How many kg of air does a person inhale per day? How many liters of air does a person inhale? thoughts about “How much does the air we breathe in a day weigh”
Description:
Calculation of the required air exchange is sufficient challenging task. Despite the long-standing nature of the problem, domestic and foreign data on optimal air exchange are still contradictory and often insufficiently substantiated.
How much air does a person need for comfort?
4. SNiP 2.09.04-87 “Administrative and domestic buildings.”
5. GN 2.1.6.1338-03 “Maximum permissible concentrations (MAC) of pollutants in the atmospheric air of populated areas.”
6. MGSN 4.10-97 “Buildings of banking institutions.”
7. SNiP 31-05-2003 “Public buildings for administrative purposes.”
8. GOST 30494-96 “Residential and public buildings. Indoor microclimate parameters."
9. ASHRAE 62.1-2004, 62.1-2007 “Ventilation for Acceptable Indoor Air Quality.”
10. Ventilation Systems. Edited by Hazim D. Awbi. London and New York. 2008.
11. A. N. Seliverstov. Ventilation of factory premises. T.1. NKTP USSR. ONTI. – M, Gosstroyizdat, 1934.
12. Yu. D. Gubernsky. Hygienic aspects of provision optimal conditions internal environment of residential and public buildings. Abstract of doctoral dissertation. – M., 1976.
13. O. V. Eliseeva. To justify the maximum permissible concentration of carbon dioxide in the air // Hygiene and Sanitation. – 1964. – No. 8.
14. SP 2.5.1198-03 " Sanitary rules on the organization of passenger transportation by rail."
15. Olli Seppa..nen. Tuottava toimisto 2005. Raportti b77. Loppuraportti 2005.
16. Adrie van der Luijt. Management CO2 levels cause office staff to switch off // Director of Finance online. 11.19.2007.
17. Handbook of heat supply and ventilation in civil engineering. – Kyiv: Gosstroyizdat of the Ukrainian SSR, 1959.
6 – 60 liters per minute
To determine how much air a person consumes, the concept of pulmonary ventilation is used. It determines how much air passes through the lungs in one minute. This value is influenced by a number of factors:
- Physical activity
- Body condition
- Presence of diseases
Since a person is in a state of calm and in motion during the day, the amount of air he needs will be different every day. There are average indicators according to which pulmonary ventilation:
- With calmness, absence of any stress and physical activity it will be 6 liters per minute.
- If you change the state, the result will change. With light physical effort, small load (walking, squats) – 20.
- In case you do more hard work(exercises with weights, digging up soil, chopping wood), then the result will increase and will be about 60 liters per minute.
Air exchange in rooms
When designing ventilation systems use a number of recommendations. Thus, the average lung volume in an adult is 4.5 liters (0.0045 m3). One breath is taken per second. Based on these data, the researchers derived the consumption rate fresh air. For an adult this is 30 m3 per hour, and for a child twenty is enough.
IN regulatory documents it was established that on square meter living space needs 3 m3 of air. This is an average figure, because no one can say in advance how many people will be in a particular room at the same time.
It should also be noted that in addition to supplying fresh air, there must also be an exhaust system carbon dioxide. It's not the same for different rooms. So, it should be done more often in the kitchen. This process is measured by multiplicity. So in the kitchen it is equal to three, and in living quarters it is 0.5-1. Also, there are tables of standards that indicate that the air consumption rate in cinemas where smoking is prohibited should be 40 m3 per person, and in cafes and restaurants where smoking is allowed - 60 cubic meters.
The main component that we extract from the air is oxygen.
- during sleep a person needs 15-20;
- if you just lie down - 20 - 25;
- for walking - 30-40 l;
- when running 120-150 hp.
Compared to other organisms, it is the growing and the human body that works a lot physically that requires much more oxygen. Interesting statistics: in one hour a person consumes 15-20 liters of oxygen; during wakefulness, but when a person is simply lying down, the amount of oxygen absorbed increases by 30-35%; a calmly walking person consumes 100% more oxygen; calm and light work leads to an increase in human oxygen absorption by 200%; heavy physical work requires a significant increase in oxygen absorption - from 600% or more (depending on the intensity of the work).
