Evaluation and Choice Criteria of Sustainable Suppliers in the Construction Industry: A Comparative Study in Brazilian Companies

Abstract

This article seeks to develop criteria for evaluating sustainable suppliers in civil construction and to contribute to improving the understanding of the factors that influence the selection of sustainable suppliers. Organizations should develop strategies that motivate suppliers to participate in green supply-chain initiatives, as supplier selection can directly interfere with sustainability performance at work. However, there is a gap in the research that addresses the selection of sustainable suppliers in the Brazilian context of civil construction related to certifications for sustainable construction. To fill this gap, the present article used literature-review methodologies, content analysis, data triangulation, and field research through a survey. The literature review identifies the certifiable standards for sustainable construction most cited in the literature: LEED, AQUA, BREEAM, and CASBEE. The standards analysis allows us to identify seven similar supply criteria for sustainable construction certifications. The parameters of each certification were analyzed to define those related to the selection of suppliers, identifying those that qualify a supplier as environmentally sustainable. We found that 60.7% of respondents work in companies without certifications, 75% know sustainable procurement, 50% of companies had established a sustainable procurement policy, and 83% of companies had a strategy for selecting suppliers. The results of this research contribute to construction companies being able to rank the importance of these criteria when choosing a supplier, in addition to having access to the mapping of essential criteria, allowing a search for greater interaction between the links of the green supply chain and rendering buildings and supplies more sustainable.

1. Introduction

Brazil’s construction sector has great economic relevance, employing around seven million people and representing 6.2% of the national GDP [1]. In addition, according to data from the U.S. Green Building Council, Brazil ranks fourth in the world among the countries that use Leadership in Energy and Environmental Design (LEED) certification to create more sustainable spaces, encompassing over 14 million certified gross square meters [2].

The rapidly growing world population and changing cultures and systems can alter the sustainable development of an organization [3], making it necessary to incorporate sustainability into supply chains after the emergence of green supply-chain management (GSCM). GSCM ranges from environmental thinking to supply-chain management (SCM) [4] and provides a competitive and managerial advantage but also depends on greater integration between suppliers and customers. Therefore, selecting suitable suppliers is a strategic decision, increasing the competitive capacity [5].

Monitoring supplier activities ensures continuous process improvement, quality, and cost reduction [6]. Conversely, the supplier’s lack of involvement may represent an obstacle to implementing new processes and technologies to manage the green supply chain [7].

A company’s performance can be evaluated by an environmental management plan performed by its suppliers; therefore, it is necessary to align strategic priorities with environmental standards and motivate suppliers to participate in supply-chain initiatives that conform to these priorities [8]. In addition, those suppliers must follow GSCM practices [9].

The supplier selection for construction work must be carried out in a structured manner so that the selection meets the financial, execution, quality, and, more recently, sustainability selection criteria. Companies need to expand their focus from internal operations to the external partners that compose the supply chain [10]. GSCM practices must be extended to a company’s suppliers because it can achieve a higher overall performance in the supply chain with the appropriate collaboration of all the chain members [7].

The performance of a sustainable supply chain relates to a company’s ability to reduce the use of materials, energy, or water and to establish more eco-efficient solutions to improve supply-chain management [11]. Management processes are based on a more comprehensive, systemic approach in organizations, integrating the various activities of a sustainable supply chain [12]. Several variables that measure GSCM practices are identified, and the most relevant are: internal environmental management, green purchasing, eco-design, collaboration with customers, and recovery of investments [13].

GSCM practices and supplier monitoring regarding their environmental actions can effectively improve environmental and financial performance, as companies can be held liable for not complying with their suppliers’ environmental requirements. Therefore, it is necessary to monitor the environmental performance of suppliers and even collaborate with them to meet sustainability requirements [10].

