The natural gas used for heating consists mainly of the hydrocarbon methane (CH₄) with 75 to 99 %. In addition to methane, it also contains various other gases such as carbon dioxide, nitrogen, ethane, ethylene, propane, butane and small quantities of noble gases. For the sake of simplicity, we call the heating gas "gas" in the article, even though we do not refer to all gaseous substances such as oxygen.
A gas explosion can discharge with such force that entire residential buildings are destroyed and people are fatally injured. In a gas explosion, an explosive gas mixture ignites and burns off in a very short time. Depending on the amount of gas, the pressure in the room and the temperature of the gas, either a deflagration occurs or the mixture detonates.
How safe is heating with gas?
Although renewable energy sources have become increasingly widespread in Germany in recent years, natural gas remains a popular heating fuel. Gas heating systems are installed in many single-family homes and apartment buildings. The reasons for this are that gas heaters:
- operate relatively cleanly and have a high degree of efficiency.
- are easy to regulate.
- cause a relatively low emission of pollutants.
- are relatively low-maintenance. This is because the boiler only needs to be checked once a year by a chimney sweep.
Despite these advantages, however, heating with gas also harbours dangers. Even low concentrations are explosive, since gas or natural gas, which consists mainly of methane, is a highly explosive fuel. The danger increases especially when interiors are not sufficiently ventilated, as in winter. Leaking pipes, faulty appliances, a defective valve or an incorrectly connected gas cooker can cause gas to escape into the room air and quickly reach critical limit values. Even small amounts of gas are enough to cause an explosion.
Can you smell a gas leak?
The problem here is that natural gas does not smell. Therefore, scents are added to the heating gas. Chemical, acrid or slightly sulphurous odours are used for this purpose, so that the escaping gas becomes perceptible. However, these odours are only noticed when people are present and they are not, for example, sleeping. Proper ventilation is therefore important when heating with gas, but it is not sufficient. Rather, you should regularly check all pipes and appliances that are operated with gas. This is because the gas suppliers are only responsible for the safety of the gas transport up to the private house connection; from your own four walls onwards, you are responsible.
How does a gas explosion occur?
For gas to explode, it needs an explosive gas atmosphere and an ignition source. Natural gas consists of 75 to 99 % methane, whose lower explosion limit is 4.5 % by volume. For comparison: the oxygen content in the air is just under 21 percent by volume. An explosion can therefore occur even with a very small amount of natural gas/methane.
Ignition sources can be both electrical and mechanical. If there is a sufficient concentration in the room, even a spark can ignite the gas and a chain reaction occurs in which the gas burns abruptly, together with a massive pressure wave. All that is needed for this is the breakaway sparks when the light switch is flicked, sparks from colliding metal or small flames when candles are lit.
How do I prevent a gas explosion?
If you suspect a gas leak, keep your hands off electrical appliances, plugs, mobile phones and doorbells. All these devices can provide the initial spark for a gas explosion. You should act quickly in the event of a gas leak:
- Reduce the gas concentration by opening all windows and doors wide. This will allow the gas to mix with the outside air.
- Immediately extinguish open fires, such as burning candles, smouldering cigarettes or your gas cooker when it is switched on.
- Prevent further gas from flowing into the room by shutting off the gas meter stopcock.
- Warn other occupants of the house by knocking or calling - not by ringing the bell - and leave the house quickly.
Not only a gas explosion is dangerous, but also the inhalation of high amounts of gas depending on its composition. This can lead to breathing problems, increase the respiratory and heart rate or even cause low blood pressure with dizziness and light-headedness. In addition, the lack of oxygen can affect the central nervous system and cause drowsiness, numbness in the arms and legs or even mental confusion and memory loss. If you have inhaled more gas, you should consult a doctor.
Safe heating with gas - monitor methane levels
Since natural gas consists mainly of the hydrocarbon methane (CH₄), it is important to check methane as the main component of the gas in the indoor air. This way you can detect an impending gas leak in good time. The air-Q air analyser is the only air measuring device to offer you a methane sensor that makes the gas specifically detectable. Thanks to infrared absorption, there is virtually no cross-sensitivity for other air components and you can evaluate your room air specifically for this measured value. In real time, the air-Q measures the air quality and warns you when methane levels rise. This way you detect gas leaks early, gain valuable time to act and prevent a gas explosion.
(Cover photo: Shutterstock/ Studio Harmony)
