Passive Design Functionality

Table 7-4 illustrates the respondents’ scores for each EUF of the PDF. This attribute of UCPBD comprises forty-three EUFs. Table 7-4 shows the number of respondents in each score for each EUF. It highlights the most effective EUFs and the least effective EUFs from the analysis of these sections. The mean effectiveness for the “Orient the building for optimum lighting, ventilation and thermal comfort” end user factor is 4.51 and has a S.D. of .896. This suggests very good agreement between respondents on the level of the effectiveness of this measure. The majority of the respondents believe that this EUF has an obvious effectiveness of score 5 (very effective). This is clear from the respond- ents’ mass in this score, as shown in Table 7-4. This aligns with the trend of various authors as introduced in the literature review, such as Fernandez-Gonzalez (2007). He designed the largest eleva- tion in the north and south to reduce the thermal transmittance, on the one hand. On the other hand, this was also to increase the benefit for the solar which of course to collect from the test cell. Appen- dix D – Table D1 shows their percentages and histogram.

The distribution of the effectiveness of the “Provide shading strategies for wall exposed to sum- mer sun to mitigate unwanted solar gain for optimum ventilation and thermal comfort” EUF is illustrated in Appendix D and Table 7-4. The scores are from 1 - ‘very ineffective' - to 5 – ‘very effec- tive’. The mean value is 4.31, and has a standard deviation of it .875. This is a clear indicator that there is a good agreement among the participants. Of course, there are various authors who have con- centrated on this strategy. The shading devices can play a clear role in optimising lighting, heating and ventilation of the space. Appreciation of shading devices should be accurate based on their orientation and compliance with site circumstances (Ministry for the Environment, 2008). There is an agreement between the literature review and participants’ perspectives.

The EUF “Orient openings to facilitate natural ventilation”, with a mean value 4.26 and S.D. of .809, has been chosen as an essential factor by the architects. This standard deviation had shown the level of agreement between the designers. In this questionnaire, 48 architects gave a score of 5, and 48 gave a score of 4 for this EUF. 96 (97.2%) designers considered this EUF as an effective EUF, as

shown in Table 7-4 and Appendix D- Table D6. The effective of this factor is agreed also by several authors as identified from the literature review. BIM (2011) and Ahsan (2009) referred to the im- portance of location and selection of openings and how they can effect optimisation of the air flow as well as cross-ventilation through the space.

The “Plan specific spaces or functions to coincide with solar orientation” end user factor carried a mean value of 4.25 and S. D. of .756, and was considered as an effective factor, as it is provided on survey data in Table 7-4 and Appendix D-Table D10. Milne, Liggett, Benson, and Bhattacharya (2008) confirm this: that the floor plan should be organised in such a way to coincide with solar orien- tation. The effectiveness of this EUF appeared on mass respondents in both effective and very effective EUFs. 46 individuals gave this EUF a score of 5, 47 a score of 4, 15 a score of 3, and 2 a score of 2, as shown in Table 7-4. 93 respondents out of 110 (84.5%) scored it as an essential EUF in UCPBD.

The “Provide high levels of insulation in the façade and building envelope to reduce summer con- ductive gain and to preserve internal heat” EUF, with the mean value 4.2 and S.D.=.833, was selected as an effective EUF of UCPBD. The survey results show that 45 individuals allocated a score of 5, 48 a score of 4, 11 a score 3 and 6 a score for 2 to this EUF. 93 respondents out of 110 (84.5%) believe that this EUF is an effective EUF, while 11 individuals (10.0%) believe it is a possible EUF, as illus- trated in Table 7-4 and Appendix D-Table D7. The percentage of respondents who agree this EUF is an effective EUF is predictable. For this reason, the Building and Construction Authority (2010) re- ferred to the importance of insulation and how it can optimise heating.

The distribution of the effectiveness of the “Design plan to create buffer zones from the summer radiation” EUF is 4.18 and it has a S.D. of .706. This suggests good agreement between respondents on the level of the effectiveness of this measure. The majority of the respondents believe that this fac- tor has an obvious effectiveness of score 4 (effective) and 5 (very effective). This is clear in the respondents’ mass in this score, as shown in Table 7-4. Also, it is shown in their percentage in Table 7- 4 and Appendix D-Table D3. Ip and Miller (2006) explained a case study from Brighton and how the sunspaces can provide both sunlight and thermal comfort. The importance of considering the distribu- tion plans is reflecting and matching what respondents said.

