A built-in chemical sensor with a service life of at least 10 years is responsible for detecting a dangerous concentration of carbon monoxide in FireProtect 2. Carbon monoxide (CO) is a colourless, tasteless, and odourless gas produced due to incomplete fuel combustion in automobile engines and heating appliances that use coal or other natural fuels. For example, it can be made by fireplaces, boilers, or heating systems. In airtight or closed rooms with poor ventilation, life-threatening concentrations of carbon monoxide can accumulate.