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The most detailed report on the EN50291 standard

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The existence of standards related to the manufacture of carbon monoxide alarms has long been a source of confusion for people who are trying to compare different models before buying. When you search for carbon monoxide detectors on Amazon, you will find that in addition to the brand, battery type, and some basic information on the product’s title, you will also find standards like UL, BS, EN, etc. These standards reflect that the performance and parameters of the product have reached the mandatory standards stipulated by the country. Today, we mainly talk about the latest European standard EN50291.

The development of EN50291

In the early days, the standard for carbon monoxide detectors was issued by the British Standards Institute, code named BS7860. Until 2001, the European Union issued a standard code-named EN50291, which ran in parallel with the British Standard until April 2006 so that it allowed all manufacturers of BS-approved products to convert to the new European standard.

Until 2010, BS 50291:2001 existed as a single standard, but in 2011 it was split into two parts. Part 1 (2018) applies to electrical equipment in domestic premises. These are intended for continuous operation in a single location, such as a home, and are not designed to be moved from one setup to another. BS EN 50291 Part 1 supersedes BS EN 50291-1:2010+A1:2012.

Part 2 (2019) Electrical equipment designed to detect carbon monoxide in recreational vehicles and recreational crafts such as boats. Due to their portability, these devices may be affected by movement or vibration and should therefore be tested under more stringent conditions. BS EN 50291: Part 2 (2019) supersedes BS EN 50291-2:2010.

As of 26th September 2021, the European Standard on carbon monoxide EN50291-1:2010 has been withdrawn by BSI, as part of the transition plan, manufacturers, distributors and retailers can continue to sell products still carrying the Kitemark based on the 2010 standard, if the detectors were produced before 26th September 2021. However, CO detectors produced after this date will need to be tested to the new EN 50291-1:2018 standard to achieve the BSI Kitemark.

Why need to upgrade the EN50291 standard?

There is no standard that can be used forever since its promulgation. It will be constantly updated according to the changes of the times, the development of science and technology, and people’s needs. The upgrade of the EN50291 standard is mainly related to people’s needs.

Here are some of the most negative reviews collected on Amazon Europe, none of these products have passed the EN50291 standard, and the problems mentioned in the negative reviews are basically the headaches for the majority of buyers.

Problem 1: The actual service life of the detector is lower than the rated service life

Problem 2: A disposable item

Problem 3: Constant false alarm

The above three buyers respectively commented that the service life of the carbon monoxide detector did not match the specified service life, a disposable product and many false alarms. These are also the top three negative reviews among many negative reviews.

In response to the above three main pain points, the new EN50291 standard has also improved this. For the problem of low service life, the new version of the standard stipulates that the manufacturer must declare the battery type of the detector and the expected service life in normal operation; for the problem of false alarm, the new version of the standard requires the detector to have a higher anti-interference ability, and the applicable scene of the mute button has been improved; for disposable products, the new version of the standard stipulates that the detectors must operate normally according to their rated service life. The followings are the major version changes:

  • Forced end-of-life indicator with audible and visible warning;
  • Additional guidance on expected battery capacity;
  • Main power alarm and backup power requirements;
  • increase the ability to identify other potentially interfering gases;
  • Potential for optional alarm muting;
  • Clarify audible and visual alert requirements (including end-of-life warnings and low carbon monoxide level warnings);
  • Align with the audible output alarm of a smoke alarm (according to BS EN 14604).

End of life indicator is mandatory

Loud audible alarms and flashing lights are designed to facilitate people to more clearly “perceive” the presence of dangerous concentrations of carbon monoxide gas around them. 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;

Additional guidance regarding expected battery capacity

Since many users report that carbon monoxide detectors are single-use products and that the actual battery life is less than the rated life, the standard requires manufacturers to declare the battery type and expected life in normal operation. The data of the self-discharge loss of the detector and the current required for the normal operation of the equipment for one year need to be estimated. This requirement is to ensure that the detector can operate normally according to the rated standard until the end of its life;

Requirements for mains powered alarms and back-up power

AC powered and plug-in carbon monoxide alarms rely on continuous power to operate. The main power source for this type of alarm is the electricity in your home. In the event of a power outage in your home, these sirens automatically switch to their auxiliary power source, the battery backup. A backup battery should power the siren for at least 7 days without power to protect your home.

Increase in potential interference gases

The detector needs to further improve the detection accuracy to avoid false alarms caused by interference gases. The following is a test that some interfering gases will not cause an alarm at a certain concentration. When these gases exist for a long time so that they will threaten the health and safety of the human body, such as 2 hours, the alarm will be triggered.

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.

