During the second half of the twentieth century, starting with the fifties
till the nineties, the urban population knew an incredible growth. Before
the 1950s the urban population was around two hundred million, while at
the end of the century the number grew to almost three billion. The specialists
foresight for the current century considers a further growth of the urban
population. However, this growth will be quite diminished by the new economic
development which implies a change from the industrial society to a post
industrial, computerized one.
The new economic development no longer requires a huge concentration
of individuals, of people working together in a delimited headquarter;
the physical contact becomes unnecessary. The ongoing development of the
internet, the real-time on line communication and teleconference make
possible the collaboration and brainstorming between people miles away,
as well as a mutual exchange of the most intimate, profound and creative
From an objective point of view it no longer requires residential programs
within the same urban area. As the progress of the society takes place
in accordance with its needs, a new process of de-urbanization appeared,
leading to the creation of suburbs and satellite towns and a renewed development
of the rural area. This trend is obvious in the developed counties where
the residential areas are located in the suburbs.
The urban population is growing at a much faster rate than the rural
one. It is estimated that during the years mentioned above the urban population
knew an exponential growth. Statistics show that almost 80% of the growth
is found in the urban concentration. Therefore, at the end of the twentieth
century there were nineteen cities which had a population more than ten
million people, twenty-two cities had a population between five to ten
million inhabitants, three hundred and seventy cities had one to five
million people and four hundred and thirty cities had a population of
up to one million people. This growth led to an exponential increase of
the energy consumption and a more than alarming exceeding of noxious gases
in the air and wastage.
There was a time when the energy consumption was considered an indication
of the quality of life. Therefore, from the point of view of the energy
consumption, many differences appeared between the developed countries
and the developing ones. Almost a third of the world population has no
access to electricity. At the same time a person living in one of the
developed countries has energy consumption twenty-five times greater than
one living in a poor country.
A popular idea was that we can fight poverty with increased energy consumption.
However, the facts showed a disturbing reality energy wastage.
In the light of the new facts, a new approach is absolutely necessary:
||Improving and promoting an efficient energy consumption
||Discovering and developing new unconventional sources of energy
Reducing the energy consumption for the material production by using
high-tech and computerized procedures.
It is particularly necessary to analyze the energy consumption in the
The construction industry with its processes of building, practical application
and essential services constitutes an important sector for the growth
of the economic progress. Specialists state the construction sector to
be an important indicator of the economic growth; that is when constructions
are going well, so is the economy. However, based on statistics, the construction
field is also a major resource user: 40% of the global energy, 16% of
the water consumption and 25% of the wood consumption. At the same time
the construction sector is a major polluter: 70% of sulfur dioxide, 50%
of carbon dioxide, etc.
A fair analysis of the resource consumption, especially energy and the
management of noxious gases show differences between the developed countries
and the developing ones.
The main issue concerning the developed countries is that of an energy
consumption exceeding the production of natural resources, combined with
a level of pollution beyond the possibilities of neutralizing its own
The ecological footprint is an assessment of the human resource demands. It
represents the amount of productive land area needed to produce the resources
human population consumes and to absorb the corresponding waste (Wackernagel
and Rees, 1995). Thus, in the developed countries, this indicator is 10
ha per person, while in the developing countries is less than one hectare per
Another indicator is the living standards represented by the space a
person needs for living; this standard is measured in square meters per
person. Thus, there can be observed significant differences: 11.6 m2
per person in Moscow, 28.2 m2 in Paris, 47.2 m2
in Oslo and only 14.3 m2 in Bucharest.
The over-consumption of resources becomes an ever more alarming issue
in large cities where the growth of energy consumption is accelerated
by the use of air conditioning, especially the cooling mode. Starting
with the summer of 2003 Italy has experienced serious problems in this
During the summer of 2002 the energy supply system of California went
into collapse leading to a substantial increase of prices within a year;
from 50 to 150 $/MW h.
The pollution is also a major indicator of poor or high standards of
living and economic development. According to UNCHS (United Nations Centre
for Human Settlements), the quality of the air was unsatisfactory in more
than 50% of the worldwide buildings. The population of the poor countries
spends on energy 15-20% of their monthly income. Similarly, the transition
economies spend 6.6%, while in Great Britain the population spends 2%.