“Use skylight, light tube and clerestory for natural illumination” has the mean value of 4.18 and S. D. of .744. The standard deviation of the questionnaire presents good agreement among the participa- tions. 39 participations gave a score of 5 and 55 gave a score of 4. 94, indicating that they accept that this is an effective EUF. The majority of respondents had the scores 4 and 5, which reflects that they gave a score more than neutral as illustrated in Appendix D and Table 7-4. The National Domelight Company (2009) indicated the role of skylights in optimising day lighting.

Another EUF, “Use central atriums, courtyards and lobbies (elevators, and stairs can be locate in central areas) for optimum ventilation”, has the mean value of 4.15 and S. D. of .822. There is very good agreement between the designers regarding this EUF. This result is expected, as the Ministry for

the Environment (2008) considered central atriums to be one of the solutions to optimise ventilation. This factor is selected by the architects as one of the effective EUFs. A total of 39 of the architects gave a score of 5 and 53 a score 4 to this EUF. In total, this EUF was selected as effective by 92 (83.7%) respondents, as illustrated in Appendix D and Table 7-4.

From 110 designers, 39 gave a score of 5 and 48 a score of 4 to the EUF “Shape the building to maximise exposure to [winter sun and summer breezes]”. 78 out of 110 believe that this EUF is an effective and very effective EUF. Finally, the mean value of this EUF is 4.06 and its S.D is .921. This result referred to the need to consider this EUF as one of the most effective EUFs in UCPBD as there is a strong agreement between designers regarding it. For example, Prom et al (1989) concentrate on building geometry and how it can be effective in PDF.

“Provide vertical air shafts/stacks, and central exhaust paths to promote interior airflow”: this fac- tor’s effect on UCPBD was scored by the architects as follows: 35 out of 110 gave it a score of 5, 53 a score of 4, 17 a score of 3, 3 a score of 2 and 2 a score of 1. 88 respondents (80%) chose this EUF as an effective EUF. The result of this survey presents the mean value of the EUF as 4.05 and S.D.=.866. The majority of the respondents agreed on the effective and very effective scores, which means this is an essential EUF that needs to be considered. The United States Department of Energy (2000) referred to how the central exhaust can affect promotion of interior air flow. This strategy has been selected as one of the most effective EUFs by the respondents. These factors are listed as a hierarchy descending based on their effectiveness.

However, the least effective EUFs are listed in hierarchical ascending order as follows. 8 architects out of 110 (7.3%) gave a score of 5, 32 (29.1%) a score of 4, and 34 (30.9%) a score of 3 for “using low mass construction to allow rapid heat-up or cooling of structure” EUF. Looking at the mean value of 3.03 and S.D. of 1.079, this factor can be seen to be considered effective. Overall, 34 respondents considered it to be an effective EUF. There is agreement shown between the respondents. The results are illustrated as a histogram and normal curve in Appendix D and Table 7-4.

The “Narrow floor width to optimise natural ventilation” EUF with the mean value of 3.46 and S. D. of 0.964 was chosen as an effective EUF in this survey. 16 respondents gave it a score of 5, 39 a score of 4 and 36 a score of 3. 55 respondents out of 110 (50%) agreed on selecting this EUF as an effective EUF, whereas 36 of them (32.7%) agreed to accept it as a possible EUF. In Table 7-4, the majority of the respondents were concentrated between 3 and 4 scores. Agreement to accept it as a EUF appeared in score 4, as shown in Appendix D and Table 7-4. The Ministry for the Environment (2008) said the narrow floor can have an affect on maximising ventilation.

The mean value of the “The proportion of the plan is long and narrow (use linear plan form, or a similar strategy) to optimise day lighting” end user factor is 3.48 and .965 for S.D., which are also proof of its acceptance. In this survey, 19 designers gave a score of 5, 32 a score of 4 and 43 a score of 3; and the histogram of this factor is shown in Appendix D-Table D3. The Ministry for the Environ-

ment (1998-2011) clarified the relationship between the area and shape of the plan and day lighting function. However, the respondents ranked it as one of the lowest effective EUFs.

From 110 designers, 14 gave a score 5 and 48 a score of 4 to the “Minimise openings in envelope to reduce thermal gain” end user factor. 62 out 110 believe that this EUF is an effective and very ef- fective EUF. Finally, the mean value of this EUF is 3.52 and its S.D is .946. This result referred to the need to consider it as one of the effective EUFs in UCPBD, as shown in Table 7-4 and Appendix D- Table D6. The United States Department of Energy (2000) indicated how façade openings can affect thermal comfort. The designers have not paid attention to this EUF.

