# Integration of Building Services in Modular Construction: A PRISMA Approach
## 2 Materials and Methods  
To achieve the study's aim, a systematic review (SR) is employed. SR involves conceptualizing the study, establishing a search strategy for related information, extracting relevant data, analyzing the data, and reporting the findings. This study employs the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guide by [25]. Figure 1: Building services engineering framework adapted from [4]. This study's SR of literature on building services integration is appropriate for the following reasons [26; 27; 28; 29; 30]:  
1. SR analyses current research, evaluates scientific contributions, and synthesizes critical facts;
2. Although a time-consuming and resource-intensive process, SR helps understand the best available evidence on a topic;
3. It identifies, summarizes, and discusses current applications of the subject area. Any systematic study must prioritize data retrieval [26]. The research approach's data retrieval step is followed by an SR [31]. This study used Scopus bibliographic data, one of the numerous data collection databases. Other prominent databases include WoS, Google Scholar, ScienceDirect, and Dimensions. Scopus was chosen because it has broader coverage and is a good literature review search engine [32; 33; 34]. In addition, the Scopus database has high standards and vast coverage in building construction information acquisition [35]. Figure 2 illustrates the study flowchart, and Figure 3 shows the PRISMA records selection flowchart. Figures 2 and 3 illustrate the systematic process employed in the study. The outlined methodologies ensure that the review is comprehensive, methodological, and reproducible, which are essential criteria for scientific investigations. Figure 2 depicts the overall study flowchart, encompassing data retrieval and quantitative and systematic analysis of the retrieved information. In contrast, Figure 3 depicts the PRISMA selection flowchart, which includes study identification, screening, and inclusion. The search keywords utilized by [26] were applied with minor modifications on the Scopus database to retrieve research articles about modular construction. Similarly, additional keywords were entered to obtain pertinent studies on HVAC, building systems, MEP, building services, facility management, and building utilities. The \"AND\" operator was then used to combine the two sets of search terms. Moreover, engineering, journal articles, and English were selected as the subject area, document format, and language, respectively. This is how the generated search query appears: _(TTILE-ABS-KEY: \"off-site construction\" OR \"modular construction\" OR \"prefabrication construction\" OR \"modular integrated construction\" OR \"modular buildings\" OR \"prefabricated building\" OR \"offset construction\" OR \"precast concrete building\" OR \"precast construction\" OR \"prefabricated housing\" OR \"off-site manufacturing\" OR \"offset manufacturing\" OR \"volumetric construction\" OR \"modern method  
Figure 3: PRISMA selection flowchart. of construction\") AND (TITLE-ABS-KEY: \"Building Services\" OR \"Facility Management\" OR \"Building Utilities\" OR \"Building Systems\" OR \"MEP\" OR \"Mechanical, Electrical, and Plumbing\" OR \"HVAC\" OR \"Heating, Ventilation and Air Conditioning\") AND (LIMIT-TO: \"ar\") AND (LIMIT-TO: \"?\") AND (LIMIT-TO: \"English\")._ Upon completion of the search, this query yielded 115 publications. Additionally, an effort was made to use comparable search terms to extract relevant studies from the WoS database. Nevertheless, a comprehensive inspection revealed that the detected results were merely a part of Scopus's results. Scopus database was used because it is found to have broader coverage than other databases [36, 37, 38, 39]. Thus, for the overview of modular construction and building service integration, the study used 115 results from the Scopus database. In addition, the abstract, title, and full text of each of the 115 publications were considered when screening them.