Automated verification of information models for capital construction projects to mitigate environmental impact

. Digitalisation of the construction industry is changing the processes of the sector and the use of information about the elements allows various automated checks to be carried out, including checks to reduce the environmental impact of capital construction projects. The study examines ways of dealing with such information, examples of verification algorithms and a means of determining the value of verification.


Introduction
The current state of digitalisation and robotisation of investment and construction processes makes this sector of the economy inefficient in terms of energy and natural resources. The application of BIM (Building Information Management) technology is a prerequisite to improve the energy and environmental efficiency of capital construction projects (CCP).
Automated verification of the CCP information model is one of the many BIM scenarios (BIM-Uses), i.e., scenarios for using BIM technology. A particular case of the BIM automated verification scenario is the verification for the attribute component of the information model, the application of which will be considered in this study.
In the architecture, engineering and construction community, the leading standard based on the OpenBIM concept is the IFC (Industry Foundation Classes) standard developed by BuildingSMART International. IFC is an open, freely available, nonproprietary data model used for the exchange of BIM data [1]. The use of IFC for automated inspections increases the interoperability of the inspection process, i.e., it enables a flexible selection of development tools. Due to the reasons described above, IFC as a standard for the exchange of BIM data is one of the main formats chosen by public supervisory authorities. Based on this, IFC was chosen as the data model for automated inspections in the study.
The purpose of this study is to apply BIM script automated checks of the attribute component of information models in IFC format in order to minimise the impact of CCP on the environment.

Using the information model as a database
A single and consolidated CCP model in IFC format should be considered as a database of all model elements, including geometric and attribute data. Certain requirements have to be imposed on this data in order to be able to work with it easily in later stages of the CCP lifecycle. These requirements are described in the EIR (Employer's Information Requirements), often divided into LODg (Level of Development geometry) and LODi (Level of Development information) by CCP lifecycle stages. The requirements must be justified and their number must be minimally sufficient to allow a decision to be made at subsequent stages of the CCP lifecycle.

IFC element attribute data
According to the latest and official (at the time of writing this article) IFC4 ADD2 TC1 specification (hereinafter IFC specification), freely available on the BuildingSMART International technical website, there are three main groups of attribute information: Attribute, Property Sets, and Quantity Sets.
The attribute group contains IFC element attributes, among which there are mandatory attributes described in the IFC specification (they are numbered sequentially in the corresponding specification table), and user attributes. Examples of attributes are PredefinedType (mandatory attribute for most elements in the IFC specification), Brand (custom attribute) and Name (custom attribute).
The Property Sets group contains sets (groups) of properties consisting of several attributes related to the information characteristics of an IFC element. The IFC specification offers specific attribute sets, and custom attribute sets are also possible. Examples of Property Sets: Pset_WallCommon (Common Attribute Sets inherent to most IFC elements), Pset_ConcreteElementGeneral and MGE_ExpCheck (Custom Attribute Set). Examples of attributes within the set: AcousticRating, FireRating and MGE_Code (custom attribute of Moscow State Expertise).
In the Quantity Sets group, similarly to Property Sets, the property sets related to the calculated characteristics of the IFC element are arranged. Examples of Quantity Sets: Qto_WallBaseQuantities and Qto_SlabBaseQuantities. Examples of attributes within a set: Width*, NetVolume and GrossWeight.
To minimise the impact of CCP on ecology, a prerequisite is to require the existence of ecology-relevant attributes in the EIR. That is, it should primarily be the client's interest to compile the EIR for all participants in the investment and construction activities at all stages of the CCP lifecycle. Based on the four sets of attributes described above and suggested by the IFC specification, automated checks can be performed. Additional sets of attributes may be added by the EIR compiler if the attributes described in the IFC specification are insufficient.

Automated verification
To achieve maximum efficiency in the digitalisation of the IFC model's processes, it is necessary to define a list of almost unlimited possible automated verifications for the initiator. In order to achieve maximum efficiency in the digitalisation of the processes of investment and construction activities, it is necessary to select a certain list from the almost unlimited number of possible automated checks of the IFC model and sort it according to the value of the check for the initiator.
Sorting out the automated checks is a prerequisite for efficient use of human resources, which entails increased productivity and targeted use of financial resources allocated for digitalisation of investment and construction activities.
The sorting of the verification value is proposed as the V parameter decreases (Equations 1).
here: is a dimensionless value indicating the value of automated verification; defines direct impact of the factor under verification on the environment, indicates how long it takes for the environmental system to return to its original state from which it can be removed directly by the factor under verification, measured in hours; defines indirect effect of the factor being checked on the environment, indicates how long it takes for the environmental system to return to its original state from which it can be removed by the factor being checked indirectly, measured in hours; labour input to implement the automated verification algorithm, determined by the BIM analyst, measured in hours; the labour involved in adapting an already created automated check to a new EIR or other new conditions, determined by the BIM analyst, measured in hours.
Sorting the automated verifications by parameter V will help to establish the order in which they are implemented, depending on their direct and indirect environmental impacts, and the labour involved in creating and adapting them. The value of the result of the automated checks at the top of the list will be greater than the value of the results of the automated checks at the bottom of the list.
The number of automated checks that are carried out to reduce the environmental impact of a CCP should be determined by the EIR compiler, based on its need for the results of the checks, to make certain decisions at all stages of the CCP life cycle.
The following are examples of automated verification algorithms that are examples of the use of the IFC model as a database of IFC elements.

Data validation
In order to perform the check of interest, the data must first be validated in the IFC model. Without data validation, no further validation is meaningful, as it may either fail or the results will be irrelevant. Figure 1 shows the validation algorithm.
Validation consists of 4 conditions and 2 possible algorithm outcomes. The first of the possible outcomes implies a positive result in all 4 conditions, so validation verification is considered passed and the model is ready for the main check. The second possible outcome means a negative result in at least one of the conditions, so the validation check fails and the model is returned to the creator for revision.
The data validation check must be run before each automatic check. V-parameter for the validation check is not calculated.

Automated environmental screening of CCP elements for inert waste during the design phase
The design phase is where most of the information in the IFC model of the CCP is filled in. This includes information about the building elements, materials and technologies used.
One of the attributes used to improve sustainability is InnertWaste, which refers to Pset_EnvironmentalImpactValues. This attribute reflects the amount of inert waste generated by an IFC element. By analysing this parameter in multiple design solutions, it is possible to select the one that will generate the least amount of inert waste. Figure 2 shows the algorithm for finding the minimum InnertWaste value. The number of design options will vary from case to case, as it depends on the specific conditions of a particular CCP and the capabilities and professionalism of the design engineers.

Automated verification of water consumption during operational phase
Automated checks can be supplemented by data from smart home devices, such as water meters. Figure 3 shows the algorithm for an automated water consumption check. The value of this check is in the rational use of water resources during the operational phase of the CCP. An indirect environmental impact in this case is the energy cost of transporting and processing the water resources.

Discussion
Presenting the information model as a database of CCP elements allows for automated checks to reduce the impact of CCPs on the environment. The acronym BIM as Building Information Management more accurately reflects the essence of digitalisation of investment and construction activities, as it reveals the essence of working with the information embedded in the model. Automated checks of the attributive component directly show the possibilities of such work with information for various purposes, including environmental ones.