Through a literature analysis, it is possible to identify the criteria used to evaluate sustainable suppliers, such as:

• Eco-design: the creation of reusable, recyclable, or recoverable products, with reduced material and energy consumption, along with avoiding the use of toxic materials [14];
• Pollution control: the average level of pollutants in terms of greenhouse emissions, generation of waste, and other materials harmful to the environment [15];
• Environmental management system: guarantees supported by environmental seals and certifications, such as Leadership in Energy and Environmental Design (LEED), International Organization for Standardization—ISO 14000, or the preservation of environmental policies [16];
• Ecological materials: the number of recyclable materials used in packaging and products [17];
• Resource consumption: energy, water, and raw material consumption indicators [18];
• Strategic alliance: establishing a long-term relationship with the supplier, perceiving them as partners rather than supplying companies [19];
• Manager commitment to GSCM: upper management actions to disseminate GSCM concepts and practices and to ensure the improvement of environmental performance [20].

These selection criteria can be verified in the literature and applicable to different segments and countries. However, there is a gap in research on local contexts, including cultures, practices, and institutions, and we suggest using expert work as an input for others [21]. In this sense, the research is based on the context of the Brazilian construction industry, with its characteristics and particularities, such as, for example, the need to meet the specific certifiable standards of the sector.

2. Literature Review

2.1. Sustainability

One of the most cited concepts for sustainable development, suggested by Dr. Gro Harlem Brundtland, who chaired the World Commission on Environment and Development, in the “Our Common Future” report, is: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [22].

The expression triple bottom line (TBL) or sustainability tripod was first used by John Elkington in the 1990s and represents the three main dimensions used to evaluate an organization’s sustainability, consisting of economic, social, and environmental aspects [23].

The TBL is a structure that incorporates three dimensions of performance rather than only sustainability. This diverges from traditional structures that measure performance in sustainability only according to the environmental or economic dimension [24]. Instead, TBL “captures the essence of sustainability by measuring the impact of an organization’s activities in the world, including both its profitability and shareholder values and its social, human, and environmental capital” [25].

Currently, in the development of the Global Reporting Initiative (GRI), the TBL framework model is used, aiming at presenting to the stakeholders a diagnosis of the companies’ actions and how to deal with the actions’ impacts in the three dimensions [26]. The authors of [27] present a framework for a sustainable model that is about people, limits, policies, values, and social and environmental aspects.

To assess the sustainability level in construction, there are certifications regarding the main aspects of sustainable construction to guarantee the minimum impact of the activity. The most used certifications in Brazil are LEED—Leadership in Energy and Environmental Design, created in 1993 in the United States and issued by the United States Green Building Council [28], and the AQUA process, established in 2007 in Brazil, based on the French methodology Haute Qualité Environnemetale (HQE (high environmental quality)) and implemented in the country by the Vanzolini Foundation [29].

In addition to these certifications, there are other norms and seals created by public and private organizations with similar goals, such as:

• Building Research Establishment Environmental Assessment Method (BREEAM), established in 1990 in the United Kingdom by the Building Research Establishment;
• Comprehensive Assessment System for Built Environment Efficiency (CASBEE), created in 2001 in Japan by the Ministry of Land, Infrastructure, Transport, and Tourism;
• Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB), established in 2007 in Germany by the German Sustainable Building System.

The authors consider establishing partnerships in supply chains important but indicate that they do not necessarily need to be established with all suppliers. Instead, partnerships should be cemented by applying the Pareto Principle, in which 80% of purchases are made with 20% of suppliers [30].

2.2. Selection Criteria for Sustainable Suppliers

It is necessary to develop suppliers committed to sustainability for the good overall performance of the supply chain. Several practices can be implemented within a company and its suppliers to achieve this, highlighting as relevant to utmost the following [31]:

• knowledge sharing about green practices through communication and training between the companies;
• environmental audit of the supplier with subsequent feedback;
• requirement of environmental certifications, such as ISO 14000;
• involvement of the supplier in the eco-design phase;
• involvement of upper management towards the goal of sustainable practices.

The length of the supply chain demands higher strictness in establishing the criteria for supplier selection, which must include audits to evaluate their performance. In the literature, the most relevant standards and certifications that evaluate the degree of compliance with the environmental criteria are LEED, AQUA, BREEAM, and CASBEE, detailed below [32].

LEED certification specifies as its main criteria: sustainable space; rational use of water, energy, and atmosphere; materials and resources; internal environmental quality; innovation and project processes; and regional credits [33].

