第 55 卷 第 3 期
2020 年 6 月
JOURNAL OF SOUTHWEST JIAOTONG UNIVERSITY
Vol. 55 No. 3
June 2020
ISSN: 0258-2724 DOI:10.35741/issn.0258-2724.55.3.17
Research articleEnvironmental Science
I
NDIVIDUAL
P
RIORITY
W
EIGHTS OF
I
NDOOR
E
NVIRONMENTAL
P
ERFORMANCE TO
S
ANCTION A
S
AFE AND
H
EALTHY
W
ORK
E
NVIRONMENT
室内环境绩效对保护安全和健康工作环境的个人优先权
N. Khalil a, *, S.N. Kamaruzzaman b, A.A.M. Bohari c, H.N. Husin a, I. Othman da
Department of Quantity Surveying, Faculty of Architecture, Planning and Surveying, Universiti Teknologi MARA
Perak Branch 32610 Seri Iskandar, Perak, Malaysia, natas582@uitm.edu.my
b Faculty of Built Environment, Universiti Malaya
Kuala Lumpur, 50603, Malaysia, syahrulnizam@um.edu.my
c Department of Quantity Surveying, Faculty of Architecture, Planning and Surveying, Universiti Teknologi
MARA
Sarawak Branch 94300 Kota Samarahan, Sarawak, Malaysia, asmahalia@uitm.edu.my
d
Civil and Environmental Engineering Department, Universiti Teknologi Petronas 32610 Seri Iskandar, Perak, Malaysia, idris_othman@utp.edu.my
Received: March 7, 2020 ▪ Review: May 16, 2020 ▪ Accepted: May 30, 2020
This article is an open access article distributed under the terms and conditions of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/4.0)
Abstract
This article presents a new idea to improve crucial ecological issues that arise due to the poor performance of indoor environments during the occupancy phase to ensure safe and healthy working conditions for building residents. Using the Delphi technique via a focus group discussion, the authors identified seven attributes that are associated with occupants’ health and safety, namely, cooling (thermal comfort), artificial lighting (visual comfort), natural lighting (visual comfort), acoustic comfort, waste reduction, ventilation, and cleanliness. We illustrate the use of Delphi in ensuring a safe and healthy working environment via two-round stages involving 22 respondents, which include building energy experts from green and environmental organizations in Malaysia. The first round confirms the suitability of the attributes while the second determines the individual priority weights of the attributes. Our method allows improving building residents’ safety and health by focusing on improving their indoor environment, where the top attributes are ventilation (30.3%), cleanliness (17.1%), and cooling (7.4%). This new method of effectiveness evaluation is based on the calculation of the individual priority weight, which is derived from the analytical hierarchy process. In this method, respondents are made to rate the importance of each attribute in pair-wise comparison during the second round. The results of this study aid in improving the indoor environment during the occupancy phase; these results can also be used for prioritizing elements that should perform well in the performance evaluation.
Keywords: Indoor Environmental Performance, Safety, Health, Analytical Hierarchy Process, Individual
摘要 本文提出了一种新的想法,以改善由于占用阶段室内环境表现不佳而引起的重要生态问题, 以确保建筑物居民安全健康的工作条件。通过焦点小组讨论,使用德尔斐技术,作者确定了与乘 员的健康和安全相关的七个属性,即冷却(热舒适),人造照明(视觉舒适),自然照明(视觉 舒适),声学舒适,减少废物,通风和清洁。我们通过两个阶段的 22 个参与者(包括马来西亚绿 色和环保组织的建筑能源专家)分两个阶段说明了德尔斐在确保安全和健康的工作环境中的用法 。第一轮确认属性的适用性,第二轮确定属性的各个优先级权重。我们的方法通过专注于改善室 内环境来改善建筑居民的安全和健康,室内环境的主要特征是通风(30.3%),清洁度(17.1%) 和制冷(7.4%)。这种有效性评估的新方法是基于对各个优先级权重的计算,该权重是从层次分 析法得出的。在这种方法中,让受访者在第二轮配对评估中对每个属性的重要性进行评分。这项 研究的结果有助于在入住阶段改善室内环境。这些结果还可以用于对应该在性能评估中表现良好 的元素进行优先级排序。 关键词: 室内环境性能,安全性,健康性,层次分析法,个人优先权
I. I
NTRODUCTIONThe high performance of environmental elements and sustainability are closely connected in the field of green study. The high performance of indoor environmental and green elements is described as the foundation of sustainable construction development [1]. A building with such elements is also known as an “environmentally-sound” building or a “sustainable building”. Sustainability refers to the capacity to endure [2]. This word explains the process by which biological systems remain diverse and productive over time. Long-lived wetlands and forests are examples of healthy sustainability. For humans, sustainability is the potential for long-term maintenance of well-being based on three main dimensions: society, environment, and economy [2]. Therefore, performance evaluation is one of the areas in which cities and constructed environments can achieve sustainability.
