As-Built Construction Assets: Key to Future Planning and Facilities Management

Preparing ‘as-built’ drawings and models is certainly one of the most crucial requirements of any design-build project. These final set of construction assets validates how the contractor built the structure including all the changes and modifications that were made in the process. The finalised drawings and models are passed on from the contractors to the building owners and property managers.

The set of as-built drawings and models, though underestimated and neglected, broadly serve a dual purpose. Firstly, the as-built drawings and models act as a guidebook to the AEC (architecture, engineering, and construction) firms that are contracted for renovation and refurbishment of an existing structure. So, the time, cost, and resources that would have been utilised during pre-renovation survey are saved. Secondly, they help owners and facilities managers to conveniently undertake maintenance and refurbishment activities besides helping them during emergency situations e.g. for rapid evacuation.

Whereas data-rich as-built 3D building information models have obvious benefits over 2D drawing sets, the decision to choose one over the other mainly involves factors, such as the scale of the project, owner’s preference, and the design-build teaming structure. The owners of relatively small building projects may prefer 2D as-built drawings of an existing building, prepared by a technician after collecting accurate data on site. On the contrary, large-scale design-build and renovation projects may require BIM-driven as-built 3D models.

Assuming that the project in question has not had a BIM model for the design process which is then updated during the as-built stage of the project, there are two typical ways of preparing as-built BIM models. Firstly, using the as-built drawings and other construction drawing sets as the starting point, 3D BIM models can be prepared using applications such as Autodesk Revit. The second method involves the Scan to BIM technique where   point cloud data of the structures. This point cloud data is then converted into an intelligent BIM model using tools such as Cloudworx and Scan to BIM applications such as Revit.

The as-built drawings and BIM models serve as a comprehensive reference tool for owners and property managers. They benefit from these as-built drawings and models in the following ways:-

·     The finalised as-built construction assets make future project planning, including renovations, extensions, and redevelopments, convenient and cost effective for the owners.

·     Since the as-built drawings and BIM models contain complete details related to dimensions, fabrication, erection, elevations, sizing, materials, location, and mechanical/electrical/plumbing utilities, the owners can use this data and conveniently manage facilities within budget.

·     The owners can use these as-built assets to resolve disputes regarding insurance claims. In case of a massive loss due to extreme disasters, the insurance company will require extensive documentation, including the as-built drawings and models to support your claims.

As the as-built drawings and models are prepared by combining the drawings/models of all the building services, the owners and property managers can schedule maintenance operations of the building’s MEP (M&E) systems in a timely manner.

Issues Affecting The Adoption of 3D BIM Modelling

Issues including cost and time overruns, material wastage, and process inefficiency have marred the architecture, engineering, and construction (AEC) industry worldwide. Whilst the reasons behind this may differ from project to project, lack of interdisciplinary coordination amongst the designers, the building services engineers, and the contractors is the most common of all. Considering these unfavourable project outcomes, there is a significant push from the governments, mainly in developed nations, to accelerate or mandate the adoption of 3D BIM modelling in varying levels for government-funded projects.

Whilst parametric modeling tools such as BIM technology is being increasingly used for government projects private construction projects are also seeing the benefits with many employing  forward-looking AEC firms that have already transitioned to using information-embedded Revit 3D models for design as well as construction stages. Although moving from traditional CAD-based design processes to modern BIM-enabled workflows is essential to eliminate design/coordination clashes and maximise project efficiency, there are some key inhibitions and apprehensions to what is a paradigm shift for the industry.

Firstly, many AEC firms have long been using the traditional 2D as well as non-BIM 3D CAD workflow for pre-construction 3D planning and are highly resistant to change their current conventional processes. More often than not, such firms are completely apprehensive of embracing new technology or are slow adopters of new technology and decide to change only if requested by clients or if they are part of a framework agreement requiring adoption of such technology.

 Another factor that pushes potential BIM implementers back is the steep learning curve of its tools and their real-life applications specific to disciplines, such as architecture, MEP engineering, and structural engineering. One common concern is training CAD technicians, who are familiar with drafting tools such as AutoCAD, and BIM and clash detection applications, such as Autodesk Revit and Navisworks.

The biggest impeding factor to BIM implementation is the perception amongst certain groups that current projects during the BIM transition period, will suffer. As BIM adoption is much more than just software training, it requires an overall change in the way a building project is conceptualised, designed, constructed, and maintained. Whilst the traditional design methods required CAD managers with a team of CAD technicians, the modern BIM-based projects require BIM managers who liaise with discipline-specific representatives to map out the level of details (LOD) or BIM Phases required by the client, worksharing protocols/processes, and assess the adherence to interoperability and information-exchange standards.

Furthermore, there is a widespread opinion amongst the AEC fraternity that whilst adopting a full-fledged 3D BIM modelling for the entire lifecycle of a building drives cost, time, and energy performance efficiencies, tremendous effort goes into preparing custom detailed content to client’s specifications. This group believes that whilst the generic libraries can be used for design and clash detection, accurately detailed models are needed to optimally use BIM for aspects, such as cost estimation, time scheduling, and quantity take-offs.