Human lung capacity
The capacity is also significantly influenced by the activity of its respiratory processes. The lung capacity of athletes exceeds the norm by 1-1.5 liters, and the lung capacity of professional swimmers can reach 6 liters. Accordingly, an increase in lung capacity reduces the respiratory rate and increases the depth of inspiration.U ordinary person(not an athlete) the breathing rate is 14-18 breaths, and for an athlete it is 6-10 per minute. Over the course of one full cycle During human breathing, 400 - 600 cubic centimeters of air are inhaled, while, accordingly, 16-24 cubic centimeters of oxygen are absorbed and 14-21 cubic centimeters of carbon dioxide are released.
A worker who does heavy work physical labor, provided that high labor intensity, absorbs about 500 cubic centimeters of oxygen in one minute. However, this same worker in a calm state, in a standing position, absorbs no more than 300 cubic centimeters of oxygen in one minute.
From all that has been said, we can conclude that a person’s need for oxygen is directly influenced by factors such as age, his lifestyle and the intensity of work. And even the presence of a short-term lack of oxygen has a detrimental effect on the functioning of the human body.
The main requirement for the ventilation system is to ensure the required level of air exchange in the room while maintaining certain climatic parameters inside the room. It is the volume of air processed by the ventilation system that determines its cost and subsequent operating costs. To answer this important question, we will decide that for now we will consider the requirements for residential and administrative premises, but we will leave the multivariate requirements for industrial premises and consider them separately.
So, firstly, everyone understands why fresh indoor air is needed at all - of course, for breathing. And so, guided by this main task, it is possible to determine the required volume supply air indoors. Obviously, it will depend on the number of people in the room. So, it is generally accepted that 30 m 3 /hour is needed for one adult, and 20 m 3 /hour is possible for a child. This figure was selected almost empirically and enshrined in relevant documents regulating the design of ventilation systems. (Imagine that the average adult has a lung volume of 4.5 liters or 0.0045 m 3, and he breathes no more than 1 time per second, and even then only with an incomplete chest - that’s only 16.2 m 3. But there is still time , which exhaust air will be in the room. It’s hard to imagine that every next breath will be fresh air.)
For residential premises in our country, a standard of 3 m 3 per square meter of living space has also been defined, and it is not meaningless, because it is impossible to accurately determine the number of people in a room, and this value is based on the accepted standards of living space per person. It is also worth considering that ventilation, in addition to supplying fresh air, removes exhaust air, which contains all the harmful substances emitted indoors - from radioactive radon to the toxic fumes of modern detergents(one comet with its wonderful chlorine is worth it!). Having touched on the problem of indoor air pollution, we come to to the next parameter ventilation systems - MULTIPLICITY. Regulatory Requirements reduced to 0.5-1 times the exchange in living quarters, and 3 times in kitchens. But note that the calculation for the multiplicity does not take into account the number of people and the intensity of indoor air pollution; the calculation for the number of people does not take into account the volume of premises and also the release of harmful substances in them.
Obviously, a more accurate calculation is needed, which takes into account both, and therefore a more accurate description of the premises. However, the experience contained in the regulatory documents should in no case be rejected. It has been noticed that when the air exchange rate in the room is less than 0.5, a person feels stuffy in the living room, and in the work office the rate is recommended from 3 to 8. Below are the recommended values of the considered parameters according to the ASHRAE standard, DIN 1946, respected all over the world for determining ventilation volume V.
Air exchange rate. Volume V=s*Vp, where s is the multiplicity, Vp is the volume of the room.
Table 1.
Calculation of the number of people in the room.
Ventilation volume V =s s* Vi, where s s is the number of people, Vi is the rate of outside air per person
Table 2.
