CO 51ppm-Brojensmarthome

Carbon monoxide expert , we have been engaged in the field of security for more than ten years. Now we will share experience and personal opinions with readers by writing articles, hoping to help readers.

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carbon monoxide detector 51 ppm

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There have been two world wars in history, resulting in a total of about 70 million deaths. In this peaceful era, people enjoy the convenience of technology and the relaxation of travel, but they have not yet realized that in this era of advanced technology, people are vaguely experiencing the “third world war”. The enemy this time is not human, but It’s carbon monoxide – the silent killer.

December 5, 1952, was a day that made all Londoners panic. A heavy fog shrouded the entire city of London. Pedestrians walked by touching the walls. Cars drove slowly with their headlights on during the day. All flights were forced to be grounded. A heavy fog made the once lively London city so silent. In addition, 4,000 people died unexpectedly in the five days covered by the heavy fog, and more than 8,000 people died one after another in the next two months. This situation may have been a mystery at the time, but in today’s, It is easy for society to explain the truth. That is, with a high concentration of carbon monoxide, 4,000 people died of hypoxia due to breathing difficulties in a short period of time. Although the remaining 8,000 people survived at that time, their body functions and brains were affected by carbon monoxide. In the following days their health got worse and worse, and eventually led to death.

The great smog of London -Brojensmarthome

The London smog event can be said to be the event with the highest number of accidental human deaths after World War II. Since then, more and more people have begun to pay attention to carbon monoxide gas, many companies have begun to put carbon monoxide detector products on the shelves, and many countries represented by the United Kingdom have also introduced laws on carbon monoxide, with the purpose of reducing the incidence of carbon monoxide poisoning as much as possible, thereby reducing mortality.

What is carbon monoxide?

Carbon monoxide is a colorless, odorless, tasteless, flammable gas which is produced by Incomplete combustion of carbonaceous materials. From chemical formula, it is made up of one carbon atom and one oxygen atom connected by a triple bond. Thats why people also call it as CO. In addition to this, it is also known as the silent killer because people often die of suffocation by inhaling carbon monoxide in their sleep.

Dangerous gas: CO -Brojensmarthome

Why carbon monoxide is dangerous?

Since carbon monoxide is diluted by the atmosphere in the environment and easily oxidized by oxygen to carbon dioxide, carbon monoxide has little impact on the environment. It is called a silent killer because when it is inhaled into the body, it will quickly combine with the hemoglobin in the human blood, so that the blood stops delivering oxygen to the brain, lungs, liver and other organs, causing people to unknowingly sleep in their dream, suffocated to death. This is the most dangerous cause of carbon monoxide.

Carbon monoxide readily binds to hemoglobin-Brojensmarthome

How long does it take to get carbon monoxide poisoning?

The speed of carbon monoxide poisoning is mainly related to the concentration of carbon monoxide. The higher the concentration of carbon monoxide around, the more likely people are to be poisoned. For example, if the surrounding carbon monoxide concentration is 1000ppm, people will feel sick within 20 minutes and die within 1 hour. More detailed carbon monoxide poisoning concentrations and corresponding symptoms are mentioned below.

Safe levels of carbon monoxide ppm

0.1 ppmNatural level and clean air
1 ppmIncreased rates of
3~7 ppmIncreased rates of asthma
5~6 ppmBaby weight is low if the pregnant woman is exposed to CO
9 ppmAffects heart function in patients with coronary artery disease
10 ppmDeath from heart disease and congestive heart failure
15~20 ppmReduced motor capacity and alertness
25 ppmIrreparable brain damage to the fetus
27 ppmCardiovascular disease increased by 21%
30 ppmEarliest oneset of exercise angina attack
35 ppmOxygen masks are required
50 ppmthe maximum concentration that healthy adults can bear within 8 hours
70~75 ppmHeart patients increased pain
100 ppmHeart and brain damage
200 ppm2 ~ 3 hours, slight headache and fatigue
400 ppmForehead pain within 1 ~ 2 hours; Life threatening after 3 hours
800 ppmDizziness, nausea and spasm within 45 minutes; Loss of consciousness within 2 hours; Died within 3 hours
1600 ppmHeadache, dizziness and nausea within 20 minutes; Died within 1 hour
3200 ppmHeadache, dizziness and nausea within 5 ~ 10 minutes; Died within 30 minutes
6400 ppmHeadache, dizziness and nausea within 1 ~ 2 minutes; Died within 10 ~ 15 minutes
12800 ppmDied within 1 ~ 3 minutes

It can be seen from the above table that 50ppm is the highest carbon monoxide concentration that the human body can tolerate, and people can last for 8 hours in a carbon monoxide environment with a concentration of 50ppm. Therefore, 50ppm is classified as a dangerous edge, which can also be called a warning line. The safe carbon monoxide concentration range is no more than 30ppm, which is also the concentration that will not trigger the alarm of carbon monoxide detectors.