The Indoor Air Quality (IAQ) in the developing countries is inferior to that
in the developed countries, because of the population private use of coal and
fossil fuels, as well as inadequate stoves and kitchen machines. The IAQ might
be low in the developed countries also for reasons of poor ventilation (Bas,
The statistical markers prove that no proportion can be established between
the energy consumption and comfort improvement.
This study aims at presenting other methods, yet less used, which could
improve the environmental comfort of the individual residential buildings.
||The analysis of all possibilities for a natural ventilation,
especially for dwellings in the temperate continental areas, during
||Ensuring optimum levels of thermal inertia so as the temperatures
inside stay within standardized limits during summer time, with no
||Natural ventilation systems to maintain within standardized limits
the pollution level inside the dwellings
||Determining the minimum energy consumption needed to heat the air
changes during winter time
||Benefiting from the thermal inertia of the buildings, during the
An ergonomic organization of the space, the fulfillment of anthropometric
demands, rational volumes, vertical and horizontal air courses.
CONDITIONS FOR THERMAL COMFORT
Human thermal comfort is defined by the thermal state of the body. Thermal
comfort depends on the level of the physical activity and clothing. It
is also influenced by the environmental conditions, such as air temperature,
the mean radiant temperature at a certain place in the room, air velocity
When the above parameters are estimated or measured, the thermal comfort
of the body can be anticipated by calculating the PMV (predicted mean
vote). The PMV index is based on the thermal balance of the body. The
human body is in thermal balance when the heat generated by the metabolism
is equal to the heat dissipated in the surroundings. The physiologic temperature
regulation system modifies, in certain limits, the skin temperature and
the activity of the sweat gland in order to maintain the thermal comfort.
In a moderate microclimate and wearing clothing suited for the activity
performed, the thermal equilibrium is maintained without overworking the
temperature regulation system. In this case the person has a neutral thermal
relation with the surrounding environment that is he/she has a neutral
The PMV index represents the average opinion of a large group of people
asked to express their thermal comfort using the following scale:
||+ 3-hot; +2-warm; +1-slightly warmer; 0-neutral; -1-slightly
cooler; -2-cold; -3-very cold
The PMV index can be estimated considering the following parameters:
||The energy produced by the human metabolism for different
levels of activity
||Mean radiant temperature
||Relative air velocity
||Partial pressure of the water vapors
The PMV index, the physiological response of the temperature regulation
system, statistically results from the opinions expressed by more than
one thousand three hundred individuals regarding their thermal comfort.
The PMV index can be calculated using the following experimental relation:
PMV = (0.303e-0.036M
+ 0.028) • (M-3.05 • 103 • (5733-6.99
-0.42 • (M-58.15)- 1.7 • 10-5M (58667-pa)-0.014M
(34-ta) -3.96 • 10-8 • Fcl
• (tr+273)4-Fcl • hc
||Metabolic rate of human body (W m2)
||Water vapor pressure in ambient air (Pa)
||Clothing area factor, dimensionless
||Mean temperature of the outer surface of the clothed body (°C)
||Air temperature (°C)
||Mean radiant temperature (°C)
||Convective heat transfer coefficient (W/(m2 • °C))
The PMV index calculated using the above ratio applies for a static level
of activity, yet it can be used for a variable level. For the last case
the parameters have minor changes and are considered with their mean value
in accordance to time and level of activity. The use of PMV index is limited
to values between -2 and +2 and the parameters considered in relation
(1) with values ranging between the following:
||46-232 W m2 (0.8-4 met)
One met represents the energy produced by an average person while sitting.
The total body surface of an average person is considered to be 1.8 m2.
(1 met = 58.2 W m2).
The energetic metabolism M is the production of the human body in connection
to the level of activity. It is commonly expressed by watt per square
meter or by metabolic units, met. The production of metabolic energy,
depending on the level of activity, can be estimated as follows:
||Lying rest position-46 W m2; 0.8 met;
||Sitting rest position-58 W m2; 1.0 met;
||Sitting light activities (home, office, school) -70 W m2;
||Standing light activities-116 W m2; 2.0 met
||Medium activities-165 W m2; 2.8 met
The PMV index can also be determined using charts presenting different
combinations of activities, clothing, temperature, humidity.