Pay attention to the values in the table. 1 and table. 2. If we take the values in Table 1 as a basis, then it turns out that they lead to a much larger volume of ventilation than what would be obtained when calculating from the Vi values according to Table 2. Well, for example, an office - the average recommended air exchange value is 5.5 times. Let's assume that in a room with an area of 100 m2 and a ceiling height of 3 m, about 10 people work (10 m2 per person is quite dense, taking into account the entire office area). Then, based on the calculation according to Table 2, the required volume of ventilation is 10 * 40 = 400 m 3 / hour, and if we start from the recommendations according to Table 1, then it turns out 100 * 3 * 5.5 = 1750 m 3 / hour - nothing it makes a difference! But, interestingly, there is no paradox here. The thing is that the recommendations in the table. 1 are based on an averaged accounting of all parameters of the internal environment of a room that determine comfortable conditions for the people staying there. We talked about this above - temperature, humidity, odors, air movement, temperature of enclosures (walls, ceilings, etc.).
My Internet search yielded from different sources the following data: average human air consumption is 0.5-1 cubic meter per hour.
However!!! These data are taken for the case of carbon dioxide carryover from humans, i.e. as if in the fresh air, and therefore these figures have nothing to do with calculations for ventilation of premises.
I came up with an approach that will help determine the ventilation needs of homes, because I don’t trust SNiPs and sellers of happiness.
Briefly: oxygen is a useful gas, CO2 is harmful. It is necessary to determine for each of them, calculate the need for ventilation (cubic meters of air per hour per person), and then select the maximum figure from the two. This will be a reasonable figure for air exchange in homes.
I found this method in this article:
Carbon dioxide is the main reason for ventilation:
“If you do a little calculation, you find out the following.
For example, in a room of 33 m3, there are 10 people. 10 people exhale approximately (10X25) 250 liters of carbon dioxide per hour. As a result, the level of carbon dioxide will double in 21 minutes, and the level of oxygen will drop by a fraction of a percent over the same period of time."
...
"In our country, research on the effect of carbon dioxide on humans was carried out back in the 60s. O.V. Eliseeva, who used the methods of pneumography, rheovasography and electroencephalography, in the article “On the justification of the maximum permissible concentration of carbon dioxide in the air” in the journal Hygiene and Sanitation . – 1964. – No. 8., came to the following conclusions:
- Brief inhalation healthy people carbon dioxide in concentrations of 0.5 and 0.1% causes distinct changes in the function of external respiration, blood circulation and electrical activity of the brain.
- Changes in these functions are more pronounced under the influence of CO2 at a concentration of 0.5%.
- The data obtained allow us to conclude that the CO2 concentration in the air of residential and public buildings should not exceed 0.1%, regardless of the source, and the average CO2 content should not exceed 0.05%.
Let's assume that in a dream - 10 liters of CO2 per hour, and in an active state - 30 liters / hour (small, domestic activity).
Let's try to figure out from here the need for ventilation while sleeping indoors.
Let's assume we have a sealed room - 20 square meters. meters (= 50 cubic meters). If, for example, it is well ventilated before going to bed, the CO2 concentration will be 0.04%. After 8 hours of sleep, a person will exhale 0.08 cubic meters of CO2, which is 0.16%, and in the morning there will be 0.2% CO2 (0.16% + 0.04%), which exceeds valid value 2 times, but presumably not fatal.
That is, during sleep, air exchange should be no less than 50/8 = 6.25 cubic meters per hour. And for healthy sleep - approximately 15 cubic meters per hour.
Let's determine the need for CO2 ventilation during wakefulness (exhalation - 30 liters of CO2 per hour).
With a sealed room volume of 50 m3, one hour of breathing will add 0.06% to the CO2 concentration. In total with the initial concentration (0.04% + 0.06%) - 0.1%. Those. There will only be enough fresh air for an hour.
Thus (in terms of CO2), air exchange during active home activity should be 50 cubic meters per hour per person (with a maximum CO2 content of 0.1%, since the average “hospital” value is not suitable here).
Probably, we need to look for and buy a CO2 meter and slowly figure out what’s going on in the apartment and at the dacha...
For example, Smart-2C02 (thanks for the tip -
