Green industrial buildings in Vietnam from experts’ point of view

. In recent years, there has been a remarkable rise in the number of certified green building projects in Vietnam, with industrial buildings accounting for the largest portion. The purpose of this research is to evaluate the ability to achieve points of industrial buildings in some green building systems under specific conditions of Vietnam. Another aim of the study is to point out the distinct features of industrial buildings that influence their design, including heavy industry, light industry, and industrial buildings with cleanrooms. Accordingly, this will contribute to increasing the number of industrial buildings that achieve green certification in the future. The study uses a mixed-methods approach, including expert interviews, field surveys, and meta-analysis. The research results will serve as a reference document for sustainable development-oriented design consultants and for organizations establishing green construction criteria systems to be able to upgrade to newer versions with higher adaptability for industrial works.


Introduction
To develop a sustainable city, it requires the elements that make it up, and industrial buildings are a part of it.The figures demonstrate that in Vietnam, there has been a significant growth in the quantity of constructions that have obtained green certification in recent years.Each green building system has different evaluation tools.However, they have not considered the different characteristics of each type of industry, including heavy industry, light industry, and cleanroom industry.The study involved interviewing experts to assess the capacity for achieving scores of industrial buildings within some green building systems in Vietnam.As a result, it will help raise the count of green industrial buildings in Vietnam in the future.

2
Literature review

The situation of green construction development in Vietnam in recent years and related studies
Vietnam has made a commitment to achieving Net-Zero carbon emissions by 2050 at the Climate Change Summit COP26 [1].The first green building in Vietnam started in 2010 and it seems quite late compared to some countries in the region [2].However, the development of green buildings in Vietnam is a positive signal for the rapid development of Vietnam's industrial brand in the global market while still ensuring sustainable development [3].Currently, there are four most popular green building criteria systems in Vietnam, including LEED, LOTUS, EDGE, and Green Mark [4].Other systems such as WELL, Fitwel, and EarthCheck have much fewer numbers.Among the certification types, LEED is the most popular certification.The number of projects that achieved LEED certification accounts for more than 52% of the total number of the four most popular certification types in Vietnam [5](Fig.1).As of September 2022, the total number of projects achieving green building certification in Vietnam among the four popular systems is 258 projects, with industrial projects accounting for 37.2% of the total.This is the type with the highest number, compared to other types such as residential, office, commercial, and education [5](Fig.2).
Although the number of green-certified buildings has increased rapidly in recent years, this field still lacks support from organizations and researchers in general.There have been studies related to sustainable development design for industrial buildings, for instance, design solutions for industrial builidng enclosure in Vietnam in the direction of sustainability [6].However, existing studies have not yet mentioned the specific characteristics of different types of industrial buildings in Vietnam and compared them with the point-scoring ability of categories within green building systems.

2.2
The current popular green building certification system in Vietnam

LEED and LOTUS
The Leadership in Energy and Environmental Design (LEED) certification program was initiated in 1993.Although most LEED projects are in the US, this criteria system is the most widely used green building program all around the world [7] and is applied in hundreds of countries.LEED has tools to assess different types of construction, and LEED Building Design and Construction (LEED BD+C) is the most popular used in Vietnam today.LEED BD+C can be used to assess the following types of projects: New construction, Core & Shell, Schools, Retail, Data centers, Warehouses & Distribution Centers, Hospitality, and Healthcare.The majority of industrial projects in Vietnam that obtain LEED certification belong to New Construction.Developers of industrial buildings in Vietnam voluntarily pursue LEED certification.LEED is the most dominant among other green building certifications in Vietnam because LEED is a prestigious green building certification worldwide and can help enhance the brand value and promote the product.A factory that obtains LEED certification increases its ability to label its products as eco-friendly, and this eco-label can influence consumers' purchasing decisions [8] (Fig. 3a).
LOTUS, a green building criteria system in Vietnam, was established as the fisrt version in 2010.The latest updated version is LOTUS for New Construction V3 (LOTUS NC V3), which was implemented in April 2019 [9].LOTUS incorporates 22 Vietnamese and 6 International Codes and Standards that are pertinent to green building construction [10].The energy requirements of LOTUS are based on the QC 09:2017/BXD standard [11].LOTUS NC V3 includes two types: Residential (R) and Non-Residential (NR).Buildings that are designed for human habitation that provide long-term lodging are classified as residential, while those that serve other purposes are known as Non-Residential (NR) buildings [12].This means that (NR) comprises School, Retail, Industrial buildings, Hospitality, and Healhcare.Therefore, it seems that there are still many aspects that are not yet compatible when using LOTUS NC V3 to evaluate points for industrial construction projects at present.Currently, LOTUS seems to be more commonly used to evaluate schools than other building types.As of September 2022, there were only 10 certified industrial projects using LOTUS, accounting for 3.8% of the total green certified projects in Vietnam [5].LOTUS is not a mandatory system in Vietnam, but entirely voluntary.It helps businesses enhance their brand and provide direct benefits to users (Fig. 3b).