The AQUA seal defines as its main criteria: the building and its surroundings; products, systems, and construction processes; and the construction site, energy, artificial lighting, water, waste, maintenance, hygrothermal comfort, acoustic comfort, visual comfort, olfactory comfort, quality of spaces, air quality, and water quality [34].

The BREEAM certification standard has macro criteria: management, health and wellbeing, hazards, energy, transport, water, materials, waste, land use and ecology, pollution, and innovation [35].

The CASBEE certification model states general criteria: building environmental quality, internal environment, service quality, outdoor environment, reductions in the building’s environmental load, energy, resources and materials, and external environment [36].

In addition to certifications and standards, several studies identified the use of criteria for sustainable purchasing in the construction sector:

• The authors of [37] defined 24 evaluation criteria used by architects and engineers in selecting materials for sustainable construction. In the study, three criteria were classified as the most relevant: aesthetics, ease in saving and preserving energy, and thermal insulation;
• The authors of [38] developed a decision model for the selection of contractors using the sustainability tripod;
• The authors of [39] identified 43 sustainable purchasing initiatives in a U.K. survey;
• The authors of [40] conducted ecological acquisition studies and developed a conceptual framework to improve the environmental performance of the construction sector;
• The authors of [41] stated that there is a lack of an appropriate framework to assist teams in implementing construction projects.

These studies demonstrate the importance of developing and selecting suppliers committed to environmental sustainability, enabling further improvement in purchasing strategies.

3. Materials and Methods

The method is applied with qualitative and exploratory approaches, through bibliographic material with validation via organizational surveys.

In the first stage, the criteria used by construction companies in selecting environmentally sustainable suppliers were mapped, with a study being conducted using a review of articles and certifiable standards. These methods are the most used in research related to construction management [42].

The second stage used an instrument survey, since it allows quick access to data collection and is a low-cost alternative to reach a wide range of respondents [43]. In addition, there are advantages to the chosen method, primarily because the researcher does not need to be present. The absence of the researcher is beneficial for the following reasons: it gives the respondent more time to participate, allows the respondent to choose the right moment to contribute to the research, and reduces the risk of biases resulting from the influence of the researcher [44].

The research was conducted from December 2018 through December 2019, following two main steps:

The first stage is a literature review, consisting of content-analysis methodologies and triangulation.

The second stage is field research, using the survey methodology.

3.1. Stage 01—Literature Review

The literature review was performed in the Scopus and Science Direct databases, considering the publication period from 2014 to 2019, aiming to obtain the most recent data on the subject. Other filters were used in the databases to obtain documents of greater relevance to the research, restricting the research to specific fields (Abstract, Title, and Keywords) and using only articles as the publication type.

The words “procurement”, “sustainable”, and “construction” were used, joined by the Boolean operator “and”, to find papers with all key terms for the search. In a first title analysis, 36 articles were identified as duplicates in the different databases. After excluding these, the number of publications was 99 articles.

Subsequently, an abstract analysis was performed to exclude articles unrelated to the scope of the research, identifying 37 articles related to the topic. The next step was a thorough reading of the introductions and conclusions of the papers to evaluate the real adherence to the scope. This step resulted in only nine articles relevant to the research, considered the main basis of consultation. The summary of exclusions is presented in

Table 1. Number of publications with the keywords “procurement”, “sustainable”, and “construction”.

	Science Direct	Scopus	Web of Science	Total
The initial number of publications	41	69	25	135
Publications after the exclusion of duplicates	22	69	8	99
Publications after abstract analysis	1	32	2	35
Publications after introduction and conclusion analysis	0	8	1	9

.

After the complete reading of the articles, the certifications for sustainable constructions were noted as highly relevant, as they were cited in seven of the nine analyzed papers. Furthermore, from reading the papers above, a relationship was observed between obtaining certification and environmental sustainability in construction [42,45,46,47,48,49,50].

Thus, the need to enhance the work with research that can aggregate the topic of certifications applicable to sustainable constructions was identified. To consolidate the current paper with the previous literature research, a new search in the literature was carried out. Using the terms “construction industry” and “certifications” to be searched in title, abstract, or keywords in the Scopus database and limiting the publication time range to the last five years, 95 articles were identified as the result of the new literature review.