Highest concentration people can tolerate in 8 hours 50ppm
Concentration which the detector will not be trigged 30ppm

Dangerous levels of carbon monoxide

As mentioned above, carbon monoxide at a concentration of 50 ppm is already the critical value of the dangerous value, which means that a concentration of more than 50 ppm is a dangerous concentration. When the carbon monoxide concentration exceeds 50ppm, people will experience dizziness, fatigue, drowsiness, and loss of consciousness, and the alarm will also goes off within 90 minutes. With higher and higher concentrations, people will experience the above symptoms earlier, and even cause people to die within several minutes. This is because high concentrations of carbon monoxide can quickly combine with hemoglobin, causing people to die from extreme hypoxia within 1 hour or even 3 minutes. The above conditions are for healthy adults, but if the elderly or children or sick people are exposed to carbon monoxide, symptoms may be more severe.

ConcentrationThe detector goes off
0~50 ppmN/A
51~99 ppmNot activate before 60 minutes but must activate before 90 minutes
100~299 ppmNot activate before 10 minutes but must activate before 40 minutes
300ppmActivate within 3 minutes

More details please click here.

CO exposure limits in UK

The World Health Organization states that 9 ppm is the maximum indoor safe carbon monoxide level for 8 hours, as UK is a developed country with heavy industry, the limit for outdoor carbon monoxide concentration is 20~30ppm, and the limit for household and indoor carbon monoxide concentration is not more than 50ppm. This is because a person can be exposed to a carbon monoxide concentration of 50ppm for 8 hours. In addition to this, in 2018, the UK also updated the limits for carbon monoxide concentrations in the workplace: Carbon Monoxide Long Term (8 Hour) Exposure Limit (LTEL) is now 20ppm and the Short Term (15 Min) Exposure Limit (STEL) is now 100ppm.

CO limits in UK (8 hours)Concentration
Maximum indoor safe level9 ppm
Workplace level20 ppm
Outdoor level30 ppm
Household and indoor level50 ppm

Indoor carbon monoxide concentration

If you turn on gas equipment such as heaters and boilers at home, and the indoor space is small, the indoor space is more airtight than the outdoors, so high concentrations of carbon monoxide will be generated in a short time. The following are the main sources of carbon monoxide indoors:

Equipment for home useConcentration of carbon monoxide
Gas stoves5~15ppm
Cigarettes20 ppm
Water heater1600ppm
Water heater3200ppm

In particular, cigarettes are mentioned here. The gas in cigarettes is directly inhaled into the lungs of the human body, which means that the smoker has a carbon monoxide concentration of 20 ppm in the body. Although it is not fatal, if you continue to smoke for a day, the concentration of carbon monoxide in the body will be higher, more likely to cause dizziness, weakness and even more serious consequences.

How to test for carbon monoxide without a detector

Due to the colorless and odorless nature of carbon monoxide, it is difficult for us to detect its presence without the aid of a carbon monoxide detector. However, we can preliminarily determine whether there is carbon monoxide around through some subtle observations, and then take corresponding measures.

Abnormal behavior of people

When people are exposed to dangerous concentrations of carbon monoxide and do not evacuate in time, they will slowly show paleness, dizziness, weakness, and even loss of consciousness. If we find that people around us have the above symptoms, or when you are also in it and feel unwell, please open the window closest to you immediately and take your family to the outside.

Abnormal symptoms after CO poisoning-Brojensmarthome

 Symptoms of equipment when leaking gas

Natural gas is also a colorless and odorless gas. However, natural gas companies often add substances to natural gas tanks that cause a pungent odor when natural gas leaks. Similarly, although carbon monoxide is also a colorless and odorless gas, we can preliminarily determine whether carbon monoxide exists through the use of some key equipment signs. For example:

  • You will see black soot marks on the cover of the gas range.
  • A large amount of condensation water formed on the window glass where the equipment was installed.
  • Soot or yellow/brown stains on or around boilers, stoves or stoves.
  • Smoke appear in the room.
  • All gas appliances except gas fireplaces emit yellow flames.
  • The indicator light often goes out.
  • Solid fuel burns much slower than usual.
  • Symptoms go away once you leave home.
  • When central heating is used more frequently, you can experience seasonal symptoms, such as winter headaches.
  • Pet is sick.
  • Symptoms can appear or appear to get worse while using fuel-burning equipment.

If you have any of the above symptoms, please move outside immediately, because your body may be out of order for a few minutes later. In addition, if you want to test your carbon monoxide detector at home, you can reffer to this article.