EDGE and Green Mark
Developed in 2014 by IFC, a member of the World Bank Group, the EDGE green building certification program has had a very fast development rate so far, especially in the field of residential and offices [13].However, EDGE certification is not yet widely used in the industrial sector.The number of industrial projects certified with EDGE only accounts for 28% of the total four popular green building systems in Vietnam [5].Instead of considering many issues comprehensively like LEED and LOTUS, EDGE only mentions resource efficiency, including Energy, Water, and Materials [14].This can be considered a simpler and more streamlined tool to easily access greener projects, which is very suitable for developing countries (Fig. 3c).EDGE consists of 3 assessment levels: Level 1 (EDGE Certified): minimum 20%, Level 2 (EDGE Advanced): minimum 40%, and Level 3 (Zero Carbon): 100% [15].To determine the level of efficiency of a project, the EDGE software application is used, and it is free at edgebuildings.com [16].This is a software that is relatively simple to approach compared to energy simulation software.In the EDGE App version 3.0.a,buildings are classified into 11 types.However, "Industrial" just only has Light Industry and Warehouse.Other types of industrial buildings such as heavy industry or cleanroom industry are not mentioned.Therefore, the current evaluation method still has many shortcomings when evaluating industrial buildings.
Singapore's green building system, known as Green Mark, was introduced in January 2005 [17].In Singapore, new public sector buildings are mandated to obtain Green Mark certification as the public sector aims to be at the forefront of environmental sustainability.Elsewhere, design teams and developers are encouraged to construct sustainable and environmentally friendly buildings [18].In Vietnam, until now there are 16 buildings that have achieved Green Mark certification, the majority of which are for residential and commercial use.There is only one industrial building, which is the XP Power factory in Binh Duong province, awarded Green Mark GOLD in 2017 [19].However, this system currently accounts for the least proportion among the four popular green building systems in Vietnam.Therefore, this study did not interview experts about this green building system.

The types of industrial buildings in Vietnam and their characteristics
Each type of industrial building has different characteristics, such as the number of employees, working conditions, ventilation, and lighting solutions.It can be classified into 3 main types, specifically as follows.a) Heavy industry (HI) requires a lot of investment capital, with its products being supplied to other industries [20], such as mechanical industry, metallurgy, mineral mining and processing [21].HI factories typically have large scales, heavy machinery, and a production environment that often generates heat and dust.They are typically designed to utilize natural lighting and ventilation solutions (Fig. 4a.).b) Light industry (LI) requires less capital investment compared to heavy industry, primarily involved in the production of consumer goods [20], such as food manufacturing, beverage manufacturing, tobacco processing, textiles, sewing, leather making, and paper industries [22].LI usually has a relatively large number of workers, and architectural design requires solutions for natural and artificial ventilation and lighting to be combined (Fig.

Materials and methods
Step 1: Overview research of green building criteria systems in Vietnam Step 2: Make a list of experts and make an interview questionnaire for experts Green building experts have over 10 years of experience in advising and designing green buildings, currently working in green building consulting units in Vietnam and holding at least one of the following green building consulting certificates: LEED AP/LEED GA, EDGE Expert, and LOTUS AP.Experts with green certification from which system are interviewed to evaluate that system.In this study, there are 14 experts, including 10 LEED experts, 10 EDGE experts, and 11 LOTUS experts.The research was conducted from January 2023 to March 2023.
Step 3: Data processing and analysis

Results
Experts are requested to evaluate the ability to achieve the score of factories in some green building systems under Vietnamese conditions (not considering the production line) according to 05 levels: 1-Not likely to be achieved; 2-Very difficult to achieve, depending on the investor's capital;3-Can be obtained, depending on the investor's capital; 4-Very easy to achieve; 5-Definitely achievable.The experts evaluate based on their knowledge and experience in consulting and designing various types of factories (HI, LI, and CI) towards green buildings.As most industrial projects in Vietnam pursue "New Construction", this study used the LEED v4 for BD+C (New construction) version 4.

Industrial buildings pursuing LEED certification
The interview results can be divided into three groups: Group I (≥3.5 points) -Easy to implement for industrial projects, Group II (from 2.6 to 3.4 points) -Can be implemented at an average level, and Group III (≤ 2.5 points) -Difficult to implement for industrial projects.

