Sep 30, 2026Regulations & Compliance
EN 50291 Explained: What the CO Alarm Standard Requires of Importers
EN 50291-1 is the European standard for domestic carbon monoxide alarms. This guide covers the standard's scope, the alarm thresholds it sets, sensor types, and what importers must check on the...
EN 50291 Explained: What the CO Alarm Standard Requires of Importers
Carbon monoxide (CO) is invisible, odourless and potentially fatal, so the European standard for domestic CO alarms —EN 50291 — is one of the strictest product standards in the home safety category. Importers who understand what it requires can separate a genuine CO alarm from a decorative lookalike in a single look at the paperwork.
This guide explains the scope of EN 50291, the response behaviour it defines, the sensor options, and the checks importers should run before committing to a container.
Scope: EN 50291-1 vs EN 50291-2
The standard has two parts:
• EN 50291-1 —*Electrical apparatus for the detection of carbon monoxide in domestic premises — Part 1: Test methods and requirements.* This is the part that applies to ordinary household CO alarms. The current edition is EN 50291-1:2018.
• EN 50291-2 — the part covering CO detection in recreational vehicles, caravans and similar environments, with different environmental requirements.
If you are sourcing a standard home CO alarm, Part 1 is the relevant document. Confirm the report cites Part 1 explicitly.
What the standard actually requires
EN 50291-1 sets out how a CO alarm must respond to defined gas concentrations, how it must behave when the sensor ages or the battery fails, and how it must be marked.
Requirement area | Why it matters to a reseller |
Alarm response at defined CO concentrations | The alarm must sound within prescribed time frames at specified ppm levels |
Alarm must not sound too early | Avoids nuisance alarms that lead users to disable the unit |
Sensor fault and end-of-life indication | The unit must warn when it can no longer be trusted |
Low-power warning | A distinct signal before the battery dies |
Response in the presence of other gases | Reduces false alarms and missed alarms |
Marking and instructions | Clear text and symbols for consumers |
A compliant alarm sounds at all of these, within limits — it does not simply "beep when it smells gas".
Why sensor type matters for your SKU range
Most domestic CO alarms use one of two sensing technologies:
• Electrochemical sensors — the dominant technology for residential alarms. They offer good long-term stability and low cross-sensitivity, which is why long-life (10-year) sealed CO alarms rely on them.
• Biomimetic / gel sensors — historically cheaper, with a shorter effective life and a reputation for more drift over time.
For a range you intend to support for years, confirm the sensor type and rated life with the factory, and check that the alarm has an end-of-life signal so users know when to replace the unit. Note the standard's requirement that sensors have a limited service life: CO alarms are not lifetime devices.
The checks importers should run
1. Standard version. The report should cite `EN 50291-1:2018` (or the current edition). Undated references are a red flag.
2. Part 1 vs Part 2. Match the report to your intended market — a Part 2 report is not the document for a household alarm.
3. Model match. The model on the report must be the model you buy.
4. Battery architecture. Confirm whether the SKU is a 10-year sealed unit or a replaceable-battery model, and that the report covers that configuration.
5. End-of-life and fault signalling. Verify the unit produces distinct signals for low battery, sensor fault and end of life.
Common misunderstandings
• "EN 50291 means the alarm detects any gas." No. It is specific to carbon monoxide.
• "CO alarms replace CO detectors for commercial spaces." Residential EN 50291-1 units are for domestic premises. Commercial/industrial detection follows different standards.
• "Low-level CO features are part of EN 50291." They are not. Low-level display or logging is a product feature, not a requirement of the standard — see our dedicated guide on low-level CO alarms.
FAQ
What is the difference between EN 50291-1 and EN 50291-2?
Part 1 covers domestic premises; Part 2 covers recreational vehicles and similar environments. A home CO alarm should be tested to Part 1.
Do combination smoke and CO alarms need EN 50291?
Yes. A combination unit must meet both the smoke standard (EN 14604) and the CO standard (EN 50291).
How long do CO sensors last?
It depends on the sensor and the product design. Sealed 10-year models use long-life electrochemical sensors; replaceable models may have shorter sensor life. Always confirm the rated sensor life and the end-of-life signal, and follow the manufacturer's replacement date.
Can I use a US CO alarm in Europe?
US models are typically tested to UL 2034, which differs from EN 50291 in test methods and alarm behaviour. Do not assume a UL 2034 unit satisfies European requirements.
About V-COME — Focused. Professional. Reliable.
V-COME Safety Technology Co., Ltd manufactures smoke alarms, carbon monoxide alarms, heat alarms and combination alarms (including smoke + CO and smoke + heat), plus RF and Wi-Fi interconnected solutions. Certified to EN 14604:2005/AC:2008, BS 5446-2:2003, EN 50291-1:2018, UKCA, CE, RoHS, REACH and ISO 9001:2015; UL 217 / UL 2034 in progress.
Contact: Jessy Chen — jessy@vcome-safety.com
