Indoor air quality, thermal comfort
and damages assessment of four
buildings in Athens
Luftkvalitet, termisk komfort och bedömning av
skador i fyra byggnader i Aten
ORFEAS STOURAS
KTH ROYAL INSTITUTE OF TECHNOLOGY
SCHOOL OF ARCHITECTURE AND THE BUILT ENVIRONMENT
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Everyone who had been involved in the realization of this research study, deserves credit. I am grateful to all of them for their contribution and their proposals.
More particularly, I would like to thank Professor Folke Björk who introduced me to the topic and gave me the opportunity to undertake this thesis project. His supervision and guidance during the whole process was very significant for the completion of this study.
In addition, i would like to express my thankfulness to all the volunteers who participated at the survey. It is greatly appreciated their confidence in me and their interest on the project.
To conclude, it is also my family and my friends who deserve a big thanks. All this time, they are always standing by my side to constantly support and inspire me.
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Nowadays individuals spend more than 85% of their total time in indoor environments, mainly at home and work. Thereby, the quality of the indoor environment plays a substantial role in human health and wellness. The four basic factors that define the perception of the indoor environment, through the senses, are the thermal comfort, the indoor air quality, the acoustical quality and the visual or lighting quality. A standard level of the above factors is ensured by the building envelope and the services systems.
At the same time, the bearing structure provides the necessary resistance and durability to the construction in order to sustain the various loads without breaking down. Inevitably, over the years, all structures’ robustness declines and their functionality state degrades. For that reason, intensive provision should be given to assure the users’ safety and well-being.
The objective of this study is to assess the current indoor air quality, the thermal comfort and the damages at four publicly owned buildings located in Athens, Greece. The evaluation was done through the facilities management contribution, a questionnaire survey and a technical visit – inspection where measurements were taken. Special focus was also put on the Sick Building Syndrome (SBS) and its effects.
The results indicated that at 3 out of 4 buildings mainly suffer from unpleasant odors and lack of fresh air intake. Therefore, the installation of mechanical ventilation systems (air handling units, outdoor air processing units) combined with an effective air distribution system (confluent jet ventilation system) is suggested. Substantial building damages were detected at the cultural center (floorings, door/window openings, fungi) and specific proposals for restoration are made.
Despite the existence of indicators of an unhealthy indoor environment, a direct correlation between the exposure to various pollutants and the SBS symptoms, cannot be established. The optimization of the research methodologies and the institution of new building design protocols is essential in order to overcome the SBS effects.
On the whole, the questionnaire achieved to fulfil the objectives of the survey. It was comprehensible by the respondents while the outcome of the questionnaire and the inspection were consistent to each other. The questionnaire and the checklists are practical tools that could be used as a guide for future investigation in similar fields.
Except for technical surveys and questionnaires, many suggestions for future maintenance of the buildings are provided aiming to retain their functionality. These proposals concern the services systems, the building envelope as well as the bearing structure of the buildings.
Keywords: Indoor air quality, Thermal comfort, Building damages, Questionnaire, Inspection, Sick building syndrome, Mechanical ventilation, Air distribution system
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1 Introduction ... 1
1.1 Indoor Air Quality and Health level ... 1
1.2 Building Damages level ... 2
1.3 Aims and Objectives ... 2
2 Previous Research - Conditions and Assumptions ... 4
2.1 Evaluation of the different variants of a Questionnaire Design ... 4
2.2 Assessing the Thermal Comfort and Air Quality by an Air Distribution Index ... 6
2.3 Indoor fungi as bioindicators of Indoor Air Quality ... 7
2.4 The European Audit Project (Bluyssen et al, 1996a) ... 8
2.5 The European ‘HOPE’ Project, 2002 ... 8
2.6 The ‘TOBUS’ method, 2000 ... 9
2.7 Biological and non-biological sources of pollution (A.P. Jones, 1999) ... 10
2.8 Assessment of the ventilation performance of different air supply devices ... 11
3 Methodology ... 13
3.1 Phase I – Questionnaire design for occupants ... 13
3.1.1 Layout of the questions ... 13
3.1.2 Association of the workplace and the symptoms ... 13
3.1.3 Accurate description of the symptoms ... 14
3.2 Phase II – Criteria for building selection ... 14
3.2.1 Sample size ... 14
3.2.2 Maintenance status ... 14
3.2.3 Age and health status diversity ... 16
3.2.4 Computer terminal, photocopying and medical equipment rooms ... 16
3.3 Phase III – Checklist design for building managers ... 16
3.3.1 Building site and construction ... 16
3.3.2 Internal environment and building services ... 16
3.3.3 Checklist completion ... 17
3.4 Phase IV – Questionnaire distribution procedure ... 17
3.4.1 Director approval and briefing ... 17
3.4.2 ‘Hand to hand’ and ‘electronic form’ questionnaire distribution ... 17
3.4.3 Time limits for distribution-collection ... 17
3.4.4 Hints during the distribution ... 18
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3.5.2 During the visit ... 19
4 Results ... 20
4.1 General characteristics ... 20
4.2 Dangerous substances ... 21
4.3 Maintenance – Renovation ... 23
4.4 Office types – Equipment ... 24
4.5 Ventilation systems ... 25
4.6 Cleaning ... 26
4.7 Questionnaire responses ... 27
4.8 Technical survey – Exterior ... 42
4.9 Technical survey – Interior ... 46
4.10Smoking policy ... 55
4.11Radon ... 55
5 Proposals ... 56
5.1 Indoor air quality and thermal comfort ... 56
5.1.1 Municipal office buildings ... 56
5.1.2 Local medical center ... 58
5.1.3 Cultural center ... 58
5.2 Building damages ... 60
6 Discussion ... 64
6.1 Relation between the Indoor Air Quality (IAQ) & the Sick Building Syndrome (SBS) symptoms ... 64
6.2 Future research ... 64
7 Conclusions ... 65
References ... 66
Appendix ... 68
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Figure 1.1 Front view of the four buildings under investigation. Upper left: Main municipal office, Upper right: Secondary municipal office, Down left: Local medical center,
Down right: Cultural center ... 3
Figure 2.1 Sample of frequency scales and different combinations of questionnaire parts. .. 5
Figure 2.2 The virtual manikin used in the CFD simulations. ... 6
Figure 2.3 TOBUS software tool for element windows ... 9
Figure 2.4 TOBUS methodology for indoor environmental quality (IEQ) ... 10
Figure 2.5 Illustration of air distribution systems: (a) Mixing Ventilation, (b) Displacement Ventilation, (c) Impinging Jet Ventilation ... 12
Figure 3.1 (a) Administration room at the main municipal office, (b) Typical office room at the interior of the moderate size municipal office, (c) Waiting room at the 1st floor of the local medical center, (d) Base floor of the cultural center used mainly for artistic events (dance and choir clubs, painting, exhibitions). ... 15
Figure 3.2 Wireless hygrometer with ventilation indicator and remote sensor ... 19
Figure 4.1 Red arrows: Salt damp patches at the top, the bottom and the water flow-paths of the façade. Blue arrows: Uncovered split air conditioner tubes. ... 42
Figure 4.2 Red arrow: Rusty railings and parapets at the terrace. Blue arrows: Bare split air conditioner tubes. ... 43
Figure 4.3 Red arrows: Plastic settlement cracks at the stairwells of the medical center. (sedimentation of concrete whilst the slab was curing) ... 44
Figure 4.4 Entrance marble tiles general degradation. Red arrow: Abruption of the tile. Yellow arrow: Abrasion of the marble surface ... 45
Figure 4.5 Discontinuity of the suspended ceiling at the lavatories. Danger of leakage (thermal, air) or condensation. ... 47
Figure 4.6 Concealed fan coil unit system used mainly for heating. ... 47
Figure 4.7 Split air conditioners installed at various locations inside the building. ... 48
Figure 4.8 Spalling of plaster at different sites at the interior of the building. ... 48
Figure 4.9 Wall mounted split air conditioner installed at the corner of the office room. ... 49
Figure 4.10 PVC anti-slip flooring at all corridors of the local medical center. ... 50
Figure 4.11 Ceiling mounted fan coil unit (cassette) as part of an air handling unit ... 51
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wall coating around the window. ... 52 Figure 4.14 Left: Unsoldered parquet tiles, Right: Fully cracked decorative cement tiles .... 53 Figure 4.15 Hairline cracks at the exterior walls of the roof due to early thermal contraction.