Location & Transportation (LT) and Sustainable Sites (SS):
Group I includes LTc7, LTc8, SSp1, SSc1, SSc5, and SSc6 (Fig. 5).LTc7 and LTc8 is quite easy to meet the LEED requirements for parking lots under Vietnam's conditions.In terms of "Green vehicles", it is not difficult to score, but the function of facilities can be changed during use.For example, green parking lots can be converted to motorcycle parking lots (Fig. 6a, b).In addition, bus stations (Fig. 6c) and charging stations for green vehicles are rarely used because the number of workers who use buses or electric vehicles to factories in Vietnam is almost nonexistent.The reasons that can be mentioned are that industrial parks are often located far from the city center, so there are no bus routes like in the urban areas, and people have a little habit of traveling by electric vehicles.With regards to "Sustainable Sites", factories are quite easy to achieve with solutions such as increasing water collection on roofs, green roofs, using roofing sheets with high SRI coefficient, and reducing pollution in construction activities and light pollution.
Group III consists of LTc1, LTc3, LTc4 (HI&LI), LTc5 (HI&LI), and LTc6 (Fig. 5).Since no area in Vietnam has achieved LEED ND, LTc1 is not achievable.Most factories are in industrial parks, so LTc4 and LTc5 are not suitable for evaluating industrial buildings because their location is far from public utilities and transportation.Except for CI, which may be in high-tech zones, and easier to access to urban areas.

Water Efficiency (WE) and Energy & Atmosphere (EA)
Group I consists of all the prerequisites and WEc4.These requirements are relatively easy to implement for factories in Vietnam.Group III includes WEc2 (LI), WEc3, EAc1 (Option 3), and EAc4.In terms of "Indoor Water Use Reduction", it is quite difficult due to the high investment cost of flowrate equipment."Cooling Tower" is almost exclusively used in CI because CI usually use cooling systems, while HI and LI rarely use them.Besides, EAc1 (Option 3) and EAc4 are not feasible for factories in Vietnam due to practical conditions and high investment costs.(Fig. 7).EQp1, EQp2, EQc1 (CI), EQc3 belong to group I. To ensure indoor air quality, it is relatively easy to arrange a smoking area outside the production area.However, if the distance between the smoking area and the production area is too far, it will be difficult to access in unfavorable weather conditions (for example, Southern Vietnam has 6 months of rainy season).In terms of "Enhanced Indoor Air Quality Strategies", CI is easier to achieve points because of better air quality conditions (Fig. 8 & Fig. 9).
Group III includes EQc5 (HI), EQc7 (LI, CI), EQc8 and EQc9.HI has a lower score in "Thermal Comfort" but has a higher score in "Daylight" compared to LI and CI.The reason is that HI often is single-story industrial buildings and use natural ventilation and lighting solution.While LI and CI are often multi-story buildings, natural ventilation and lighting are limited.For all types of factories, scores in "Quality Views" and "Acoustic Performance" are the lowest because working conditions inside factories are usually not as comfortable as other buildings, so these two credits are not suitable when applied to factories (Fig. 8 & Fig. 9).MRp1, MRp2, MRc5, INc1, INc2, and PRc belong to group I.Although waste collection and sorting are not difficult to implement, it is not effective due to the current waste collection process in industrial zones in Vietnam lacking the ability to sort.Group III includes MRc2 and MRc4, because market conditions for materials in Vietnam have not been met (Fig. 10).

Industrial buildings pursuing LOTUS certification
LOTUS has many similarities with LEED, and the results of expert interviews are as follows: a) Site and Environment (SE): This category is a combination of Location & Transportation (LT) and Sustainable Sites (SS) from LEED, but with adjustments to better suit the conditions in Vietnam.Specifically, LOTUS has additional credits for SE-1 and SE-3.In the "Vegetation" credit, there is a list of native plants in Vietnam, which is more convenient for the design process.However, similar to LEED, SE-9, SE-10, and SE-11 are not suitable for factory conditions because factories are often located in industrial zones and far from city centers, making it difficult to access public utilities and transportation.SE-9 can be achieved, but it may not be used for its intended purpose.SE-2 is difficult to implement because owners often maximize building density (Table 1).collecting rainwater for reuse in irrigation and toilet flushing.In addition, demand for water depends on number of users: number of workers in LI is usually higher than in HI and CI.Therefore, implementing water-saving solutions (W-1) in LI will be more effective than in HI and CI (Table 2).Energy (E): This category is evaluated based on the Vietnamese standards -QCVN 09:2017/BXD.However, since QCVN 09:2017/BXD does not apply to industrial projects, there are still many aspects that are very difficult for evaluating this type of buildings, especially heavy industry.Similar to LEED, LOTUS requires reducing energy consumption levels through the use of energy modeling to demonstrate the effectiveness of solutions.The higher the LOTUS certification level achieved, the higher the energy savings level, leading to an increase in investment costs (Table 2).c) Health & Comfort (H): This is the category with the lowest average score compared to others.Although LOTUS has applied Vietnamese standards to provide a scoring scale, there are still many issues when evaluating industrial buildings because there are no specific regulations for them.For instance, "Thermal comfort" condition in HI factory is often much lower than in others, making it very difficult to achieve points in H-6.Furthermore, it is also challenging for factories to attain scores in H-3, H-4 (LI & CI), H-5, and H-7 (Table 3).Materials & Resources (MR) in LOTUS has adjusted that is more appropriate for the material market in Vietnam, so it is easier to achieve points compared to LEED.Regarding MR-1, HI has an advantage over LI and CI because HI often uses prefabricated steel materials for load-bearing structures.MR-2 is difficult to achieve in Vietnam's conditions.In Management (Man) and Exceptional Performance (EP), it seems relatively easy to implement according to experts' evaluations (Table 4).

