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The Comprehensive Guide To EN50291:2018 – Detailed Changes Of 9 Points

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1. What is EN50291

EN50291 standard was approved by CENELEC (CE) on August 1, 2000. It publishes standards to help improve the quality and safety of products, services, and systems. If a product wants to be sold in the European market, it must meet this standard. EN50291 specifies the general requirements for the construction, testing, and performance of carbon monoxide gas detection devices designed for continuous operation in residential buildings. It is important to know that the use of this standard is not to monitor low concentrations of carbon monoxide for health purposes.

EN50291-1: this standard specifies the general requirements for the structure, testing, and performance of electrically operated carbon monoxide gas detection equipment, which is designed for continuous operation in domestic places.

EN50291-2: this standard specifies the general requirements for the structure, testing, and performance of electrically operated carbon monoxide gas detection devices, which are designed for continuous operation in recreational vehicles and fixed devices in similar places (including recreational boats).

EN50292: this standard provides information on the selection, installation, use and maintenance of carbon monoxide detection equipment for continuous operation in fixtures of family houses, caravans and ships. The standard is intended to cover any type of family or residential accommodation, including leisure accommodation vehicles, such as tourist and static caravans and RV and recreational vessels, such as canal barges. It should be read in conjunction with EN 50291-1 and EN 50291-2 and any other relevant national or local regulations.

EN50291 standard specifies two types of apparatus, these are:

—Type A: Provides visual and audio alarms and execution actions in the form of transferable output signals that can be used directly or indirectly to drive ventilation or other auxiliary devices;  

—Type B: Provides visual and auditory alarms only.

Generally speaking,type A is a networked intelligent carbon monoxide detector and type B is an ordinary carbon monoxide detector.

2. History of EN50291

2.1 Evolution process

The above versions update and adjust the test standards and performance specifications of carbon monoxide detectors. The really big changes are EN50291:2010 and EN50291:2018, which will be compared below.

2.2 The improvements upon the latest EN50291:2018

2.2.1 End of Life indicator has been made mandatory and must include an audible and visible warning:

When the battery is low, the device will beep once a minute and the yellow indicator light will flash once a minute; At the end of service life, the equipment will send out three fast beeps per minute, accompanied by three fast flashing yellow indicators per minute;

2.2.2 Guidance has been added for assessing battery capacity and expected life:

The manufacturer should declare the type of battery and its expected service life in normal operation. The service life should be based on the main current consumption and the capacity of the battery. Meanwhile, the battery manufacturer’s data on self-discharge losses and their estimation of the expected life of the battery should be declared too. When calculating the expected battery life, We need to calculate and sum up the minimum current for normal operation of each kind of power consumption. For example, we should consider the current required for the normal operation of the equipment for one year; The current required for beeping when the power is insufficient for 30 days. If you want to know the detailed current calculation method, you can fill in the form and contact us;

2.2.3 Requirements for mains powered alarms with back-up supply have been added:

Backup battery shall be provided for mains powered equipment whose objective is to demonstrate that the back-up power source is correctly monitored. This helps people make decisions in the face of detector’s short circuit, open circuit and low backup;

2.2.4 The number of potential interference gases has been increased:

The detector needs to further improve the detection accuracy to avoid false alarms caused by interference gases. For example, in winter, people like to sit by the fireplace and drink alcohol to warm up. The ethanol gas emitted by alcohol will interfere with the carbon monoxide detector and produce false alarms. There are many interference gases similar to ethanol. For details, please refer to Section 3.3 below;

2.2.5 Tests have been added for an optional alarm silence facility:

The setting of silence button is designed for those situations that affect people’s normal rest due to false alarm. Under alarm conditions, people can silence the equipment by touching the silence button, but the visual alarm signal should not be suppressed. If the concentration of carbon monoxide remains at or above 50ppm, the audible alarm will be triggered again after 15-minute of operating silence button. In addition, it shall not be possible to silence the alarm at concentrations above 300 ppm;

2.2.6 Requirements for the audible alarm and associated red visual signal have been clarified; low battery, fault and End-of-life audible and visual warnings are given in an informative annex:

It is suggested that the following indication sequences are used for visual and audible fault warnings.

