INTEGRATED ENVIRONMENTAL DESIGN of BUILDINGS Professor
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INTEGRATED ENVIRONMENTAL DESIGN OF BUILDINGS Professor P E. O'Sullivan The Welsh School of Architecture, University of Wales Institute of Science and Technology Introduction Historically, the concept of buildings as a means intarnal envirOnment and known physical optima of protection against the more inimical natural for human comfort and convenience, with elements, predators and the like has gradually economy and efficiency of means; in short, in given way, with social and cultural development, designing an effective filter between man and to increaSingly sophisticated control and his natural environment. On occasions, modification of the natural climate in the environmental effects resulting from decisions interests of more efficient and comfortable about the building itself through the subsequent participation in more and more complex installation of services. Such a concept demands human activities. At any given time the degree a new rationale of collaboration in the design of success has been related to the state of process. The partiCipants, building owner scientific and technological development. The or client, the design and building teams all former has made possible increaSingly accurate contribute toward a common and speciflcation of psychophysical conditions for comprehensive view of long and short term aims. optimum efficiency and comfort, the latter the All share the decision at the inception of a means of achieving them with greater certainty. project to integrate design factors for which Though reJa tions hips between cause and effect they are normally individually responsible. are far from simple, theoretical knowledge has Furthermore, decision making thereafter becomes usually been in advance of applicable a concurrent process in all the disciplines techniques, and fragmentation in the interests involved in a nd not sequential (and, therefore, of deeper speCialised knowledge (as in the logically isolated) as in the n'Jrmal case of medical sciences, for example) has tended to building design. produce isolated techniques for the better achievement of specifications - whether visual (eg the glare indexes of the IES Code) 1 thermal The Environmental 'Era' (eg Webb's work on effective temperature) 2 or aural (eg the Dutch work on the sound It is important to note, yet not generally insulating properties of glass) 3 - to accord recognised, how new the current approach to with the individual criteria emerging from environmental design is, for it can well be specialist studies in depth of each aspect. argued tha t the environmental era began It is only recently that efforts have been 'offiCially' in November 1967, when the made to bring together a number of environmental Institution of Mechanical Engineers held their and building design factors. It is the intention Conference on 'Heating and Ventilating for a of this paper to trace the brief but important Human Environment'. For this reason the history of these efforts in Great Britain and the results, although fully documented are worth effects they have had on building design. summariSing here. Billington -4 and Crenko 5 in the separate ways, Integrated Design reviewed the work on di scomfort. They indicated that under 'stress' conditions, The concept of integrated design adopted in increasing the air temperature, varying the thi s pap er recognises that the building itself, humidity and rate of air airflow, and increasing its fabric, shape and relation to local the Effective Temperature, could and indeed climatic conditions, its effect on those had been correlated with a fall off in conditions and its internal organisation of space, productivity and Health, and an increase in are no less important than installed services industrial accidents. However, when' stress' in effecting a close relationship between condi tions did not apply, for example, in air 25-2-1 t'emperatures of 20"C or less,comfort Envelope itself, ie, by the properties conditions were assumed to occur. In this of the materials in construction. 'region' no optimum standards had been determined, nor indeed what tolerances exi sted. Further, that it was these first two stages What was true in the Thermal Environment combined, which should act as the course appeared als~ to be true in the Acoustic control on the environment to produce the Environment . (basically) correct internal climate. That mistakes made in (a) and (b) could not be 7 The state of the Art of Heating and Ventilating ,8 rectified in stage (c) which conSisted of the was widely discussed, mainly in terms of 'fine tuning' of the environment so produced, by 'hardware'. The control of the thermal the thermal plant, the lighting etc. environment, however, appeared to be easily 'dismissed' with such statements as .•....... Inherent, in this concept was a numerate based if 'normal' heating and ventilating is unable to probabilistic view of design, which can be cope with the internal conditions, and in some summarised as .... 'you can never be cases this happens, then Air Conditioning can absolutely right, so how wrong do you want and must be provided ..... either by traditional to be?' or by packaged units 9. The implication being that Heating and Ventilating plant sometimes in Stage (a) above was further set on a firm the form of air conditioning, can and will solve 'climatic' basiS by Lamb 11 in his the environmental problems created by the discussion on Heat Islands. building, albeit at a cost. Further, that the key to this problem solution was through Controls Force was added to the argument in Stage (c) and Control Theory. New and better controls, by Eccleston 12 who showed how the wi th increa sed rate s of response, for example, performance of thermal plant was dependent on would- make up for the deficiencies of plant and the building envelope. Finally, Scott 13 buildings. demonstrated that these new ideas, required a new role, that he and other people were already The cost of building services, both as a total beginning to define. and as a percentage was increasing rapidly. The suggestion was that this cost could be offset to some extent by 'standardisation' always Window Function allowing that 'flexibility' was maintained. This concept of Climatic Modification, with So the 'traditional' service arguments were the enphasis on the building as the prime restated as they had been done so clearly for control, was seen by some Architects and many years. The picture which emerged was indeed some Heating and Ventilating Engineers, that of a technology, highly developed but with as a means of establishing a new route through no theoretical base to relate it to 'buildings'. the problem of environmentally uncontrollable buildings and the attendant blame that attached However, at this same Conference where the to them. An analyst s of thi s problem wa s , tradi tional view wa s so powerfully put I the attempted under the heading of 'window beginnings of a new Concept emerged. function' 14. The Concept of Climatic Modification 10 in Window function may be regarded a s three foid: which the building is considered as a filter to provide planar illumination (the specified between man and hi s environment, a filter level determines the area of gla ss required); to between the meteorological climate on the provide a directional component in the lighting one hand and the required private climate on (which varies with shape and position of the other 'appeared'. This filter was considered windows); and to provide a view out (which may to have three sections. Namely: determine the number, the size, and to some extent the position of windows). A basic a. The conversion of the meteorological environmental deSign deCision is how to allocate climate of the region, to the correct priorities to these three functions, and how to microclimate around the building. combine them in such a way as to achieve a b. The modification of this microclimate specified integrated environment. The by the properties of the Building relationships of window function to the principal 25- 2-2 aspects of the physical environment are dealt brightness sky may be the area of greatest wi th separately and collecti vely below. luminance visible from inside the room, causing serious visual distraction and a serious reduction in visual acuity. If, in addition, the The Visual Environment windows admit direct sunlight, excessive luminous contrasts can result, reducing visual A fixed quantitative stand"lrd for natural acuity still further, and possibly producing lighting has three 'effects' on building design: reflected glare from specular surfaces, and so still greater vi sual di scomfort. a. For a given floor to ceiling height it limi ts room depth (Fig 1) or restricts The distribution of daylight within a sidelit room the buildings to a single storey, unless (Fig 1) is such that the illumination levels close clerestory windows or roof lights are to the windows are very high compared with the used to augment the unidirectional levels at the back of the room, particularly, if it lighting. is more than 4· 8m deep. For example, in an b. It produces designs with a high ratio office with no rooflights and deSigned to give a of external wall area to internal volume. minimum of 2% DF at points most distant from the wi ndow, there could well be a 20% DF near the c. It produces designs with a high window wall. Though the quantity of daylight proportion of glazed to unglazed external reaching the rear of the room is 'adequate' in wall. terms of the recommendations, it appears gloomy by comparison, and artificial light is used for subjective, as apposed to funcational, rea sons. It can be seen, therefore, that in buildings with windows designed for planar illumination, artificial lighting is often used and/or blinds may be drawn 18 to reduce visually uncomfortable luminous contrasts between the sky and room interior or within the room between the working areas near to and distant from the ~or fOoIlitIItllllM ~ ..