Sustainable Buildings in Practice

What the Users Think

George Baird

• Publisher: Routledge
• Year: 2010
• Print ISBN: 9780415399326
• eBook ISBN: 9781135222895
• Topic: Architecture
• Subtopic: Architecture General

Current assessment methods of sustainable buildings do not adequately account for the users' needs. Given that over the life of a building, total salary costs far outweigh both operating costs and combined capital and rental costs, the occupants' needs are not something which should be sensibly ignored.

This book presents an unbiased evaluation of thirty of the most cutting-edge, sustainable buildings in the world, in terms of the users' perceived comfort, health and productivity. The author has visited the buildings, interviewed the design teams and examined the findings of a sixty-question standardized user questionnaire. The book provides:

• thirty case studies covering mixed-mode, passive and environmentally sustainable commercial and institutional buildings
• detailed insights into the principles underlying the design of sustainable buildings worldwide, over several climatic zones and eleven countries, together with clear explanations and illustrations of innovative design practice
• a discussion of common issues and the lessons that may be learnt from a study of the performance of sustainable buildings in practice, from the point of view of the people who use them.

This important book will be of great benefit to architects and engineers, facility managers of commercial and institutional buildings, as well as developers and researchers, academics and students in these fields.

1
Overview of the buildings and their performance

As previously intimated, I shall present an overview of the findings from the entire set of buildings in this chapter. This will serve not only to summarise the characteristics and users’ perceptions of this particular set, but also to explain the nature of the scoring systems used and the computation of the various indices employed.

Following a description of the nature of the buildings and their users, an outline will be given of the working arrangements of the latter and the extent of their involvement with the building. Next, the users’ perception scores for individual performance factors will be presented, together with a number of indices and rating scales, designed to give an indication of performance over a range of factors. The derivation of these indices and rating scales will be explained at this point. It is recommended that readers make themselves thoroughly familiar with the characteristics of these indices and rating scales in order to appreciate their application and presentation in the individual case study chapters that follow.

As well as asking the users to rate the individual factors on a 7-point scale, the questionnaire also invited brief comment on several of these. While the individual case study chapters will scrutinise the comments in more detail, a section of this chapter will be devoted to outlining their general tenor. A limited amount of statistical analysis was also undertaken to gauge the extent of correlations between the various individual factors and indices of performance and some of the key findings will be presented. Finally, an attempt will be made to summarise some of the main overall issues that emerged from the study of this set of sustainable buildings.

However, no overview can possibly do justice to the detailed information, analyses, and insights contained in the individual case study chapters. Having ‘digested’ this overview, I trust readers will be encouraged to dip into the case studies, perhaps starting with buildings of a type and in a climatic zone with which they are particularly concerned.

THE BUILDINGS

The 30 buildings were spread over 11 countries and a number of continents: six from North America (four from Canada and two from the USA); eight from Europe (six from the UK and one each from Germany and Ireland); ten from Australasia (seven from Australia and three from New Zealand); and six from Asia (two from Malaysia, two from Japan, and one each from Singapore and India).

As noted earlier, virtually all were recipients of national awards for sustainable or low energy design, or were highly rated in terms of their respective country’s building sustainability rating tool (BREEAM in the UK, CASBEE in Japan, LEED in the USA, Green Globes in Canada, etc.) or in some way pioneered sustainable architecture.

The buildings were also located in a range of climatic zones. For the purpose of this exercise, these have been broken down into four categories which I have labelled Cold–Temperate (with wintertime design temperatures of -5°C or less), Medium–Temperate (with wintertime design temperatures between -4°C and zero), Warm– Temperate (with wintertime design temperatures ranging from +3°C to +7°C), and Hot–Humid (with temperatures ranging up to +40°C or more). The six cold–temperate zone buildings were located in Canada, the USA (Vermont), and Germany; the 11 medium–temperate in the UK, Ireland, Tasmania, and the South Island of New Zealand; the nine warm–temperate in mainland Australia, the North Island of New Zealand, and the USA (Santa Monica, California); and the hot–humid in Malaysia, Singapore, and India.

The 30 buildings were all commercial or institutional in nature, housing anything from 15 to around 350 staff with a mean of approximately 66 per building. Thirteen of the buildings accommodated office activities predominantly, ten were tertiary-level academic teaching buildings, four housed laboratories or research organisations, and two contained a combination of light industrial and administrative functions.

In terms of the ventilation systems employed in these buildings, 15 had what have been termed advanced natural ventilation systems, broadly defined as natural ventilation where some of the ventilation openings are automated or some specially designed natural ventilation elements have been incorporated into the design. Most of the remainder (some 13 buildings) utilised a mixed-mode system of ventilation – these were predominately changeover systems where the mechanical systems were designed to operate during cold or hot conditions, and the natural ventilation systems during mild conditions. Two buildings had zoned systems where large parts of the building were either air conditioned or naturally ventilated. Only three of the buildings were fully air conditioned with predominantly sealed facades. Astute readers will have realised that amounts to 31 cases, rather than 30 – the reason for this is that one of the case studies (the Torrent Research Centre in Ahmedabad) had both air conditioned and advanced naturally ventilated buildings, and these were surveyed separately. Fuller details of the systems of environmental control are given in the individual case study chapters.

Most had been built or refurbished in the course of the past decade, and all of them had been occupied for a year or more before the survey work was carried out, giving most occupants sufficient time to experience their new surroundings over at least a full annual cycle.

