# **SpringerBriefs in Applied Sciences and Technology** PoliMI SpringerBriefs

**Bruno Daniotti · Sonia Lupica Spagnolo · Alberto Pavan · Cecilia Maria Bolognesi** *Editors*

**Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings**

SpringerBriefs in Applied Sciences and Technology

# **PoliMI SpringerBriefs**

#### **Editorial Board**

Barbara Pernici, Politecnico di Milano, Milano, Italy Stefano Della Torre, Politecnico di Milano, Milano, Italy Bianca M. Colosimo, Politecnico di Milano, Milano, Italy Tiziano Faravelli, Politecnico di Milano, Milano, Italy Roberto Paolucci, Politecnico di Milano, Milano, Italy Silvia Piardi, Politecnico di Milano, Milano, Italy

Springer, in cooperation with Politecnico di Milano, publishes the PoliMI Springer-Briefs, concise summaries of cutting-edge research and practical applications across a wide spectrum of fields. Featuring compact volumes of 50 to 125 (150 as a maximum) pages, the series covers a range of contents from professional to academic in the following research areas carried out at Politecnico:

http://www.polimi.it

Bruno Daniotti · Sonia Lupica Spagnolo · Alberto Pavan · Cecilia Maria Bolognesi Editors

# Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings

*Editors* Bruno Daniotti Department ABC—Architecture, Built Environment and Construction Engineering Politecnico di Milano Milano, Italy

Alberto Pavan Department ABC—Architecture, Built Environment and Construction Engineering Politecnico di Milano Milano, Italy

Sonia Lupica Spagnolo Department ABC—Architecture, Built Environment and Construction Engineering Politecnico di Milano Milano, Italy

Cecilia Maria Bolognesi Department ABC—Architecture, Built Environment and Construction Engineering Politecnico di Milano Milano, Italy

ISSN 2191-530X ISSN 2191-5318 (electronic) SpringerBriefs in Applied Sciences and Technology ISSN 2282-2577 ISSN 2282-2585 (electronic) PoliMI SpringerBriefs ISBN 978-3-031-04669-8 ISBN 978-3-031-04670-4 (eBook) https://doi.org/10.1007/978-3-031-04670-4

© The Editor(s) (if applicable) and The Author(s) 2022. This book is an open access publication. **Open Access** This book is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

The images or other third party material in this book are included in the book's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the book's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

# **Preface**

Since the last decades of past century, a change of paradigm entered the construction sector: the introduction of Building Information Modelling (BIM) has given the sector new opportunities to enrich the whole process with new potentialities for the relevant stakeholders. In particular the "Information" managed at the level of projects' objects allowed to apply a set of methods developed in the past century which still were pending as theoretical: for example, the systemic and performancebased approaches has found in the ICT developments the perfect ground to pass from theory to practice.Within this framework this EU project BIM4EEB, represents a step focused on the development of a BIM based toolkit for building renovation, which is fundamental for Europe in a period during which there is the need to recover existing buildings, rather than constructing new ones, considering sustainability development goals.

**Fig. 1** BIM4EEB BIM based toolkit

**Fig. 2** BIM4EEB overall work plan

Specifically, BIM4EEB has been developed with the intention to make the flow of information efficient, to decrease intervention working time and costs, and to improve building performances, with a specific focus on quality and comfort for inhabitants. In this book we report the chief BIM4EEB results represented by the BIM bases buildings renovation toolkit (see Figs. 1 and 2).

BIM4EEB project has been developed since 2019, starting with the definition of the information requirements (see chapter 2) and the development of specific ontologies to deal with linked data to support efficient interoperable, open data exchange within the toolkit (see chapter 3).

In the following chapter 4, 5, 6 and 7 the different tools developed by BIM4EEB are presented, while in chapter 8 it's shown the practical application of the toolkit to 3 demo sites (Italy, Poland, Finland) in order to have a complete validation of BIM4EEB results.

The hope in publishing BIM4EEB results is that the contribution of the project will be useful in supporting relevant stakeholders improving the whole renovation process.

Milano, Italy Bruno Daniotti

# **Contents**

# **Chapter 1 Information Requirements for an Efficient Renovation Process**

**Sonia Lupica Spagnolo, Martina Signorini, Teemu Vesanen, Alberto Pavan, and Spiros Kousouris**

**Abstract** When a renovation process takes place, different stakeholders are responsible of several activities and their interaction occurs at different stages of the building process. Therefore, a deep analysis of possible activities for different stakeholders in each different stage of the life cycle helps outlining how to optimize their interaction, thanks to the use of BIM-based tools that can smooth collaboration and data gathering. As it is commonly agreed that information losses, data lacks or redundancies are one of the main causes of time delay and cost increase, a flowchart representing the building process in case of renovation has been developed and then used to design a BIM management system (BIMMS) to allow every stakeholder along the life cycle of a building (and built asset) finding required information and share existing or new datasets in a straightforward and conflict-free manner. A particular attention has been paid in individualising differences between the public and private sectors, to be successfully applied to the renovation process in both the sectors.

**Keywords** Renovation processes · Stakeholders · Information requirements

# **1.1 The Information Workflow in a Renovation Process**

When a renovation process takes place, different stakeholders are responsible of several activities. For mapping a renovation process, first of all, a list of involved stakeholders has been produced considering also the literature review (CCC 2006;

e-mail<EMAIL_ADDRESS>
T. Vesanen VTT Technical Research Centre of Finland Ltd., Espoo, Finland

S. Lupica Spagnolo (B) · M. Signorini · A. Pavan

Department ABC—Architecture, Built Environment and Construction Engineering, Politecnico di Milano, Milano, Italy

S. Kousouris SUITE5 Data Intelligence Solutions Limited, Limassol, Cyprus

B. Daniotti et al. (eds.), *Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings*, SpringerBriefs in Applied Sciences and Technology, https://doi.org/10.1007/978-3-031-04670-4\_1

GBPN 2013; RIBA 2013). Furthermore, stages of building processes have been defined, according to (EN 16310:2013), (ISO 6707-1:2020) and (ISO 6707-2:2017).

The process of renovation needs a methodology that takes into consideration several parameters such as the cost of the renovation measures, the targeted performance (Key Performance Indicators like indoor thermal comfort levels, CO2 emissions, energy, safety), national building regulations, building specific information and the end user needs. Also, the process must be adjusted to allow some iterations, because the planning and the implementation of the renovation measures and the conditions surveys during the process might bring up some hidden deterioration of the building components having an effect either positively or negatively on the targeted performance of the renovation actions.

By listing all the possible actors involved along a renovation process, information workflow can be defined to be considered when developing the BIM Management system to assure a proper definition of ontologies and interoperable exchange formats.

The output of this deed analysis is a flowchart representing actors and actions where:

These activities are the starting point for mapping outputs of such activities (that could be mapped in a traditional process and in BIM-based processes) and for estimating times spent for carrying activities and achieving defined outputs. The synoptic flowchart will be used to outline how ICT and BIM can support the rationalisation of information flows (BIM4EEB D2.1, 2019) (Fig. 1.1).

# **1.2 Definition of Designers' Needs and Requirements for BIM-Assisted Decision Support for Performance-Based Refurbishment**

The previous paragraph presents the renovation process described in the project from the general point of view. When the BIM4EEB project proceeded further, that process was updated from the designers' point of view related to the new activities and roles found. A general view of the designer requirements and the concept of performance-based decision making with a specific use case of the BIM-assisted scenario simulator is shown.

The model and energy calculation gradually refine in the energy performance design from a simple monthly calculation with basic information into a dynamic simulation with an accurate building information model (BIM) and detailed information about technical building systems. Figure 1.2 illustrates the scope of the work.

#### 1 Information requirements for an efficient renovation process 3

**Fig. 1.1** Extract of the developed flowchart for a renovation process

**Fig. 1.2** The information gap between the early-stage information need

In this task in the BIM4EEB project the requirements for the data regarding successful performance-based design were studied. This chapter is based on the project deliverable (BIM4EEB D2.2, 2019), which is available in the project website https://www. bim4eeb-project.eu/.

Building Energy simulation (BES) tools are used for analysing energy need and expected indoor environmental quality in the buildings under different retrofitting plans. It essential to analyse not only the energy, but also the value for which the energy is used. We are not interested to just conserving energy, but also optimising the comfort and productivity in the buildings. Typically, BES can calculate performance indicators such as CO2 emissions, LCC, LCA, occupant's satisfaction and indoor environment quality.

On a general level, the input data to BES are the weather, building envelope, geometry and orientation, HVAC system and the occupant's behaviour. The heating and cooling set-points and the air ventilation rates are the most influential parameters on the building's energy consumption. Besides, in cold weathers, main effects on the heating load come from the building envelope parameters of the window U-value, window g-value and wall conductivity. In hot weathers, the cooling load is mainly affected by the solar-heat gains, the internal heat gains from the occupant's behaviour, and the heaviness of the structures. In addition to its influence on the output results of BES, occupant's behaviour related to people existence and use of appliances and lighting is one major factor that can cause discrepancies between simulation prediction and the real energy use.

A first use case in the project is to model the building as it is before the renovations. This is called an As-is model. The accurate acquisition of data for the As-is models of the buildings that are subjected to retrofitting is the first challenge for BIM-based energy simulations. Old buildings normally lack complete and updated documentation of all data that are required by energy simulation. Appropriate equipment and methods are needed to monitor, collect, and manage the data and the tools developed in the project are expected to fit the need.

In addition to its completeness and updated information, the BIM data should also be interoperable with BES in an easy and automatic manner without a need for the repetition of the exhaustive input data. BIM4EEB tools and methods were developed to also fulfil this need, which is not always possible with the existing tools. There is often a need for different levels of manual interventions.

The model for the BIM Assisted Scenario Simulator tool, called BIMeaser, is presented and the workflow of its use is defined. The most important finding related to the renovation process is the importance of the need for the performance-based building design in the early design phases, where the most important decisions are made according to costs and performance as shown in Fig. 1.3.

The data definitions related to the commercial energy simulation tool IDA Indoor Climate and Energy (IDA-ICE) by the Swedish company Equa Simulation AB open a landscape of huge set of details to be defined. This huge set (more than 1000 parameters) was narrowed according to the findings listing the most important input variables related to the impact on the indoor climate and energy, but still was a big challenge in the project.

**Fig. 1.3** Committed costs and possibilities related to energy performance decay, adapted from (Pietiläinen et al. 2007)

The second finding derived from tool definition was the need for the enhanced collaborative design work. The indoor climate and energy design is a multi-domain challenge, and it should always be considered as a teamwork. All tools around the future building renovation design should comply and support this approach. The performance-based building design process assumes that design selections are validated against the Owners Project Requirements (OPRs) in each design stage before moving to a following design stage. The design team will handle the detailed technical selections affecting to the OPRs using the tool. The management of the consistency of the detailed technical parameters against the OPRs has traditionally been handled manually between design domains resulting to the design errors or time-consuming updates, whenever the technical detail has changed. The BIM Assisted Scenario Simulator will tackle the complexity of the energy and indoor climate design by:

The implemented BIM Assisted Scenario Simulator, called BIMeaser, is presented in Sect. 5.2.

### **1.3 Information Requirements for Construction Companies in Renovation Interventions**

In the last years some studies have been developed regarding the application of BIM in the construction enterprises, but research on BIM adoption in small and mediumsized enterprises (SMEs) have remained an under-represented area (Hosseini et al., 2016; Li et al., 2019). The research on SMEs it is of fundamental importance because SMEs have greatly contributed to the economic development of regions or countries and, currently, guidance to assist SMEs to make an informed decision about BIM adoption are lacking (Lam et al., 2017). It is necessary to understand the main challenges delaying the adoption of BIM in SMEs and to consider corresponding strategies that can be applied to obtain further understanding of BIM in SMEs (Li et al., 2019).