... 53 Figure 4.16 Typical office room of the permanent employees. One wall mounted fan coil unit
corresponds at each room. ... 54 Figure 4.17 Radon map as given by the Greek Atomic Energy Commission. Red arrow:
Classification of the radon concentrations. ... 55 Figure 5.1 Typical rooftop packaged units installed at the terrace of an office building in Japan... 57 Figure 5.2 Air motion in the confluent jet ventilation system. ... 57 Figure 5.3 Outdoor air processing unit that combines ventilation and fresh air treatment in a
single system. ... 59 Figure 5.5 Sound absorption panels post installed at the wall of an office building. ... 61
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Table 4.1 Main hazardous substances in the four buildings. ... 22 Table 4.2 Maintenance method and frequency according to the building managers. ... 24 Table 4.3 Office types, average floor area and number of video display units per person. 25 Table 4.4 Heating, ventilation and air conditioning systems at each of the buildings. ... 26 Table 4.5 Questionnaire responses concerning the total hours in the building, in the office
unit or in front of screens. (a) Large municipal office ... 27 Table 4.6 Responses about the smoking habits and the allergic background of the survey
participants. (a) Large municipal office ... 28 Table 4.7 Annoying or undesirable factors to be mentioned by the occupants of the building.
(a) Large municipal office... 28 Table 4.8 Spectrum of symptoms and their frequency among the occupants. (a) Large
municipal office ... 29 Table 4.9 Overall assessment of the air quality, the thermal comfort, the services systems
and the symptoms condition when away from the office. (a) Large municipal office ... 30 Table 4.10 General work-related questions. (a) Large municipal office ... 30 Table 4.11 Questionnaire responses concerning the total hours in the building, in the office
unit or in front of screens. (b) Moderate-size municipal office ... 31 Table 4.12 Responses about the smoking habits and the allergic background of the survey
participants. (b) Moderate-size municipal office ... 31 Table 4.13 Annoying or undesirable factors to be mentioned by the occupants of the building.
(b) Moderate-size municipal office ... 32 Table 4.14 Spectrum of symptoms and their frequency among the occupants. (b) Moderate- size municipal office ... 33 Table 4.15 Overall assessment of the air quality, the thermal comfort, the services systems
and the symptoms condition when away from the office. (b) Moderate-size municipal office ... 33 Table 4.16 General work-related questions. (b) Moderate-size municipal office ... 34 Table 4.17 Questionnaire responses concerning the total hours in the building, in the office
unit or in front of screens. (c) Local medical center ... 35 Table 4.18 Responses about the smoking habits and the allergic background of the survey
participants. (c) Local medical center ... 35
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Table 4.20 Spectrum of symptoms and their frequency among the occupants. (c) Local medical center. ... 37 Table 4.21 Overall assessment of the air quality, the thermal comfort, the services systems
and the symptoms condition when away from the office. (c) Local medical center ... 37 Table 4.22 General work-related questions. (c) Local medical center ... 38 Table 4.23 Responses about the smoking habits and the allergic background of the survey
participants. (d) Cultural center ... 39 Table 4.24 Annoying or undesirable factors to be mentioned by the occupants of the building.
(d) Cultural center ... 40 Table 4.25 Spectrum of symptoms and their frequency among the occupants. (d) Cultural
center ... 41 Table 4.26 Overall assessment of the air quality, the thermal comfort, the services systems
and the symptoms condition when away from the office. (d) Cultural center .... 41 Table 4.27 Temperature and relative humidity values, indoors and outdoors, for each
building. ... 46 Table 5.1 Review of the proposal for the ventilation of the examined buildings. ... 59
ix ADI Air Distribution Index
AHU Air Handling Unit
BRI Building-Related Illnesses CFD Computational Fluid Dynamics DSD Displacement Supply Device DV Displacement Ventilation
FCU Fan Coil Unit
FRP Fiber Reinforced Plastic
GAEC Greek Atomic Energy Commission (EEAE)
HOPE Health Optimization Protocol for Energy-Efficient Buildings HVAC Heating, Ventilation and Air Conditioning
IAQ Indoor Air Quality
IJ Impinging Jet
IJSD Impinging Jet Supply Device IJV Impinging Jet Ventilation MSD Mixing Supply Device MV Mixing Ventilation
OAPU Outdoor Air Processing Unit OES Office Environment Survey PCB Polychlorinated Biphenyl PSI Personal Symptom Index PVC Polyvinyl Chloride
RH Relative Humidity
RTU Rooftop Unit
SAC Split Air Conditioner SBS Sick Building Syndrome
TOBUS Tool for selecting Office Building Upgrading Solutions
UK United Kingdom
VOC Volatile Organic Compound WCJSD Wall Confluent Jets Supply Device WHO World Health Organization
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1 Introduction
It is common knowledge in the civil engineering community, that every building comprises of three main parts which are the bearing structure, the surfaces and its systems.