By filtering only the peer-reviewed articles, which have higher austerity in the reviews, 56 articles were identified, of which the abstracts were read to evaluate their relevance for this research.

After an abstract analysis, 17 articles were excluded because they did not relate to the paper’s scope. Therefore, 39 articles considered relevant remained in the final selection, being thoroughly analyzed with a focus on identifying the citations on certifications applicable to sustainable constructions. To carry out this identification, the content-analysis technique was used [51]. Content analysis is a qualitative methodology for capturing and processing information from documents and texts [52].

Only when based on proper conceptualizations and informed by data can effective methods be devised to improve sustainable construction design, engineering, and environmental assessment tools [53,54,55]. That the mathematical modeling developed is capable of providing satisfactory results in the reality of the sustainability sector [56] can be revealed in systematically studying the sustainability of the process and establishing a broader view of the process [12]. Sustainable project management practices for construction and the promotion of civil construction innovation can improve contractors’ competitiveness [57,58,59]. ISO 26000 and supply chains include the social and responsibility aspects of construction companies [60], considering responsible sourcing in creating a sustainable construction supply chain and including practical relationships between lean construction tools and sustainable development [61].

In this set of articles, 28 different types of certifications applicable to buildings were identified, with some articles citing more than one, adding up to 63 citations about certifications. The specific analyses can be visualized in Section 4 in the Results section of this paper.

3.2. Stage 02-Survey

The survey was carried out using the Google Forms^® tool. To ensure a complete understanding of the questions by the professionals in the area, the survey was applied in person, with interviews scheduled for a pilot test. Two civil engineers responsible for construction work in renowned construction companies in the city of Curitiba, state of Paraná, were invited to participate in the interviews, making appropriate adjustments to some issues. The interviews happened in September 2019.

In the pilot test, the respondents suggested the inclusion of the certifications commonly obtained and/or desired by the companies, which were not available in the possible answers, in addition to the certifications verified in the literature. Those requested by the respondents are ISO 9001, ISO 14001, OHSAS 18001, and the Brazilian Program of Habitat Quality and Productivity (PBQP-H). A brief analysis of the objectives of these certifications was carried out, showing that ISO 9001 and PBQP-H essentially address quality issues, OHSAS 18001 focuses on health and safety, and ISO 14001 addresses environmental management. Among these, only the PBQP-H certification is specific to the construction sector. Since the questions submitted to the respondents were only intended to check the overall attributes related to obtaining certifications, the suggestion was accepted.

The public selected to participate in the research were construction engineers with experience in building construction who were responsible for managing one or more works in the city of Curitiba/PR, which according to IBGE data [62] is the eighth most populous city in the world, and was estimated in 2018 at 1,917,185 people and tenth in the Human Development Index (HDI). The group of professionals was motivated by the possibility of having a direct influence on the selection of suppliers [63]. Email and/or phone contacts were captured on the social media site LinkedIn.

The professionals were considered a target audience since contract managers must participate in all stages of the acquisition process, including supplier selection [64].

The invitation to participate in the survey was sent to 453 civil engineers using three communication approaches:

• WhatsApp^® (communication application that supports the sending and receiving of media, texts, photos, videos, documents, and location): to the respondents that made their cell phone numbers available and that had the application, a message was sent with the survey link;
• landline telephone: to the respondents that made it available, a call was made, and an e-mail address was requested to send the survey link;
• e-mail: the other respondents provided only their e-mail address, through which the surveys were sent.

The interviews were carried out between August and September of 2019, being available to the respondents for 58 days.

The data obtained were organized in a spreadsheet to enable a thorough analysis of each of the questions. Of the total of 112 responses received, five were disregarded because they were not answered by professionals that fit the survey’s target population.

To organize the information and rank it by criteria, for each answer, a numerical value was assigned in the following order: extremely important: 5 points; very important: 4 points; important: 3 points; low importance: 2 points; not important: 1 point.

Through a statistical analysis of the data, it was possible to identify the hierarchy the respondents gave to the criteria for selecting sustainable suppliers. This hierarchy enabled the completion of criteria mapping related to environmental sustainability that can be used in supplier selection.

