Why natural gas (methane) alarms can't be installed near the floor?
Natural gas is lighter than air and tends to float updwards. The natural gas alarm should therefore be placed on a wall not more than 30cm from the ceiling and not more than 5 meters from the gas appliance.
Natural gas (also known as methane) has become a widespread energy source. Although it is a clean, efficient and relatively safe gas it can cause carbon monoxide poisoning and when a gas leak occurs a small spark from simply turning on a light switch can cause a fire (as natural gas is highly flammable) or create an explosion.
To guard against Natural Gas (Methane) leakage, we recommend that there should be one natural gas alarm per floor in the home.