Standardised rules on alarm silence facility

The mute button is set up for situations where false alarms interfere with people’s normal rest. In an alarm situation, people can mute the device by touching the mute button, but the visual alarm signal will not be suppressed. Although the probability of false alarms triggered by detectors that meet the EN50291 standard is small, this possibility cannot be ruled out. So the mute button isn’t superfluous. The new version of the standard stipulates the following for the mute function: if the carbon monoxide concentration remains at 50ppm or above, the audible alarm will be triggered again after 15 minutes of operating the mute button. In addition, the detector cannot be muted at concentrations above 300 ppm;

Clarification of audible and visual alarm requirements

When the room is full of smoke, it is very dangerous for the detector not to respond at all, especially if there is a pregnant woman. It is suggested that the following indication sequences are used for visual and audible fault warnings.

Alignment with soundoutputalarms for smoke alarms

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.

3 Main contents of EN50291:2018 standard

1.Design Requirements

For the internal design, for safety reasons, the detector should be designed as non-replaceable hardware except for the battery and sensor. This is to prevent users from privately modifying the detector and causing unnecessary security risks. In addition to this, the construction of carbon monoxide detectors is subject to a number of criteria. If the sensor or battery is replaced, the detector shall automatically give a fault signal in the event that the detector recognizes a faulty connection or a missing sensor. For the external design, the detector needs to be equipped with indicator lights and a digital display, as shown in the figure below.

2.Fault warnings

If the sensor is replaceable, the device shall provide an audible and visual failure warning within 10 minutes of the sensor losing continuity or short circuit; if the sensor is not replaceable, audible and visual failure warning within 1 day. Audible fault warnings and low battery warnings shall be clearly identified and distinct from gas alarms.

3.Testing for Performance Requirement

Test different concentrations of carbon monoxide

Can a carbon monoxide detector that meets the EN50291 standard be called the best product?

What kind of carbon monoxide detector can be called the best detector? Some people think that the more expensive the better, the more features the better, the better the brand, these types of detectors are the best. In fact, it is not. The purpose of the detector is to detect the concentration of carbon monoxide in the air to give people enough reaction time to run to the open space. In my opinion, carbon monoxide detectors that can accurately measure carbon monoxide in the air without false alarms and premature shutdowns are the best detectors.

Compared with the previous version, the latest version of EN50291:2018 is very suitable for the best carbon monoxide detector. The reasons are as follows: the materials used in its internal structure and performance tests have reached a high standard of safety; mandatory increase visual indicators, end-of-life reminders and mute buttons; new battery capacity specifications; mandatory visual + audible reminders for any fault, low battery, low voltage alarms; the above are only the necessary performance requirements for the product, the next is very strict testing standards.

Before any carbon monoxide detector passes the EN50291 standard, the following tests are required: drop test, alarm triggering conditions, temperature and humidity effects, gas velocity test, power supply voltage test, carbon monoxide and other mixed gas test, long-term stability test, interconnection test, and a series of tests such as battery replacement, backup power supply, etc., the most important is the gas test. It is necessary to accurately test the carbon monoxide concentration from the mixed gas under any extreme conditions of high humidity and high temperature. In addition, the test speed is also very strict. For example, that a carbon monoxide concentration of 300ppm must be detected within 3 minutes and an alarm should be given.

Therefore, in such high standard test conditions, the detectors that can pass the latest version of the EN standard are very durable, high-quality products with high detection accuracy, low failure rate, and low false alarm rate. There is absolutely no problem, I would like to say that the detectors that pass the EN50291 version are the best detectors.

How to apply for passing the EN50291 standard

After reading this article, do you also have the idea of making your carbon monoxide detector pass the EN50291 standard? The following are the steps to apply for passing the EN50291 standard, hope it will be helpful to you:

1. Read the EU certified Country Commercial Guide

2. Identify applicable directive (legislation)

3. Determine the basic requirements in the directive

4. Pay attention to the unified European EN standard

5. Find a notified bodies (accredited testing laboratory)

6. Create technical documents and declaration of conformity and apply for CE marking

Declaration of Conformity:

The doc must be issued by the importer or manufacturer placing the product on the EU market. Doc is not issued by third parties or government agencies. The doc may need to be presented upon arrival at the customs authority or at the request of the market surveillance authority or the customer.

Information required:

  • Product ID / SKU
  • Product features
  • Name and address of manufacturer / importer
  • List of EN standards and / or EU directives
  • Place
  • Person in charge

Technical documents

In addition to the declaration of conformity, importers and manufacturers must prepare a technical document – a set of documents supporting doc. Here are some of the documents you may need to include in the technical documentation:

  • Design drawings
  • Technical drawings
  • Packaging design documents
  • List of applicable directives / regulations / EN standards
  • Test report
  • Quality control records
  • User manual
  • Risk assessment

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