The requirement for BIM adoption also requires a level of interaction along the design and contracting teams that is not usual and has certainly been accelerated with the use of BIM practices.  Clearly defining BIM scope and requirements between the parties involved is already becoming a challenge, especially for the MEP sector where designers and trade contractors have traditionally handled conceptual design and detailed design individually.  The overlap in conceptual design and detailed design is becoming the type of challenge that MEP trades and MEP designers are getting used to resolving as part of BIM adoption.

Collectively these issues pose a challenge and sometimes cause the apprehension involved for BIM project take up, something that we observe will change with continued demand for intelligent building design.

Crucial Developments in 3D Building Services Design and Coordination Field

Building services projects have benefited from many developments that have occurred in the last decade. Whether in the areas of MEP (M&E) systems design, 3D building services coordination, or interdisciplinary collaboration, the major advances seen in this field have emanated both from within the industry as well as from other sources, such as government regulations and economic developments.

•  Intelligent BIM Software for Planning and Design of Projects

One of the biggest changes in the modern building services industry is the use of intelligent building information modelling (BIM) software tools that allow for the creation of accurate and detailed representations of mechanical, electrical, plumbing, and fire protection systems using computable data. The fact that there are BIM tools more intelligent than ever and also which work across disciplines, such as architecture, structural engineering, and building services engineering, increases interdisciplinary coordination and reduces construction waste and rework.

For instance, the BIM models created using Autodesk Revit Architecture and Revit MEP can be used by building service designers for developing concept designs, schematics, and tender drawings. The same parametric model can be worked upon and used by contractors to create detailed installation and 3D MEP (M&E) coordinated drawings, including services-specific as well as multi-service coordinated plans, sections, and elevations. Furthermore, fabricators and installers can use the BIM model in conjunction with FAB MEP, a fabrication tool, to manufacture pre-assembled modules for installation on-site.

Not only does BIM allow creation of a coordinated 3D model, it also allows for information to be added to the model that can be used for project-critical purposes, including schedule creation, cost estimation, energy analysis and facilities management.

• Greater Interdisciplinary Collaboration

Due to the growing adoption of BIM tools industry-wide complemented by the availability of sophisticated hardware systems and online collaboration channels, there is a far greater degree of interdisciplinary coordination between different stakeholders involved in AEC projects. As a result, architects, structural engineers, MEP consultants, MEP engineers, main contractors (general contractors), cost estimators, and fabricators can seamlessly collaborate during the design and planning stages and avoid costly rework during the construction stages.

For instance, large-scale construction projects generally have a complicated project structure comprising diverse project teams based in different geographical areas. During the pre-construction stage, sharing and interlinking the BIM model prepared by architects, structural engineers, MEP specialists and contractors enables respective designs to stay coordinated. Due to cloud-based collaboration tools, team members can hold review sessions online without having to be physically present together.

•   Higher Degree of Pre-Fabrication and Just-In-Time Delivery for Installation

With the widespread use of parametric modelling techniques in MEP design and planning, a major trend is to use BIM models for pre-fabrication purposes with a view to enhance the logistical cycle on the construction site. When used in conjunction with CNC fabrication applications, such as FAB-MEP, the BIM design data can be used to create fabrication drawings that can be recognised by CNC machines. Such a BIM-led prefabrication can streamline the installation process on site and avoid costly miscalculations.

Taking into account the complexities of the MEP (M&E) systems industry, BIM-driven prefabrication and modularisation has led to multifaceted benefits: reduced rework, in-time project completion, cost savings and increased efficiency.

• Government Intervention 

Another critical development from outside the industry is the government policies in different parts of the world either promoting or mandating the use of BIM in varying levels for government-funded or private projects. In the US, the General Services Administration (GSA), through its Public Buildings Service (PBS) Office of Chief Architect (OCA), established the National 3D-4D-BIM Program in 2003. GSA mandated the use of spatial program BIMs as the minimum requirements for submission to OCA for Final Concept approvals of all major projects receiving design funding in 2007 and beyond.

In Europe, the UK Government has made Level 2 BIM compulsory for all publicly-funded projects from 2016 onwards with a view to trim the cost of public-funded projects and to reduce carbon emission to meet its EU commitments. Government agencies from the Scandinavian nations have played an important role. Senate Properties, Finland’s state property services agency, required the use of BIM for its projects since 2007. Neighbouring Norway and Denmark have also made sufficient headway towards adopting BIM practises in their public-funded projects. Statsbygg, the Norwegian government agency that manages public properties, including heritage sites, campuses, office buildings and other buildings, employed BIM in all its projects by 2010.

In Asia, Singapore was in the forefront of driving the adoption of BIM. After implementing the world’s first BIM electronic submission (e-submission) system for building approvals, the Building and Construction Authority (BCA) mapped the BIM Roadmap with the aim to adopt BIM for 80% of construction projects by 2015. In Hong Kong, the Housing Authority (HA) not only developed a set of modelling standards and guidelines for BIM implementation but also stated its intent to apply BIM to all its new projects by 2014-15. South Korea’s Public Procurement Service, which reviews designs of construction projects and provides construction management services for public institutions, has made BIM mandatory for all projects worth more than S$50 million and for all public sector projects by 2016.