The Indoor Environment Handbook

How to Make Buildings Healthy and Comfortable

Philomena Bluyssen

• Editore: Routledge
• Anno: 2009
• ISBN:
  9781136544811
• Edizione: 1
• Argomento: Architektur
• Categoria: Nachhaltigkeit in der Architektur

Winner of the Choice Outstanding Academic Titles of 2010 award.

Ensuring that buildings are healthy and comfortable for their occupants is a primary concern of all architects and building engineers. This highly practical handbook will help make that process more efficient and effective.

It begins with a guide to how the human body and senses react to different indoor environmental conditions, together with basic information on the parameters of the indoor environment and problems that can occur. It then moves on to give a background to the development of the study and control of the indoor environment, examining the main considerations (including thermal, lighting, indoor air and sound-related aspects) for a healthy and comfortable indoor environment and discussing the drivers for change in the field. The final section presents a new approach towards health and comfort in the indoor environment, where meeting the wishes and demands of the occupants with a holistic strategy becomes the over-riding priority. The book is filled with useful facts, figures and analysis, and practical methods that designers who are keen to assess and improve the user experience of their buildings will find invaluable.

Part I

Humans and the Indoor Environment

1

Health, Comfort and Indoor Environmental Control

In this chapter, an introduction to Part I is presented. Possible diseases and disorders related to the human body and caused by indoor environmental stress factors are described (see Chapter 2 for fuller discussion) and general strategies to control environmental factors such as thermal comfort, lighting quality, indoor air quality and acoustical quality are presented (see Chapter 3). These indoor environmental parameters are defined and identified with quantitative indicators, largely expressed according to (assumed) acceptable numbers or ranges. Although many control strategies have been identified for these parameters, it should be emphasized that control strategies that focus on one parameter and numbers only will probably not be optimal because the health and comfort of humans in the indoor environment is not easy to define and is difficult to relate to the even more complicated characterization of diseases and disorders. Knowledge of how the human body and its systems function is of utmost importance.

1.1 Introduction

From the occupant’s point of view, the ideal situation is an indoor environment that satisfies all occupants (i.e. they have no complaints) and does not unnecessarily increase the risk or severity of illness or injury. (Bluyssen et al, 2003a)

The importance of the indoor environment has been recognized since the first century BC, particularly indoor air quality, as is described by Vitruvius in his ten books of architecture (Rowland and Howe, 2007).

Although chemistry was only seen as a separate science during the 17th century, from the Middle Ages until the beginning of the 19th century people began to realize that air in a building should be good and, if not, could result in diseases or at least extreme discomfort (bad smells). The miasmatic theory of disease, now taken over by the germ theory of disease (micro-organisms are the cause of many diseases), was used to explain the spread of disease such as cholera (Madigan and Martinko, 2005). Miasma (Greek for pollution) was considered to be a poisonous, smelly vapour or mist that is filled with particles from decomposed matter (miasmata) which can cause illnesses. Ventilation thus became an important part of the indoor environment. Discussions on how much ventilation is sufficient to prevent the spread of disease and to provide adequate comfort (no noxious odours) were thus born and are still taking place (Billings, 1893).

During the late 19th century, ‘thermal comfort’ was introduced as an environmental factor that is part of overall indoor comfort. In addition to poor air quality, poorly ventilated rooms can result in unwanted thermal effects (both through temperature and humidity) (Billings et al, 1898; Janssen, 1999).

Figure 1.1 The human being in an indoor environment

Source: drawings by eight-year-old Anthony Meertins

The positive health effects of (sun) light were already acknowledged by the Egyptians, Romans and the ancient Greeks, who worshipped the sun gods. Much later, at the beginning of the 1900s, sanatoria were built for light therapy for people suffering from, among other ailments, skin diseases. During the late 1980s, light therapy, with artificial light, began to be used to cure winter depressions. Artificial lighting has been an applied science since around the 1890s, when the development of the first electrical lamps made the extension of the working day into the dark hours possible (Encyclopaedia Britannica, 1991a).

With regard to sound, the ancient Greeks and Romans realized that good auditory conditions for an audience listening to speech or music, whether indoors or outdoors, are important. They placed audiences on steep hillsides in order to reduce distance and to concentrate sound. However, not all noise was welcome: like bad air, it can be something that we would rather do without. Noise or unwanted auditory experience became an important aspect of practical acoustics during the 1970s. It was considered a form of environmental pollution, and noise control developed into a major branch of acoustical engineering.

By now, the indoor environment had begun to be described by environmental factors or (external) stressors, such as:

• indoor air quality: comprising odour, indoor air pollution, fresh air supply, etc.;
• thermal comfort: moisture, air velocity, temperature, etc.;
• acoustical quality: noise from outside, indoors, vibrations, etc.;
• visual or lighting quality: view, illuminance, luminance ratios, reflection, etc.

These various factors have slowly become incorporated within the building process through environmental design. However, aesthetic quality and spatial and ergonomical quality are also part of the indoor environment. In fact, historically, these parameters received the most attention when designing a building. This book merely focuses on environmental parameters, without downgrading the dimensions and aesthetics of shapes and spaces. As Hawkes (2008) writes: ‘The interaction of light and air and sound with the form and materiality of architectural space is of the very essence of the architectural imagination.’ And note the way in which Pallasmaa (2005) describes the essence of architecture, which comes even closer to the meaning of this book: ‘Architecture is the art of reconciliation between ourselves and the world, and this mediation takes place through the senses.’

The human senses, the so-called ‘windows of the soul’ (Encyclopaedia Britannica, 1991b), are basically the instruments we have to report or indicate whether we feel comfortable (and also how we feel our health is affected) in terms of acceptability with respect to heat, cold, smell, noise, darkness, flickering light, etc. With respect to health effects, not only are the human senses involved, but the entire human body and its systems. Indoor environmental (external) stressors that can cause discomfort and health effects are represented by environmental factors and psycho-social factors, such as working and personal relationships, as well as factors such as sex, whether we smoke, genetics, age, etc.

1.2 Disorders and Diseases

External stress factors influence all three systems of the human body (the nervous system, the immune system and the endocrine system) and can result in both mental and physical effects. Given that diseases and disorders of the human body could be caused by or related to an ‘unhealthy indoor environment’, the following division of diseases and disorders can be made:

• Diseases/disorders that are stress induced by external stress factors and that are ‘handled’ by the cooperation between the nervous system and the endocrine system, but can be influenced by the status of the immune system, such as:
  • direct noticeable comfort-related complaints by the human senses (e.g. smell, noise, heat, cold, draught, etc);
  • systemic effects (e.g. tiredness, poor concentration, etc.);
  • psychological effects (e.g. not being in control, depression, anxiety, etc.).
• Diseases/disorders that are induced by external noxious effects and are ‘handled’ by the cooperation between the immune system and the endocrine system, but where the handling can be influenced by the nervous system, such as:
  • irritation, allergic and hyper-reactive effects (e.g. irritation of the mucous membranes of the skin and respiratory tract, asthma, rashes on skin caused by allergic reactions to certain pollutants, sunburn, hearing loss, damage of eyes caused by too bright light, etc.);
  • infectious diseases (e.g. Legionnaires’ disease);
  • toxic chronic effects that gradually increase or appear (e.g. cancer).

Besides the effects of external stress factors, the performance of the human senses (internal stress factor) can also have a major influence on the first category of complaints. Degradation of the eyes, ears, olfactory bulb, etc. which usually occurs with age is an example of this. Degradation of the immune system functions also increases with age. And, lastly, genetics can also be of influence, such as colour blindness or being anosmic (not being able to smell normally).

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