Psychophysiological effects of building objects per person, Natural hazards, Technogenic threats - Reliability of construction sites and human life safety

3.12. Psychophysiological effects of building objects per person

The state of people, in addition to many other factors, can be affected by the height of the building object and the level of location of the premises in which it is necessary to live and work. For example, in high-rise buildings, many people have a psychophysiological effect of discomfort when they are at elevations above 30 m from the ground level. And when you are near such high objects there is a feeling of oppression by the external environment.

At present, for example, objects with a height of 828 m (Figure 3.6) and in different countries continue to design and build buildings with a height of 1 km or more, we should, in addition to architectural and design advantages, assess the dangers of people staying in these buildings and determine what may be a threat to their health and life.

People in high-rise buildings are subject to the influence of numerous factors that cause threats of natural, man-made and anthropogenic nature.

Natural Hazards

The source of natural threats are wind, sudden pressure and temperature changes, thunderstorms, earthquakes, changes in groundwater movement, subsidence, including due to suffosive and karst phenomena. They can cause static and dynamic stresses, leading to slope, deformation and displacement of building structures, which can lead to collapse of the building.

Technogenic Threats

Technogenic hazards can be attributed to induced electromagnetic fields, accidents and critical disruptions in the processes of operation of engineering life support systems, leading to fire, flooding, releases of poisonous substances (eg refrigerants of the cooling system) into the ventilation system, explosions, electric shock and other consequences. The fire, in turn, can lead to a violation of the load-carrying capacity of the building's structures and to the progressive collapse.

Fig. 3.6. View of the high-rise building of Burj Khalifa, built in the United Arab Emirates (Dubai)

Anthropogenic threats. These threats can be caused by the manifestation of the "human factor" (mistakes, ignorance, negligence), different categories of persons (from service personnel to inmates, including elderly people, persons with disabilities and children). Another source of these threats is malicious actions of people (hooliganism, theft, attacks, sabotage, etc.). Of the anthropogenic threats, the most dangerous terrorist acts are those aimed at causing maximum harm, accompanied by explosions, arson, spraying of toxic and radiation substances in the air through the ventilation system, etc.

Explosions, cracks and fires can lead to a violation of the integrity of the structure of the building, its collapse and the death of people in it.

The presence of these threats, even a simple awareness of the possibility of their implementation (with the probability of a risk of 10-6-10-8) already causes anxiety in people and has a very negative impact on the psychophysiological state of people. This is confirmed by statistics, which indicates the increase in the distance from the earth diseases, stresses and even suicides. As a consequence, consideration of the psychophysiological safety of people who are (and even more so) residing in high-rise buildings and subject to the influence of the listed threats is highly relevant and necessary.

However, experts sound the alarm, noting that when building skyscrapers, "the man is forgotten - the user of these pompous structures, neither the physical nor psychological state of people staying for a long time at high altitudes is studied; hygienists do not participate in the evaluation of new buildings, as it was before & quot ;. How can the fate of the future inhabitants of the skyscrapers be solved without the help of hygienists? After all, at the top, the effect of climate on the building and the state of health of a person will be different than with the usual number of storeys, it is possible that at the height of "blossom" cardiovascular and neuropsychic disorders.

Speaking about the protection of load-bearing and enclosing structures, indoor and outdoor buildings of sky-high buildings from strong (up to 20-25 m/s) gusts, shock waves of lightning discharges, powerful charges of rain and hail, which at an altitude of more than 100 m are not rare. It is necessary to bear in mind also such phenomena as fog, loss of quite significant amounts of snow, formation of ice and frost during thaws and cold snaps, as well as the effect of smoke-suffocating smog from urban fumes and possible fires of forests and peat bogs.

Among natural threats, it is necessary to distinguish also atmospheric pressure and temperature jumps, which adversely affect people climbing for several to three minutes to a height of several hundred meters. At this rate of recovery in vivo, cardiovascular diseases can exacerbate, which can even lead to death. For example, as statistics show, such exacerbations and increase in lethal outcomes are observed already at atmospheric pressure jumps of 10-15 mm Hg. Art. during few hours. What can we say about pressure jumps in 18 mm Hg. Art. and more when climbing to a height of 200 m or more in a few minutes? For meteodependent people, this is undesirable.