Focusing on the small and medium enterprises, the main barriers derived from the risks associated with an uncertain Return On Investment (ROI) for BIM implementation. The findings of (Hosseini et al., 2016) show that currently around 42% of Australian SMEs use BIM in Level 1 and Level 2 with only around 5% that have tried Level 3. According to (Lam et al., 2017) there is evidence to suggest that small and medium sized enterprises are currently losing out in winning publicly funded projects. (Hosseini et al., 2016) affirm that the findings of their study show that around 42% of SMEs have been engaged in BIM, instead of the 25% provided by the study by (Gerrard et al., 2010). This gap indicates how fast-moving BIM is within the Australian construction industry, but the findings also indicate that the immaturity of BIM implementation is still a problem within Australian market because only the 5% of SMEs had used Level 3 and 8% had utilized Level 2 BIM on their projects. According to (Li et al., 2019), based on previous studies and interviews, in SMEs six challenges exist: (1) SMEs are short on resources, (2) collaboration challenges, (3) lack of BIM awareness, (4) legal disputes and uncertainties in policies, (5) difficulties in meeting SMEs' needs, and (6) concerns about data and information. (Bosch-Sijtsema et al., 2017) assert that the results from their study on SMEs indicated that more than half of medium-sized contractors in the sample used BIM in some projects and the main obstacles for BIM implementation is related to the lack of normative pressure. (Tranchant et al., 2017) carried out an immersive 3D projection for the simulation of the Ajaccio hospital in France. According to (Tranchant et al. 2017), the heart of the economy of France is that of SMEs, which represents 96% of companies. As a result, the innovation of the BIM is becoming a necessity for SMEs, even if they do not practice public contracts. (Malacarne et al., 2018) affirm that the BIM Pitch concept that they developed in their research is unsuitability for SMEs since it is highly time consuming to develop as additional model, as consequence further study are required.

The framework on the recent studies on SMEs underlines that they are limited to few countries. As consequence, additional research is needed to understand the needs of the industry and existing barriers in digitalization and BIM use in AECOO sector.

The exchange of information between the three main parties of a project is a common problem in construction sector.

#### 3. Information exchange from the supplier to the contractor

The traditional information exchange is done by paper or digital format, using graphics, pictures, documents, and static media documents. This type of exchange of information has several limitations that can be improved utilizing a more digitization method such as BIM.

The BIM method includes the use of information models to replace documents that can be digitalized, and it optimizes the transmission of data, promoting interoperability between the parties involved in the project.

However, the geometric representation is not the only purpose of a BIM model; in fact, this type of approach is used with the addition of data and information characterizing the model itself. From the informative model, it is possible to extrapolate, in addition to the geometric visualization, also data of an informative nature and the latter can be contained in documents linked to the model, such as quantities estimation, specifications or reports, or within the objects constituting the model itself.

Commonly, information exchange issues are related to three main parties involved in a project, namely client, contractors and supply chain as following explained based on (Franchini, 2018).

#### *1.3.1 From the Client to the Company*

At the base of the process, there is the need of the client to have the work carried out. The client, therefore, represents the main Fig of every transaction. To this end, the company should clearly understand what the client's objectives are.

To clarify these intentions, the client trusts the elaboration of the project to a team that draws up part of the documents that must be supplied to the companies.

In a frequent scenario, once they have received the material, they must analyse the information and data received from the design team and verify the completeness. If the papers are inadequate, the responsibility of filling these gaps will nevertheless remain with the company, to draw up a complete construction project.

Often, for example, the executive project is incomplete, leading to a loss of time and resources for the company.

At the end of the process, the company should deliver to the client the complete As Built, including all the information useful for the maintenance of the work. Currently many companies have an ERP system (such as SAP), where part of the As-Built information is collected. However, many documents remain stored in other location in the company there is the need to transfer all this inputs to the client and the end of the project.

#### *1.3.2 From the Company to the Supplier*

This exchange of information happens to present an offer.

The traditional exchange of information between the company and the supplier happens by paper or digital support, exploiting the use of graphic, documentary, and static multimedia documents. This type of information exchange is usually successful but has several limitations, including:

This way often leads to the loss of time and valuable information, and the waste of a large amount of paper.

Even the world of construction companies is getting closer to a more complete digitization; an act that regards information exchange very closely. However, it is important to emphasize that this step forward by companies lies not only in the digitization of their process, but in the use of information models to replace the documents which can be either digital or not. All this makes it possible to optimize the transmission of data, promoting interoperability between subjects, limited by having to know how to use the tool.

If the company was digitized, in the BIM sense, the transfer of information to suppliers would be difficult, if not impossible. The supplier would not be able to open and exploit the information models received, because he is used to using antiquated methods (paper) and/or non-standardised practices. In fact, a supplier may deliver products to hundreds of companies and each of them may have different practices.

#### *1.3.3 From the Supplier to the Company*

This exchange of information happens to allow the company to present an offer; to realize the as built, and the maintenance documentation.

This passage of information is significant at different stages of the process starting from the pure design phase, in which the company must take care to carry out the constructive translation of the client's requests, up to the preparation of the maintenance plan that will be used by the final users.

The necessary inputs can be multiple, such as:

There are two possibilities to solve this issue:

The first point is feasible but would lead to a waste of time and resources that could instead be addressed elsewhere. It is necessary to carry out an accurate investigation to try to better understand the needs of the companies, in such a way as to be able to obtain results that are practically exploitable and standardized.

#### *1.3.4 Attributes and Requirements*

To explore solutions related to the above-mentioned information exchange issues, it is necessary to know some information regarding the companies, such as:

To find out what are the attributes three types of objects are considered, representing the category to which they belong, such as:

The first step is to create a basic list of attributes, useful for the company to characterize the object.

It is important that this list can be implemented to be able to add both specific needs and attributes, expressly requested by the client or designer, and new attributes considered essential by the supplier (Table 1.1).

• Is each proposed attribute necessary?

### **1.4 Definition of Owner and Inhabitants' Needs and Requirements in Renovation Interventions**

An important and difficult step in designing a software product is determining what the end-user expectations of the software will be, such as what activities the user will be able to perform once the platform is operational. This is because the users (especially non expert's users) are often not able to communicate entirely their needs, or the information they provide may be incomplete, inaccurate and/or self-conflicting. On the other hand, nowadays there is the increasing need of the active enrolment of end users towards the provision of personalized services to the potential customers.

The scope of this document is to blueprint a methodological approach and a user requirements extraction process for the building owners' and inhabitants' as main stakeholders in a building renovation and management project. In general, by engaging the owners and inhabitants of a building, enables them to participate as active players in the renovation process, which in turn increases their awareness about their influence on the way a building function. As such, their input during the whole process ensures that their requirements and needs in relation to the renovation's outcome are considered; additionally, it increases the chances of a successful renovation design outcome achieved.

Towards this direction, a detailed methodology is established at the early phase to ensure the proper extraction of end-user's feedback. The definition of the target groups is a primary step along with the definition of the main use cases associated with the roles. Then, to extract the relevant requirements, dedicated to the building owners and inhabitants' questionnaires are structured, while semi-structured interviews (to be addressed by the building representative) were defined, towards co-creating a shared value and directly addressing the owners and inhabitants needs. More details about the methodological framework as well as the results from the analysis are presented in the following.

As shown in figure below, the proposed methodology is composed by three steps through which the requirements coming from the building owners and inhabitants can be captured.

The different steps shown in Fig. 1.4 are detailed in the following text.

**Table 1.1** Description of informative attributes

(continued)

**Table 1.1** (continued)

**Fig. 1.4** Steps of the followed workflow

#### **Step 1: Selection of end users usage scenarios**

The starting point for this analysis, is the identification of the end-users (namely the building owners and inhabitants) business needs and priorities, following consultation with building occupants. A non-exhaustive list of usage scenarios is defined for analysis in the project:

The definition of the different Usage Scenarios highlights the key differentiation among the stakeholders (owners versus. inhabitants).

#### **Step 2: Questionnaires/Interviews analysis to the extraction of the end-users needs**

Following the definition of the Usage Scenarios, a set of questionnaires were prepared to address the needs of the building owners and inhabitants (as end-users of the project). The scope was to engage these end-users in the project's activities and further retrieve their valuable feedback towards the extraction of their needs and requirements related to building renovation and management activities. The intended type of information to be gathered from the end users is classified into the following groups:

Further to the use of questionnaires for extracting the owners' and inhabitants' needs and requirements, the building site representative partners were also engaged in semi-structured interviews to extract further pilot specific requirements. The use of these semi-structured interviews allowed new ideas/concepts to be examined, as well as further technical requirements to be identified regarding ethical/legal barriers imposed at the different pilot sites.More specifically, the goal of these semi-structured interviews was threefold:

A total number of 102 questionnaires were responded by building owners and inhabitants—45 for building owners & 57 for building inhabitants. Also, a limited number of semi-structured interviews was answered by the pilot representatives (Italy, Poland, and Finland) to express their needs and main expectations from the project.

#### **Step 3: Owners and Inhabitants requirements extraction**

Finally, in step 3 we consider the questionnaires/interviews analysis results which are transformed to building owners and inhabitants requirements. A total number of 97 end-user's requirements were extracted incorporating also some technical constrains. The list of the extracted requirements derived from the active participation of the pilot sites. These are further complemented by additional requirements mainly related to ethical and any legislation constrains imposed at the pilot regions of the project.

In total, 30 pilot specific requirements are to be considered at the instantiation/configuration of the framework at the different pilot sites. Further to the above work and the elicitation of the non-exhaustive list the requirements, we categorized them considering the hierarchy and the project's objectives. The prioritization of the end-user's requirements is also a critical task performed to elucidate the requirements to be considered on the analysis. The different layers of priority are:

Overall, the outcome of the work is (a) the definition of the relevant for the building owners/inhabitant's usage scenarios to further enable the (b) extraction of the user specific requirements for this target group of the BIM4EEB project. The extraction of the requirements will further facilitate the design and development of the different software implementations targeting building occupants: inhabitants and owners.

#### **References**

**Open Access** This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

The images or other third party material in this chapter are included in the chapter's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

# **Chapter 2 Linked Data and Ontologies for Semantic Interoperability**

**Karsten Menzel, Seppo Törmä, Kiviniemi Markku, Kostas Tsatsakis, Andriy Hryshchenko, and Meherun Nesa Lucky**

**Abstract** The purpose of Linked Data and ontologies is to achieve semantic interoperability across different systems and agents. As a concrete implementation, Digital Construction Ontologies (DiCon) are meant to provide efficient information sharing and utilization between the tools in the BIM4EEB toolkit. This section explains the motivations, design principles, and organization of DiCon ontologies.

**Keywords** Semantic interoperability · Linked data · Ontology

# **2.1 The Role of Linked Data and Ontologies**

Construction and renovation industry is nowadays filled with digital solutions to support numerous tasks in design, planning, quantity estimation, procurement, logistics, site management, quality inspections, sensor data gathering, and so on. However, due to their specific origins and history, different solutions manage and represent data in an incompatible manner. The result is a fragmented systems landscape and the

S. Törmä (B) VisuaLynk Oy, Espoo, Finland e-mail<EMAIL_ADDRESS>
K. Markku VTT Technical Research Centre of Finland Ltd., Espoo, Finland

K. Tsatsakis SUITE5 Data Intelligence Solutions Limited, London, UK

A. Hryshchenko University College Cork (UCC), Cork, Ireland

© The Author(s) 2022 B. Daniotti et al. (eds.), *Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings*, SpringerBriefs in Applied Sciences and Technology, https://doi.org/10.1007/978-3-031-04670-4\_2

K. Menzel

Technische Universität Dresden (TUD), Dresden, Germany

M. N. Lucky Department ABC—Architecture, Build Environment and Construction Engineering, Politecnico di Milano, Milan, Italy

consequent need for repeated manual work to transfer information from one system to another or for costly integrations between pairs of systems.