4. Results and Analyses

The analysis of the articles that refer to the terms “construction industry” and “certifications” identified 28 different types of certifications applicable to the construction, and the ten most cited in the literature are described in

Table 2. The ten most cited certifications for sustainable construction.

	Certification	Citations	%	Country of Origin
1	LEED	17	27%	United States
2	BREEAM	7	11%	England
3	AQUA	4	6%	France
4	CASBEE	4	6%	Japan
5	Selo Casa Azul	2	3%	Brazil
6	ISO 9001	2	3%	Switzerland
7	CE3X	2	3%	Spain
8	DGNB	2	3%	Germany
9	EPCB	2	3%	Australia
10	FSC	2	3%	Germany

.

The first four certifications were the most representative since they accounted for 50% of the citations. An analysis was carried out to identify, within the total set of parameters of each certification, which ones were related to environmentally sustainable supply. The parameters were listed and organized in a spreadsheet.

The listing of each certification criteria evidenced that several parameters considered by a norm also appeared in others, not necessarily with the same description but with a common purpose. Therefore, these similar criteria were grouped according to

Table 3. Similar parameters in the certifications.

Certifications	Certification Criteria	Related Theme
LEED	Alternative transportation, use of low-emission vehicles	Transport alternatives
BREEAM	Alternative modes of transportation
BREEAM	Transport routing
AQUA	Technical and environmental quality of materials, products, and equipment	Resources’ life cycles
CASBEE	Component life
BREEAM	Life-cycle impacts
LEED	Regional extraction, processing, and manufacture of materials	Regional suppliers
LEED	Regional priorities
LEED	Regional-specific environmental priorities
CASBEE	Use of locally significant materials
BREEAM	Proximity of suppliers
LEED	Destination and collection of recyclable materials	Waste management
LEED	Management of construction waste destined for reuse
AQUA	Management of construction waste
AQUA	Choice of collective modes of waste storage
AQUA	Conditions for the collective storage of waste
AQUA	Waste removal independent of the enterprise
BREEAM	Management of construction waste
BREEAM	Operational waste
BREEAM	Resource efficiency	Resources quality
LEED	Fundamental management of refrigerant gases, no use of CFCs	Reductions in toxic emissions
LEED	Low-emission materials, adhesives, and sealants
LEED	Low-emission materials, paints, and varnishes
LEED	Low-emission materials, carpets, and floor systems
LEED	Low-emission materials, composite woods, and agrofibers
BREEAM	Reductions in energy and carbon use
BREEAM	Low-rate carbon design
LEED	Innovative technologies	Innovative technologies
LEED	Rapid renewable resources
BREEAM	Innovative products and processes

.

After identifying similar parameters, seven aspects directly related to the supply activity were concluded to be within the norms of certifications for environmentally sustainable constructions, named by this research as supply criteria.

To verify the relation between the supply criteria found in the second sample of 39 articles and the first sample of 9 articles, the data triangulation procedure makes it possible to consolidate conclusions by combining different data-collection methods, populations, or distinct samples at different periods [65].

Thus, the nine articles were again analyzed to verify that the authors of the first sample considered the criteria found in the second sample of articles as relevant for environmentally sustainable construction. The results of the triangulation can be seen in

Table 4. Certifications applicable to sustainable construction.

		Literature Review	Švajlenka, Kozlovská 2018 [45]	Alia et al., 2017 [46]	Brooks, Rich 2016 [47]	Kwok et al., 2016 [48]	Renukappa et al., 2016 [49]	Loosemor 2016 [66]	Ruparathna, Hewage 2015 [67]	Ruparathna, Hewage 2015a [42]	Mokhlesian 2014 [50]	Total of Authors per Criteria
Supply Criteria			1	2	3	4	5	6	7	8	9
1	Transport alternatives							X				1
2	Resources’ life cycles		X	X		X	X	X	X	X		7
3	Regional suppliers					X	X	X	X	X		5
4	Waste management			X		X				X		3
5	Resource quality		X	X		X	X	X			X	6
6	Reductions in toxic emissions		X	X	X	X	X		X	X		7
7	Innovative technologies		X		X		X	X				4
Total of criteria per author			4	4	2	5	5	5	3	4	1

.