The purpose of the bearing structure (including the foundation and the skeleton) is to provide the necessary resistance and robustness to the construction in order to sustain the various loads without breaking down. The role of the surfaces and the envelope of the building (including the roof, the sub-floor, the exterior walls, windows and doors) is to protect the occupants from undesirable intrusions (rain, snow, noise, solar radiation) and at the same time provide comfort, security and privacy. Finally, the various technical systems (heating, ventilation, air conditioning, lighting, plumbing, smoke exhaust system etc.) are usually treated as something to be added for the comfort and the optimization of the envelope’s efficiency.
1.1 Indoor Air Quality and Health level
Nowadays, people tend to spend much of their time indoors. Quite many reports have proved that individuals in developed countries spend over 85% of their total time in indoor environments (home, work).
This fact can be mainly attributed to the technological development, which created more white-collar vacancies and at the same time improved the communication tools. For example, in the past, many activities required many displacements and the physical presence in an organization to handle a case. To the contrary, today, this can be managed easily by distance.
Consequently, the indoor environment plays a key role in human health and well-being. The four basic environmental factors that determine the perception of the indoor environment through the senses is the thermal comfort, the lighting quality, the air quality and the acoustical quality. The thermal comfort is related to parameters such as moisture, air velocity and temperature while the air quality is a factor associated to indoor air pollution, fresh air supply or various odors. The lighting quality is mainly determined by the illuminance, the view and the reflection and the acoustical quality by the noise or the possible vibrations.
It is more than evident that wellness in an indoor space is much related and dependent on the above-mentioned factors. Numerous scientific studies and research suggest that a wide spectrum of symptoms and illnesses are associated with poor indoor climate, low air quality and air pollutants.
All these symptoms and health complaints were suggested in 1984 by the World Health Organization (WHO), as the Sick Building Syndrome (SBS). According to a citation by Lahtinen in 1998, all symptoms of SBS are relatively minor, non-specific and common
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amongst the general population, but are more frequent amongst the occupants of ‘sick’
buildings. Thus, SBS is an aggregate of symptoms that have no evident etiology and appear after exposure to a specific building environment. Symptoms usually include eye, nose and throat irritation, dry, itching and red skin, headaches, mental fatigue, coughing, wheezing, sneezing, nausea and general unspecific hypersensitivity.
The thermal comfort and the air quality are greatly affected by a well-designed ventilation system. A high-quality ventilation system is more than substantial nowadays since it can supply with infiltrated outdoor air a closed space, to remove high heat loads, to regulate the indoor temperature and dilute any possible pollutants. Therefore, it can possibly even eliminate the SBS symptoms and improve occupants’ health and productivity.
1.2 Building Damages level
Over the years, buildings’ serviceability and functionality state is deteriorating. This fact endangers above all the user’s safety, well-being and health. Secondly, it sets critical doubts about buildings’ robustness and persistence.
At all constructions, by the design level, particular protocols regulate the inspection schedule and the maintenance-remedy proposals. The end of service life of a building is defined by criteria that reflect the inadequacy of the structure to meet the specified performance requirements or when an unacceptable state is exceeded.
Inevitably, buildings’ damages is an issue that will always be on the table and careful manipulation is required for a number of reasons. Some reasons are vital and are already mentioned at the first paragraph of this subchapter. Others are related to the need for sustainability at a technical, economic and environmental level.
1.3 Aims and Objectives
The purpose of this report is to evaluate the current functionality and performance of four publicly owned buildings, in Greece. The assessment concerns the Indoor Air Quality (IAQ) and thermal comfort of the buildings, as well as, the recording and the classification of possible damages.
The four buildings are all located in Athens, the capital city of Greece. The first two, operate as main municipal offices, the third one as local medical center and the last one as cultural center.
At this study, the following tasks where performed. Initially, the occupants of all four buildings were asked to fill in a properly designed questionnaire concerning the symptoms of the sick building syndrome and the thermal comfort at their working environment. After that, a building survey – inspection was done in order to identify and record any visible and non-visible defects of the premises. According to the occupants’ statements and personal survey, specific proposals come to discussion where different alternatives are compared and contrasted.
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Figure 1.1 Front view of the four buildings under investigation. Upper left: Main municipal office, Upper right: Secondary municipal office, Down left: Local medical center, Down right: Cultural center
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2 Previous Research - Conditions and Assumptions
Many studies over the years have investigated the indoor air quality, the thermal comfort, the ventilation systems and the moisture levels of various buildings and facilities. The possible correlation of these terms to the symptoms of the SBS is usually the objective of such research.
Surveys, computational models, laboratory measurements and microbiological analysis of atmospheres are the methods used by the scientific community to examine and verify multiple hypothesis. For that reason, researchers have developed particular indices in order to quantify and classify their data. These indices are used for the standardization of the procedures and certain limits are defined for the evaluation of each case.
Scientific research that is considered to be a landmark in the field of the nonspecific building-related illnesses (BRI) will be summarized at the following paragraphs.
2.1 Evaluation of the different variants of a Questionnaire Design
The standardization of the SBS questionnaires requires a suitable calibration of the available instruments and resources. In that way, different questionnaires generate results of the same phenomenon with high validity. Thus, remote researchers can determine and compare reliable data, produced under a common acceptable validity.
An extensive study was conducted in the United Kingdom (1995) in order to compare the possible options of a SBS questionnaire. Five thousand five hundred sixty-six (5566) occupants of eleven (11) office buildings in the UK were asked to fill in twenty-five (25) variants of a questionnaire design. All variants correspond more or less, to previous questionnaires and studies developed. More particularly, the study is relied on the Office Environment Survey (OES) questionnaire which was developed by Wilson and Hedge in 1987 and the Swedish MM questionnaire which was developed by Anderson et al. in 1993.
Both of them are widely used in the original or adapted form in the UK, in Sweden and at the rest European countries.
At this study, the impact of specific characteristics of a questionnaire design was investigated. First of all, the planning of the symptom questions was an issue to be delivered since there are two available options, the table format and separate questions. Another issue under inquiry, was the wording to be used whether the symptoms are building related or not. The distinction between similar or linked symptoms, listed or not, on the questionnaire, was also a matter to be addressed since many participants on the surveys get confused.
Finally, the different response scales used for recording the frequency of the symptoms and discomforts was also a question to be examined.
After the process of the available data, the researchers concluded that separate questions provide more accurate answers especially for the frequency of occurrence of each symptom,
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compared to a response table. Inevitably, this comes to the cost of more space on the questionnaire, but it might be a less time-consuming procedure if not all the symptoms are experienced. So, a SBS measure can be extracted both by tables or separate questions depending on the available resources and the degree of accuracy required.
As far as the building-relatedness is concerned, the best option is asking whether the symptoms get decreased when occupants are away of the building. This approach is independent of the home-environment and at the same time avoids blaming the working environment. All symptoms are not exactly the same, so small changes in wording or description has great impact when reporting. The frequency scale is not necessary to obtain a Personal Symptom Index (PSI), thus, the symptom questions could be asked separately.