Linked Data and ontologies provide a generic solution that enables systems to interoperate; that is, share information and act on the information shared. The need for manual information exchange is reduced or even removed since the interaction between systems can be automatized.

The following levels of interoperability can be identified (Singh and Huhns 2005):

The solutions to tackle technical and syntactic interoperability, at least in ordinary domains, are already available, and to achieve interoperation at those levels is generally a matter of willingness and effort of implementation. Semantic interoperation is still an area of active development, with promising technologies and initial results. However, even after the problems of semantic interoperability have been tackled, challenges of the pragmatic level remain to be solved to make systems work seamlessly together.

In the case of the BIM4EEB toolkit, the Digital Construction Ontologies and the Linked Data principles take care of the semantic interoperability but as of now the solutions for the problems arising at the pragmatic level must still be separately agreed among the tools.

#### **2.2 The Need to Supplement BIM with Ontologies**

While in the future the design in renovation projects will be based on building information modelling (BIM), the information contained in the models will not be sufficient to comprehensive planning and modelling of different aspects of a renovation. Rather, BIM models will be related to multiple other areas as shown in Fig. 2.1: built assets, agents, legal roles, products and materials, classifications, information entities, plans, activities, sensor data, and so on. The entities in these areas need to be linked with the entities in BIM models but the different origin, lifecycle, and rate of change of the data in those domains imply that they are best managed separately from BIM models. That is, interlinked but separately managed.

There are several areas where comprehensive renovation management requires supplementary representational agreements:

1. *Occupancy and ownership*. In renovations, information about ownership, occupancy, and use of spaces of the building to be renovated require the concepts for built assets, including their division into individual residential and nonresidential units in buildings. This is used in the early stages of renovation planning to organise the information about occupancy profiles, and requirements and preferences of stakeholders. In the execution phase it is used to coordinate the renovation activities with the stakeholders.

**Fig. 2.1** Examples of domains relevant for renovation management

The representation of these areas has been addressed at least partially by many

The previous work on ontologies needs to be considered in any subsequent ontology development, and new ontologies should be aligned with existing ones.

#### **2.3 Tool Interoperation Using Ontologies**

The applications that utilize ontologies can originally be standalone tools. It is expected that future solutions for renovation management are likely to be implemented as systems of systems (Maier, 1998). There will be independently developed and used systems serving their specific purposes that will produce and consume information. The overall information system environment in any specific renovation project will be built from the existing systems of the parties involved. The essential goal is to have interoperability between different systems because it allows to connect them together to serve the goals of the project.

The constituent systems must relate to each other for the duration of a renovation project to act in complementary roles in the project. Detailed data remains inside each system, but the systems can share the relevant part of their data with others. To achieve interoperability, the constituent systems must have interfaces for the required interactions and semantic interoperability relevant to the renovation domain.

Figure 2.2 illustrates the role of the ontologies with a high-level architectural diagram as realized in the BIM4EEB project. There is a set of renovation tools that interoperate by sharing data through a common data sharing platform. The tools do not interact with each other directly; all interactions happen through shared data.

Data sharing is based on the Linked Data principles and the use of ontologies that enable the semantic interoperability among tools. Both the tools and the data sharing platform access the ontologies either by downloading whole ontology modules or through URI lookup of individual terms. Downloading of whole ontologies is needed for performance reasons and to support reasoning functionalities.

The data sharing platform stores data in files and in databases. There is both a relational database (SQL) and a graph database (RDF) between which the data contents are synchronized.

**Fig. 2.2** An architectural overview ontology-based toolkit of BIM4EEB

**Fig. 2.3** High-level example of data sharing between tools in a workflow

The tools can access the data sharing platform in several different ways: by downloading IFC files and through SPAQRL queries, URI lookup and ordinary REST interface. Finally, the ontology modules are aligned with external ontologies through the alignment modules that import both the external and internal ontologies and connect the terms across them with alignment axioms.

A high-level example of the kind of data sharing that can happen between different tools in the workflow of BIM4EEB toolkit is shown in Fig. 2.3. The tools are shown in the middle level of the figure. The tasks that are performed with the aid of the tools are indicated at the top of the figure. At the bottom is the data sharing platform. The arrows between the tools and the data sharing platform describe the kinds of data that is exchanged between the tools and platform. It should be noted that there can be also other data that is directly loaded on the platform. The main message to take away from the figure is that there are various kinds of data that is exchanged, and that the data produced by one tool can later be utilized, enriched or modified by other tools. The interoperation is based on shared data, and it can support different kinds of processes, depending on the companies involved in projects and the tools utilized by them.

#### **2.4 The Design of Digital Construction Ontologies**

The main principles that have driven the design of Digital Construction Ontologies (DiCon) are compliance with relevant standards, compatibility with a standard toplevel ontology to provide fundamental categories and therefore increase conceptual integration, support for information evolution which is a crucial phenomenon in renovation and construction projects, the flexible mechanism to connect the entities with different identifier schemes and classification systems.

#### *2.4.1 Standards Compliance*

An important objective in the design of Digital Construction Ontologies was to support relevant standards in the AEC domain. Most important standard is IFC (Industry Foundation Classes) (ISO16739, 2018) that has also been converted into an ontology ifcOWL (Pauwels, 2016). The BIM models created by designers can be exported into IFC, and the IFC model contains all spatial and physical entities as well as building systems of a buildings. Another important standard is ISO 19650 that specifies the principles of BIM-based information management. DiCon provides a formalization of the central concepts of ISO 19650 standard (ISO19650, 2018) ranging from built assets, appointments and project teams to information models consisting of a federation of information containers. Finally, the informationrelated concepts of DiCon are compatible with the Container ontology of Information Container for Linked Document Delivery (ISO 21597, 2020) that enables the exchange of packages of interlinked datasets across parties.

#### *2.4.2 Top-level Ontology for Fundamental Categories*

Since DiCon covers a wide range of concepts—physical entities, spatial entities, information entities, events, processes, properties, roles, capabilities, etc.—there is a need for generalized concepts or higher-level categories as one method to interrelate different domains of information. Instead of ad hoc generalizations, a standard and widely used top-level ontology Basic Formal Ontology (ISO/IEC 21838, 2021) is used as the source of fundamental categories. BFO is a compact ontology based on ontological realism—according to which ontology represents entities in the world that better promotes interoperability than ontologies that allow cultural or mental concepts with more diverse interpretations.

#### *2.4.3 Support for Information Evolution*

In renovation and construction projects it is crucial to support the evolution of information. Information will be accumulated, refined, and changed during the project execution. DiCon supports the evolution of information with two different mechanisms. Firstly, objectification of properties is used for the small-scale evolution, e.g., for values changing over time because of sensor observations. Objectification also enables the representation of other metadata about properties: quantity kinds, units of measure, and property definition entities. Secondly, the large-scale evolution is based on the ISO 19650 information containers. This enables the storage and management of alternative renovation scenarios, different versions of BIM models, releases of operational plans, and entity organizations such as breakdown structures.

#### *2.4.4 Flexible Labelling of Entities*

All DiCon entities can be labelled with identifiers and classifications. Every independent entity has a URI as its main and retrievable identifier but, in addition, the entity can have additional identifiers in different information systems and other scopes. Identifiers can be globally unambiguous such as a GUID, or locally unambiguous, such as a room number in a building (where the building defines the scope of the identifier). Likewise, since different classification systems in the construction sector are used in different geographical regions and organizations, DiCon supports the flexible labelling of entities with categories based on the needs of a project. The goal of DiCon is to avoid duplicating information that is already in classification systems; after all, classifications are complementary to ontologies in the sense that they capture the variety in the domain with an extensive set of detailed classes (possibly with classspecific attributes), while ontologies represent the complexity in it with a compact set of essential classes, each with a distinct set of constraints and relations to other classes.

### *2.4.5 Modularization and Alignment Using Vertical/horizontal Segmentation*

DiCon is modularized using the vertical and horizontal segmentation approach of the Semantic Sensor Network Ontology (Haller, 2019). In the *vertical dimension*, a new module imports the previous one and deepens the representation of the underlying domain by defining additional subclasses, properties, restrictions, or alignments (therefore, alignment is always vertical segmentation). In the *horizontal dimension*, a new module broadens the domain by defining classes complementary to the previous ontology as well as properties to connect them to the previous concepts.

In the vertical dimension, the new module should support selected use cases better, having perhaps a narrower user base when compared to the previous module, while horizontal segmentation should extend the set of supported use cases, therefore broadening the potential user base.

In accordance with vertical segmentation, the approach to integrate DiCon ontologies with external ontologies is based on the use of alignment modules. It should be noted that there are several alternative ways to promote integration: (1) direct imports of external ontologies, (2) references to terms of external ontologies without importing them, and (3) utilization of SHACL to create application profiles as graph templates that incorporate terms from several ontologies. The resulting integration is different in each case; for instance, the consistency checking with ontology reasoning works in a different manner.

In the alignment approach the ontology modules to be aligned do not reference each other at all. Instead, a separate alignment module first imports the ontologies to be aligned and, second, provides additional alignment axioms that establish relationships between the terms in the imported ontologies. The alignment module can then be checked for consistency to reveal whether the alignments are compatible with the definition of the terms in the aligned ontologies.

According to the alignment approach all the references from DiCon ontologies to classes and properties defined in external ontologies are made explicit in the alignment modules; that is, the DiCon ontologies do not refer to any external classes or properties. However, it is still possible that they have references to individuals defined in external vocabularies. This applies especially to individuals representing quantity kinds and units of measure.

#### **2.5 Definition of DiCon**

The overall DiCon ontology is divided into a set of modules shown in Fig. 2.4. The arrows indicate the import relationships (owl:imports) between the modules.

**Contexts**—The DiCon Contexts (dicc) ontology defines the basic concepts to manage data in different alternative realms, such as planned or actual data, models at different levels of detail, different renovation scenarios, versions of construction plans, and so on. The main concept is dicc:Context, each of whose data is contained in its own named graph of an RDF dataset.

**Variables**—The DiCon Variables (dicv) defines an enriched representation of the properties. It uses the objectification of properties as the basic mechanism. The properties of entities can be associated with additional objects to represent quantity types or units. Moreover, the value can be represented with property states that enable the values at different time points or levels of detail. The ontology is aligned with

**Fig. 2.4** DiCon ontology modules and their import relations (owl:imports)

QUDT, SOSA, and Saref Core. It allows to associate, for instance, series of sensor values to the properties of entities.

**Entities**—DiCon Entities (dice) defines the basic entities of renovation and construction processes, ranging from building objects, real estate, devices, equipment, locations, roles, and capabilities to spatial regions and time intervals. The ontology observes the general structure of the Basic Formal Ontology (BFO) and is aligned with it.

**Processes**—DiCon Processes (dicp) defines the concepts for activities (intentional processes with start and end), activity flows and resources. An activity can have any number of sub activity layers, and it can represent anything from projects to tasks. The activity flows are relations that activity can have to different other entities: the object to transform, agents, locations, equipment, material batches, information entities, and to external conditions such as temperature or humidity. Resource is treated as a role that any entity can have with respect to an activity and activity may require different kinds of resources to appear in different activity flows.

**Agents**—DiCon Agents (dica) represents the concepts for actors and stakeholders, persons, organizations, and legal persons, as well as the basic organization concepts from ISO19650. The legal persons can have specific roles with respect to assets, for instance, as an owner or tenant.