THE OCCUPANTS

Overall, there were some 2035 respondents to the questionnaires. While not everyone scored every question (the questionnaire simply asked them to fill in as many as they could), the vast majority did so. The staff numbers responding ranged from a low of 13 (the small staff group at the Toronto Military Families Resource Centre) to a high of 334 (London City Hall), with a mean of approximately 66 persons per building. In a number of the academic buildings, responses were also sought from the students. A shorter questionnaire was use for this – the data are not included here but are presented in the relevant case study chapters.

For 98 per cent of the respondents (43.3 per cent female, 56.7 per cent male), the building was their normal place of business – the rest tended to be contractors of one kind or another. They worked 4.73 days per week on average and 8.01 hours per day, of which around 6.48 were spent at their desk or work space and 5.47 at a computer screen. The ratio of under-30s to over-30s was 32.6 to 67.4 per cent and most (75.1 per cent) had worked in the building for more than a year, but only 38.5 per cent at the same desk or work area. In broad terms, around 30 per cent of respondents either had a single office or shared with more than eight others, with around 13.3 per cent each sharing with either one, two to four, or five to eight colleagues. On average, slightly over half the occupants (51.5 per cent) had a window seat.

SCORING OF THE INDIVIDUAL FACTORS

Table 1.1 lists the means and standard deviations of the users’ perception scores for each of the 45 factors that respondents were asked to score. Each factor corresponds to a specific question – these are necessarily abbreviated to fit the table, but reflect the nature of the full question posed to the building users.

The factors have been grouped into the following categories:

• Operational (eight factors)

• Environmental, with the following four sub-categories:

– temperature and air in winter (eight factors) – not applicable in the case of the hot–humid climatic zone buildings

– temperature and air in summer (eight factors)

– lighting (five factors)

– noise (six factors)

• Personal control (five factors)

• Satisfaction (five factors).

For some 22 of the factors, a score of 7 would be considered the ideal; in 15 cases, a score of 4 would be deemed best; and in seven instances a score of 1 would be the ultimate target. The relevant factors are noted in Table 1.1. The only exception to these guidelines is the Productivity factor which is expressed as the percentage by which the respondents thought their productivity had increased or decreased.

Of the 22 factors for which a score of ‘7’ would be the ideal, no less than 17 had an average score greater than 4.00, the mid-point of the scale. Seven of these were greater than 5.00, indicating that for this set of buildings, the occupants perceived the following factors as reasonably satisfactory, on average:

• image (to visitors)

• furniture (in the occupant’s work area)

• cleaning (standard of)

• availability of meeting rooms

• meets work requirements

• lighting overall

• needs (building as a whole).

TABLE 1.1 Means and Standard Deviations of the users’ perception scores for each factor they were asked to rate on a 7-point scale

That is not to say that every building scored well on these factors. As indicated by the standard deviation (SD) figures, there was quite a spread of scores (but more on that later). The five factors below the mid-point of the scale were all in the Personal Control category (more on these later too).

In the case of the 15 factors where a score of 4.00 would be deemed best, the averages for no less than 11 of them were clustered between 3.50 and 4.50. The four exceptions all related to temperature and air in winter and summer, where it was perceived to be too cold and dry in winter, and too hot and still in summer, on average.

For the seven factors where a score of 1 would represent the ultimate, all of the average scores were less than 4.00, the midpoint of the scale. It is good to see, given the effort that has been put into the design of the ventilation systems for these buildings, that the air was perceived to be well on the odourless side of the odourless/smelly scale in both winter and summer.

Finally, in this overview of the individual factors, it was particularly encouraging to see that the users considered their productivity to have increased by 4.07 per cent on average as a result of the environmental conditions in the building.

Turning now to the mean scores within each of the categories, it can be seen that of the eight operational factors, five were greater than 5.00. However, the mean score for Storage was only 4.20, indicating that a perceived lack of storage could be an issue in many cases. Interestingly, with an average score of 4.32 (on a scale where 4.00 represents the ideal) there is a hint that some occupants consider they have too much space at their desk or work area.

In the case of the four Environmental sub-categories, there were mixed results. Temperature Overall and Air Overall averaged out at around 4.43 and 4.32 in winter and summer respectively, just over the mid-point and on the satisfactory side of their respective scales. As mentioned earlier, the air was perceived to be well on the odourless side of the odourless/smelly scale, but only just on the fresh side of the fresh/stuffy scale in both winter and summer. In general, conditions were perceived to be on the cold, still, and dry side in winter and on the hot and still side in summer.

Of the Environmental factors, Lighting Overall, with a mean score of 5.15 was the highest by far, with mean values close to the ideal for the amount of both natural and artificial light. While the scores for glare were less than the scale mid-point (the ideal was 1.00 in this instance), the SD values hint at some variability in users’ perceptions.

The mean score for Noise Overall, at a modest 4.42, was similar to that for Temperature and Air Overall. Noise from colleagues and other people seemed to be the...

Table of contents

• Contents
• Preface and acknowledgements
• Contributors
• Introduction
• 1 Overview of the buildings and their performance
• Part 1 Buildings in Cold–Temperate Climates
• Part 2 Buildings in Medium–Temperate Climates
• Part 3 Buildings in Warm–Temperate Climates
• Part 4 Buildings in Hot–Humid Climates
• Index