The reason is that the frequency of existence of symptoms has an illogic impact on the PSI.
Figure 2.1 Sample of frequency scales and different combinations of questionnaire parts.
Also, many other researchers contributed significantly to the validation of questionnaire surveys. For example, Burge et al. (1990) proved that self-completion questionnaires validity is comparable to medical interviews. In addition, Hodgson and Turner (1993), established that there is a difference between questionnaires in which symptom questions are asked in a formal sentence and those that use a table format. Moreover, according to Gaskell et al. (1993), a frequency scale provokes a comparison shift where the response alternatives are not independent. The first steps towards a well-established questionnaire format were done.
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2.2 Assessing the Thermal Comfort and Air Quality by an Air Distribution Index Nowadays, the objective of all ventilation systems is to ensure both a high level of indoor air quality and thermal comfort. Previously, these two variables were examined independently when an air distribution system evaluation was performed. Quite often, the ventilation units are efficient in providing only good air quality or thermal comfort. Thus, it was necessary to develop a reliable index through which we can assess the two parameters of a ventilation system the same time.
At the current study, Almesri et al. (2012), introduced a new Air Distribution Index (ADI)New in order to assess the ventilation effectiveness in uniform and nonuniform thermal environments. This particular index (ADI)New includes parameters for the evaluation of the indoor air quality and thermal comfort in occupied spaces. For that reason, Computational Fluid Dynamics (CFD) simulations were carried out to predict the airflow properties in a chamber where a virtual manikin was placed. At the same time, eight (8) human subjects were exposed to two experimental tests where their actual thermal sensation votes were asked and measured.
The predicted CFD and the subjective (measured) quantities were in good agreement according to the authors. Based on this conclusion, this new index (ADI)New can provide a reliable assessment of the existing ventilation systems. In particular, the Mixing Ventilation (MV) and the Displacement Ventilation (DV) systems were contrasted using both the CFD simulations and experimental data. The comparison proved that the DV system succeeds a higher (ADI)New value and therefore provides better air quality and thermal comfort.
Figure 2.2 The virtual manikin used in the CFD simulations.
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2.3 Indoor fungi as bioindicators of Indoor Air Quality
Numerous studies carried out between 1960s and 1990s demonstrated the existence of fungi in all types of atmospheres. Cladosporium is usually the prevalent fungus despite that the climate and the human activity define the species of fungi at each region or surface.
In the past, it was considered that indoors, fungi exist mainly as spores. After sufficient research it was proved that fungi survive and grow in culture media or building materials.
And the worst is that when exposed to a draught they release spores and fungal fragments.
These spores and fungal fragments are present in bioaerosols and can easily penetrate into the human body through the respiratory system. Inflammatory reactions such as asthma, hypersensitivity pneumonitis, breathlessness, bronchiectasis and fibrosis are common symptoms mentioned among various surveys.
Reports published by Pasanen et al. (1997) and Claeson et al. (2002), confirmed the fact that indoor fungi growing in culture media, building materials and house dust can produce Volatile Organic Compounds (VOCs). Among them, mycotoxins are considered to be the most dangerous compounds at high concentrations. More particularly tricothecenes can cause severe and acute intoxications whose symptoms include internal burning, vomiting, diarrhea with blood, cutaneous necrosis even internal hemorrhages.
A certain investigation conducted by Croft et al. (1986) at a block of flats in Chicago suburbs, revealed the presence of tricothecenes (S.Chartarum spores) in ventilation ducts, walls and ceilings. The same time the occupants had a variety of symptoms such as headache, fatigue, dermatitis, hair loss, throat pain and diarrhea which could not be explained by normal medical tests. When these substances were introduced to laboratory mice all animals died very shortly. A clear evidence that VOCs are linked to health problems and their symptoms. Another study by McGrath et al. (1999) concerns a hotel whose visitors were complaining of typical Sick Building Syndrome symptoms. Microbiological analysis showed the existence of penicillium fungi in very high concentrations.
Positive correlation between high indoor moisture and respiratory problems was described by Mendell et al. (2009). The elevated indoor humidity enhances the development of fungus and through their spores or fragments they insert into the human body causing many relevant symptoms.
Usually, people with a strong immune system have very mild or no symptoms when exposed to similar environments. However, when they stay in a ‘polluted’ area for a long time (e.g.
work office, house) this can lead to chronic intoxications and SBS symptoms. All in all, there is a definite association between the IAQ and the fungi. So, the existence of certain species of fungi can demonstrate a possibly contaminated atmosphere.
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2.4 The European Audit Project (Bluyssen et al, 1996a)
The purpose of this study was to create evaluation processes on ventilation and pollutant source control, in order to guarantee a high level of indoor air quality and optimize energy use in office buildings.
At this effort, fifteen (15) institutes from eleven (11) countries agreed at a common Europe- wide method for the investigation. This included identical questionnaires and survey checklist which were developed by Clausen et al in 1993. To the point, a total of six thousand five hundred thirty-seven (6537) occupants, properly trained to assess air quality, participated at the survey. Fifty-six (56) office buildings in nine (9) European countries were evaluated by questionnaires and physical-chemical analyses of air.
As far as the chemical analyses of the air is concerned, the findings were impressive. It was proven that the ventilation systems, the construction materials and the activities done by people are the major source of pollution in indoor environments. Of course, the occupants contribute to this pollution but at a lower degree. Further research was decided aiming to the search for the sources, the compounds and their effects on human health.
According to the questionnaires’ responses, thirty per cent (30%) of the occupants and fifty per cent (50%) of the visitors of the buildings perceive the air quality as unacceptable. In addition, the indoor climate was considered to be dry and the thermal sensation as neutral or a bit warm. The most peculiar result is that although a considerable variation was detected between the various European buildings, the occupants’ responses presented a uniform trend.
2.5 The European ‘HOPE’ Project, 2002
At the European HOPE project (Health Optimization Protocol for Energy-Efficient Buildings, 2002) one more initiative for the definition of the performance criteria was made.
According to these criteria, guidelines and design solutions for healthy buildings can be constituted and applied.
A total of two thousand seven hundred three (2703) accomplished questionnaires concerned residences and five thousand nine hundred ninety-two (5992) concerned offices. The questions addressed to the occupants were related to the sensation comfort and their health status. More particularly, the comfort included thermal, visual, acoustical and indoor air qualities while the health status included the SBS symptoms and allergies.
As stated in the project, a building is defined healthy, comfortable and energy efficient if
‘the building does not cause or aggravate illnesses in the buildings’ occupants; it ensures a high level of comfort for the building’s occupants; it minimizes the use of energy to achieve desired internal conditions’. So, the survey was mainly focused on the identification of the association between the perceived indoor environmental characteristics and the well-being of its occupants.