The predicted percentage of dissatisfied: The average predictable point
established by the PMV index represents a statistic value based on the opinion
of a group of people exposed to the same microclimate (Parsons,
The PPD index (predicted percentage of dissatisfied) determines the predicted
number of individuals (in percentage) that may not be satisfied with the
surroundings, either because its hot (level +3), warm (level +2), cold
(level -2), very cold (level -3).
The PPD index can be calculated based on the PMV index using the following
||The predicted percentage of dissatisfied given by the
predicted mean vote
The PPD index anticipates the number of dissatisfied due to thermal reasons,
while other people appreciate the microclimate as being neutral, warm
or cool. The predicted distribution of estimation is presented in Fig.
Draught rating: A draught of air is mainly a movement of the air
which produces a decrease of the human bodys temperature and its perceived
as being uncomfortable. The discomfort produced by air draughts can be
expressed by the predicted percentage of dissatisfied with the draught.
The DR index, draught rating, can be calculated using the
following experimental ratio:
DR = (34-ta) • (v-0.05)0.62
• (0.37 • v • tu + 3.14)
||Draught rating index
||Local air temperature (°C)
||Mean air velocity (m sec1)
||Local intensity of turbulence
The method of evaluating the discomfort produced by the air draughts is based
on the opinions of a group of people exposed to temperatures between 20-26°C
when the mean velocity of the air ranged between 0.05-0.4 m sec1.
The level of activity is light, mainly sedentary. It is common knowledge that
the discomfort is less felt when the activity is energetic (Bust
and McCabe, 2005). In order to limit the discomfort produced by air draughts,
that is DR<15%, the local mean air velocities should be maintained below the
values indicated in Fig. 2.
The curves are based on the model of evaluation for the discomfort produced
by air draught in the case of 15% dissatisfied performing a light, sedentary
activity and having a metabolism of 1.2 met.
The PMV and PPD indexes describe a warm or cold sensation of the human
||Admissible mean air velocity given by air temperature
and turbulence intensity
The thermal discomfort can also be produced by a cooling or warming
of a small part of the body. In this case the discomfort is local; one
of the main causes of local discomfort is air draughts.
THE EXIGENCIES OF THERMAL COMFORT
Human thermal comfort is defined as the state of mind that expresses
satisfaction with the surrounding environment. The discomfort can be caused
by different sensations of either too cold or too warm. The discomfort
is expressed by PMV and PPD indexes. Thermal discomfort can also be sensed
when only one part of the human body gets too cooled or too warmed, due
||Difference between the temperature of body and that of ankles
||Asymmetric thermal radiation
However, it is virtually impossible to find a thermal regime that could
satisfy each and every individual, considering all objective or subjective
differences between people. There will always be a percentage of dissatisfied.
Nevertheless, it is possible to establish the parameters of a microclimate
that could satisfy the demands for thermal comfort of a large group of
individuals living or in the same surroundings.
There are cases when a higher value of the parameters adopted for a specific
microclimate lead to a small percentage of dissatisfied, whilst an inferior
quality of the parameters lead to a larger percentage of dissatisfied.
||The optimum temperature considering the level of activity
Figure 3 shows the optimum temperature considering the
level of activity and clothing. The optimum operative temperature corresponds
to a PMV = 0. The darker surfaces indicate comfort areas ±Δt
close to optimum temperature. The following relation applies: 0.5<PMV<+0.5.
Thermal resistance of clothing
||Nude body-0 m2 °C/W, 0 clo
||Shorts-0.015 m2 °C/W, 0.1 clo
||Summer clothing (light trousers, short-sleeved shirt, sandals)-0.08
m2 °C/W, 0.5 clo
||Light/casual clothing (trousers, jacket, shoes) -0.11 m2
°C/W, 0.7 clo
||Winter indoor clothing (trousers, jumper, socks, slippers)-0.16
m2 °C/W, 1.0 clo
||Winter outdoor clothing (long-sleeved underwear, vest, suit, overcoat,
winter shoes) -0.23 m2 °C/W, 1.5 clo
clo-clothes, 1 clo = 0.015 m2 °C/W
It is generally accepted a PPD index below 10% corresponding to PMV index
ranging between-0.5<PMV<+0.5. Light, sedentary activities, 1.2 met,
are especially under consideration since they are specific to a large
number of occupied spaces, such as dwellings, offices, schools.