Architects emphasize sustainability concerns in office buildings during the initial design and construction phases. These concerns are also important during occupancy. Designers' team, building management and operations must address crucial concerns of sustainability during the building operation to ensure the occupants’ comfort. They must also ensure that the structure is suitable for its users. Employees are often more satisfied and productive when they feel healthy, safe, and comfortable [3]. Indoor environmental performance depends on a building’s lifespan as well as changes in the physical requirements and activities of the occupants. [4] supported that most of the environmental impact is due to high energy consumption in buildings. High pollution energy sources and high usage equipment are
examples of such consumption. Efficiency and staff productivity may decrease in a poorly performing building environment.
An office building survey [5] revealed that 47 percent of its respondents indicated that their work productivity decreased because of a poor indoor environment. Their continuous exposure to inadequate ventilation and indoor air pollutants elevated the risk of potential health problems [6]. Increased attention from stakeholders, developers, building owners, manufacturers, and investors in public or private sectors has prioritized sustainability in the development of construction practices. [7] stated that environmental problems are becoming social issues in need of solutions because of rapid industrial development. The social issues also include safety and health aspects, comfort, perceived needs, and satisfaction.
Numerous studies (e.g.,
[13], [29], [30])
focus on newly constructed buildings, with a goal of green remodelling to achieve green-certified buildings with a low carbon zero impact. However, performance optimization cannot take into account qualitative objectives such as aesthetics and constructability [8]. Therefore, optimizing the performance of buildings calls for environmental risk management for their occupants, visitors, and passers-by [9]. It also demonstrates the need to address occupants’ social issues in indoor environmental performance evaluations.
This study intends to determine the attributes of indoor environment performance enabling a safe and healthy workability living of the building users/occupants. This study also prioritizes the elements of indoor environment for performance evaluation that may resonate
with aspects of occupants’ safety and health. Health can be defined as the likelihood of negative health consequences due to specific building conditions impacting on human health. Safety aspects can be defined as the likelihood of harmful consequences to the building users related to safety or security, such as injury, death, crime, theft, nuisance or burglary.
II. I
NDOORE
NVIRONMENTALP
ERFORMANCE:
T
HEC
ONCERNS ONG
REEN ANDS
USTAINABILITYTowards achieving an advanced Malaysian economy by 2020, the country has come out with a momentous milestone, namely the Eleventh Malaysia Plan (2016-2020). It features six strategic thrusts and game-changers, whereby one of them is focusing on pursuing green growth for sustainability and resilience. This calls for the country to embark upon green growth for it to be a way of life for all Malaysians. Aside from the public and government sectors that are encouraged to respond at initiatives geared towards developing a green environment and culture, private companies and non-government organizations are also targeted. For instance, the prime objective of the Ministry of Energy, Green Technology and Water (MESTECC) is enhancing the green technology and environment. Meanwhile, the Malaysia Green Technology Corporation (MGTC) has been established to enact the legal mechanisms for regulating and enforcing green technology, as well as define the role of every governmental agency involved in its implementation in the country [10]. This shows that Malaysia has noticed and is moving towards environmentally sustainable living with the prominent need of energy efficiency, water efficiency, sustainability and planning management, material and resources, indoor environmental quality, and new innovation.