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Quite often people’s needs and satisfaction can vary over time and per person. This is attributed to a high degree to the fact that the people always emphasize to what is missing in their lives and not to what they already have. Thus, their expectations, wishes and demands can greatly affect a questionnaire survey and yield different results.
2.6 The ‘TOBUS’ method, 2000
Trying to meet occupants’ expectations, many methods and systems were developed. One noteworthy among them was the TOBUS method (Tool for selecting Office Building Upgrading Solutions) which is a knowledge-based system for the assessment of the refurbishment needs of office buildings. This tool definitely promotes the concept of improved energy performance and is supported by a powerful software.
Figure 2.3 TOBUS software tool for element windows
The steps of the methodology are as following. First of all, the building manager collects all necessary information about the building structure and its services. After that, questionnaires are distributed to the occupants in order to record all information concerning the perceived comfort and complaints. During the visit the auditor registers his own observations which an contribute significantly to the diagnosis of the buildings’ problems.
After the visit, all possible reasons behind the problems are examined and analyzed.
Recommendations for intervention proposed include both object-related and non-object related actions.
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Figure 2.4 TOBUS methodology for indoor environmental quality (IEQ)
All in all, the method is structured and implemented in a way that helps the user throughout the project. Some important fields are the organization of the building audit, the collection of all necessary data, the quick evaluation of different scenario using the software, the analyzation of the results and finally the preparation of the report. Thus, the retrofitting and the renovation procedure becomes an interactive process, where the user of the software for each decision gets all the feedback involved in a technoeconomic point of view or sustainability issues. The first integrated and robust method to assess and to improve the performance of an existing building was created.
2.7 Biological and non-biological sources of pollution (A.P. Jones, 1999)
At the University of East Anglia, in the UK, the researchers tried to review the current understanding of the relationship between indoor air pollution and health. Many epidemiological studies were used as evidence for their results and conclusions.
Indoor air pollutants can derive from a range of sources. Some of them are related to the indoor human activities while other contaminants infiltrate from outside through water, air or soil. Combustion products from heating, cooking, the smoking of tobacco and emissions from building materials contribute much to air pollution. Substances known as volatile organic compounds (VOCs) which come mainly from paints, varnishes and solvents are to blame for many adverse health effects. Radon, this radioactive gas along with its decay products, is considered to provoke serious health problems when found and inhaled inside buildings.
At this study, pollutants were also classified according to whether they arise from biological or non-biological sources. The most widely recognized pollutants from non-biological sources is asbestos, carbon monoxide and dioxide, formaldehyde, nitrogen dioxide, sulfur
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dioxide, various respirable particles, tobacco smoke and all VOCs. Biological sources of pollution include indoor biological allergens (house dust mite, cats, rodents) and microorganisms (fungi, bacteria, viruses).
The paper concludes that SBS has a multi-factorial etiology where biological, chemical, physical even psychosocial factors interact to produce symptoms and discomfort. Various studies (Wallace et all 1993, Eriksson and Hoog 1993 etc.) found that the combination of a high workload, role ambiguity and low status were associated with headaches, eye irritations, dizziness and chest discomfort. Thus, despite the multiple of theories that are already proposed none can describe the exact mechanism of the SBS and many doubts still remain. Refinement and further research is needed for better understanding of the causality of the SBS as well as its health effect in a long term.
2.8 Assessment of the ventilation performance of different air supply devices A large-scale investigation was conducted in the context of a dissertation study (Huijuan Chen) at the university of Linkoping. The purpose of the study was to explore the flow field, thermal comfort and the ventilation effectiveness of the Impinging Jet Ventilation system (IJV) in an office environment.
The study consists of three independent parts, where in the first, velocity and temperature distributions of Impinging Jet (IJ) flow field are compared with detailed measurements. The second one, was a parametric study with respect to the configuration of an impinging jet device, the air supply conditions and the room design parameters, by using CFD simulations. The third part, examines the performance of the Impinging Jet Supply Device (IJSD), compared with other supply devices and more particularly with the Mixing Supply Device (MSD), the Wall Confluent Jets Supply Device (WCJSD) and the Displacement Supply Device (DSD).
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(a) (b)
(c)
Figure 2.5 Illustration of air distribution systems: (a) Mixing Ventilation, (b) Displacement Ventilation, (c) Impinging Jet Ventilation
A short description of each system will be given since the conclusions of the third part are of particular interest in my study. Impinging jet is the flow produced from an air supply opening situated away from a surface, with the flow impinging on the surface. The MV aims to provide uniform conditions throughout the ventilated space by supplying high momentum air jet. On the other hand, at the displacement method, cool air is supplied in lower level into the room with low momentum. The cold air moves the contaminated air to a higher part of the room due to buoyancy forces. At the confluent jets ventilation (WCJSD) air is supplied from a large number of small air nozzles on a duct, creating a wall jet on the floor.
A combination of mixing and displacement flow is created.
According to the authors, the IJSD could provide a better overall performance compared to the alternatives because it combines positive properties from the mixing and displacement ventilation function. The fields examined were the overall and local thermal comfort, the heat removal effectiveness, the air exchange efficiency and above all the energy-saving output.
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3 Methodology
As it was mentioned at the introduction chapter, the questionnaire survey was carried out at four publicly owned buildings which are all located in Athens. The topics covered in the questionnaires is the thermal comfort and the IAQ in the workplace.
The whole procedure was divided in distinct phases as described at the following sections.
3.1 Phase I – Questionnaire design for occupants 3.1.1 Layout of the questions
At this phase, the preparation of the questionnaires was made. The separate questions format was employed to obtain a measure of the SBS and acquire the frequency of occurrence of each symptom.
Although separate questions require more space in the questionnaire, they record the frequency of the symptoms more precisely. Through tables many frequency scales have to be used and even this, can lead to ‘missing’ cases (no response) or an approximate approach.
For example, if someone does not experience a particular symptom or cannot identify his own case in any of the frequency columns, may leave the question blank. Even worse, can mark the column which reflects approximately his situation. This definitely affects the validity of the survey and may be misleading when evaluating the results.
3.1.2 Association of the workplace and the symptoms
When designing a questionnaire one of the most critical questions concern the effect of the indoor environment to the occupants’ well-being. The wording of the question was very precise and emphasized in two particular issues.
First of all, the direct comparison of the office environment with the home environment was avoided. Not only with the home, but with every building where people spend a large percentage of their time. The reason is that in many buildings the IAQ is low, something that people is difficult to know in advance. This could affect people’s responses and attribute all symptoms to non-building related causes.
Secondly, a question that directly judges or even worse accuses the office environment for SBS symptoms, was excluded. From the employees’ perspective this may create an inherent link that since the indoor environment is unpleasant, this is to blame for the symptoms. This incident could definitely spoil the survey results.