Light, mainly sedentary activity during winter time: The situation
refers to winter time activities considering clothing of 1 clo and thermal
resistance of 0.16 m2 °C/W. Thus:
||Acceptable operative temperature 22 ± 2°C
and temperature for a definite space 20-24°C
||Vertical air temperature difference below 3°C
||The temperature of floor surface range between 19-26 °C, but
no more than 29°C for the under floor heating systems
||The asymmetry of the radiant temperature of windows or other surfaces
be less than 10°C
||The relative humidity range between 30-70%
Light, mainly sedentary activity during summertime: The situation
involves summer clothing of 0.5 clo, respectively a 0.08 m2
°C/W thermal resistance. Thus:
||Acceptable operative temperature 24.5 ± 1.5°C,
in a definite space the temperature should be 23-26°C
||Vertical air temperature difference should be less than 3°C
Radiant temperature asymmetry: The radiant asymmetry is defined
as the difference between the plane radiant temperatures of two opposite
sides of a small plane element. The mean radiant temperature is calculated
using the relation:
(tr + 273)4
= Tr4 = F1 • T14
+ F2 • T24 + … + Fi
||Mean radiant temperature (K)
||Mean radiant temperature (°C)
||Form factor between subject and interior surface
||Temperature on internal surface (K)
The heat exchange between human body and environment: The thermal comfort
of a person is the result of the equilibrium between energy produced by human
body and loss of heat conduction, convection, radiation and evaporative heat
loss (Awbi, 2003). When the equilibrium fails, that is
the loss of heat is rather significant, the person starts to feel cold or hot,
leading to changes of temperature at skin level. Figure 4
shows heat loss during light, mainly sedentary activity.
Experiments showed that in the buildings with natural ventilation, the
thermal comfort depends only on the internal operative temperature and
the external one. During the experiment, thermal comfort was reached when
the temperature ranged between 20-24°C and the heat radiation, convection/conduction
and perspiration/ evaporation losses were almost equal.
When the temperature of the environment rises, the process of evaporation
becomes predominant in order to regulate the bodys temperature around
37°C; otherwise, the amount of heat lost through evaporation rises
and thermal discomfort is felt.
|| Heat loss during light, mainly sedentary activity
When the surrounding temperature is low,
the metabolic activity has to increase to compensate for heat losses.
A healthy body will always tend to maintain equilibrium between the produced
metabolic heat and conduction, convection, radiation and perspiration-evaporation
losses. This equilibrium is necessary to keep a constant body temperature
of 37°C. Subconsciously, the equilibrium is obtained through metabolic
processes; consciously, the level of activity and thermal insulation of
clothing help maintain equilibrium.
Also, a moderate metabolism in a certain type of microclimate is maintained
when the person wears adequate clothing that does not interfere with the
Environment adjustment of the inhabitants of a built space, a dwelling:
Thermal comfort requirements (Hawkes and Forster, 2002)
stipulated by standards are based on measurements performed on subjects having
a passive reaction to thermal stimuli. Day-to-day experience shows that the
sensation of thermal comfort is not a constant. Secondary to opportunities,
persons can change the interior climate or they can adjust to thermal climate
by changing their clothing or the level of activity. Experiments also demonstrated
that people can accept wider variation of temperatures. Thus, in the case of
buildings with air-conditioning systems thermal comfort can be determined using
agreed standards, while the inhabitants of spaces with natural ventilation tolerate
wider variation of temperatures (Fig. 5).
Ninety percent of the subjects agreed that temperatures between 17-22°C make
them feel slightly cold, while the range 25.5-30.5°C make them feel hot. These
facts lead to adopting a new type of thermal regime during summertime in the
natural ventilated buildings (Givoni, 1998).