Malaysia is one of the tropical countries located in the South China Sea, and lies at the coordinates of latitude 3.12 °N and longitude 101.55 °E [11]. The tropical region is a particularly uncomfortable climate zone that receives a large amount of solar radiation, has a high temperature, a high level of relative humidity, and long periods of sunny days all throughout the year [12]. [5], in their study, also described Malaysia’s location within the tropical climate region, which is naturally hot and humid. Moreover, the rapid growth of the urban population has led to it experiencing a regional rise in urbanization, especially in the developed countries of Singapore, Malaysia, and Indonesia
[12]. Due to such a landscape, the majority of office buildings in Malaysia have air conditioning and mechanical ventilation systems to maintain a thermally comfortable indoor environment. Besides, rapid development of office buildings that are normally located in the city area leads to various issues in terms of cleanliness, and noise and air pollution.
Theoretically, the elements of the indoor environment in building performance poses a more instant and direct impact on building users compared than attributes of the external environment. They are often related to safeguarding the health of a building and its occupants or users. [3] explained that the social aspect of occupants’ lives are directly affected by these environments. This includes the period of time spend in the building, their experiential aspects on the building conditions and also indoor environmental quality. Possible synergistic effects of criteria in the performance elements may affect from one to another. According to [13], Considerations of the maintenance management of facility at the planning and design stage are of utmost importance for the facility’s future performance attributes. Hence, to assess the performance indoor environmental attributes or parameters, the determinants of the attributes are firstly required to satisfy the viability in the context of local climate and building requirements.
Based on review analysis of green performance and indoor environmental elements, the performance is closely related to parameters of noise comfort, visual comfort, thermal comfort, cleanliness, ventilation, sick building syndrome and waste reduction [14], [15], [16], [17], [18]. Lighting is also important parameter in environmental performance in office buildings. Office Building lighting is much more than LED. Beyond LED, a green solution for office lightings also depends on the orientation, daylight and lighting control system. These aspects was clearly determined during the initial design of building. It was found that indoor environmental elements are appropriate for assessing social aspects in meeting demands for reducing risk to building users.
Based on the review, the initial construct of the indoor environmental elements had listed nine (9) attributes, namely; i) thermal comfort (heating), ii) thermal comfort (cooling), iii) visual comfort (artificial lighting), iv) visual comfort (natural lighting), v) waste disposal, vi) building ventilation, vii) humidity level, viii) acoustic comfort and ix) level of cleanliness. The attributes were relatively compiled from the
literature, the existing green rating tools, and some precedent studies concerning risk in building performance [19], [20], [21], [22], [23]. In the current study, the indoor environmental attributes are depicted as predictor variables of the impact on occupants’ safety and health, which are social factors. A reduction of the performance of the indoor environmental elements would generally expose the building occupants to safety and health hazards. Therefore, prioritizing the abovementioned attributes is needed to improve the performance assessment during the building operation stage.
III. M
ETHODOLOGYThis research adopted the quantitative approach using a structured questionnaire that consisted of the Analytical Hierarchy Process (AHP) as the main instrument. The AHP is a measurement theory by means of pair comparisons and relies on expert judgments to derive priority scales [24], [25], [26], [27]. In the AHP, the weight score showing the importance of each criterion is assigned to all criteria or parameters. The AHP approach has been widely adopted as a decision-making tool in the fields of green and energy [28], [29], [30], [31], [32], [33]. In the current study, the indoor environmental attributes were confirmed using a Delphi technique via a focus group discussion (FGD) workshop. The workshop was carried out in two-round stages and attended by 22 individuals with building energy expertise from leading organizations related to green and environmental performance, including Malaysia Green Technology Corporation (MGTC); Energy Commission (ST); SIRIM QAS International; and Ministry of Energy, Science, Technology, Environment, and Climate Change (MESTECC). First, consensus among these participants was required to determine the suitability of the indoor environmental elements for the performance assessment. The list of attributes was presented to the participants during the FGD, which was associated with occupants’ health and safety and initially constructed to provide guidance to the respondents. Next, the final set of the weights assigned for each indicator was presented at the end stage, during which the data obtained were crucial for this survey and the study alike. Hence, each respondent was briefed by the researcher regarding the procedure for rating the importance scale of the AHP.
IV. R
ESULTS ANDD
ISCUSSIONA. Administration of the Delphi and AHP Survey via a Focus Group Discussion (FGD)
The indoor environmental attributes were confirmed using a Delphi technique via an FGD workshop. The workshop was carried out in two-round stages and attended by 22 building energy experts. In the first round, consensus among the respondents was required to determine the suitability of the indoor environmental attributes for the performance assessment. The list of attributes was presented to the respondents during the FGD, which was associated with occupants’ health and safety and initially constructed to provide guidance to the respondents. During the first round of the process, the respondents were asked to assess whether the attribute was suitable or irrelevant for the performance assessment of office buildings (“Yes” if relevant or “No” if irrelevant).