Others may also feel uncomfortable or afraid to declare, in black and white, that their office environment is responsible for the deterioration of their health. Such declarations
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may lead to a low productivity evaluation on purpose or a dismissal. Not to skip the fact that such a question is not unaccepted by some directors and building managers for their own reasons.
3.1.3 Accurate description of the symptoms
Each symptom was mentioned clearly and separately. According to previous research, an ambiguous wording or grouping of similar symptoms is detrimental and the participants at the questionnaires may be misled.
Characteristic examples are the eye and respiratory symptoms. Often, ‘itching eyes’
and ‘red eyes’ or ‘shortness of breath’ and ‘wheezing’ are terms overlapping each other.
In reality, between these symptoms there is also a causal relation since when rubbing itchy eyes, redness may appear.
3.2 Phase II – Criteria for building selection
Certain criteria were set as far as the building selection is concerned. This stage is also critical since an ‘effective’ building choice can enhance the validity of the findings.
3.2.1 Sample size
The most important is to carry out the survey at buildings with a large sample size. In statistics, large sample size is fundamental at every measure, at every research, at every conclusion.
It is more representative of the population, limiting the influence of outliers or extreme observations. A sufficiently large sample size is also necessary to produce results among variables that are significantly different.
For that reason, where possible, buildings with more than one hundred fifty (150) occupants were selected. In that way, even with a sixty-seven per cent (67%) response rate, we could have at least one hundred (100) questionnaire respondents. Both municipal office buildings achieved this requisite, since the biggest one has five hundred ninety (590) occupants and the smallest one, one hundred ninety-five (195).
3.2.2 Maintenance status
Another fact that was taken under consideration was the current state of the buildings.
The age of the building, the maintenance and the renovation status are terms of substantial impact. These three variables can determine to a high level the occupants’
responses and the results of the survey.
For example, a recently renovated building maybe is less vulnerable to the consequences of the Sick Building Syndrome. Thus, at the present study all kind of buildings were selected.
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More particularly, the large municipal office building is not renovated and is subjected to predetermined maintenance intervals. The smaller municipal office building is also not recently renovated but gets under a systematic maintenance schedule. The local medical center as well as the cultural center are relatively recently restored.
(a) (b)
(c) (d)
Figure 3.1 (a) Administration room at the main municipal office, (b) Typical office room at the interior of the moderate size municipal office, (c) Waiting room at the 1st floor of the local medical center, (d) Base floor of the cultural center used mainly for artistic events (dance and choir clubs, painting, exhibitions).
16 3.2.3 Age and health status diversity
It is medically accepted that there is a strong link between the reaction of the humans’
organism to the environmental stimuli and their age or health status. Possibly, the same person if exposed to particular environmental factors when young and older will react differently. Or in general people of various health status will respond in a different way to the same stimuli.
Thus, the effects of the SBS may affect people in alternative ways. This includes the intensity of the symptoms, the duration of them or the sensitivity to particular indoor environmental factors.
The buildings selected belong to the public sector and all employees are civil servants.
That means that the sample is more diverse and representative of the population. At the private sector, quite often, during the selection procedure there is discrimination against elder or people with underlying diseases.
3.2.4 Computer terminal, photocopying and medical equipment rooms
Some factors that are known to be detrimental to people’s health and maybe responsible for the SBS effect, is smoking and radiation emitted by computer terminals, photocopying and medical devices rooms.
The two municipal office buildings are more representative of an office environment where computer and photocopying rooms exist. The same for the local medical center where there are many medical devices installed.
3.3 Phase III – Checklist design for building managers
In order to obtain a better knowledge about the characteristics of each building, a checklist was prepared. This list, in a questionnaire form, inquires all necessary information to be considered before a building evaluation.
3.3.1 Building site and construction
One part of the checklist involved general questions, not directly associated to the topic of this report. However, a global view could always be useful before an assessment.
More particularly, the date of erection, the location, the access of the building, the maintenance schedule, the structural-material considerations, any recent disasters and the latest damages were demanded.
3.3.2 Internal environment and building services
This part of the checklist includes questions related to the IAQ and the thermal comfort.
Topics covered are the building services such as the Heating, the Ventilation and the
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Air Conditioning (HVAC), the electrical services, the smoking policy, type of materials for furniture and equipment and the cleaning frequency.
3.3.3 Checklist completion
The facilities management belongs to an enterprise controlled by the state but is a separate organism. Everything associated to the buildings is regulated and performed by them.
One week before the visit to the four (4) building facilities, i contacted the building managers so we fixed a meeting at their offices. Although they could not share with me a lot of information, due to protocols, I managed to gather as much information as possible.
3.4 Phase IV – Questionnaire distribution procedure 3.4.1 Director approval and briefing
Two days before the questionnaire distribution, all directors’ and managers’ consent was asked. In that way, the survey was made formal and all employees were in advance aware of the questionnaires via a briefing that followed.
The purpose of the management approval was to assure a high response rate and elimination of any bias. Through a transparent procedure people feel more comfortable to accomplish the questionnaires and the same time to answer sincerely.
3.4.2 ‘Hand to hand’ and ‘electronic form’ questionnaire distribution
Principally, the questionnaires were distributed by hand to everyone within each building. Quite often, this was accompanied with a little chat or some explanations about the project. Personal contact is usually necessary since it enhances people’s interest to complete the questionnaire and participate at the survey.
For those who were absent during the questionnaire distribution an alternative was given. The electronic form of the questionnaires was sent to their professional email the day after. Those who were willing to participate to the survey, had a three-day deadline for submitting their responses.
3.4.3 Time limits for distribution-collection
The questionnaire distribution was done the same day (08.30am - 18.30pm) at all four buildings. It was a time-consuming process since the four buildings were located in different places and the traffic congestion is heavy in Athens. The collection of them was done the next day, so all participants had one full working day to fill in the forms.
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This strategy enabled me to visit all four buildings the same day and distribute the questionnaires on paper form. Simultaneously, the occupants of the buildings were given enough time to fill in the questionnaires.
The occupants of the cultural center were asked to fill in only the questions Q11 to Q21 since most of them do not work permanently and full time. Their responses were handled with more carefulness compared to the rest of the building cases.
3.4.4 Hints during the distribution
All participants to the survey were given four (4) particular advices-instructions. This was done via an extra paper-supplement that was distributed separately from the main body of the questionnaire.
First of all, the occupants were asked to answer individually and record only their own views. Any conversation or comments should be avoided before the completion of the questionnaire. In addition, in case that they were uncertain about a question and its answer, they were recommended to either answer ‘not sure’ when possible or leave it blank and proceed to the next question. Sincerity was requested since the results of the survey will not threaten or affect their lives. Everything asked is in the context of a master thesis, the results of which can be consultative. Finally, all questions concerning symptoms refer to the last three (3) months period.
