Lean v traditional construction processes
Khaleel Ahmed, Lecturer, Dudley College of Technology
THIS article focuses on lean processes and how these could help yield productivity and efficiency on construction projects. Although, other sectors such as health have benefitted from such adoption; there appears to be some level of resistance its adoption within the architecture, engineering and construction (AEC) sector. Some of the issues faced within AEC have are discussed as example observations and alternative lean approaches.
Issues
The fist observation is where a company’s focus is primarily over short-term gains. For example, this can be reflected by health and safety incidents on a site. This can be caused by poor communication/ collaboration and fatigued staff where a lack of detail could correlate with long working hours causing tiredness. This has a direct impact on the employees’ reaction to site-based hazards. A master plan may not be addressing the training and safety of employees working on site due to experience gaps. This could be in contrast to a company’s philosophy of improvement of safety of staff and accelerated turnaround times.
If the current master plan is generic it fails to reflect needs on key elements such as staff training, software development/ requirements, relevant site-speci fic procedures. These can be asbestos survey requirements, equipment requirements including purchase, rentals and servicing, selection of staff including apprentices and most importantly the availability of existing site information and data.
The training needs could be poorly identified with key stress on meeting deadlines only. As these incidents may not have been properly investigated with no lessons learnt, it results in more delays on site due to unsafe activities.
Employees/apprentices working on a site may represent countries with different cultural backgrounds and hence different level of communication skills. If these gaps/training needs are not accounted for, these might result in poorer collaboration and communication between different team members.
These shortcomings within the master plan can lead to non-value adding activities on site. According to Liker (2020), the processes are supposed to dynamic and not static, and these should be improved through lessons learned from previous experiences. Koskela (1992) has also attributed such non-value adding activities to waste, which do not add value for the end client.
As Ohno neither defines waste exactly nor does he offer any theoretical views on seven types of waste, the concept of the waste can be widened to include events which result in non-value adding activities (Tzortzopoulos, Kagioglou and Koskela 2020).
Alternative approach and target process
Based on above findings, an alternative master plan can be based on lean construction approaches using visual management and big room planning. Visual management could significantly improve the highlighted problems by implementing, for example:
- Use of different colour helmets for apprentices/newer staff for easy identification of less experienced staff.
- The use of dedicated noticeboard(s) and/or digital screens to display current activities and associated paperwork e.g., permit to work.
- Display of sign boards/posts signposting to mandatory (wearing ear defenders), prohibitive (no drugs), caution (risk of electrocution) and safe (fire assembly point) signs.
- Use of NAVISWORKS could also help detect clashes within design and hence mitigating various risks on site. The use of mixed reality hardware such as Trimble XR10 could also be an excellent example of this visual approach. As multiple teams could be involved on a typical project, the use of XR10 will allow field team to report back any issues directly from field, which can be supplemented by video or images. This will result in better collaboration between different teams.
- Mercury Engineering has implemented the same approach in one of its 7000m2 construction sites in Europe. Some of the key benefits found were the ability to communicate with videos, clash detection and better tracking of site issues (KOREC, 2020).
Big room planning will also prove to be an effective approach by:
- Ensuring the site personnel are competent; such as having the necessary certifications and competence (CSCS card) before allowing work to start. This can be implemented by organising regular training on site and installing technology at sites entrances which could automatically retrieve workers’ competence before allowing them to proceed. Site office (big room) will also be useful in ensuring presence of key stake holders before activity commences (toolbox talks, briefings).
- By implementing administrative controls (travel time plus site work not to exceed 12 hours) and site specific/ mandatory trainings on diversity and inclusion, communication protocols and reporting of safe/unsafe acts. This might require fitting tracking devices to company’s vehicles and introducing testing on more hazardous sites (alcohol and drugs testing).
Above points fit well with part 3 (people) of the 4P model (Liker, 2020).
Lowest price
Where work has been procured for the lowest price, this could compromise quality and timely delivery. As a result, unnecessary methods could be chosen with the wrong scope. Delays caused can result in small share of weekly activity targets being met. The choice of wrong scope could lead to a rush in the delivery of deliverables without the appropriate data quality checks. A reduced scope of work could still meet the client’s expectations and hence delivering the end products on time and within budget.
These delays/issues can affect the progress of other connected activities. For example, a contractor employed to install fibre cable and water pipes may have to wait before starting excavations causing disruption to traffic and other activities on-site. These issues are another example of waste (muda). In principle 2, Liker (2020) talked about one-piece- flow within Toyota Production System (TPS) and considers blockages to flow as being all waste.
He also discusses how pure value can be delivered to end client by avoiding interruptions and reworks. Toyota has categorised waste into seven categories, which contribute to non-value adding activities. By making small modifications, these categories can be applied to other office processes too (Liker, 2020).
These observations of delays in key information and poor collaboration can be easily related to waste of waiting from this list of seven categories. As these problems result in non-value activities, this waste can also be linked to taxonomy of waste based on transformation- flow-value. This taxonomy of waste has been proposed by Bolviken, Rooke and Koskela (2014).
Alternative approach and target process
A target-value-design approach will help by collaborating with the client on the priorities and agreeing the deliverables/accuracy. For a large infrastructure project, capturing and agreeing information to BIM standards will prove to be more cost effective. A focus on client requirements and quoting for the appropriate survey type for the area will also benefit. Adopt a holistic approach to understand what is already present on site by referring to existing drawings/information and then agreeing relevant survey type(s) for different areas of the site.
A target-value-design approach will help by collaborating with the client on the priorities and agreeing the deliverables/ accuracy.The deliverables could be BIM compatible models, which can be shared/collaborated with other team members using relevant hardware/software. By using a BIM platform such as Trimble Quadri, it is possible to combine data from utility companies with the site design (Trimble Sitevision, 2020). This is an example where visual management can be used effectively along with display of relevant drawings.