Industrial buildings pursuing EDGE certification
The expert interview form for EDGE consists of two parts: Part 1: Assess ability to achieve EDGE certification at three levels (20%, 40%, and 100%), and Part 2: Evaluate the accuracy of EDGE App software in calculating indicators.According to the experts' evaluations, EDGE Certified has a very high likelihood of being achieved (mostly at level 4 -Very easy to achieve), in all three categories: energy, water, and materials.In the energy category, HI has slightly lower attainable scores compared to LI and CI.With regards to EDGE Advanced, the capacity of achieving certification decreases at level 3 (Can be obtained, depending on the investor's capital).And HI still has the lowest score compared to LI and CI.For the highest level of EDGE certification -EDGE Zero Carbon, the likelihood of achieving certification is below level 2 (Very difficult to achieve).Overall, LI and CI have similar potential scores across the different levels of EDGE certification (Fig. 11).

Fig. 11. Capacity of achieving EDGE certification at different levels and for various types of industries
In addition to evaluating the ability to achieve EDGE certification at different levels and for various types of factories, the study also suggested that experts assess the accuracy of the EDGE App in calculating savings values, costs, and payback at three levels: 1-Low accuracy, 2-Acceptable accuracy, and 3-High accuracy.The results are shown in Table 2.

Discussions
Investing in green industrial buildings brings many long-term benefits to businesses such as energy savings, providing a better working environment for workers, and thereby increasing labor productivity.The growing number of industrial projects achieving green building certification over the years demonstrates the potential for industrial buildings to develop towards green building standards.Not only foreign-invested industrial projects, but many domestic investors have also shown interest and invested in green factories.However, in comparison to the total count of industrial projects constructed in Vietnam during the same period, this figure of green factories remains relatively minor.In order to achieve the goal of net-zero emissions by 2050 as committed in COP26, Vietnam needs to have a specific development roadmap.In addition to raising awareness and promoting the construction of green buildings, the government should introduce preferential policies, such as tax incentives or lower interest rates for certified green buildings.Furthermore, training programs should be established to enhance the technical capacity and knowledge of stakeholders in developing green buildings in the construction industry.

Conclusions
The paper provides an overview of existing literature on green building certification and explores the status of green buildings in Vietnam, particularly in the industrial sector.This study has identified the potential for achieving green building certification for industrial projects in Vietnam today.This will contribute to increasing the quantity and quality of factories that obtain green certifications in Vietnam in the future.The results of the study will become a reference for design consulting firms and educational institutions that offer training on green building design.Furthermore, it will help organizations upgrade their green building systems to new versions that consider the specific characteristics of industrial buildings.

Fig. 1 .
Fig.1.Statistics on the number of green industrial projects in Vietnam (as of September 2022)[5]

Fig. 2 .
Fig. 2.Statistics on the number of green-certified construction projects in Vietnam by type of construction (as of September 2022)[5]

Fig. 4 .
Fig. 4. The main types of industrial construction in Vietnam: a-Heavy industry, b-Light industry, c-Cleanroom industry c) Cleanroom industry (CI) requires a control level of dust and air quality in the production area, such as pharmaceuticals, cosmetics, and biotechnology.CI design typically has a specific ventilation system [23] and mainly utilizes artificial lighting, with little use of natural lighting.(Fig. 4c.) 1 and LOTUS NC V3 tools to create interview questionnaires for experts, and EDGE version 3.0.0was used as well.The results are as follows: https://doi.org/10.1051/e3sconf/202340301019E3S Web of Conferences 403, 01019 (2023)

Table 2 .
Capacity of achieving points in Water (W) and Energy (E)

Table 3 .
Capacity of achieving points in Health & Comfort (H) d) Materials & Resources (MR), Management (Man), and Exceptional Performance (EP)

Table 4 .
Capacity of achieving points in Materials & Resources (MR), Management (Man), and Exceptional Performance (EP)