The hints mentioned above had a clear role. If possible, to eliminate any factors that could undermine the quality of the survey.
3.5 Phase V – Checklist for inspection 3.5.1 Before the visit
One more checklist was prepared this time for audit purposes. It is a very crucial procedure which combines the general principles of an inspection visit and the information obtained by the building managers.
The inspection was planned in advance, in order to focus directly on the critical areas.
Quite often, the time is pressing at the visit, so all the necessary information must be collected as soon as possible.
A wireless hygrometer with a remote sensor was bought to capture the indoor and outdoor temperature and the relative humidity levels. The device has also a ventilation indicator which depending on the humidity levels and the upcoming atmospheric change recommends ventilation or not to the room. The pictures were taken by my smartphone and a notebook was used to write down my observations.
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Figure 3.2 Wireless hygrometer with ventilation indicator and remote sensor 3.5.2 During the visit
The inspection was done after the collection of the questionnaires of the occupants for each building. The technical survey of the buildings and their installations was based on the checklist and included the following measurements and observations.
Initially, the capture of the indoor and outdoor temperature and humidity was done.
After that, I looked for condensation in windows, traces of moisture load in windows or on the walls and the recording of any odors at all rooms. The window frames were also checked against corrosion and mold.
Any traces of water or dampness on ceilings, floors, walls and the rest structural elements were also recorded. Discoloration, flaking or bubbles on any surface was also noted down. Pictures were taken when the damage was obvious, and the managers of the building allowed it.
Where possible, all building services were checked for any obvious damages and their functionality was asked. This includes the ventilation, the air conditioning, the heating, the electrical, the water supply and the drainage system.
Finally, the structural integrity of the building was registered. This includes cracks, spalling of the concrete cover, carbonation, leaching and erosion, sulphate attach, or alkali silica reaction that belong to the ‘illnesses’ of the concrete deterioration. Also, the reinforcement corrosion and the coatings condition were issues to be inspected.
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4 Results
At this section, the results for each building are reported. All relevant information was obtained from the building managers checklist, the questionnaire responses and the inspection checklist.
4.1 General characteristics
a) Large municipal office building
According to the building managers the building was erected in 1982 and has not undergone any major rehabilitation.
It is located in the city center of Athens where high-rise buildings and commercial centers are dominant. The traffic is also heavy and all roads around the building are very busy.
b) Moderate-size municipal office building
This building was constructed in 1958 and has been renovated in 1998. At this one, restoration aluminum windows were installed and a dropped ceiling was placed at the last floor.
It is also located in the center of Athens and it is surrounded by high-rise buildings. All streets around are moderate busy.
c) Local medical center
An old residential 2-floors building built in 1958, was transformed to the medical center of our survey. The total rehabilitation took place in 2014, when large-scale works were made for two years.
The structure is located at a suburban area of Athens city, with residential areas and a few parks. In front of the building, there is a moderate busy road but at the other directions the streets are usually quiet.
d) Cultural center
The cultural center is accommodated at an old classic mansion built in 1934. Except for the housing, the mansion included exterior spaces (gardens, vineyards) and a summer cinema stage.
It was abandoned by its landlords and it was at the end donated to the Greek state. The mansion was in an extremely faulty condition, so a restoration was performed in 2015.
The structure is established at a suburb of Athens full of dwellings and some green spaces.
At the perimeter of the old mansion only local roads exist, thus the traffic is light.
21 4.2 Dangerous substances
a) Large municipal office building
Asbestos was used as insulation for the heating pipes connected to the boiler and the burner system. The electric conduits are made of lead and the ceiling fixtures operate with fluorescent lamp tubes. Obviously, the capacitors contain Polychlorinated Biphenyl (PCB) oil which is accused to be very harmful for human health. Also, PCBs were used as sealant to the window frames.
Most of the furniture equipment (desks, bookcases) are of medium quality, so formaldehyde is definitely used for the manufacturing. The production of particleboards, fiberboards and plywood is relied to a great extent to the use formaldehyde for the binding of various layers and sawdust.
b) Moderate-size municipal office building
According to the building managers there are no clues for the existence of cadmium, lead or asbestos in the construction. The suspended ceiling that was added in 1998 is made of mineral fiber, and the troffer lights accommodate led tubes and not fluorescent lamps for lighting.
At the aluminum windows there are sealing compounds which contain PCBs and all furniture are of low quality (particleboards, plywood), thereby, formaldehyde has been definitely used at the manufacturing.
c) Local medical center
In general, not many dangerous substances where used for the restoration of the building.
The sealants of the glazing units were polyisobutylene based and therefore no proven serious health risks exist. In addition, the troffer lights at the dropped ceilings utilize led tubes instead of fluorescent lamps.
The Polyvinyl Chloride (PVC) flooring is definitely the only major source of dangerous substances to be mentioned. The amount of plasticizers that were used in the mixture, define the extent of harmfulness. These floors are preferred in hospitals due to their anti-slip and acoustics properties.
In addition, it is the existence of formaldehyde at the furniture equipment. The furniture is of moderate quality and during the manufacturing formaldehyde is probably used. The building managers could not confirm it.
22 d) Cultural center
The building managers assured me that the only dangerous material that was added during the rehabilitation, were the extruded polystyrene thermal insulating boards. These blue- colored boards were installed in the roof as the thermal insulation layer.
The wooden stairwells and doors that were restored are made of beech solid wood, thus no health risks are implied. On the other hand, all newly added wooden furniture and surfaces are made of chip wood or plywood thus formaldehyde is used at the processing.
Finally, all paints and plasters applied, were eco and health friendly. No substances such as PVC, PCB, cadmium and asbestos were used as additives or stabilizers.
Building
Harmful substances
Asbestos Lead PCBs Formaldehyde PVC Extruded
polystyrene Mold
Large municipal
office
Insulation (heating
pipes)
Electric conduits
Lamp tubes, Window
sealants
Furniture
equipment — — —
Medium municipal
office
— — Window
sealants
Furniture
equipment — — —
Local medical
center
— — — Furniture
equipment Floor — —
Cultural
center — — —
Furniture
equipment — Thermal
boards
Black mold (ceiling)
Table 4.1 Main hazardous substances in the four buildings.
23 4.3 Maintenance – Renovation
a) Large municipal office building
The building envelope and the interior surfaces are maintained less than once per year. The maintenance strategy is risk-based and is relied on measurements and periodic test activities to define any upcoming deficiencies.