What to do if carbon monoxide alarm goes off

Mentioned above are two methods of indirectly proving the possible presence of carbon monoxide gas around without the aid of a carbon monoxide detector. Of course, the easiest and most efficient way to detect carbon monoxide is to install a carbon monoxide detector. When the detector detects a dangerous concentration of carbon monoxide and alarms, people tend to evacuate to the outdoors for the first time. However, not all situations in which the alarm goes off require people to move outside, as the alarm will also have false alarms. To reduce unnecessary hassles, here are a few steps you can follow.

1.When you hear the siren, please keep calm first.

When people are highly stressed or frightened, they often forget what to do and miss the best time to evacuate.

2.Spare yourself 5 minutes to determine whether there is a false alarm.

Please understand that the minimum concentration to trigger a carbon monoxide alarm is 50ppm, and even if the concentration reaches 1000ppm in a short period of time, people will experience dizziness, weakness, nausea and other symptoms after at least half an hour in the environment. So be sure to stay calm when you hear the sound, because people are still safe within 5-10 minutes while the detector going off. People can use this short 5 minutes to first open the nearby windows to see whether their family members have obvious symptoms such as paleness and weakness. If not, then focus on checking the kitchen and rooms with gas equipment. If you don’t see obvious smoke, water droplets, etc., you can initially judge that it is a false alarm. At this time, you only need to press the mute button of the detector to stop the alarm. Certainly, You also don’t have to worry about hitting the mute button due to your misjudgment. If dangerous concentrations of carbon monoxide do exist around, the alarm will go off again within 10 minutes, even if you hit the mute button. At this time, you can take your family directly to the outside, and then call for help and wait for a professional inspection.

It is recommended here to install a carbon monoxide detector with a concentration display in your home. When the detector alarms, people only need to check the readings on the detector. If the reading is higher than 50ppm, it means that there do exist carbon monoxide gas. At this time, you should wake up your family immediately and evacuate the house; if the reading is lower than 50ppm, it means that the detector is falsely reporting, and you only need to press the mute button.

3.Go to the hospital immediately.

If somebody accidentally inhale carbon monoxide, please go to the hospital immediately for a comprehensive examination. If the poisoning is serious, oxygen inhalation and first aid are also required.

Sequelae of carbon monoxide poisoning

Patients with mild carbon monoxide poisoning can recover within a few hours or the next day if they get out of the poisoning environment in time and breathe fresh air, and usually there will be no sequelae.

For patients with severe poisoning, the residual sequelae are mainly due to the manifestations of severe ischemia and hypoxia in the brain. After the nervous system is damaged, the incidence rate is more than 80%. Its performance is diverse, mainly in several aspects:

Dementia type, patients often have mild disturbance of consciousness or intelligence decline, unresponsiveness, and incontinence.

Mental confusion, for example, patients often cry and laugh, usually have hallucinations, auditory hallucinations, moodiness, and sometimes even bipolar disorder, manifested as depression or mania and other symptoms.

Physical barriers, manifested as motor sensory disorders, most patients with decreased limb muscle strength, unable to walk, or walking unsteadily, panic steps and so on.

In addition, the more serious patients suffer from severe brain damage, resulting in a decline in the body’s immunity and resistance, which greatly increases the risk of other diseases in the body. torture, thereby increasing the fatality rate. More than 4,000 people died of severe carbon monoxide in the two months after the London Fog.

Main styles of beep people should know

Carbon monoxide detectors have different beep modes, we need to understand the meaning of the beep modes to determine if there is a danger around or just need to replace the detector. Normally, there are three main reasons for triggering a carbon monoxide detector alarm:

ModeBeep stylePower light
Detect COLoud and continuous 4 beeps4 rapid flashes/min
Low battery1 Beep 1 flash/min
End of life3 beeps3 rapid flashes/min

The above three beep methods are suitable for most detectors, and there are also a few brands of detectors that need to determine the alarm method according to the attached instructions.


As mentioned above, carbon monoxide is a very harmful and imperceptible gas. It is difficult to accurately determine whether there is a dangerous concentration of carbon monoxide around without the help of a carbon monoxide detector. In order to further reduce unnecessary trouble and accurately detect the concentration of carbon monoxide around, I recommend that every household install a carbon monoxide detector with a number display. Considering that 50ppm is the maximum concentration that the human body can withstand within 8 hours, when the concentration reaches 51, the detector should also sound an alarm within a specified time. In addition, the UK’s latest and strictest EN50291-1:2018 standard is the most stringent quality inspector for carbon monoxide detectors. If there is a detector that can pass this standard, then this detector must be very sophisticated and reliable. Therefore, I highly recommend the Wolf Shield brand carbon monoxide detector, which in addition to meeting all the requirements mentioned above, but also the smallest, lightest and very durable detector on the market. I believe that with its protection, you and your family can sleep at home without any worries. When danger comes, you will be notified as soon as possible and evacuate to a safe area in time.

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