**Information**—DiCon Information (dici) defines concepts of information content entities such as information containers, information models, designs, plans, messages, and so on. The concept of a project information model is defined based on the description in ISO19650.

**Materials**—DiCon Materials (dicm) ontology defines the layer structures of building objects, and different kinds of properties of materials from carbon content to thermal and dynamic properties.

**Energy**—DiCon Energy (dices) defined the concepts for life cycle assessment, energy efficiency and energy systems, including the related information content entities, processes, and objects.

**Occupancy**—DiCon Occupancy (dicob) covers the occupancy profiles of inhabitants, and acoustic performance and indoor air quality of building units.

**Lifecycle**—DiCon Lifecycle (dicl) addresses the representation of information specific to LOD levels and building lifecycle stages.

The overview of how the concepts in the different DiCon modules are related with each other through the upper-level categories is shown in Fig. 2.5. In the interest of legibility, not all the modules are presented in the figure.

#### 2 Linked Data and Ontologies for Semantic Interoperability 27

**Fig. 2.5** Overview of central concepts of DiCon

#### **References**

**Open Access** This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

The images or other third party material in this chapter are included in the chapter's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

# **Chapter 3 Development of BIM Management System**

#### **Alberto Pavan, Vittorio Caffi, Alessandro Valra, Davide Madeddu, Diego Farina, Jacopo Chiappetti, and Claudio Mirarchi**

**Abstract** With BS 1192:2007 and even more so with BS PAS 1199-2:2013 and 1192-3:2014, the concept of Common Data Environment (CDE) of the order (project, construction or management that is). Originating from a standard dedicated to design (BS 1192:2007) and although its concept has been extended to information management in general: Capex (strategy, project, construction: PAS 1192-2) and Opex (exercise: PAS 1192-3), the CDE, as it is understood today in common practice, is still very much affected by the original link with the design and the design phase (and in particular the design in the new building). All this according to an information flow that is still very linear and sequential: client, designer, builder, manager, user; more than circular, as the so-called BIM methodology would like. The risk, therefore, is that the commercial software market is affected by this CDE approach, which is also useful for the very rich real estate market of the emerging economies, neglecting the construction market of the more consolidated economies (Europe for before), very built up, and aimed more at housing quality, sustainability, reuse, and renewal of the existing heritage rather than the new one. It is consequently necessary to define new information flows and a new type of information management environment (CDE) for the phases of use, conservation, and renovation of buildings for the European market. The need arises for a specific BIM Management System (BIMMS, overcoming the classic CDE) for asset management and their enhancement that collects information from the buildings themselves and its users (Digital Twins, IoT, sensors, etc.). A new CDE / BIMMS that uses semantics and open dialogue, via API, with multiple Tools rather than acting as a repository of files and models. BIMMS is a new concept of CDE created for the operation/renovation phases in mature real estate markets (such as the European one).

A. Pavan (B) · V. Caffi · C. Mirarchi

© The Author(s) 2022

Department ABC—Architecture, Built Environment and Construction Engineering, Politecnico di Milano, Milano, Italy e-mail<EMAIL_ADDRESS>
A. Valra · D. Madeddu · D. Farina · J. Chiappetti One Team S.r.l., Milano, Italy

B. Daniotti et al. (eds.), *Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings*, SpringerBriefs in Applied Sciences and Technology, https://doi.org/10.1007/978-3-031-04670-4\_3

**Keywords** Common data environment · BIM management system · Digital platform · Digital twins · IoT

#### **3.1 Common Data Environment**

#### *3.1.1 Introduction to the Topics*

The sharing and conservation of information are two critical issues that have always been present in the construction sector. They have been handed down over the centuries and have become increasingly important with the increase in regulatory, technological, requirements, etc. complexity. typical of our days.

Today, digitalisation offers new tools to solve this critical information throughout the construction chain, both in terms of containers (files) and in terms of content units (single information and data). With the BS 1192:2007, in the UK, the concept of the Common Data Environment in constructions is born, then resumed in a more digital sense in the PAS 1192-2: 2013. Since the CDE has been "subject", of other standards, at national level (UNI, DIN), European (CEN) and international (ISO), and "object" of new tools (360DOCS, Aconex, BIM+, etc.). Tools that from simple document repositories have increasingly turned to the management of the "models" generated by the various "BIM Authoring" software, in their different component files (architectural, structural, MEP, etc.).

The writing of a new type of CDE, aimed mainly at the built environment, cannot therefore ignore a careful analysis of the standards that define its contours and the commercial software that characterize its operational use.

The creation of a CDE aimed at the construction supply chain, and which sets the life cycle of buildings (50, 100 and more years), also cannot omit even a general analysis of the systems for sharing and preserving "data" (and not just files). These systems have been in use for decades in other industrial sectors (Data Base Management System: DBMS; Enterprise Resource Planning: ERP, etc.) and must also be analysed to define the architecture of BIM4EEB's new CDE system. In the same way one cannot forget all the new technologies that increasingly appear in the informative panorama also of the constructions: sensors (Internet of Things—IoT), DB to Objects, non-relational DBs, etc.

Finally, the same concept of CDE addressed to the single order, or intervention, is now losing more and more meaning towards that of digital platform, collaboration and sharing: organization, supply chain, national and transnational (see the DigiPLACE project, EU, H2020).

The architecture of the BIM4EEB CDE defined in BIM4EEB must take all these variables into account and give them an operational response.

Building Information Modelling (BIM) is gaining momentum in the AEC industry for design and construction and one of the most significant technological advancements in recent years that has been adopted by the design and construction industry (Khaja et al. 2016, Parlikad et al. 2019).

Traditional method is mainly concerned with 2D representation of information throughout all the entire project phase; however, Building Information Modelling leads to the re-shaping of the construction industry as it stands for the necessary evolution of the design approach linked to the increasing complexity of the building process. BIM lays down the transition from unidirectional and asynchronous workflows to integrated and shared models. Most research has agreed that BIM is a process of expanding 3D models to computable nD models to simulate the planning, design, construction, and operation of a facility. In particular, 3D BIM makes it possible to perform specific analysis based on the geometrical information of the model, such as 3D visualization, clash detection and code checking (Solihin et al. 2017).

To put it in a nutshell, the five most important benefits include: better cost estimates and control, better understanding of design, reduce construction cost, better construction planning and monitoring, and improvement of project quality.

Despite many advantages of BIM, the slow adoption to date has inspired researchers worldwide to investigate existing barriers; these barriers include technical problems (compatibility and reliability), fragmentation of the project team, the inherent resistance to change by construction stakeholders, lack of training, and business process related issues, inadequate organizational support and structure to execute BIM, and lack of BIM industry standards.

The Common Data Environment was originally defined in BS 1192:2007, then in PAS 1192-2:2013, finally it has its own international standard, ISO 19650. There are also other standards from Italy and Germany with similar approach. The contents of the CDE are not limited to assets created in a 'BIM environment' and it will therefore include documentation, graphical model, and non-graphical assets. In using a single source of information collaboration between project members should be enhanced, mistakes reduced, and duplication avoided. The advantages of implementing a CDE include:

BIM teams are those whose possibly geographically dispersed members from various organizations and disciplines, perform project tasks on BIM-enabled projects. even though achieving BIM's full capabilities relies on effective collaboration among the team members in BIM-based construction networks, it is still a struggle for these members to collaborate. Nonetheless, only a few studies have been conducted to identify the barriers to strengthening team collaboration in BIM-based construction networks.

BIM methodology is mainly developed and applied for new building projects. Its use for renovation and retrofitting projects is still in its infancy. On the other side, there is a strong present need to improve the quality and the functionality of the existing building (Scherer 2018). To encourage BIM adoption for renovation project, there is a need to examine refurbishment project stakeholders' separate roles, responsibilities, relationships, and interactions among themselves of which can be hampered by internal or external environmental factors. Although BIM adoption environment requires a more multidisciplinary collaboration effort of different disciplines against information sharing, building design, construction techniques.

#### *3.1.2 Principal of CDE*

Traditionally, interdisciplinary collaboration in the fields of Architecture, Engineering, Construction (AEC) is based on the exchange of 2D drawings and documents. Although the different disciplines use 3D models for development, design, and visualization, the collaboration between them has developed especially in 2D. Traditionally used CAD tools have some significant limitations such as the separation between the design and the information associated with it.

The creation of a common portal, a source of information, reduces exchange times and costs because it makes an easy collaboration between team members who can draw from a single source. In the traditional information sharing, each subject exchanges data with all the other subjects involved causing inevitable information losses (Fig. 3.1).

The structured use of a data-sharing environment requires rigorous discipline on the part of all members of the design team, in terms of adherence to agreed approaches and procedures, differently from what happens for more traditional procedures (Fig. 3.2).

**Fig. 3.1** Traditional approach versus ideal BIM-CDE

The BIM design was born as an evolution of the process that starts from the design of the 2D paper, to 2D and 3D CAD systems, parametric modelling up to digital modelling in a collaborative 3D environment. The BIM methodology in fact, in addition to requiring the use of specific modelling technologies for the various dimensions, must follow a flow of information that follows well-defined rules and standards.

The main CDE standards are:

#### *3.1.3 Practice Applications BIME4EEB–BMS*

The DBMSs (Data Base Management Systems) have been created to make a coherence between the independent data and created by different applications. However, this improvement in data management has led to the emergence of independent databases originating from individual organizations that do not talk to each other. The situation remains devoid of a unified vision where data from different databases

**Fig. 3.3** Independent files versus integrated database+DBMS

can communicate quickly and strategically, bringing the process to a higher level (Fig. 3.3).

The ACDat is information content represented by data and data structures (files or containers). Despite wanting to distinguish itself from a file and file sharing system and from a document manager it performs the same function. In general, they are relational databases, but there are ACDat prototypes based on non-relational DBs. The main objective of the ACDat is to guarantee over time the digital sharing of the data created by the various subjects that collaborate in the construction process.

Originally the use was based on the sharing of graphic models (generated by BIM authoring software) within the design team elaborated by the various disciplines: architectural, structural, plant engineering, mechanical, hydraulic, electrical, etc.

"Issues relating to the coordination of (graphic) files, federation of models, verification of geometrical interferences (clash detection), processing of files at the same time by more operators, etc. (see BIM Plus, Trimble Connect, Collaboration for Revit, BIM 360 Team, BIMX, etc.)." (Daniotti et al. 2020).

Today there are platforms that have generated or are evolving into real ACDats /CDEs in which the original function is added to the management of data, files, and documents of various origins; moreover, the coordination will not only be of 3D models but also of time management (4D), costs (5D), maintenance (6D), etc.

Every time a new job is opened, the organization creates a new CDE. The various CDEs (of the various orders) are organised in a collaborative platform. The client is always responsible for the CDE as the owner of the results of the order (Appointing Client, Owner). The designated subjects, who will intervene in the job, interact directly in the CDE. The designated parties and the Lead Appointed parties operate in their own WIP and make their own models and documents available to the other parties. The appointed party approves the documents located in the WIP space and makes them visible in the conditional space for the coordination of all parties. Once the coordination is concluded, the appointed party authorizes the publication (models and documents can be reused by others), and for the appointed party they are ready to be deposited in the Appointing party's CDE.

#### 3 Development of BIM Management System 35

**Fig. 3.4** CDE flow

"Therefore, the CDE managed by the Appointing Party receives the definitive data coordinated in advance between the Appointed parties in the Lead Appointed Party's CDE. The entry of the Appointed parties' coordinated data in the CDE job order takes place in the Sharing environment, it assumes value of deposit for the client, and is always subject to the client's approval and verification. The CDE data—coordinated, approved and verified, upon the client's prior authorization—can therefore be shared with third parties (Publishing) or in conclusion archived (Archive) for their following possible mining, should they be re-processed" (Daniotti et al. 2020) (Fig. 3.4).