The mean effectiveness for the “Minimise the ratio of exterior surfaces to interior floor areas” end user factor is (3.58) and it has a standard deviation of (.828). This indicates good agreement between respondents regarding the effectiveness. Frequencies of responses show that 10 architects (10.9%) gave a score of 5, 51 (46.4%) a score of 4, 37 (33.6%) a score of 3, 9 (8.2%) a score of 2, and 1(.9%) a score of 5 to this end user factor. The fact that the higher score has gained more than the neutral one shows that the architects recognised this factor as an effective factor which could play an essential role in user centred passive building design. An S.D of .828 indicates the level of agreement between the architects regarding this factor. Finally, the histogram and normal curve of this factor is illustrated in Appendix D-Table D5. Several authors such as BIM (2011) and Ahsan (2009) concentrate on the relationship between the proportion of both glass area and floor plan area. The designers gave it one of the lowest factors. However, it still can be accepted as an effective factor.

The mean effectiveness of the “Attenuate plan to promote ventilation” end user factor is 3.61 and it has a standard deviation of .939. For this factor, 20 designers selected a score of 5, 40 a score of 4, 39 a score of 3, 9 a score of 2 and 2 a score of 1. The outcome of this survey is that 60 architects (54.6%) assumed that this factor is an effective factor that should be involved in user centred passive building design; and 39 architects (35.5%) accepted it as a possible factor. The finding for this factor is sum- marised in Appendix D-Table D4. The Ministry for the Environment (2008) referred to how attenuating the plan is important to maximise ventilation. This reflects the designers’ rankings. It is still acceptable.

The “Use higher window to wall area ratios to maximise solar access and ventilation” end user fac- tor with a mean value 3.64 and S.D. of .864 has been chosen as an essential factor by the architects. This standard deviation shows the level of agreement between the designers. In this questionnaire, 14 architects gave a score of 5 and 55 gave a score of 4 for this factor. 69 (62.7%) designers considered this factor as an effective factor in Table 7-4 and Appendix D-Table D7. Ihm (2009) clarified how the size of the window can affect the amount of lighting on the space. The designers considered it as a demand factor. The respondents selected it as one of the lowest effective end user factors.

The “Subdivide interior to create separate heating and cooling zones” end user factor is one of the most effective factors. Its mean value is 3.64 and its D.V=.993 in the survey. 18 respondents have giv- en it a score 5, 53 a score of 4, 24 a score of 3, 11 a score of 2 and 4 a score of 1. 71 respondents look

to this factor as an effective factor, as illustrated in Appendix D-Table D2. From the result of the D.V=.993, there is obviously a very good agreement between the respondents. The Ministry for the Environment (2008) and the Department of Education, Northern Ireland (DENI) and corpcreator (1998) agreed about the effectiveness of subdividing the spaces on passive design strategies functions. The “Use exterior elements to direct summer wind flow into the interior” end user factor’s effect on user centred passive building design was scored by the architects as follows: 17 of 110 gave a score of 5, 52 a score of 4, 28 a score of 3, 12 a score of 2 and 1 a score of 1. 69 respondents (62.8%) chose this factor as an effective factor. The result of this survey presents the mean value of the factor as 3.65 and the S.D.=.903. The majority of the respondents agreed on the effective and very effective scores, which means that exterior elements are an essential factor, as shown in Appendix D-Table D7. BIM (2011) and Ashan (2009) refered to direct the natural sources to the interior space.

The distribution of the effectiveness of the “Use open plan interior to promote interior airflow” end user factor is 3.65 and has a S.D. of .913. This suggests good agreement between respondents on the level of the effectiveness of this measure. The majority of the respondents believe that this factor has an obvious effectiveness of score 4 (effective) and 5 (very effective). This is clear in the respondents’ mass in this score, as shown in Table 7-4. The means of the rest factors are between 3.65 and 4.05. However, all of them are more than neutral, so they could be considered as effectiveness factors. Lev- el (The authority of sustainable building) (2011) indicated that open plan can lead to maximising ventilation. However, it is placed on the lowest rank.

Code End User factors of Passive Design Functionality

T o ta l N u mber Frequency of scores M ea n S td . D e- v ia ti o n R a n k in g 1 2 3 4 5

AA1 Use vegetation for optimum lighting, ventilation and thermal comfort 110 3 6 25 50 26 3.82 .950 25 AA2 Orient the building for optimum lighting, ventilation and thermal comfort 110 3 2 6 24 75 4.51 .896 1 AA3 Use nearby landforms and structures for wind protection and summer shading 110 2 8 17 50 33 3.95 .956 14 AB1 Design compact building form for optimum heating and ventilation 110 4 6 25 51 24 3.77 .974 27 AB2 Use low mass construction to allow rapid heat-up or cooling of structure 110 9 27 34 32 8 3.03 1.079 43 AB3 Shape the building to maximise exposure to [winter sun and summer breezes] 110 2 5 16 48 39 4.06 .921 9 AB4 Use high mass construction with appropriate insulation to promote night ventilation 110 2 10 23 54 21 3.75 .933 30 AC1 Subdivide interior to create separate heating and cooling zones 110 4 11 24 53 18 3.64 .993 36 AC2 Locate thermal mass on the floor and wall to be exposed to direct sunlight if possible 110 1 8 27 54 20 3.76 .867 28 AC3 Use central atriums, courtyards and lobbies (elevators, and stairs can be locate in central