|| Peoples temperatures variation adaptability
Requirements of indoor air characteristics: These requirements
deal with ensuring certain characteristics of the indoor air in residential
buildings that will satisfy a large percentage of the inhabitants. Thus,
the following measures can be taken:
||Limiting/reducing odd odors to the level of perception
of an individual with a medium olfactory sense; mostly these odors
come from the disposal of industrial and household sewage and waste
||The maximum accepted concentration of volatile formaldehyde is 0.035
mg m3, considering it a medium value of the most polluted
30 min within 24 h range. Consequently, there will be used construction
materials that have less than 25 mg formaldehyde/100 g solid material
||The maximum accepted concentration of radon 220 or 222 is 140 Bg/m3/year
||It is forbidden the use of construction materials containing radioactive
||It is strictly forbidden the use of radioactive waste, sand, slag
and lime residue from chemical fertilizer processing; all these substances
contain a higher percentage of natural or artificial radioactive elements
that is usually accepted in construction materials
||The accepted maximum concentration of carbon monoxide is 6 mg m3
air, considering the most polluted 30 min within 24 h range. This
concentration of carbon monoxide in air keeps the concentration of
carboxyl-hemoglobin in blood within agreed value, that is 1.5% COHB
||The accepted maximum concentration of carbon dioxide is 1600 mg
m3, not exceeding 0.05% of the room volume. The amount
of carbon dioxide found in the air is mainly due to the metabolism
of people occupying a specific space.
The production of CO2 during metabolic processes happens because
the organic elements inside the organism oxidize. These processes largely
depend on the way the glucose, lipids and proteins are absorbed by the
organism, their preponderance and the heat produced through physiologic
The volume/amount of CO2 produced by the human organism can
be determined using the experimental ratio:
K = 85 • 10-4 •
M • A (m3 h1)
||Metabolic rate of human body during a specific activity
||The total surface of the human body, A ≈ 1.8 m2
The concentration of water vapor:
||Summer: max 15.400 mg m3 (tmed
= 25 ± 3°C)
||Winter: max. 9.450 mg m3 (tmed = 20 ±
The content of water vapor found in the air is due to the metabolism
of the people occupying the space, the level of different household activities
and the number of plants. The air contains a specific amount of water
vapors expressed by the concentration of water vapor in the air, C, also
named absolute humidity, in g m3 or in g kg1.
At a specific temperature, the quantity of water vapors cannot be over a certain
agreed limit, called saturation point or absolute humidity at saturation Cs
expressed in g m3 or g kg1. The maximum quantity
is closely related to air temperature. Currently, the term relative humidity
of air is used; it is expressed in% and represents the ratio between the actual
vapor pressure of the air and the saturation vapor for the air. When reaching
a certain temperature the air contains the maximum quantity of water vapor,
that air is saturated and the relative humidity is 100%. The relative humidity
is an important indicator of the thermal comfort, as the values of the air humidity
must be situated within agreed limits, closely related to human metabolism.
The oxygen concentration should be a minimum 16.3% of the room volume and never
below this value (Heinsohn and Cimbala, 2003).
There are many standards recommending natural ventilation systems or
mechanical aspiration so as the occupants of the building would not breathe
noxious gases. This is the case of:
||The utility rooms without windows facing the exterior
(bathrooms, shower rooms, toilets, pantries)
||The rooms having windows facing the exterior which are used for
cooking or heating water on open fire (bathroom, kitchen), rubbish
dump room, basements
During the designing stage of a building and further on during examination
the changes of air/transformation are extremely important. In order to
make estimative calculus, the composition of the external dried air is
as following: Oxygen O2: 20.94%; Carbon dioxide CO2:
0.03%; Nitrogen N2 and inert gases 79.03%.
The quality of the air largely depends on the concentration of different
substances like gases, vapors or dusts that form the air. These concentrations
can be expressed in different ways:
||Volume or mass percentage (%)
||Mg of polluting substance/kp of air (mg kp1)
||Parts of polluting substances related to 1 million parts of air
expressed in volume (ppm)
The percentage of CO2 found in the air might be less than
0.03% in the rural areas, while in the urban areas might be higher, up
The composition of the air also presents other particles and water vapors:
||The relative humidity can reach 80-95% in the winter
||The relative humidity can reach 50-75% in the summer
It is strongly forbidden to place residential or public buildings in
areas where the concentration of noxious gases in the air is over the
agreed limits. The concentration of noxious substances cannot be more
than 10 ppm, which is the average value for short periods of time, or
4 ppm, the mean day value. The above-mentioned values regarding the air
humidity, the following relations (Eq. 6, 7)
||Relative humidity (%)
||Partial effective pressure of water vapors (Pa)
||Partial saturation pressure of water vapors (Pa)
||Concentration of water vapors (g m3)
||Saturated concentration of water vapors (g m3)
When the concentration are expressed in g kg1, than the relations
Eq. 8, 9 are:
The indoor air humidity may come from different sources:
Metabolic activity: The emission of metabolic water vapors comes
||Breathing, the air exhaled from the lungs is saturated
with water vapors
||Diffusion of water vapors through the skin, perspiration
||Evaporation of sweat; the degree of perspiration is correlated to
the sensation of thermal comfort
The production of water vapors for a person experiencing thermal comfort,
0.5 < PMV < +0.5, is represented by the following experimental relation
K = 87 • 0.185 • A •
(M2+0.4 • M) • 103 (mg h1)
||Debit of water vapors (mg h1)
||Total surface of the body (met)
||Metabolic rate of human body (W m2)
In the case of an adult (A = 1.8 m2) the relation (Eq.