The main scope of the BIM4EEB BMS is the development, starting from a Common Data Environment, a management platform able to collect and manage the amount of data useful for BIM4EEB project. Such a platform should be open, interoperable and provided of a specific toolkit to optimise the management of information (collection, share, update, and exchange) during the different stages of a BIM-based renovation process. This for making it more efficient with respect to traditional processes. The open and interoperable platform will be based on a BIM management system (composed of different BIM tools) allowing different stakeholders (as designers, architects, construction companies and service companies, owners, and inhabitants) to exchange data and to efficiently manage renovation works.

The BIM4EEB BIM Management System aims to be an open integrated BIMbased collaboration environment, enabling the continuous updating, enhancement, improvement, and enrichment of available models by the AEC industry stakeholders based on robust modelling guidelines that will be provided by the project, to ensure sustainability of the project developments and enhance its exploitation potential even after the end of the project.

The BIM management system will host a variety of applications to ensure timely and uninterrupted realisation of standardised renovation processes and smooth collaboration between the different stakeholders in a cost-efficient and timesaving manner.

Initially, the first one (field survey) will be accelerated thanks to a specific tool for fast mapping that apply the latest information technologies to create BIM models of existing buildings in a quick and accurate way. Then, the second one (initiation and design) will be improved thanks to a tool that support decision-making and a BIMassisted energy refurbishment assessment tool.Moreover, the third one (construction) will see a BIM-enable tool for the renovation intervention management to organise, plan and track site operations.

The BIM management system will have a set of Application Programming Interface (API) and Services specifically developed to give complete and interoperable access to the BIM4EEB project data. It will be realised as a web platform, and it will serve to all project partners to connect their tools and applications used and developed during the project.

The BIM Management System will be built around a general schema of Common Data Environment (CDE) that will store all the data and information gathered through different sources and along the whole building life cycle, acting a single source of truth (SSOT), with dedicated interfaces and capabilities that will work as a central repository enabling the data exchange with connected tools for providing better coordination among users and process phases.

Common Data Environment (CDE) with dedicated interfaces and capabilities that will work as a central repository enabling the data exchange with connected tools for providing better coordination among users and process phases. All the data will be shared and accessed with pre-established rules, traceable with historical records and revisions, and interoperable through service-based software interfaces. Building related geometry will be stored and viewed as BIM Models using an AEC industry recognized standards as ISO 16739 Industry Foundation Classes IFC.

### **3.2 Collaborative Workflow and Information Exchange Requirements**

The building renovation works, involve several stakeholders, each of them having different and specific needs in terms of information they request and produce for their activities.

To identify how the information workflow has to be organised to support at best the renovation process, it is crucial analyse the relationship among the different actors and their interactions. This becomes even more important when the process is BIM enabled: identifying the information exchange process is a must to fully exploit the potential benefit offered by the new technologies.

This section highlights the relationships and interactions over the whole process, it identifies the actors' profiles and clarifies their interaction. Some general schemes and use cases are presented to highlight how to determine the information exchange requirements and workflow.

The methodology that has been followed to define the stakeholders' profiles and the phases of the workflow they are involved in are described. Visual schemes are presented to highlight sequences and relationships among actors, tasks, phases.

The specific graphical schemes that have been designed to illustrate the relationship at each stage of the workflow, among the actors and with the tool categories are here presented and explained. 21 actors were identified in the former paragraph, using such diagrams. Each profile is accompanied by a table showing the relationship among BIM tools categories that might be involved in the process, the information flow among the actors, the performed actions.

A Use case Matrix is suggested, to establish a general method to define User profiles.

#### *3.2.1 Methodological Approach*

To achieve the goals of identifying how the information flow has to be organised to support at best the renovation process, the building renovation process has been analysed through all its stages including initiative, initiation, concept design, preliminary design, developed design, detailed design, construction, use, and end of the life cycle. The steps of the analysis are highlighted in Table 3.1.

The workflow is analysed to define the relevant stakeholders, the relevant input and output information for each possible activity, the related BIM tool available on the market, the priority level of BIM technology adoption for each action or activity. The users' profile for a BIM management system, are eventually determined in relationship to the information workflow, and required function, required BIM tool categories for each stakeholder.

A further study and analysis related to the process workflow has been carried out in order define the relationships between the different actors, how actions are connected and connect the actors and if and how BIM tools are involved in the process, according to a priority scale. The outcome has eventually produced the

**Table 3.1** Sequential methodology of the work

User profiles identification or a method to identify other User profiles following the workflow, actors involved, required actions, tools categories.

#### **3.3 The BIM Management System**

The BIM Management System (BIMMS) is a software platform designed to manage all the buildings' data and to perform as a single source of truth for the stakeholders involved in the renovation project. The platform was developed around a common data environment (CDE) used to store data coming from different sources and along the whole building life cycle. The CDE allow users, to upload, share and manage information containers and provide functionalities to visualize their properties, download, rename and manage document versions. The BIMMS' CDE manages different kind of resources and file formats, and let the user to define properties, set classifications, assign mappings with ontologies according to their role permissions and resource status. A BIM Viewer supports the 3D IFC BIM resources with functionalities to pan, rotate, zoom the models, select geometry items, and view their properties both in 3D and in a hierarchical tree view. The BIMMS' IoT middleware retrieve and save sensor measurements from a Samsung SmartThings Hub (Samsung 2020) collecting the data streaming from the devices placed in the demonstration buildings.

The measurements are stored in the BIMMS and shared, with authorization and permissions defined, to the end-user tools and applications. The BIMMS provides a SPARQL Endpoint to receive and process requests to the resources stored in the CDE using SPARQL queries. The SPARQL Endpoint is compliance with SPARQL 1.1 (W3C 2012) and allow connections to other SPARQL Endpoints to retrieve data from different repositories using the federated queries. To facilitate the visualization of the ontology relationships between classes and properties, the BIMMS implement a graph visualization of the ontologies. Finally, the developers can connect their tools to exchange data with the BIMMS using the BIMMS' REST API.

#### *3.3.1 The BIMMS Architecture*

The Common Data Environment (CDE) is the core of the BIMMS, and a service interoperability interface works as a module that enables all the functionalities to be performed like upload, view, manage versioning, sharing, and permissions management. To guarantee the access to the data, an exchange layer service has been developed working as an interface between the external applications to exchange data directly from the application.

The BIMMS database architecture is composed of two main databases, a relational database management system based on MySQL and a hybrid triple store database system based on Virtuoso.

The MySQL database is used to manage and store data for the File management, Users' management, Roles management, 3D BIM Model IFC entities, Building activities, alerts, and occupancy, Sensor's data streaming, Application errors and logs. The Virtuoso database is used to manage and store RDF data for the BIMMS resources, IFC models, sensors data, geospatial data, and the RDF data directly saved by the tools.

The BIMMS provides different functionalities that allow the users to manage all the resources, being unaware about the complex technical workflows happening in the backend.

In a typical workflow the user logs in and is authenticated as profiled account in the BIMMS and then, using the BIMMS' "New resource" functionality, he can upload files, set properties, classification, and mappings with other resources. When a new IFC resource is created, the 3D IFC model is uploaded and the BIMMS, in background, starts a batch process to parse the model and store the items in the MySQL RDBMS, and the RDB-to-RDF conversion. The process does not block the users' activities and can continue to work in the BIMMS. At the end of the conversion, the user will be notified by email about the availability of the BIM Model ready in the resource list.

The resource data is immediately available in the BIMMS' Resource list, ready to be referenced.

When the BIM Model is ready, the user can navigate through the model and view the model's element properties in the BIMMS' BIM Viewer.

The data stored in the MySQL RDBMS are also available in the Virtuoso triple store as ontological representation and stored in specific Virtuoso named graphs.

The data is then available also through the BIMMS' SPARQL endpoint.

#### *3.3.2 Data as Resource*

All the contents of the BIMMS' CDE can be considered as resources using the Resource Description Framework (RDF) specifications. A resource is an any physical or virtual entity connected to a computer system. Using the RDF, the resources can be read as a statement in the form of triples (subject-predicate-object). To describe a resource is possible to declare more triples that define the resource parameters, descriptions, and relations with other resources. In the triple, the subject denotes the resource, and the predicate expresses a relationship between the subject and the object. As an example, we can consider as resources different types of entities such as a 3D model, a building element, a user, a task, a sensor, or a document. Each resource will be referenced in the CDE by a unique identifier. This unique reference will be used to retrieve the representation of the resource and to establish links among other resources stored in BIMMS' CDE and across the Web. The RDF representation may contain links to further objects whose content—if considered relevant—can be retrieved by following the links.

The data of the BIMMS' resources, the sensors streaming, and other data stored in the MySQL database is also represented as RDF data through the Virtuoso Linked Data Views functionality (OpenLink 2018). The Virtuoso Linked Data Views is a feature of Virtuoso server that allows to generate RDF views over SQL Data using "machine-readable relations semantics via terms defined in a vocabulary or ontology" (Heward-Mills 2018). The data stored in the MySQL relational database can be available in Virtuoso database as RDF, through a mapping of the MySQL table views with terms and ontologies schemas. This configuration allows to bring all the benefits of using the two platforms and made available as Linked Data the information stored on the relational MySQL database.

The feature can be accessed through an application wizard in the Virtuoso Server that create the mapping definitions in R2RML standard language, that can generate a Quad Map Definition using an ontology based on the data headers available on the source tables and the RDF Schema vocabulary. The R2RML language is a W3C recommendation that define a language that allows to create mappings from relational databases to RDF datasets (W3C 2012). The Quad Map refers to the Virtuoso storage schema that uses quads instead of triples using a field to refer to the source application or resource (OpenLink 2018).

The ontological representation of the resources is defined using the Virtuoso Linked Data View through the R2RML mapping from MySQL logical tables to RDF. The Virtuoso's R2RML processor generate the R2RML default mapping based on the input database schema: the logical tables are mapped as rdfs: Class with the same name, the contents are mapped in data properties defined with owl: DatatypeProperty, and object properties defined with owl: ObjectProperty. The mapping generates an internal ontology that support the generation of the triples composed by a subject map and multiple predicate-object maps, that is used to map each row in the logical tables. The internal ontology is stored in Virtuoso Server and is checked with the OOPS! OntOlogy Pitfall Scanner! (Poveda-Villalón et al. 2014), the University of Manchester OWL Validator (Horridge 2009), and the Vapour Linked Data validator (CTIC 2011). The result is a Direct Mapping that is further customized to include classes and properties defined in the Digital Construction Ontologies (DiCon). The DiCon ontologies are modularised and cover the digitalized construction processes domain. The resources stored in the BIMMS are first covered by the Information ontology module, that provide classes and properties for the information content entities, information containers, designs, plans, events, and issues. The integration was done defining some classes as rdfs:subClassOf and properties as rdfs:subPropertyOf.

For the resources, the mapping uses both classes and properties of the custom ontology based on the MySQL table column headers, the Digital Construction Information ontology that "defines the representation of information content entities in construction and renovation" (Törmä 2020), and the ISO 21597-1:2020 Container ontology (ISO 2020).

For the IFC models, the mapping uses both classes and properties of the ifcOWL ontology (Pauwels 2019), the Building Topology Ontology (BOT) (Linked Building Data Community Group 2021), and the Digital Construction Entities ontology that "defines the basic classes and properties needed for the representation of construction and renovation projects" (Törmä 2020).

For the sensor's data, the mapping uses both classes and properties of the custom ontology based on the MySQL table column headers, and the Digital Construction Ontologies (DiCon) that "act as an enabler of semantic interoperability between systems in the construction and renovation domain" (Törmä 2021).