A big planner approach is equally beneficial where the practitioner, client and other relevant team leaders can meet to discuss the survey progress and any issues/constraints e.g., access can be discussed. Big planner will also be helpful in setting relevant target time frames for various project stages e.g., 28 days for desktop search where the utility practitioner will need to obtain existing drawings of the area.
One-piece flow
Liker (2020) discussed the benefits of one-piece flow in principle 2, where he links higher productivity to appropriate utilisation of equipment and people. He has also discussed the application of continuous flow and talk time and argues how this concept can be extended to any repeatable process in which non-value activities can be mitigated or removed to create a better flow.
The ability to convey/display complex information on movements using charts and graphs and the ability to create visual and/or audio warnings without having to configure the system/ databases are excellent examples of visual management where relevant information is shown in visual format only instead of complex data e.g., angular readings, tilt values etc.
The use of digital screens in site offices (big room) and by automating the process via cellular control, companies can make steps towards lean implementation and the adoption of TPS principles. Liker (2020) has discussed various case studies in principle 8 where automation and real time data feed has helped companies like Drishti develop strong lean systems.
Adoption of BIM to reduce/mitigate site waste
The adoption of BIM will assist in better understanding of complex projects and if the design is made available at a suitable BIM level, better estimates for pricing could be created as BIM should allow to extract quantities. This would also be helpful in minimising a company’s dependence on predictions (RICS, 2014). By using relevant standards such as ISO 15926, designer/ architects can make use of the large sets of available libraries in the design process and subsequently provide the model earlier for procurement purposes (Nawari and Kuenstle, 2015).
Liker (2020) has talked about just-in-time (pull) approach in principle 3 which recommends procuring items when they are needed instead of current approach of obtaining items at a cheaper price causing waste (push).
Adoption of BIM will also ensure that all parties have access to the same coordinated design, which would restrict the company’s tendering analysis to comparative rates, overheads and other costs (RICS, 2014).
This can result in a more collaborative approach within office meetings, which is a good example of last planner as well as visual management.
Another advantage is that spatial conflicts between different design objects can be found by running automated detection facility such as within NAVISWORKS. This method would allow contractors to identify objects within same space (hard clashes) or objects which are very close to each other (soft clashes) and hence finding and rectifying the defects before the work starts (Eastman et al., 2018).
Similarly, the issue of cost for rectifying the issues after the handover can be mitigated/eliminated by implementing COBie within BIM environment. By embedding COBie framework, information can easily be retrieved about different elements at a later stage, which would be very helpful in operation and maintenance of assets (Eastman et al., 2018).
This is an excellent example of a target-value-delivery (TVD) approach, where cost can be used as a driver for design and hence constraining the construction of a facility to a maximum cost (Tzortzopoulos, Kagioglou and Koskela, 2020). Zimina, Ballard and Pasquire are of the opinion that TVD is an effective management technique for predicting cost and accomplishing tasks with financial returns (Tzortzopoulos, Kagioglou and Koskela, 2020).
As fabrication of materials also happen on site, it is recommend to use prefabricated components and then implementing lean tools such VisiLean. By using VisiLean, it will become possible to track individual shipments.
By integrating VisiLean with BIM, defects can be reduced, and costs can be minimised by improving the effectiveness of weekly meetings. As the project information and design can be readily available, this can result in a more collaborative approach within office meetings, which is a good example of last planner as well as visual management. VisiLean has been successfully implemented and documented for a construction project in Finland (Tzortzopoulos, Kagioglou and Koskela, 2020).
The integration of unmanned air vehicles (UAVs) for construction sites can prove cost effective and reduce waste due to transportation, unnecessary movement, and excess inventory. Regular use of UAV will not only allow to do cut/fill calculation much faster than a conventional surveying method (GNSS or total station), but the maps created can also be overlaid on the existing drawing to check work progress.
This can be shown using digital displays alongside VisiLean. By using a mobile app, various team members can collaborate more effectively and fulfil their commitments.
The use of Internet of Things (IoT) devices can also be useful in the maintenance/running of the building and can help with predictive maintenance by gathering and analysis information from various sensors e.g., peaks times for lift use.
Khaleel Ahmed, Lecturer, Dudley College of Technology
Bibliography
Eastman, C, Teicholz, P, Sacks, R, & Lee, G (2018) BIM Handbook: A Guide to Building Information Modeling for Owners, Designers, Engineers, Contractors, and Facility Managers. 3rd edn. Newark: John Wiley & Sons, Incorporated.
KOREC (2020) Adopting Mixed Reality - Three clear benefits underline how the Trimble XR10 is delivering for Mercury Engineering. Available at www.korecgroup.com/wp-content/uploads/2022/07/Casestudy-Mercuryweb.pdf (Accessed: 11 March 2024).
Koskela, l. (1992) Application of the New Production Philosophy to Construction. Centre for Integrated Facility Engineering, Department of Civil Engineering, Stanford University. Technical Report number:72.
Liker. (2020) The Toyota Way, Second Edition: 14 Management Principles from the World’s Greatest Manufacturer. 2nd Edition. New York: McGraw-Hill.
Nawari, NO, & Kuenstle, M (2015) Building Information Modelling: Framework for Structural Design. London: Taylor & Francis Group.
RICS (2014) Tendering strategies. London: The Royal Institution of Chartered Surveyors (RICS).
Tzortzopoulos, P., Kagioglou, M., & Koskela, L. (Eds.). (2020) Lean construction: Core concepts and new frontiers. Oxon: CRC Press LLC.