In the first-round results, seven attributes received more than 50% consensus, while the two attributes of heating (thermal comfort) and humidity level received a low consensus (less than 50%). Hence, the two attributes were removed from the list for the second-round process. Table 1 depicts the results of the first round. Next, the second-round process showed that all seven attributes attained 100% consensus from the respondents, thus confirming their suitability as contributing factors to occupants’ health and safety (Table 2).
Table 1.
Delphi result of consensus – first round
No Indoor environmental
attributes
Consensus of respondents
1 Heating (thermal comfort) 25% consensus 2 Cooling (thermal comfort) 94% consensus 3 Artificial lighting (visual
comfort)
94% consensus
4 Natural lighting (visual comfort)
72% consensus
5 Waste reduction 100% consensus 6 Building ventilation 100% consensus 7 Humidity level 47% consensus 8 Acoustic comfort (noise) 83% consensus 9 Cleanliness level 89% consensus
Table 2.
Delphi result of consensus – second round
No Indoor environmental
attributes
Consensus of respondents
1 Cooling (thermal comfort) 100% consensus 2 Artificial lighting (visual
comfort)
100% consensus
3 Natural lighting (visual comfort)
100% consensus
4 Waste reduction 100% consensus 5 Building ventilation 100% consensus
6 Acoustic comfort (noise) 100% consensus 7 Cleanliness level 100% consensus
The respondents were then asked to rate the importance of the confirmed attributes by pair wise comparison. A 9-point scale of importance was used in the AHP survey by [24]. Figure 1 depicts the scale of importance ranging from 1 to 9. The importance of the attributes was compared to each criterion in the indoor environmental performance. The results of the rating are presented in Table 3. The weightings were extracted from the calculation of individual priority weights (IPW) with the aid of the AHP computer software package, the Expert Choice 11.
Figure 1. AHP scale of importance [24]
Table 3.
Method of rating the pair wise comparison
B. The Results of the AHP
The IPW of each attribute were established using a square matrix structure. The weights were calculated by the geometric mean of the values from the questionnaires filled by all respondents. The final step in the process combined the ratings of the criteria to form an overall rating for each decision alternative. The numerical pair wise comparison and the IPW obtained by combining the overall judgment from the respondents are shown in Figures 2 and 3, respectively. To obtain the priority weight, the distributive mode was chosen, as it normalized the alternative scores under each criterion so that they summed up to one (1.00). This created a dependency on how well all other alternatives performed, thus allowing the potential for rank reversal. It showed that the internal consistency ratio (CR) was .02, whereas in the AHP, the CR must be less than 0.1 (10%) [25]. Therefore, the data were reliable and achieved consistency.
Figure 2. Pair wise comparison of the attributes using the Expert Choice 11
Figure 3. Individual priority weight of the attributes using the Expert Choice 11
Next, the weights were multiplied to 100 (%) to obtain the percentage distribution of the attributes. This is illustrated in Table 4, wherein the weightings show that ventilation is ranked as the most important attribute with a weight of 30.3%. It is followed by cleanliness level (17.1%), cooling (7.4%), waste disposal (12%), acoustic comfort (10.6%), artificial lighting (8.4%), and natural lighting (6.6%). The dimensions of the attributes have been supported by previous researchers [34], [35], [36], who highlighted ventilation, temperature, lighting, and cleanliness as the factors that affect the quality of the indoor environment the most. Furthermore, this result suggested that three attributes, that is, ventilation, cleanliness level, and cooling, are the most important factors influencing the results of indoor environmental performance assessments. This is due to their potential capacity to generate a larger impact on occupants’ health and safety. Focusing on the indoor environmental performance and social aspects related to ventilation would be more significant than that for the remaining six attributes.
Table 4.