#### *3.3.3 Working with IFCs*

The BIMMS' CDE manages different kind of files that ranges from the 3D BIM models, drawings, reports, spreadsheets, to images and other kind of medias used to store the building documentation. The 3D BIM models are stored using the interoperable IFC file format. The IFC file defines an EXPRESS based entity-relationship model, consisting of several hundred entities organized into an object-based inheritance hierarchy. The structure of the IFC allows to parse the files to extract all the IFC entities, their properties and relationship and save them in the MySQL database maintaining the relationships of the original file.

Although the BIMMS store the original IFC files in the file system, the availability of the content of the IFC files stored in the database improved the speed performance to read and write IFC data, and to retrieve object data in real time to support the visualization in the BIM viewer. Moreover, the applications can define complex queries in the database and retrieve data faster than reading the IFC files on the fly. An application "IFC to Relational DB" runs as a service on the BIMMS' server, that parse asynchronously the IFC files uploaded in the Common Data Environment (CDE) and write the contents in the MySQL database. The application is scheduled and can catch the file version changes, updating the data stored in the database in near real time as the IFC files being updated. The service uses the xBIM Toolkit, a software development toolkit (SDK) that allows to read, write, and view the BIM models in the IFC format (xBIM 2020). Another application "IFC to RDF" runs as a service in the BIMMS' server, to parse the IFC files uploaded in the BIMMS' CDE and to convert them into RDF graphs. The conversion was carried out using an application that convert IFC files in RDF using ifcOWL ontology (Pauwels 2019) and the Linked Building Data (BOT) ontology (Linked Building Data Community Group 2021). The original source code of the application is made by Jyrki Oraskari, Mathias Bonduel, Kris McGlinn, Anna Wagner, Pieter Pauwels, Ville Kukkonen, Simon Steyskaland, and Joel Lehtonen, is also based on some third-party dependencies, and refers to the work of Pieter Pauwels for the main Java components like the IFCtoRDF converter (Oraskari 2020). The source code had been modified to adapt the URI to the BIMMS URI and are automated to be run asynchronously after the IFC has been uploaded in the BIMMS. Once the converted RDF files are available, are stored in the file system, available in the MySQL database as resources, and then loaded in the Virtuoso Server as RDF triples in the named linked data graph.

The BIMMS' BIM Viewer allows to view and navigate through the IFC BIM models, selecting the elements and view its properties. The BIMMS embedded the xBIM Toolkit Libraries to manage the viewing, reading, and modify the IFC files (xBIM 2020). To speed up the visualization, the IFC files are converted using the xBIM libraries in an optimized xBIM webGL format (wexBIM). The webGL format is widely used and supported as web standard to visualize 3D geometry in the web pages (Khronos 2020). As described before, an internal BIMMS' application (namely IFC-to-DB) parse and store the IFC data of the model items in the MySQL database.

The data is used to speed up the visualization of the properties in the BIM Viewer and to support the creation and editing of the IFC spatial elements like IfcZones and IfcGroups. This feature allows to edit the spatial hierarchy of a IFC model adding or modifying IfcZones and IfcGroups used to manage thermal zones for energy simulation, spatial zones for location-based activities, locations for sensors positioning, and element grouping for activities and resource management. All changes are saved in real time in the MySQL database and are available immediately in the BIM Viewer, in the IFC model when downloaded, and in the Virtuoso triple store. All functionalities to add, delete and modify IfcZones and IfcGroups are available via REST APIs for the applications (BIM4EEB 2020). The IFC hierarchy panel in the BIMMS' BIM Viewer with the IfcZones defined to group IfcSpaces for the apartment sensors setup: all IfcZones are defined using the BIMMS' APIs (Fig. 3.5).

**Fig. 3.5** The IFC hierarchy panel in the BIMMS' BIM viewer

#### *3.3.4 Working with Linked Data*

The BIMMS' "Geo Linked Data" functionality allow to define one or more positioning of a resource or a thing in the world through its latitude and longitude. This feature allows to search a resource by its location and retrieve additional information of its neighbour's geographic elements like cities, towns, buildings, hospitals, streets, factories, shops, points of interest, etc. The user can navigate in the map panning and zooming, and then clicking on a specific point on the map can define the positioning. The positioning data is defined with the Digital Construction Entities ontology (dice) developed in WP3, with dice: Location and dice: SpatialPosition and the data properties hasLongitude, hasLatitude, has Altitude, and isLocatedIn. The dice ontology is aligned with the WGS84 Geo Positioning Ontology.

The definition of the location of a resource can be done during the creation of the resource using the BIMMS' "New resource" and "New Linked Data object" functionalities. These functionalities are based on a step-by-step wizard that include a step dedicated to the GeoLinked Data. The GeoLinked Data are then available for consultation through the BIMMS' "Geo Linked Data" functionality that shows all the locations in a map with single points or clusters depending on how much locations are defined near each other. When the point is selected (clicking on it), a new panel will be shown. This panel shows a map with the results of a federated query done using the Wikidata Query Service to retrieve information about geographic elements located near the location. This feature allows to exploit the data distributed on the Web and improve the knowledge of the neighbours where the project resource is located. The query uses the wikibase service in Wikidata Query Service, passing the Latitude and Longitude of the dice: Location as center of interest that, combined with a radius (by default 1 km), will get the results shown in the map as coloured points.

This feature allows to select the points that will open a descriptive label with a few links to the main Wikidata web page where are listed all the property statements available (Fig. 3.6).

The Wikidata Query Service was chosen among others thanks to the high availability of their datasets and for the high reliability of their endpoints and servers. Unfortunately, most other interesting open data sources in the field of geospatial information that were available with their SPARQL Endpoints in the beginning of the project have their services temporarily down due to long maintenance downtime or capacity problems.

#### **3.4 The BIMMS Tool-Kit Integration**

The BIMMS REST APIs allow the connection of external tools to the BIMMS environment promoting the development of specific applications that can work in the different areas of the renovation process responding to the specific needs of the

**Fig. 3.6** Wikidata query service

stakeholders involved in the process itself. In the BIM4EEB project different tools have been developed according to this schema while the BIMMS REST APIs can be used to develop further applications after the BIM4EEB completion. This approach sees the integration of BIMMS and tools and requires the development of dedicated testing and validation activities that, on the one hand can assess the function of the single tools and, on the other hand, can test and validate the integration between tools and BIMMS guaranteeing the correct information flows between the two.

#### *3.4.1 Tools Definition and Integration with BIMMS*

As already mentioned, the BIM4EEB project sees the development of a BIMMS that allows the integration of different tools through REST APIs. The structure of the BIMMS and the integration with the dedicated tools developed in the project can be described through the following image (Fig. 3.7).

The BIM toolkit comprehend six tools integrated around the BIMMS. The tools are following listed.

The first step in the testing and validation activities consists in the identification of the main components in terms of both functionalities of the single tool and integration

#### 3 Development of BIM Management System 45

**Fig. 3.7** Overview of the BIM4EEB toolkit framework

process between tools and BIMMS with the aims of assuring that these components can fulfil the project KPIs and can work with the expected performance in real environments.

#### *3.4.2 Tools Testing and Validation*

The testing and validation activities are based on a structured methodology that contains two main components, namely the testing actions of all the tools, system, and processes of the BIMMS toolkit, and the collection of the feedback by the stakeholders for the different components of the BIMMS toolkit with the aims of identifying mitigation actions applicable for future developments of the system. The main elements of this methodology are depicted in the following image (Fig. 3.8).

According to the series of standards ISO 29119 the testing activity has been organized according to two parallel dimensions. On the one hand performance tests have been developed considering the specific time and resources constrains of each

**Fig. 3.8** Methodology structure

toolkit component. On the other hand, the so called *"use based tests"* represent a set of tests that are related to the procedure and scenario testing developed through the definition of dedicated test cases documented according to a specific shared template defined in this methodological section and used for the development of all the activities. All the tools and the BIMMS have been tested according to this structure to guarantee both the IT performance and the capability of responding to specific use-based scenarios that can simulate the foreseen uses of the tools.

The testing activities should be considered as circular ones where thanks to the results of the testing the tools are progressively improved and re-tested to reach their final version ready for the validation activities. Hence, after the development of the testing activities and the positive results of all the testing considering both the performance based and the used based ones it is possible to move to the validation activities with the stakeholders described in the following section.

#### *3.4.3 User Feedback and Improvements*

The validation activities are based on the development of structured workshops dedicated to the different components of the BIMMS toolkit. The workshops aim at collecting the feedback of the stakeholders that may use the toolkit components to understand their perception in terms of usability, improvement of the performance, collaboration, etc. according to the KPIs identified in the BIM4EEB project. Each workshop has been organized according to the specific functionalities and application of the tools presented in the workshop itself. Nevertheless, to optimize the feedback collection from the stakeholders the workshops will use a standardized questionnaire where the questions are then scaled according to the specific needs and objectives of the workshop itself.

The feedback collection is based on a liker scale to identify the agreement or not of the respondents to specific statements about the presented tools and functionalities (Fig. 3.9).

**Fig. 3.9** Linkert scale identification

**Fig. 3.10** Overview of the questionnaire results

The feedback of the user will be then used to understand if the BIM4EEB toolkit is able to answer to the needs of the involved stakeholders and to identify possible issues that should be corrected improving the toolkit itself. In the following is reported an example of the results obtained from the BIMMS workshop held in November 2021 (Fig. 3.10).

The results clearly represent that the BIMMS responds to the stakeholders' expectations showing an alignment with the majority of the proposed statements. Only four points report a disagreement (even if with a very low percentage—around 3–5%), namely:

Hance future actions can be activated to provide user guides and resources that can support the stakeholders in using the BIM4EEB toolkit mitigating the highlighted points.

#### **References**

**Open Access** This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

The images or other third party material in this chapter are included in the chapter's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

# **Chapter 4 Digital Tools for Fast Mapping of Buildings**

#### **Cecilia Maria Bolognesi, Eva-Lotta Kurkinen, and Per Andersson**

**Abstract** While the construction sector embraces digitalization, new technologies related to it are spreading benefits. The need of creating a 3D model of a building, a digital copy of something existing, is not new.Mediated by the advent of photographic and laser instrumentation, the construction of a digital model has crossed the fields of surveying with increasing accuracy and precision, imposing standards of capturing the existing first and modelling then ever higher. But while the Building Information Modelling allows a virtual representation of the existing asset enriching its geometry with precious and significant information related to its properties, advanced survey has always faced the impossibility to break the surface of the building, surveying what is inside walls, thus excluding what necessary should be contained within a BIM model. Also, BIM models do not consider the real-time component and do not report the real-time behaviour of the building. In this chapter we will investigate several technologies and instruments exploited till now for the surveying and positioning of existing buildings, plants included, and a new toolkit based on AR that, coupled with sensors and visualisation tools developed by BIM4EEB, offers many advantages when surveying the whole building.