K = 29 • (M2+0.4
• M) • 103(mg h1)
The quantity of water vapors produced by the body of an adult experiencing
thermal comfort varies in accordance to the level of activity performed,
thus (Table 1):
Household activities: The activities performed indoors (cooking,
dish washing) generate water vapors. Experiments showed that, statistically,
four inhabitants of the same residence produce:
||700 g water vapors in the morning
||1700 g water vapors at noon
||800 g water vapors in the evening
|| The quantity of water vapors produced by the body
An estimated water vapors debit of 120 g h1 is an average
daily rate, as follows:
||Bathing, shower-4 persons-600-1000 g day1
||Laundry washing-3000 g week1 and laundry drying-9000
||Floor cleaning-300 g week1
||Electronics having special burning systems-natural gases 160 g h1,
paraffin oil 100 g h1, bottled gas 130 g h1
Construction humidity refers to the quantity of moisture in a building
after the execution works are completed. The causes of this humidity are:
||The water contained by the construction materials after
pre-fabrication, usually higher than the equilibrium humidity
||The mixing water needed to work the materials on situ
||The water from rainfalls during different stages of execution
It is estimated that the amount of water that has to evaporate after
the completion of a building ranges between 3000-5000 L. Two years after
the building has been completed its humidity should be 10 l m2.
The specialists recommendations refer to:
||Water proof finishing (polymeric paint coats, washable
plastic wallpapers) should be avoided
||After the building starts being exploited, it should be heated and
ventilated more than the norms stipulated, for a period of 2-3 years
The equilibrium humidity is determined many years after the building
started functioning and it has to be maintained within normal limits.
The following procedures are used to maintain the equilibrium humidity:
||In the rooms with moderate humidity emission, permeable
finishing are used to take over and then transfer the humidity (lime-based
plaster, water vapor permeable painting)
||The rooms with high emissions of humidity, during short periods
of time, should be provided with natural ventilation systems and/or
mechanical ventilation that will absorb the humidity
EXIGENCIES ON ODOR ISSUE
Apparently, the human olfactory system is inferior to that of animals.
This statement is confirmed not by the size of the human olfactory mucous
membrane (5 cm2), but by the size of the feline one (100-200
cm2). The olfactory sense is not indispensable for human survival
and does not ensure the perennial existence of our race.
Certain smells can unconsciously set off hormonal stimuli that control
our appetite, our body temperature, different superior functions of the
brain, emotional behavior, ability of thinking and memories. The nose
is concerned with conditioning the entering air by warming and humidifying
its temperature. The viscous layer of mucous secreted by the nasal mucous
membrane is there to intercept and exclude any solid matter in the air
we breathe (dust, pollen, bacteria, viruses etc.). The surface of the
membrane is covered with countless cilia, tiny hair-like cell structures
which normally undulate to keep the mucous moving towards the pharynx.
Smells, as a result of the olfactory systems function, are stimulated
by chemicals and are different from any other sense because of the unwanted
reactions they cause. A pleasant smell will bring to mind a nice, comfortable
sensation, while an unpleasant one will trigger ugly, uncomfortable sensations.
Although the nose warns us about chemical pollutants existing in the
air we breathe, it is not infallible. Several compounds like benzene,
ammonia or formaldehyde are detected by the olfactory system only when
their concentration exceeds a certain limit. Several noxious gases, like
carbon monoxide or radon, are not detected even when their concentration
is extremely high, sometimes even lethal.