2.2.7 An informative annex has been added for apparatus displaying low (Warning) CO levels:

Although low carbon monoxide concentration will not pose a life threat to human body, people’s health will also be damaged if they are exposed to low carbon monoxide for a long time. If the carbon monoxide alarm has the low concentration alarm function, it should meet the following requirements:

20ppm co concentration, No audible warning before 30 min; 30ppm co concentration, No audible warning before 15 min.

2.2.8 Requirements have been added for apparatus using radio links: 

The working range of the sample in free air shall be exceed 100 m. If the radio transmission fails, the function of a single equipment shall not be affected. The radio equipment shall have sufficient coding scheme to avoid cross interference, for example, by triggering alarms or receiving alarms from nearby systems. There shall be at least 65000 identification codes.

2.2.9 The sound output alarm requirement has been increased in line with the EN 14604 smoke alarm requirements:

For battery operated alarms: the sound output shall be at least 85 dB(A) at 3 m after 1min of alarm operation and at least 82 dB(A) after 4 min of alarm operation.

For mains powered alarms: the sound output shall be at least 85 dB(A) at 3 m after 4 min of alarm operation.

For both battery operated and main powered alarms: the maximum sound output shall not be higher than 110 dB(A) at 3 m after 1 min of alarm operation.

The maximum nominal frequency shall not exceed 3,5 kHz.

2.3 Latest EN50291:2018 does not include the following devices:

EN50291:2018 applies to carbon monoxide gas detection devices that detect defective    fossil fuel or solid fuel appliances for repair or replacement.EXCLUDES:

①Combustible gas detection except carbon monoxide itself.

②CO testing in industrial installations or commercial primes.

③CO testing for smoke and fire detection.

④CO testing of parking lots and tunnels.

3. Main contents of EN50291:2018 standard

3.1 Design Requirements

For safety reasons, except for batteries and replaceable co sensors, other parts of the detector shall be designed as fixed and non repFor safety reasons, except for batteries and replaceable co sensors, other parts of the detector shall be designed as fixed and non replaceable accessories. At the same time, the equipment shall also have visual indicators and alarm sound, as shown in the figure below.

Green: power indicator

Red: alarm indicator

Yellow: fault alarm indicator

NOTE: Visual indicators should be visible when equipment is installed in its operating position.


The construction of carbon monoxide detector needs to follow many standards, and the following figure will be attached. In the case of electrical recognition of the incorrect connection or absence of the sensor, the apparatus shall give an automatic signal of a fault. Moreover, it shall either be impossible, or recognized as an error, to connect a sensor not designed for carbon monoxide to a carbon monoxide apparatus.

Table 1 — Construction requirements

Fault warnings

The apparatus shall provide an audible and visible fault warning within 10 min of loss of continuity or short circuit to the sensor if the sensor is replaceable or within 1 day if the sensor is non-replaceable. The audible fault warning and low battery warning shall be clearly identified and different from a gas alarm.


All text on the apparatus shall be in accordance with national regulations and the apparatus shall carry durable label(s) or markings carrying the following information:

a.  the manufacturer’s or supplier’s name, trademark or other means of identification;

b.  the name of apparatus, model number (if any) and the type of gas to be detected;

C.  the number of this European Standard;

d.  the type of apparatus, A or B;

e.  the serial number or manufacturing date code of the apparatus;

f.  for mains-powered apparatus the electricity supply voltage and frequency and maximum power consumption;

g.  for battery-powered apparatus the type and size of replacement batteries (where replaceable);

h.  indication of the maximum lifetime recommended for the apparatus.

