The manufacturing standard for carbon monoxide detectors is divided into two sections. The earlier standard, BS 50291: 2001, was replaced in April 2011, leading to its division into two parts: Part one addresses CO detectors for domestic use, while Part two focuses on detectors designed for recreational vehicles like caravans and boats.
Part One specifies the test methods and performance requirements for “electrical apparatus for the detection of carbon monoxide in domestic premises,” commonly referred to as carbon monoxide detectors. It covers a broad range of performance and durability criteria, including testing for sensor reaction times, resistance to temperature changes, and minimum alarm volume levels.
This standard is the most widely used for carbon monoxide detectors and establishes a baseline performance level for devices designed for continuous operation in domestic settings.
When purchasing a CO detector for home use, ensure it complies with either Part One or Part Two of BS EN 50291.
Part Two outlines the additional testing and performance requirements for carbon monoxide detectors designed for environments where movement or vibration is expected during their use. Generally, detectors meeting this standard are considered more durable than those certified under Part One alone.
This standard is becoming increasingly common, likely driven by a growing demand for portable CO detectors. Public awareness campaigns have worked to highlight the risks of carbon monoxide exposure during activities like camping or boating.
For holidaymakers or frequent users of boats and caravans, this standard provides a clear way to identify detectors specifically designed to protect them while travelling. Always ensure that CO detectors intended for use outside standard domestic settings comply with Part Two of BS EN 50291.
A CO alarm detects the presence of carbon monoxide (CO) gas in order to prevent carbon monoxide poisoning. CO alarms have evolved to become safety-critical devices, constantly monitoring to protect people from poisonous CO gas, known as the silent killer.
Carbon monoxide starves the body of oxygen. Making individuals feel unwell, and therefore is potentially mistaken as a cold or flu. The longer the exposure to carbon monoxide, the worse the symptoms become. High levels of carbon monoxide exposure can be fatal.
If you suspect carbon monoxide poisoning, it is crucial to act quickly. Move to fresh air immediately and seek medical attention.
Everyone is at risk of carbon monoxide poisoning. However, there are certain groups that are particularly vulnerable due to the nature of carbon monoxide and how it affects the body. Ensure you take the necessary steps to protect yourself and others from carbon monoxide poisoning.
It’s critical that appliances in the home do not leak carbon monoxide. These appliances – such as boilers, gas fires, chimneys, and flues – should be serviced by a registered engineer, and an alarm should be fitted in the same room as the appliance.
It’s not just inside the house where carbon monoxide safety matters. Anywhere fossil fuels are burned, CO can be produced. Ensure that appliances are checked and maintained, barbecues are always used in open air (even after they have gone out), and that a CO alarm is present.
Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.
Doc: 392 | Last Updated at: 2026-08-10 09:41:42