Gas boiler with control box and gas explosion warning
Air quality

Safe heating with gas heating & gas boiler

Unfortunately, gas heaters repeatedly cause devastating gas accidents with high levels of property damage and personal injury. This is because under certain conditions, the gas ignites and causes an explosion. In the fall of 2024 alone, explosions in Memmingen and Bochum claimed victims. We explain how a gas explosion occurs and how you can prevent it.

Author:

Undine Jaehne

Date:

29.11.2024

You will find the following content in our article:


The natural gas used for heating consists mainly of the hydrocarbon methane (CH₄), which accounts for 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 if 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, an explosive gas atmosphere and an ignition source are required. Natural gas consists of 75 to 99% methane, the lower explosion limit of which is 4.5% by volume. For comparison: the oxygen content in the air is just under 21% by volume. Even a very small amount of natural gas/methane can therefore cause an explosion.

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:

  1. Reduce the gas concentration by opening all windows and doors wide. This will allow the gas to mix with the outside air.
  2. Immediately extinguish open fires, such as burning candles, smouldering cigarettes or your gas cooker when it is switched on. 
  3. Prevent further gas from flowing into the room by shutting off the gas meter stopcock.
  4. 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.

What is the best way to measure methane?

Heating gas, especially methane, can be measured in various ways. One simple method is to use an oxygen sensor to measure the oxygen content in the air. As soon as another gas appears - in this case methane - oxygen is displaced in the gas mixture, and thus the falling oxygen value indicates the methane content. This method is well suited for long-term monitoring, but is less accurate. For precise and direct measurements, a special methane sensor that specifically detects the gas is recommended.

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.

air-Q science detects dangers such as smoke, gas leaks, break-ins and pollutants at an early stage for maximum safety
References

(Cover photo: Shutterstock/ Studio Harmony)

Safe heating with gas heating & gas boiler
NOW | the air-Q science with oxygen sensor
Carefree breathing with air-Q science. For a home where you can breathe freely!

Summary

What are the most common risks when heating with gas?

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The main dangers are gas leaks, which can lead to explosions, and carbon monoxide poisoning. These are often caused by incomplete combustion or defective heating appliances. As both gases are odorless, they can go unnoticed and be life-threatening.

How do I detect a gas leak in my home?

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Natural gas has a smell that is reminiscent of rotten eggs or sulphur. If you smell this odor, you should open the windows immediately, turn off the gas supply and leave the house. Electrical appliances must not be used as sparks could ignite the gas.

How can I prevent a gas explosion?

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Ventilate immediately if gas is suspected. Switch off all gas sources. Do not use any electrical appliances or open fires. Have your gas pipes and appliances checked regularly by specialists.

How does an air measuring device protect against hazards?

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An air measuring device monitors the room air in real time and detects methane, carbon monoxide and other pollutants. It warns you visually, acoustically and via app when critical levels are reached. This enables early intervention

What to do if the CO detector sounds the alarm?

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Open all windows. Leave the room immediately. Call the emergency services. Do not continue to operate the heating until a specialist has clarified the cause.

What is the lower explosion limit of methane?

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Methane becomes explosive from a concentration of around 4.4% by volume in the air. Therefore, even a small leak is potentially dangerous if it occurs in a closed room.
air-Q Air Quality Meter

Monitor air quality, all air components and environmental influences with the air-Q. For your health and performance.

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