There are several methods of quantifying the smells; one of them consists
in determining the percentage of persons that might feel uncomfortable
because of an odor. This percentage will be then compared to that obtained
when testing the people reaction to body odor.
One Olf is defined to be the quantity of body odor from an average adult
with a daily hygienic standard and regularly changed underwear. The Pole
is the concentration of body odor resulting from an on-going emission
of one Olf in a volume of 1 l/s air.
In order to avoid more than 10% of dissatisfied it is necessary to ensure
a flow/amount of 16l/s/Olf, 60 m3/h/Olf or 15 m3/h/pers.
Calculating the quantity of fresh air necessary to satisfy the demands
of users; the design stage: Realizing a synthesis of the conditions
mentioned above, there can be determined the values of indoor air characteristics,
correlated with the demands of the users (Table 2).
The number of air changes in the residential buildings: The individual
residences intended for the use of one family require the following air
change rate per hour (n h1) (Table 3).
According to the type of protection and shelter (Table
||No protection: Very tall buildings, buildings
placed at the periphery or in open markets
||Partially protection: Buildings inside the city, having at
least three other buildings nearby
Buildings placed in the city centre or in the woods.
According to the degree of permeability (Table 3):
||High: Buildings having the exterior joinery without
any type of air-tightening systems
||Medium: The exterior joinery of the buildings has air-tight
||Low: The exterior joinery has special hermetic systems
|| Values of indoor air characteristics
|| The air change rate per hour
The residential buildings constructed by man, function as shelter where
multiple processes of the social and material life takes place. Therefore,
there are many factors to take under consideration when projecting, constructing,
using and post-using these buildings.
All aspects should be first considered in the processes of their interaction
and interdependency and then to be systemically approached and analyzed.
During the first stage, that is the design and project of the building,
it is not completely professional or sufficient enough to simply juxtapose
principles, calculus, construction elements and building blocks.
The process of design work for residential buildings should be an act
of creation; the professional should be not only a man of science, but
also an artist, a creator. Both the architect and the engineer cease being
just a designer or a calculus machine; the result of his work should carry
the mark of his personality.
It is also important to take the time and observe the elements of progress
in order to understand the major differences between reiterative activities
and creative ones, between calculus and conception, quantity and quality,
law and phenomenon, pure science and creation, rational and intuition,
routine and new activities. Man has always been concerned with discovering
the factors leading to performance and progress.
Science by itself is not progressive. It represents quantitative, rational,
conscious and logic accumulations of information. The processing of the
information does not lead to progress by itself; information only represents
the known, the old and the past.
Science, with its accumulation of information and processing of facts
create favorable conditions for infralogic activities starting the need
for quality, the creation, the new, the present and the future.
Science does not nor cannot give solutions. The solutions are acts of
creation; they are unique, rising in the mind of an individual. Science,
with its reasoning, logic and methods, only prepares the field for finding
solutions; it provides optimum, sometimes multi-criteria conditions but
it cannot establish their importance. Science is schematic, sometimes
even stiff; it works with simplified hypothesis, with physical models
representing a poor, sometimes rough image of reality.
The apparently unique, quantifiable solutions provided by science come
from ignoring many aspects of the reality; closer to reality is the multitude
of solutions found in an optimum field.
Choosing the optimum solution in that field is an act of creation, of
art specific to one individual only; his/her subconscious is properly
stimulated. Simple actions such as gathering information, synthesis, analysis
and comparison of results does not make it be new, does not lead to progress.
The result of the work and efforts of specialists should be an act of
creation, of realizing the new; the sum of all results should lead to
a qualitative decision for the achievement of progress. The whole should
be greater than the sum of all parts.
The professional is the result of a subtle osmosis phenomenon between
learning, research, creation and real economic life. The professional
has titles and diploma to certify his status, but he is validated only
by true realizations that generate progress. The architect or the constructor
should stop acting as simple sketcher, project planner and start being
a creator of forms and structures. The computer overtook the technique,
the routine and the repetitive. The act of creation, the only generator
of progress, is an exclusive characteristic of the living material, the
superior, organized material, the grey matter, the human brain. The progress
and its amplitude are ensured by the relation between the act of creation
and the routine. There is no progress without new, without creation.