Summary of individual priority weights for indoor environmental attributes Indoor environmental attributes Individual priority weight (%) Rank
Thermal comfort (cooling) 15.0 3 Visual comfort (artificial
lighting)
8.4 6
Visual comfort (natural lighting) 6.6 7 Waste disposal 12.0 4 Ventilation 30.3 1 Acoustic comfort 10.6 5 Cleanliness level 17.1 2 C. Discussion of Findings
From the AHP results, the summation scores of the indoor environmental attributes identified the top three priorities: in the order of their ranking, the top three attributes were ventilation (30.3%), cleanliness level (17.1%), and cooling (15%). Figure 4 shows the performance dimension of the indoor environmental attributes using a radar chart.
Figure 4. Performance dimensions of the indoor environmental attributes
The discussion of result is therefore focusing on the top three ranked attributes, whereby ventilation is revealed as the top priority for performance assessment as it poses a larger impact to the occupants’ health and safety. This suggests that this attribute is more significant than the remaining seven attributes and for it to be prioritized in the focus upon building performance and occupants’ safe and health. Ideally, poor ventilation can cause occupants to experience further health effects, such as flu-like symptoms, dermatitis, irritation, systemic toxicity, headache, fatigue, and chest tightness [37]. This is supported by [17], who underlined the poor quality of ventilation in indoor air will affect individual wellbeing and constitutes as a risk of accident in a work place. Other than that, health effect resulted from the exposure to indoor air contaminants was sick building syndrome and it was a major potential risk that can be happened to all building users [6]. Thus, it affects the safety and health of building occupants. It also influences the work productivity and urge the staff to opt for sick leave frequently and cause recurring health disorders. It is recommended by [6] that installation of effective ventilation system was essential to maintain healthy indoor air quality.
The second-ranked attribute in indoor environmental performance is cleanliness level. The result supported the importance of providing a clean environment in office buildings. Infections and cleanliness are closely related to hygiene [38], which does not merely generate hygienic environment; it also prevents a direct exposure to the occupants’ health. [39] described that the cleanliness of a building or complex impacts the health of its occupants since a clean and healthy environment is a representation of the building’s image and its community. An unhygienic environment not only creates nuisances to its occupants, it is also conducive to pest problems and the growth of micro-organisms
that further leads to the spread of infectious diseases [40].
The next priority ranked for the indoor environmental attribute is thermal comfort. Poor cooling performance generates health and safety issues for occupants. [41] states it also leads to faulty indoor environmental performance, and [42] adds the discomfort aspect to occasions when there is no prevailing cool breeze. Furthermore, a study by [43] shows that people who are exposed to poor thermal comfort and low indoor environmental quality could have different symptoms, which include short term memory and work performance reduction, due to the improper working conditions. Besides, [44] highlights that buildings should provide socially acceptable levels of health, safety, welfare, and amenity for the inhabitants, which have to be accomplished through regulatory controls on the building operation. Buildings have a long service life, during which end users’ expectations should be met, including thermal comfort, [45]. [35] supports that sustainable buildings are to be expectedly designed with "breathable” strategies that accommodate occupants with thermal comfort without the use of any mechanical ventilation system.
Moreover, the empirical findings of this study indicate that the experts’ criteria, knowledge, and experience ensure that their judgment is collectively reliable and able to justify the acceptance of the subsequent results on health and safety impact. To summarize, the attained significance of indoor environmental performance suited the support from academic theories and literature.
V. C
ONCLUSIONThe prioritized statistics provide important information regarding the safety, health, and overall livelihood of the occupants, who are considered the entity or group of individuals affiliated with the building operation stage. The range of the article covers office buildings, where it was found that the integration of well-designed and maintained office buildings could help the creation of sustainable environmental performance and promising public health interventions. This research thus suggests that performance optimization sanctioning to the building users’ safety and health is to be further enhanced in terms of economics, life cycle costing, procurement, incentives, and capacity development strategies. The findings also indicate that the reliability of using expert judgment has been shown in similar studies to assess the significance in the development of
green and indoor environmental performance tools. Concerning the United Nations Sustainable Development Goals (UNSDG), the ability to provide good health and well-being is clearly highlighted in SDG No. 3 and No.4, and it is also emphasized that the certainty and promotion of healthy lives of all ages are essential to sustainable development.
A
CKNOWLEDGMENTThe study did not operate from any sort of external funding sources. The authors wish gratitude to the respondents who have participated and supported for this research.