areas) for optimum ventilation

110 2 1 15 53 39 4.15 .822 8

AC4 Provide vertical air shafts/stacks, and central exhaust paths to promote interior airflow 110 2 3 17 53 35 4.05 .866 10 AC5 Use open plan interior to promote interior airflow 110 2 8 35 46 19 3.65 .913 34 AC6 The proportion of the plan is long and narrow (use linear plan form, or a similar strategy)

to optimise day lighting

110 1 15 43 32 19 3.48 .965 41

AC7 Organise rooms, corridors, stairwells in a way that uploads a low resistance airflow path through the building

110 0 7 33 54 16 3.72 .791 32

AC8 Consider interior surface colours and finishes for optimum day lighting 110 0 10 16 54 30 3.95 .887 13 AC9 Design plan to create buffer zones from the summer radiation 110 0 1 16 55 38 4.18 .706 6 AC10 Plan specific spaces or functions to coincide with solar orientation 110 0 2 15 47 46 4.25 .756 4 AC11 Narrow floor width to optimise natural ventilation 110 1 18 36 39 16 3.46 .964 42 AC12 Provide solar-oriented interior zone to store and maximise solar heat gain 110 1 8 23 58 20 3.80 .855 26

AC13 Attenuate plan to promote ventilation 110 2 9 39 40 20 3.61 .939 38

AC14 Link the exterior and interior airflows by single-sided, cross or stack ventilation 110 0 10 19 61 20 3.83 .833 24 AD1 Use roof elements for stack effect ventilation 110 0 3 20 64 23 3.97 .710 12 AD2 Use skylight, light tube and clerestory for natural illumination 110 0 3 13 55 39 4.18 .744 7 AD3 Use solar roof collectors on the south-oriented surfaces 110 0 9 18 47 36 4.00 .909 11 AD4 Use double roof and wall construction for ventilation within envelope 110 0 9 36 42 23 3.72 .890 31 AD5 Use ventilated roof to lower summer gains through roof 110 0 7 21 54 28 3.94 .838 15 AD6 Use of an appropriate shape and angle of the roof for optimum ventilation and thermal

comfort

110 2 7 20 52 29 3.90 .928 18

AE1 Minimise the ratio of exterior surfaces to interior floor areas 110 1 9 37 51 12 3.58 .828 39 AE2 Use high-capacitance materials to store solar heat gain and control heat flow through

envelope

110 0 7 18 61 24 3.93 .798 17

AE3 Optimise south-facing glazing 110 1 5 25 49 30 3.93 .875 16

AE4 Use Trombe wall or double façade to collect solar gain 110 3 8 24 53 22 3.75 .950 29 AE5 Locate thermal mass inside the envelope to store heating 110 0 7 21 66 16 3.83 .752 23

AE6 Minimise openings in envelope to reduce thermal gain 110 2 15 31 48 14 3.52 .946 40 AE7 Use solar wall on south-oriented surfaces 110 0 7 19 62 22 3.90 .789 20 AE8 Develop details to minimise air infiltration and ex-filtration 110 2 8 28 37 35 3.86 1.009 21 AE9 Provide shading strategies for wall exposed to summer sun to mitigate unwanted solar gain

for optimum ventilation and thermal comfort

110 1 4 12 36 57 4.31 .875 2

AE10 Use louvred wall for maximum ventilation control 110 1 8 35 46 20 3.69 .886 33 AE11 Use exterior elements to direct summer wind flow into the interior 110 1 12 28 52 17 3.65 .903 35 AE12 Orient openings to facilitate natural ventilation 110 1 3 10 48 48 4.26 .809 3 AE13 Details openings to limit undesired air infiltration and ex-filtration as well as to reduce

convective gains

110 2 6 22 58 22 3.84 .873 22

AE14 Provide light shelves to allow daylight to penetrate deep into a building 110 1 4 23 59 23 3.90 .801 19 AE15 Use higher window to wall area ratios to maximise solar access and ventilation 110 1 11 29 55 14 3.64 .864 37 AE16 Provide high levels of insulation in the façade and building envelope to reduce summer

conductive gain and to preserve internal heat

110 0 6 11 48 45 4.20 .833 5

Table 7-4: Descriptive Information of the First Part of the Questionnaire Survey: Passive Design Functionality