Analyzing Table 4, it is possible to confirm the close relationship between the two reviews carried out in the literature, since the sample articles consider all seven criteria, and 67% of articles consider at least four identical supply criteria.

Furthermore, the seven similar supply criteria for sustainable construction certifications identified in Table 3 and Table 4 are listed in

Table 5. Certification criteria applicable to supply.

		Certifications for Construction
Supply Criteria		Leed	Aqua	Casbee	Breeam
1	Transport alternatives	X			X
2	Resources’ life cycles		X	X	X
3	Regional suppliers	X		X	X
4	Waste management	X	X		X
5	Resource quality				X
6	Reductions in toxic emissions	X			X
7	Innovative technologies	X			X

, identifying which certifications it is being cited.

In an analysis of supplier-selection methodology carried out by the authors, it was identified that in a sample of 56 articles, 75% presented up to seven criteria for supplier selection, which is consistent with that indicated by the literature [68].

These criteria were used in one question of the survey. The elaboration is described in detail in the next step.

5. Discussion

The respondent rate was calculated separately for each communication approach, according to

Table 6. Survey’s respondent rate.

	E-mail	Landline Phone	WhatsApp	Total
Initial population	272	60	121	453
Responses received	44	6	62	112
Respondent rate	16%	10%	51%	24%

.

The research was developed in the state of Paraná; the criterion used considered the population of 32,743 registered civil engineers, a sample of 112 respondents, a confidence level of 90%, and a sampling error of 7.74%.

It is noted in Table 6 that the respondent rate for the WhatsApp^® application was much higher than for other types of approaches, perhaps because of the great popularity and ease of communication that instant messaging offers. However, analyzing the total number of respondents, the rate can be considered acceptable since it approached the response rate of other papers using the survey as a data-collection tool [69,70,71]. These authors obtained, on average, a respondent rate of 27.09% for their surveys.

A low response rate is a disadvantage in a survey. One possible cause for a low response rate is the researcher’s absence during the survey’s completion process. The participants might easily disengage if faced with extensive questions [44].

The survey results indicated that 70% of the responses were obtained from companies working in the field for over five years. Only 5 of the 107 responses came from companies with less than one year of existence. A probable reason for this low number is the economic downturn in Brazil since 2014, which has impacted the survival rate of many of the country’s companies. The ones established in 2012 had a survival rate of 77% in 2014. There is still a downward trend in the survival rate for companies created in recent years, due to an economic crisis that worsened in 2015 and 2016 [72].

Another aspect of the survey enabled the researchers to evaluate the respondents’ education level. Over half of the participants of the survey (54% of the 107 respondents) had a specialization course, which in Brazil is taken after the completion of a bachelor’s degree. Specialization courses widen knowledge to professionals and assist in fulfilling sector-related requirements [73]. Specialization courses are sought to ensure a distinction from other candidates, improve knowledge, and refine professional skills. Another observation is that the number of professionals with master’s or doctorate degrees is small and totals only 9% of the respondents [74].

The survey showed that from the beginning, there was an appropriate target respondent population. However, in a preliminary analysis, it was verified that 5 of the 112 respondents did not work with civil construction specifically, so for that reason, these were not considered in the analysis any further. After the exclusion, it was found that 81% of the respondents worked in civil construction for over five years.

Table 7. Certifications held by the companies.

Certification	% of the Respondents
None	60.7%
PBQP-H	29.9%
ISO 9001	24.3%
ISO 14001	6.5%
LEED	5.6%
Under implementation	3.7%
OHSAS 18001	2.8%

presents the responses regarding the certifications that the companies have. Again, it is noted that the respondents could choose more than one option, which is why the sum of the answers is over 100%.

Table 7 shows that over half of the respondents (60.7%) work in companies that did not have or were not implementing certifications. Additionally, according to the respondents, the number of PBQP-H certifications held by the companies was not only the norm that appeared most in the responses but also represented almost a third of the participants.