**Keywords** Advanced survey · Digital · Augmented reality · IFC · Sensors

C. M. Bolognesi (B)

E.-L. Kurkinen RISE Research Institutes of Sweden AB, Stockholm, Sweden

P. Andersson CGI Sverige AB, Stockholm, Sweden

© The Author(s) 2022 B. Daniotti et al. (eds.), *Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings*, SpringerBriefs in Applied Sciences and Technology, https://doi.org/10.1007/978-3-031-04670-4\_4

51

Department ABC—Architecture, Built Environment and Construction Engineering, Politecnico di Milano, Milano, Italy e-mail<EMAIL_ADDRESS>
### **4.1 Surveying and Mapping the Existing**

# *4.1.1 Existing Praxis, State of the Art, Tools and Workflows for Surveying and Mapping*

The existing tools for surveying technologies are multiplying, specialising in relationship to the size of surveying objects and their visibility inside the building also. What can be precisely detected on a surface by one tool can be ignored by another; on the contrary, what is inserted inside a masonry is ignored for example by a laser scan or photogrammetric techniques. Depending on the peculiarities of each one a survey of the building could have to do with:

• Lidar technologies (Light Detection and Ranging or Laser Imaging Detection and Ranging) that allow to reconstruct three-dimensional models through the recording of single or multiple scans determining the distance of an object or surface using a laser pulse, based on the time of flight (the time it takes for the laser beam to travel to the target and reflect back) (Achille et al. 2017); the emitter generates a coded light known to the electronic sensor that strikes the object being measured. The working principle of laser light-based optical 3D measurement sensors can be briefly described as generating a pulse and analysing the signal reflected from the struck object to determine a distance measurement.

The sensor is defined as active because there is an emitter that emits encoded light, which invests the object to be measured, as opposed to photogrammetry which is passive; in fact, the camera sensor only captures light. Laser emits electromagnetic radiation, it is a wave emitter with time coherence, with same frequency and same phase.

Considering the different structure and nature of data acquired it is natural to investigate a digital database as the structure that can possibly collect them; in the AEC sector a geometrical model is the unique container and the digital replica of what we can investigate. Therefore, difficulties derived from the measurements with different tools are not the only issue; the need to match and position the measurement we are performing is the other one.

Spatial positioning of the model within a Coordinate System and an Internal Positioning System of the surveys carried out becomes a challenge.

In the case of heat cameras matching images in the geometric model can be done manually. In the case of some laser scanners the connected applications allow the automatic recording of the user's movements from one scan to another for prerecording in the field without manual intervention but the acquisition of associated images in HDR (High Dynamic Range) becomes an automatic process. However, in the case of more precise detection positioning, it may be necessary to scale down the indoor positioning with tolerances of just a few mm.

Almost all indoor positioning systems also lack external reference systems due to their nature and are anchored to temporary positioning systems that should be linked to more general systems.

The GPS geolocation system is particularly effective in open spaces but inside buildings or in heavily urbanised areas, the GPS easily loses operation, and it is necessary to play hard to find other alternatives.

Among the most used technologies for indoor positioning, we consider with different functionalities:

a 30 Hz update time. There are some limitations in the dimension of the spaces that must be related to the sensor's possibility of detection. Oculus rift uses LED markers on the headset, handles and trackers and then uses cameras to track their position. The cameras are both fitted in the headset as well as the on stands in the room. The accuracy of this system is around 3.5–12 mm but just as with the HTC vive errors increase on distance to the cameras (Weinmann 2021).

• QR codes attached to objects is the most traditional tool we can use but still one of the most accurate. A simple camera tracks objects when the QR code is attached to a fixed object as a reference point. Doing so that position will be geographically known for a camera. The orientation, angle and the position of the camera can be calculated by registering the symmetry and size of the QR-code in the image. Image recognition is used in AR-tools, allowing to anchor/position a virtual model to the real world so that they match each other.

#### *4.1.2 The Survey Process in BIM4EEB*

The whole process of BIM4EEB (Daniotti 2021), is structured around the idea of a BIM model enriched with data from different areas of data collection; the data base collects both data coming from users than related to energy needs and consumption and is located in an IFC file in the BIM Management System. However, the model used, a digital twin of the existing, must be reproduced with extreme accuracy to be able to intervene in a punctual way for the renovation process.

One of the tools developed by the project relates to the ability to systematise a variety of existing survey tools to produce a more complete and rapid mapping of buildings. The coupling of different instruments for different purposes has allowed us to realise a new tool used to deepen and speed up the survey.

Installations within walls can be easily detected by the new tool and reconstructed with augmented reality within the realised IFC model.

At this point, the following definitions should be given:

Virtual Reality (VR): VR is an immersive experience based on realistic 3D contents, sounds and other sensations to replicate a real environment or create an imaginary world that you can view through glasses.

Augmented Reality (AR): AR is a live view of a real-world environment with augmented and superimposed contents. The augmentation is achieved utilising devices like smartphones, tablets or custom headsets and dedicated apps that overlay digital contents onto the scene real environment (without interaction).

Mixed Reality (MR): MR—or hybrid reality, is the merging of real and virtual worlds to produce a new environment where physical and digital objects interact and cooperate in real-time.

In our experiment the AR overlapped to the digital model, i.e. a point cloud, is modeled and geolocated starting from the survey that the sensors have captured.

The creation of an AR-tool for fast mapping has been divided into development of a sensor stick with several functions for detecting installations inside walls to be coupled with IFC-file coming from general point clouds previously surveyed.

AR visualisation is used to give detailed information about a placed virtual object, in this case hidden pipes and cords inside the walls and materials. The data from the mapping is shaped as an IFC-file and is transferred to the BIM Management System to be used in a larger workflow for renovation processes.

The AR-tool has been developed to collect sensor data, laser scanning data and mix the data in a 3D-model environment in Hololens.

AR-tool development has been an integration work, divided into development work of sensor-stick, testing of measurement results from sensors in different environments, evaluation of testing data, decision making of methods and choice for type of sensors. The results from the work have confirmed it can be possible to show objects inside walls as electricity cables, humidity, metals, studs, know and locate the position in the building.

#### **4.2 Functionalities of a Fast-Mapping Toolkit**

#### *4.2.1 The Hardware*

The end goal of the fast-mapping toolkit is to produce an IFC-file that contains information about the building's construction, geometry, and installation. For years now, there has been a consolidated awareness that an accurate and complete 3D digitization is indispensable for various maintenance activities. In our project the IFCfile collects information from a point cloud, a sensor stick used through HoloLens 2 device (AR glasses) and a laptop (Fig. 4.1).

Using surveyed 3D data in the field can facilitate the interpretation and fruition of geometrical shapes in real-time; the opportunity to consult surveying results overlaid to real scenarios improves the building management process. Maintenance actions

could also benefit from VR/AR/MR solutions and the main idea is to apply concepts taken from Industry 4.0, where AR and MR systems are used to reduce production costs, increase efficiency, and ease working processes faster.

In the fast-mapping workflow the point cloud obtained with a TLS campaign will be visualised in HoloLens two, where Augmented elements surveyed with sensor stick are created.  They can handle and render 600,000 points inside its field of view before a noticeable frame drop. Battery life is set around 2–3 h, depending on the workload. For this reason, it would be impossible to use, visualise and interact with full-resolution 3D datasets composed of hundreds of millions or even billions of points—typical of large surveys, and this is a limit. The HoloLens 2 can recognize hand gestures, gaze and voice commands. When a user's hand approaches the field of view of the HoloLens 2, one of its depth sensors begins to monitor the user's hand.

Any laser scan can be used to create a setup that is then aligned to create the point cloud; BIM4EEB project tested three demo cases in three different residential buildings, verifying the usability of the system at the scale of an apartment. All the difficulties that can be found in a normal survey remain: the presence of visual impediments to the survey of the normal geometry of the walls, the limited size of some rooms, the presence of reflecting surfaces.

When the point cloud is done, the scan is then imported to the toolkit using a laptop running the so-called Companion App. The Companion App has been developed to prepare the point cloud to stream and to make it available to the point cloud streaming service that is also running on the laptop.

All the workflows need to be accompanied by a wi-fi connection and this may be considered another limit.

The laptop is connected to Wi-Fi to allow other devices to stream and view the point cloud in the same environment.

The point cloud is visualised inside the HoloLens and becomes a reference for creating accurate geometries manually. In order to do that the user on the HoloLens basically creates a specification of the geometry that is sent to the laptop. Another service on the laptop takes this specification and translates it to an IFC-file. The results are sent to the HoloLens device and visualised. Together with all this we have the sensor stick that is also connected to the same Wi-Fi, the HoloLens connects to the sensor stick pulling data from it, translated to the correct position relative to where the HoloLens sees the sensor stick, that creates a position sensor cloud (Fig. 4.2).

#### *4.2.2 The Companion App*

The Companion app is written in the programming language Unity and has the task of communicating with the HoloLens and sensor stick. To be able to handle big amounts of data in a Hololens2 device with limited computer resources the calculation parts of the program are put into the Companion app instead of the Hololens2 glasses. This has created a big stream of data between Hololens2 to Companion apps and it

**Fig. 4.2** The companion app prepares the point cloud to streaming and makes it available to the point cloud streaming service that is also running on the laptop. The laptop is then connected to a Wi-Fi that makes possible for other devices to stream and view

was decided to use a standalone WIFI. As already said HoloLens2 are small devices and fail in handling big point clouds; to handle big point clouds in a small device like this was created an algorithm that worked together with HoloLens2 device. The algorithm shows the position of the HoloLens2 and its direction part view into the Companion App.

The algorithm then streamed that part of the point cloud that the HoloLens2 devices just needed. By this algorithm we could use a big high density point cloud of a big building into a small device with limited resources. The Companion app has three tabs in the menu; Settings, Ifc Files and Point-Clouds.

Under settings, you set the IP addresses and ports for the HoloLens and sensor stick. You also name where (in which map) point cloud will be picked up and where IFC-files will be stored.

The point cloud and IFC-files are visualised in the Companion App. It is also possible to see where the HoloLens are. The below figure shows the Companion App when the point clouds at CGIs office in Sweden are visible. The red glasses in the left lower corner shows where the HoloLens are and in which direction it is looking (Fig. 4.3).

#### *4.2.3 The HoloLens 2 Device*

The training with the Point Cloud started with Hololens1 but shifted to HoloLens 2 as soon as we realised the new more powerful device with the new hardware had more power and features. The new interaction model was also something that was greatly appreciated, the HoloLens2 can track both hands fully which then means that we can have richer, more life-like experience. Interactions with the menu will be more natural and the need for a secondary hand controller we earlier use is no more. But as the HoloLens2 was introduced, some problems did arise, some expected and some

**Fig. 4.3** The Companion app when the point cloud at CGIs office in Sweden is visible. The red glasses show where the HoloLens is

unexpected. To be able to use them in the fast mapping they need the App "PolyTech" which is written in Unity and makes it possible to download the point cloud, run the sensor stick and create IFC-files. The menu in the PolyTech app contains; settings, point cloud, IFC-files, the sensor stick, workspace (where the IFC-objects are created) and home (Fig. 4.4).

When creating an object in the HoloLens, it's possible to choose between; 4 Point cube, 3 Point cube, Simple Cubic and Spline. Once objects are created you can

**Fig. 4.4** The home menu in the HoloLens app PolyTech

4 Digital Tools for Fast Mapping of Buildings 59

**Fig. 4.5** In the workspace it's possible to create objects. You can choose between; 4 point cube, 3 point cube, simple cube and spline

**Fig. 4.6** When creating an IFC-object, you need to choose which kind of object types it should be

change position, rotation, and size of it. When creating the objects, you also select which type it shall be. There are different options to choose between. In the figure below IFC\_BEAM is selected (Figs. 4.5, 4.6 and 4.7).

#### *4.2.4 The Sensor Stick*

The sensor stick is the tool used for the survey of hidden data; it is part of the fast-mapping toolkit together with a laser scan and the HoloLens. It is a hardware

**Fig. 4.7** Beams are created as IFC-files in the HoloLens (orange). Now they need to be tilted in the correct position so that they are behind the wall

instrument that detects through different sensors what is not visible to the naked eye. The sensor stick contains four different sensors to catch: temperature, voltage, inductance, and conductance. The temperature sensor detects the temperature at the surface of an object, of a wall, floor, or ceiling. The voltage detects electrical AC 50 Hz voltage at different depths in a construction. It is possible to change the sensitivity of the metre to find what is desired. The inductance measures the relationship between a magnetic flux and the current strength. This indicates where there might be beams in the construction. The capacitance measures the resistance in the material and can in that way among others detect moisture.