A very unpleasant and dangerous factor is altitude sickness (high altitude hypoxia) - a painful condition associated with oxygen starvation due to a decrease in the partial pressure of oxygen in the inspired air, which occurs at high altitudes.

Protection against the negative impact of pressure spikes and altitude sickness on the body requires the sealing of elevators and high-rise buildings at heights of more than 200-300 m and the use of engineering systems in them to create a safe and comfortable microclimate.

The tallest buildings (Burj Dubai, Taipei, etc.) meet these requirements, but this is also associated with increased construction and operating costs.

An important psychological property of many people is the fear of heights (acrophobia). Considering this, for example, in the buildings of the International Center for World Trade with a height of 410 m, the designers chose the horizontal pitch of the outer columns equal to 1.015 m, and the windows are only 480 mm wide and 1980 mm high, so that people working on the floors of the skyscraper would not be afraid of height.

The negative impact on the psyche of a significant part of people also has a feeling of detachment from the habitual habitat. Researches of scientists and doctors show that it is impossible to get a structure of the surrounding space in a high-rise residential building, therefore it is deprived of a humane and full-fledged living environment that meets the real, inherent habits, needs and capabilities of the human body.

Significant impact on the psychophysiological state of a person has weather conditions: the presence of clouds, fog or cloudless sky. On the floors of high-rise buildings in the cloud zone, the surrounding world appears in a different form, and a long stay in the fog (for several months a year) adversely affects a person's mental state. To this, we should add that a person experiences discomfort in the absence of & quot; anchor points & quot; due to fatigue of the eyes, making involuntary movement.

The next negative factor for high-rise buildings is the impact of wind loads caused by cyclones, vortices, hurricanes, tornadoes and other non-stationary atmospheric processes (Figure 3.7). When airflow around high-rise buildings and breakdown of vortices from their enclosing structures, significant loads arise that can cause bending and unstable oscillations: transverse (galloping) and torsional (divergence), as well as other deformations of high-rise buildings that affect the safety of buildings themselves and the well-being of those in their people.

Fig. 3.7. Air flow around a high-altitude rectangular object

Wind impacts, accompanied by accelerations of structural vibrations under dynamic gusts of wind, can cause disturbances in normal operating conditions in the upper floors of high-rise buildings.

In this case, both the disturbance of the stability of the situation (shaking of chandeliers, furniture movements, splashing of water from the glass) and unpleasant physiological sensations in people living or working in the building can arise (Table 3.3).

Table 3.3. Psychophysiological sensations of people with various accelerations of structural vibrations

Acceleration of oscillations,% of g (9.81 m/s2)

Boundaries of sensations: comfort/discomfort

& lt; 0.5% g (0.05 m/s2)

Impressively

0.5-1.5% g (0.05 - 0.15 m/s2)

Perceptible

1.5-5% g (0.15-0.49 m/s2)

Worrying

5-15% g (0.49 - 1.47 m/s2)

Very restless

& gt; 15% g (1.47 m/s2)

Intolerable

In accordance with the characteristics given in Table. 3.3, in the Moscow norms for the construction of high-rise buildings (MGSN 4.19-2005), a practically insignificant amount of acceleration of oscillations is regulated - 0.08 m/s.

In connection with the noted features in the developed countries of Europe, the construction of skyscrapers with residential functions over the past 20 years has been an exception to the rules. And in such a highly developed country like Sweden, there is a gradual decrease in the height of even 9-12-storey residential buildings.

When building high-rise buildings, the requirements for resistance to wind blowing of enclosing structures, including windows and stained-glass windows, acquire special significance. It is also important to protect the interior, especially residential, from the effects of background noise (hum) surrounding the urban environment. It is necessary to take into account the upward air currents arising in the high-rise buildings, which require special solutions for locking the entrances to the building and staircases, sealing the floors and garbage chutes, filtering and cleaning the used air in the ventilation and air-conditioning system. This is especially important for the observance of comfortable conditions in the living quarters that meet sanitary and hygienic standards.

Other services that we offer

If you don’t see the necessary subject, paper type, or topic in our list of available services and examples, don’t worry! We have a number of other academic disciplines to suit the needs of anyone who visits this website looking for help.