The relevant number of companies that have the PBQP-H certification is possibly related to the requirement for the certification in the Minha Casa, Minha Vida program, created by the Brazilian government to facilitate the purchasing of houses by low-income families. The main advantages of having the PBQP-H certification are enhanced material management, improved project efficiency, and more accurate cost analysis [75].

Another element to note is that, even though it is a quality certification, PBQP-H contains environmental sustainability aspects such as waste reduction and management [76].

Table 8. Certifications preferred by the companies.

Preferred Certifications	% of the Respondents
LEED	33.6%
ISO 9001	30.8%
None	29.0%
PBQP-H	28.0%
ISO 14001	18.7%
AQUA	14.0%
OHSAS 18001	10.3%
Others	7.5%

shows the percentage of companies interested in obtaining certification. It is also noted that the sum of the responses does not equal the total number of respondents for the reason mentioned above.

Table 8 shows that LEED certification is the most preferred certification for the companies. This converges with another study, which identified that the predominant use of the LEED certification by civil engineers in the United States could define commonly considered sustainability requirements [77].

Another highlight is the ISO 9001 certification, with 30.8% of the respondents showing interest in obtaining it, possibly due to the popularity of the ISO series. The norm has been implemented by more than one million organizations in 187 different countries [78].

Regarding the 29% of the respondents that answered “None” to a question about preferred certifications, it is possible to explain this by the costs associated with implementing a certification. When a company implements a certification, there are highly necessary investments, from consulting specialists for the implementation, to adapting the equipment and productive processes, contracting with the certification company, audits, and maintaining the system itself [79].

Table 9. Practiced sustainability initiatives.

Sustainable Initiatives	% of the Respondents
Waste management	63.6%
Rational use and reuse of water	60.7%
Energy saving	57.0%
Use of renewable resources	32.7%
Assessment and mitigation of environmental impacts	24.3%
None	18.7%
Product life-cycle analysis	15.9%
Carbon neutralization	2.8%

presents the initiatives related to environmental sustainability practiced by the companies of the respondents, whether or not they have certifications.

Table 9 shows that 63.6% of the respondents participate in at least one of the mentioned initiatives: waste management. However, it is worth noting that 18.7% do not comply with any of the initiatives.

After the analyses of the information of the participating companies, it is essential to compare the results obtained in the literature review with the current use of certifications by construction companies.

Most respondents (75%) admitted having some knowledge of sustainable procurement. Regarding implementing a procurement policy, 50% of respondents said their companies had an established sustainable procurement policy. Managers seeking to demonstrate corporate social responsibility in their supply chains have an increasing preoccupation with sustainable procurement [80].

Regarding the supplier’s choice, 83% of respondents acknowledged that their companies had a strategy for selecting suppliers. To improve sustainable procurement, it is important to ensure that products or services purchased are environmentally sustainable, that the working conditions of suppliers’ employees are decent, and that socio-economic issues are addressed [80].

Table 10. Results for sustainable procurement criteria.

Decision Criteria in Sustainable Procurement	$\overline{\mathit{x}}$	$\mathit{s}$
1. Uses alternative transportation	2.04	1.08
2. Analyses resources’ life cycles	2.82	1.11
3. Is a regional supplier	3.33	1.16
4. Employs waste management	3.21	1.13
5. Is committed to quality	4.40	0.85
6. Reduces toxic emissions	2.86	1.09
7. Uses innovative technologies	3.30	1.11

presents the average degree of relevance and the standard deviation identified for each of the seven criteria used in the selection of suppliers, as answered by the respondents. The analysis considered a scale ranging from 1 to 5, in which 1 means “not important” and five means “extremely important” for the representativeness of the responses. To evaluate the robustness and reliability of the data, Cronbach’s alpha was calculated to measure the internal consistency of the survey. This is calculated according to the number of questions and the variances of each set of responses, in addition to the total variance observed. The results in Table 10 indicate an index of 0.77, meaning that the survey had an acceptable internal consistency.

Of the seven criteria analyzed, the one that presented the highest degree of relevance and the lowest variability was Criterion 5 (“Is committed to quality”), while the least important, according to the respondents, was Criterion 1 (“Uses alternative transportation”). To analyze the order of the degrees of relevance, this was displayed as shown in Figure 1.