All four sensors are active at the same time and the measures are both recorded and visualised in real time by the HoloLens. When the camera at the HoloLens sees the sensor stick (which has an QR-code on its top) its position is registered. The result from the sensor stick is visualised in the HoloLens both by different collars at the point cloud and in the menu as diagrams.

The results from the sensor stick are then used to identify where beams, water pipes etc. are located. The IFC objects are then created with help of the sensor sticks results within the HoloLens. The figure below shows the result from the sensor stick as blue and orange colours. With the colour indication, the beams are then created (Fig. 4.8).

### *4.2.5 Modelling Objects in a 3D-Environment by a Unity Based AR Visualisation*

All interactions with users using a HoloLens2 is based on the users' hand moves that the camera in the HoloLens captures. After scanning with a laser scanner and **Fig. 4.8** The results from the sensor stick are visualised at the point cloud as different colours. Each sensor gives a specific colour. Here the green colours indicate where the beams are in the construction

the sensor stick you can create the 3D Ifc image of the single room and, adding one to the other of the flat and of a building. The HoloLens could then put out an Ifc building element based on the point cloud and the data from the sensor stick scan. The user is then able to choose which Ifc element to use and then put it into the area based on that kriterium. For example, the application based on the data inside the wall could automatically put out the beams inside a wall. All elements can be moved in all directions and rotated inside the application from the device.

#### *4.2.6 Main and Open Issues*

The software is working well but there seems to be some things that could make it more efficient to use after some more development. The workflow has shown that interaction between different data is possible through the interfaces we create with Ifc data even if it comes from different sources, whether laser scan or sensor stick. However, the manual recognition of different objects for the reconstruction of elements in Augmented reality in the long run can be complex and cumbersome. A possible application to further speed up the survey process could be to develop machine learning processes that would allow us to automatically recognize the most recurring parts within a building and be able to create templates of doors, windows, openings that are placed often, so we don't have to redo as much of the mapping. Also, more improvements should be directed to the positioning of the augmented elements in the walls as it seems that is not as accurate as it should be in terms of positioning.

#### **References**

**Open Access** This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

The images or other third party material in this chapter are included in the chapter's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

# **Chapter 5 Digital Tools for HVAC-Design, Operation and Efficiency Management**

#### **Teemu Vesanen, Jari Shemeikka, Kostas Tsatsakis, Brian O'Regan, Andriy Hryshchenko, Eoin O'Leidhin, and Dominic O'Sullivan**

**Abstract** The project BIM4EEB aims also to develop digital tools to support the design, procurement, installation, post-renovation operation, user feedback and profiling of building automation systems for HVAC. This helps supporting decision making, interaction with tenants and owners during the design, construction, and post-renovation operation phases. The development of the tools will be underpinned by a sound methodological approach. Work will include considerations of interoperability with Smart City technology of automation systems for HVAC. Specific objectives will be related to the development of the following software tools:

T. Vesanen (B) · J. Shemeikka

VTT Technical Research Centre of Finland Ltd., Espoo, Finland e-mail<EMAIL_ADDRESS>
K. Tsatsakis SUITE5 Data Intelligence Solutions Limited, Limassol, Cyprus

B. O'Regan · A. Hryshchenko · E. O'Leidhin · D. O'Sullivan University College Cork (UCC), Cork, Ireland

<sup>©</sup> The Author(s) 2022

B. Daniotti et al. (eds.), *Innovative Tools and Methods Using BIM for an Efficient Renovation in Buildings*, SpringerBriefs in Applied Sciences and Technology, https://doi.org/10.1007/978-3-031-04670-4\_5

**Keywords** HVAC · Decision making · User feedback · BAC

# **5.1 Constrains Checking, Performance Evaluation and Data Management in Building Renovation Processes**

In any renovation project time is an important factor, the ability to have an early indication of a building's requirements, in terms of quantities and positions, of HVAC, lighting and other equipment, can significantly reduce costs and time. In addition, performance evaluation and efficient management of data is essential to the monitoring of any project. As part of BIM4EEB, the BIMcpd Platform was developed, and it contained features to help address this.

The constraint checking module specifically focused on providing an overview of the locations of diffusers, ducting, lamps, sockets, and electrical conduits. Users were able to upload 2D images or 3D models, create zones and select products from a catalogue database. The recommended positions for diffusers, lamps and sockets were calculated, with Dijkstra's algorithm being applied after this to find the shortest path to connect these back to a central point. This offers huge potential to combine with other applications such as computational fluid dynamics (CFD), VR/AR and quantity surveying, to carry out further analysis on the recommendations (Fig. 5.1).

To ensure that the renovation process delivers the savings (energy, carbon emissions and cost reduction) data needs to be gathered, stored, processed, and analysed. In BIMcpd, two modules were used for this: (a) data management and (b) performance evaluation. Data management consisted of two options for the users, file upload or the API which was connected to the BIM Management System

**Fig. 5.1** Constraint checking module: model viewer

(BIMMS). Once uploaded/connected, the user mapped the data to the BIMcpd structured database, which ensured that the data being uploaded to the database included essential metadata (such as unit type for temperature). The structed database is core to the performance evaluation module and guaranteed that the information displayed in this tool was accurate (Fig. 5.2).

The performance evaluation tool consisted of several features and was designed with the end-user in mind. Firstly, the user did not have to choose which way to display the data, BIMcpd used an algorithmic approach to determine which way was best. Users could query the database without any experience of database querying languages by simply choosing from a series of drop-down lists. Once displayed, they could apply one of many outlier detection algorithms included in the tool to identify, and if they choose, remove them, and reload the visualisation (Fig. 5.3).

**Fig. 5.2** Performance evaluation module

**Fig. 5.3** M&V change point regression

Measurement and verification (M&V) is the industry standard for energy efficiency projects, BIMcpd contained a full-featured M&V tool, which enabled users to create a baseline (simple linear, change-point or multi-variate regression) and then once the renovation works have been completed (i.e. application of the energy conservation measures or ECMs), re-evaluate by creating a reporting period and comparing this with the baseline to determine if the expected reductions/savings were achieved.

In any M&V project, non-routine adjustments can be made, due to changes in circumstances between the baseline and reporting periods, BIMcpd contains this option also. Therefore, BIMcpd can help reduce time, costs, and maximise data use in renovation projects.

#### **5.2 BIM-Assisted Energy Refurbishment Assessment Tool**

The BIMeaser (BIM Early-Stage Energy Scenario) tool is a tool that supports the energy related decision-making process in the early design stage of the renovation process. The tool enables the assessment of several energy refurbishment design options enabling architects and engineers to provide solutions that best fit to the client requirements while optimizing the energy use and comfortable indoor climate conditions for the occupants. The intended use event of the BIMeaser is the collaborative design session, where building designers (architect, structural, HVAC, electricity) discuss about the expected energy saving measures of the renovated building.

One of the important benefits of the BIMeaser tool is the faster energy modelling compared to the traditional approach. The energy modelling time reduction is − 75% compared to the traditional manual description of the renovated building in the sophisticated energy simulation program.

### *5.2.1 The Collaboration in the Energy and Indoor Climate Design Process*

BIM4EEB BIMeaser tool enables easy build-up of the "As-is" energy and indoor climate model of the building, applying the renovation scenarios and presenting the impact of each renovation scenario. The targeted user role is "Energy expert", who is a separate consultant or a member of the design team. The simulated renovation scenario results will enrich the BIM Management (BIMMS) system content. These will be stored in RDF compatible format into the BIM Management system containing links to IFC model used in the simulation. The linking of OPR's and the BIM model in the BIM Management system enables tracking of the building energy performance during the evolution of the renovation design, which is an important part of the performance-based design approach.

**Fig. 5.4** Overview of BIMeaser data exchange

The OPR's—e.g., operational energy cost, payback time of renovation and summer thermal comfort—are an essential part of the performance-based building design process, which assumes that design selections are validated against the OPR's in each design stage before moving to a following design stage. The design team will handle the detailed technical energy selections affecting to the OPR's using the tool as part of the collaborative work (Fig. 5.4).

#### *5.2.2 Tool Operation, Outcomes, and Benefits*

The BIMeaser tool and the supporting national renovation measure database was implemented as a web application. The commercial IDA Indoor Climate and Energy 4.8 simulator was connected as a back-end solver with the help of the available API. The technology readiness level of the tool and the API-integration is TRL6.

The intended use event of the BIMeaser is the collaborative design session, where building designers (architect, structural, HVAC, electricity) discuss about the expected energy saving measures of the renovated building. The BIMeaser is connected to the BIMMS, which contain the digital model of the building to be renovated. The digital model is imported to the BIMeaser from the BIMMS. The designers agree several renovation options, which are modelled as energy scenarios by using the supporting "drag and drop" functionality in the tool. The tool contains a national database for the "ready-made" renovation measures, which support the easy application and remembers the previously added measures for further use. Also new measures can be defined into the database if none of the existing ones are suitable. The simulation can be started and after the finalisation of the energy simulations, the

**Fig. 5.5** An example of the OPR result summary in the BIMeaser tool

values of the Owners Project Requirements (OPR's) can be reviewed. Finally, the OPR's can be published back to BIMMS for further use of other services (Fig. 5.5). The main functionalities of the BIMeaser tool are:

#### **5.3 Energy-Related Behaviour Profiling Mechanism**

One of the main innovations related to building management process is the incorporation of building occupants in the overall analysis. Building occupants are the active entities on the building environment and thus a thorough analysis of this interaction should be considered in any building related decision making. In this section, we present an innovative data driven framework towards the extraction of user-centred knowledge about the building environment. More specifically, the objective is to establish an occupant's context-aware behaviour modelling engine, which will continuously monitor and learn transparently the operational and behavioural patterns (i.e., the preferences) of building occupants, while on the same time interact with the occupants in an ambient manner to define user preferences and extract comfort levels, while taking into consideration also health boundaries. In addition, the overall framework will enable the delivery of Context-Aware Energy Behaviour Profiles, reflecting occupants' energy behaviour as a function of multiple parameters, such as time, environmental context/conditions occupant comfort preferences and health/ hygienic constraints etc.

### *5.3.1 Occupancy and Behavioural Profiling Modelling Framework*

The occupancy profiling modelling framework is targeting on extracting near realtime information about occupancy presence by processing data coming from different types of sensors in the building. On the other hand, comfort profiling is defined as a non-parametric model which consider the contextual conditions and user preferences to extract dynamically updated information about users' comfort preferences. In more details, the details of the algorithmic framework towards the extraction of Occupancy and Behavioural Profiling are provided in the following.

Occupancy diversity profiles: The scope of this module is to enable the extraction of accurate occupancy profiles. To exploit the full set of data available, a twostep approach is adopted. At first, initial profiles are defined by an expert and consist of the configuration occupancy file for a building zone. Information about typical occupancy profiles is available at software libraries of professional BIM software. Then, user defined information is incorporated in the analysis. First, the end users of the building may be provided with a tool (user application) to fine tune the accuracy of profiling information. Then and if sensor data available, occupancy diversity profiles are extracted by incorporating actual measurements in the analysis. The overall workflow for the extraction of occupancy profiles is presented in the following figure (Fig. 5.6).

Comfort analytics engine: The process includes data acquisition of sensorial data from different end points. More specifically, indoor temperature, humidity etc.… data are tracked from sensorial equipment installed in building environment (Fig. 5.7). Outdoor environmental conditions can be available either via outdoor sensors installed or via weather service available in public.