glass and ceramic products.
LPG is a flammable mixture of hydrocarbon gases used as fuel in heating appliances, cooking equipment, and vehicles. It is prepared by refining petroleum or “wet” natural gas and is almost entirely derived from fossil fuel sources, being manufactured during the refining of crude oil or extracted from petroleum or natural gas streams as they emerge from the ground.
It was first produced in 1910 by Dr Walter Snelling and the first commercial products appeared in 1912. It currently provides about 3% of all energy consumed and burns relatively cleanly with no soot and very few sulfur emissions. As it is a gas, it does not pose ground or water pollution hazards. LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and 43.5 MJ/kg for premium grade petrol (gasoline). However, its energy density per volume unit of 26 MJ/L is lower than either that of petrol or fuel oil, as its relative density is lower (about 0.5–0.58 kg/L, compared to 0.71–0.77 kg/L for gasoline).
As its boiling point is below room temperature, LPG will evaporate quickly at normal temperatures and pressures and is usually supplied in pressurized steel vessels. They are typically filled to 80–85% of their capacity to allow for thermal expansion of the contained liquid. The ratio between the volumes of the vaporized gas and the liquefied gas varies depending on composition, pressure, and temperature, but is typically around 250:1. The pressure at which LPG becomes liquid, called its vapour pressure, likewise varies depending on composition and temperature; for example, it is approximately 220 kilopascals (32 psi) for pure butane at 20 °C (68 °F), and approximately 2,200 kilopascals (320 psi) for pure propane at 55 °C (131 °F). LPG is heavier than air, unlike natural gas, and thus will flow along floors and tend to settle in low spots, such as basements.
WHY WE NEED TO PAY ATTENTION:
There are two main dangers from this. The first is a possible explosion if the mixture of LPG and air is within the explosive limits and there is an ignition source. The second is suffocation due to LPG displacing air, causing a decrease in oxygen concentration. In addition to this,
- LPG forms a flammable mixture with air in concentrations of between 2% and 10%.
- It can, therefore, be a fire and explosion hazard if stored or used incorrectly.
- Vapour/air mixtures arising from leakages may be ignited some distance from the point of escape and the flame can travel back to the source of the leak.
- At very high concentrations when mixed with air, the vapour is an anaesthetic and subsequently an asphyxiant by diluting the available oxygen.
- LPG is approximately twice as heavy as air when in gas form and will tend to sink to the lowest possible level and may accumulate in cellars, pits, drains etc.
- LPG in liquid form can cause severe cold burns to the skin owing to its rapid vaporization.
WHAT CAN BE DONE ABOUT IT?
- Always turn on the fan when you cook. Keep it on the highest setting.
- Automatic fire /smoke detection and gas detection and control system to alert in the case of leaks either caused by accident, by you or someone other than you. This alert can reach you even while you are away from home.
- If your fan vents back into the house rather than to the outside, open a window.
- Cook with a blue gas flame. If you see an orange flame, it means you need to have your stove adjusted.
- Have a qualified contractor inspect your gas range. Keep it maintained.
- For those renovating their homes, a conduction cooktop is an improvement. It uses magnetic energy. Thus, you will not have noxious combustion by-products. However, you will still have some pollution from heating food and cooking oil, as in all types of stoves
- Do not use your gas range to heat your home
LPG is stored in pressurised Cylinders, and like tyres, they have Expiry dates. They are not safe for use if expired so please be careful. The expiring date is coded on the side of the Cylinder in alphabetical order, A, B, C, D in quarters.
A is for March 1st Qtr
B is for June. 2nd Qtr
C is for Sept. 3rd Qtr
D is for Dec 4th Qtr
There is some two digit number that follows, e.g. D06. The digit stands for the year the validity expires. D06 stands for 4th Quarter ( December) 2006. That is the expiring date of that Cylinder, so be careful to avoid domestic accidents. Please share to save a life.
Photo and Text Credit: Wikipedia