The building services systems (HVAC, electrical), by contrast, are maintained every six months. The strategy followed here is preventive maintenance in order to reduce the failure risk or performance degradation of the equipment.
b) Moderate-size municipal office building
For the envelope and the interior surfaces the maintenance model is risk-based and is performed once a year. For all building services systems the maintenance is preventive and has a frequency of six-months.
c) Local medical center
The maintenance schedule is very strict and has a frequency of once per three months. This concerns the building envelope, the interior surfaces, and the building services systems. The type of maintenance followed is the preventive and is made according to strict prescribed criteria and protocols.
d) Cultural center
All indoor surfaces and the building envelope are restored only if a failure happens. This is called only on breakdown maintenance and is not performed in predetermined intervals.
On the other hand, the building services systems are maintained less than once per year according to a risk-based maintenance schedule.
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Buildings
Maintenance strategy Building envelope-interior
surfaces Services systems
Method Frequency Method Frequency
Large municipal
office Risk-Based Once per year Preventive 6 months Medium
municipal office Risk-Based Once per year Preventive 6 months Local medical
center Preventive 3 months Preventive 3 months
Cultural center Breakdown 18 months Risk-Based Once per year
Table 4.2 Maintenance method and frequency according to the building managers.
4.4 Office types – Equipment
a,b) Municipal office buildings
Both municipal office buildings share the same characteristics at this section. At all floors of the buildings, the same pattern of zonal offices is prevalent. Desks are placed in an open space and there are a few partition walls for meeting and reception rooms. Each person has less than 10m2 available floor area.
The ergonomics criteria are achieved only for the chairs and the bookcases. The desks height cannot be adjusted and there are not any rollers to displace them. In front of each employee there is one computer screen, one printer and one photocopier per room.
c) Local medical center
The medical center has an activity-based workplace pattern. Each room serves a different purpose and operates separately. There is the administration room, the medical examination rooms, the doctors’ and nurses’ rooms, the maintenance officers’ room and the cleaners’
room. The rooms are spacious, so more than 10m2 are available for each employee.
All chair and some desks satisfy the ergonomics criteria while the rest should be renewed.
On average, for each occupant correspond two computer screens and there are in total two photocopiers in the building and one printer per room.
25 d) Cultural center
The cultural center is mainly used by various cultural clubs or separate artists who do not acquire their own workshop. For that reason, the workplace pattern is activity based, where the permanent administration and IT support employees have their own office-rooms and the other users share the common rooms. More than 10m2 floor area is available per person.
Also, at this building only the chairs are ergonomically designed and the desks have to be replaced. All permanent employees acquire one computer or laptop screen and the building is also equipped with three laser printers and two photocopiers in total.
Building Office type Floor area per person
Nr of VDUs per person Large municipal
office Zonal <10m2 1
Medium municipal
office Zonal <10m2 1
Local medical
center Activity based >10m2 2
Cultural center Activity based >10m2 1
Table 4.3 Office types, average floor area and number of video display units per person.
4.5 Ventilation systems
a) Large municipal office building
The ventilation is mainly done naturally via the windows. Fan Coil Units (FCUs) and Split Air Conditioners (SACs) also exist and contribute to the ventilation of the office space.
The duct material for the FCUs is carbon steel, while the air conditioner filters are replaced every six months.
b) Moderate-size municipal office building
Only natural ventilation is available by opening the windows. The SACs are used mainly for cooling purposes and cannot be characterized as mechanical ventilation.
The filters of the air conditioners are substituted every six months and there is not any clue about the ventilation rate of the spaces.
26 c) Local medical center
The medical center is equipped with ceiling mounted FCUs (cassettes), which are connected to Air Handling Units (AHUs). In that way, the indoors air is purified and is mixed with fresh air from outdoors.
The duct material of the whole system is galvanized steel and the filters of the system are changed every three months. The average ventilation rate is defined to be 1.7 l/s.m2. d) Cultural center
Split air conditioners are installed at the wall of certain rooms and provide only heating and cooling. This is definitely not a ventilation system and the renewal of the air is made by the windows (natural ventilation).
The filters of the internal units are replaced once a year and the metal used for the duct work is galvanized steel.
Building Heating Cooling Ventilation Large municipal
office FCUs SACs, FCUs Natural (Windows)
Medium municipal
office SACs SACs Natural (Windows)
Local medical
center FCUs (cassettes) FCUs (cassettes) AHU
Cultural center SACs SACs Natural (Windows)
Table 4.4 Heating, ventilation and air conditioning systems at each of the buildings.
4.6 Cleaning
a) Large municipal office building
Once per week a general cleaning is done. This includes vacuum cleaning and mopping of floors in office rooms, corridors and stairwells, as well as cleaning of all furniture surfaces.
b) Moderate-size municipal office building
The cleaning is done once per two weeks and this includes vacuum cleaning, mopping of all floors and furniture surfaces.
27 c) Local medical center
Every two working days vacuum cleaning and mopping of all floors is done. The cleaning of the furniture surfaces is done once per week or sooner if there is evidence for virus, bacteria or microbes in the space.
d) Cultural center
Once per two weeks takes place the vacuum cleaning and mopping of the floor surfaces.
The desks, chairs and rest surfaces are cleaned once per month.
It is also the cultural clubs’ responsibility to maintain the place tidy and hygienic because they do not pay any rent.
4.7 Questionnaire responses
Symptoms or annoying factors that were experienced by less than 5% of the sample were discarded and are not mentioned to the following tables.
a) Large municipal office building
At this building, a total of 510 occupants participated at the survey and answered the questionnaires.
Q7, Q8, Q9 Hours and Percentages
Hrs / day in building > 8.5 hrs (85%) < 8.5 hrs (15%) Hrs / day in office unit > 8.0 hrs (82%) < 8.0 hrs (18%)
Hrs / day in front of
electronic screens > 7.5 hrs (73%) < 7.5 hrs (27%)
Table 4.5 Questionnaire responses concerning the total hours in the building, in the office unit or in front of screens. (a) Large municipal office
28 Q10, Q11,
Q12,Q13,Q14 Yes No
Window view 209 (41%) 301 (59%)
Active smoker 134 (27%) 376 (73%)
Ex-smoker 75 (19%) 59 (81%)
Chronic asthma 34 (6.5%) 476 (93.5%)
Allergic rhinitis 77 (15%) 433 (85%)
Atopic dermatitis 12 (2.5%) 498 (97.5%)
Table 4.6 Responses about the smoking habits and the allergic background of the survey participants. (a) Large municipal office
Q15 a)....j) Yes Average
Frequency/weekdays
Unpleasant odors 321 (63%) 3 times
Stuffy air 148 (29%) 2 times
Dry air 46 (9%) 1 time
Humid air 133 (26%) 2 times
Temperature variation
during the day 71 (14%) 2 times
Cold feet 107 (21%) 2 times
Draught 148 (29%) 3 times
Table 4.7 Annoying or undesirable factors to be mentioned by the occupants of the building. (a) Large municipal office