From the analysis of Table 10 and Figure 1, it is noted that Criterion 5 (“Is committed to quality”) is the most important according to the respondents. This result implies a higher alignment of suppliers with customer expectations and a search for continuous improvement of their products and processes to remain competitive.

For Criterion 3 (“Is a regional supplier”), Criterion 7 (“Uses innovative technologies”), and Criterion 4 (“Employs waste management”), the numerical results were higher than 3.00, indicating an average degree of relevance to the criteria. Regarding regionality, the search for a partnership with local suppliers should be encouraged so that suppliers can meet customer demands and strengthen the local companies economically. It is important to assess the applicability of sustainability indicators to local achievements [81].

With the use of innovative technologies, companies need to keep up with rapid technological evolution and offer innovative and increasingly sustainable products, ensuring a competitive advantage. The challenge is providing a product that looks and feels the same as current conventional housing but is significantly more sustainable. It is possible development the capacity and ability to drive a more innovative, sustainable product into the marketplace with no need to increase costs [82]. Waste management is an aspect that interferes with environmental sustainability since, by doing so, it is possible to reduce all kinds of waste and avoid the inappropriate destination of materials.

The numerical results for Criterion 6 (“Reduces toxic emissions”) and Criterion 2 (“Analyses resources’ life cycles”) are below 3.00, but these criteria are not considered to have the lowest degree of relevance. The concern about reducing emissions is not merely a recent issue. The importance given to life-cycle analysis may be related to the increasing use of the technique, which can lead to lower costs associated with a project and can help in the assessment of the impacts that changes in requirements may have during the phases of the system’s life cycle [83].

The lowest degree of relevance related to the criteria applies to Criterion 1 (“Uses alternative transportation”), which is probably because the companies have not yet identified that such action influences the sustainability level of construction.

6. Conclusions

This article presented a survey of parameters and normative requirements identified in the international certifications for sustainable constructions related to an environmentally sustainable supply.

With the criteria defined, it was possible to create a survey to verify the degree of relevance given to the criteria regarding the selection of a supplier by Brazilian construction companies. Furthermore, the analyses enabled a mapping of the criteria according to the degree of relevance, in which the criterion “Is committed to quality” was considered the most important of the seven that were presented.

Another conclusion of the research is that sustainable procurement practices have yet to be further explored in Brazil, since 25% of the companies analyzed in this paper did not know the practice. This research result allows building builders to know the essential criteria of the main certifications of sustainable constructions and to seek interaction between the links of the green supply chain, in order to make buildings and supplies more sustainable. The construction industry tends to follow sustainability policies and practices in supply-chain management due to the public and stakeholders’ increased awareness of economic, environmental, and social issues [84].

As a major contribution to the academic community and building construction companies, this study presents the ranking of importance of the selection criteria for green suppliers chosen by construction engineers in Curitiba, Brazil.

As recommendations for practitioners, it is important to take effective actions to implement sustainable purchasing practices in both the public and private sectors, as well as implementing business initiatives that can lead to the mandatory inclusion of sustainability requirements for procurement, at the same time as it is disseminated throughout the supply chain. However, conflicting sustainability legislation, suppliers’ performance evaluation, and the selection and organizational goals are considered complications for the process [84]. Some limitations were identified during the research, such as our consideration of only the environmental sustainability requirements, which suggests the need for a study that includes the social and economic dimensions of sustainability.

Another recommendation for future studies is to expand this research to other regions in the country or internationally, considering the same sector, to compare the results and evaluate any differences. The use of KPIs as a tool to measure competitiveness and sustainability is still a subject considered scientifically novel [85]. Some gaps in the literature involving impacts and the correlation between sustainability, certification, and the supply chain could be researched.

An investigation could be made into the reasons a company would engage in making sustainable purchases, seeking also to understand the methods used by suppliers to capture customers’ needs, especially regarding sustainability.

Furthermore, future research can explore the types of suppliers and materials needed for each construction project, detailing the requirements for each one and performing information analysis to evaluate the most sustainable option regarding all the triple bottom line dimensions.