3.2 Testing for Performance Requirement

Test gas referenceCO volume ratioTest gas volume ratio Alarm Time
A30 ppm27 ppm±3 ppmNo active within 120min
B50 ppm55 ppm±5 ppmNot activate before 60 minutes but must activate before 90 minutes
C100 ppm110 ppm±10 ppmNot activate before 10 minutes but must activate before 40 minutes
D300ppm330 ppm±30 ppmActivate within 3 minutes
Test different concentrations of carbon monoxide

3.3 Gas Interference

In order to reduce the probability of false alarm, it is necessary to continuously test and adjust the detector so that it will not trigger alarm in the environment mixed withother interfering gases.

a. Methane at a volume ratio of (500±50) ppm for 2h;

b. Ethyl acetate at a volume ratio of (200± 0) ppm for 2h;

c. Hexamethyldisiloxane at a volume ratio of (10±3) ppm for 40min;

d. Ammonia at a volume ratio of (100±10) ppm for 2h;

e. Ethanol at a volume ratio of (2000±200) ppm for 30min;

f. Toluene at a volume ratio of (200±20) ppm for 2h;

g. Acetone at a volume ratio of (200±20) ppm for 2h.

3.4 Power

For mains powered apparatus, the electricity supply shall be within ± 10 % of the nominal value declared by the manufacturer. 

4. Testing Agency in Europe

As I mentioned above, if your carbon monoxide product want to be sold in Europe, it must meet EN:50291. In each country, there are many certification authorities to help the company evaluate whether carbon monoxide products meet the standard of EN50291, among which TUV is the more authoritative certification body.

5.  Future trend of CO Alarm upon EN50291 standard

5.1 The installation of carbon monoxide detectors has gradually become a rigid requirement

About 60 people in England and Wales die from accidental carbon monoxide poisoning every year. In order to further reduce the number of accidental deaths caused by carbon monoxide, the UK has published a new policy on November 23, 2021: except for gas stoves, all rooms equipped with fixed combustion devices need carbon monoxide alarms. This policy was introduced to save more lives. It can be seen that the market prospect of carbon monoxide in the UK is very broad.

5.2 The earlier you enter the market, the easier it is to gain popularity

At present, there are not many companies that meet the EN50291 standard and are also certified by relevant institutions, which means that a few companies can sell their products to the European market without too much competitive pressure. In addition, the earlier a product enters a new market, the easier it is to attract customers and quickly increase customer stickiness, which is very helpful to improve the popularity of the product.

6. Factors to consider when purchasing carbon monoxide detectors

If you are in the market for a carbon monoxide detector or purchase in bulk, here are the first things to notice.

6.1 Kite Mark —approved

CE originally utilized the Kitemark emblem for numerous popular items, including construction products. It means that CE has independently evaluated the product and certified that it complies with applicable Europe standards. Manufacturers must pay to test and validate their goods and manufacturing processes before they can be licensed to use the logo. In addition, CE will repeat the test to ensure that the product under test is consistently compliant. A licensed manufacturer will generally utilize the Kitemark emblem on a product. Simply look for it on the outside of the packaging or on the package itself.

6.2 EN50291-1:2018 is the latest standard

After locating the logo, you must verify which version of the product has been certified; The latest version of the standard was changed in 2020, and the previous standard has expired, so manufacturers are required to retest their products and re apply for authorization.

6.3 Comprehensive comparison of product quality and appearance

We may proceed with the comparison after the first two filters have been passed.

Battery: take note of the type of battery; if it is a replaceable battery, you must set a battery low alert after self-replacement; if it is not a replaceable battery, you must differentiate between battery life and product life match. There are also certain goods on the market with built-in batteries that have a long life and consume less power.

Guarantee: Given the lengthy life of the carbon monoxide detector, it is vital to examine the product’s warranty to ensure long-term safety. For example, suppose you buy a 10-year-old carbon monoxide alarm but it only has a three-year guarantee, and three years later your carbon monoxide alarm goes off and there is no means to repair it after the sale. Then you could be concerned about his ability to detect carbon monoxide accurately.

Portability: Consider whether a product offers this functionality if you want it to be utilized in numerous areas.

Look and feel:Carbon monoxide products on the market are often large in size and single in shape, so choosing a small and beautiful carbon monoxide product is easier to integrate into the home style.

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