Designing MEP systems intelligently in 3D
How to reduce the risk of errors when engineering, designing and constructing buildings? Engineering company Zeisig shows how to do it by applying a precise, cross-discipline MEP design method to a new residential building in the St. Johannis district in Nuremberg, Germany. Using the example of the challenging static piping system, practical solutions from digital MEP engineering are being presented.
Text: Felix Berthold, M.A.
The district of St. Johannis is located at the north-western city entrance of Nuremberg. By 2017, the company wbg Nürnberg GmbH will create modern living spaces at an estimated cost of 20.3 million Euro. For a long time, the respective land lot has only been used for subordinate buildings, such as garages. The engineering company Zeisig (ibz) was in charge of engineering the complete building services for this project, which also included the CAD-supported design of a very demanding static piping system. The engineers at ibz used Data Design System’s modern BIM solution DDS-CAD to design the MEP systems. The project started in 2014, tendering and construction plans were completed by the end of 2015.
Once completed, the building will serve as a perimeter block, integrated into the settlement structure of St. Johannis. It comprises five interconnected building units with a complex architecture, including underground parking facilities. The building is designed by Blauwerk architects from Munich. The project includes a total of 74 residential units (of which 18 are subsidized), rooms for a two-tiered children’s day-care center with open spaces as well as two business units. The total land area is 7.157 square meters.
Identifying and solving clashes between other disciplines
The complex building structure and its refined architecture were a particular challenge, even for ibz’s experienced engineers. “Within the already exhausted static system, there were virtually no reserves,” recalls Managing Director Sebastian Zeisig. The entire piping network for potable water, heating and wastewater had to be designed in such detail, that all information on the structural construction needed to be available in their MEP engineering software.
Thanks to an integrated design approach of all disciplines, collision points could be detected more easily in order to find ideal solutions. DDS-CAD provided the possibility to model the complete design and dimensioning of the pipe and wastewater network in both 2D and 3D.
The importance is shown by the underground car park, explains Zeisig. Because of its many projections and joists as well as different heights, the construction effort was especially high. Each structural penetration was to be considered during the design process. Due to the wastewater pipes and the roof drainage, several collision areas with other mediums (e.g. electrical) occurred. When planning the wastewater pipes, not only the necessary slope had to be taken into account, but also the minimum clearance heights in the underground car park were relevant parameters. Thanks to the 3D design and collision detection features of DDS-CAD, these critical points were easily identified and solved.
This also applied to collision points of floor constructions, connections to kitchen areas, sinks, bathrooms, guest bathrooms and so on. Everything that was being laid across the slab floor had to be designed accurately, since there were no reserves for chiseling in the ceilings. On top of this, there were numerous crossovers between the electrical and heating systems.
The complete bathroom installation was also modeled with DDS-CAD. The bathrooms and their connections were designed inside room-high facing formwork. This way, all eventual projections could be considered. Peculiarities were the additional intersections with the exhaust air system, which is routed across the roof.
The integrated heat load calculation is directly based on the 3D model of the building. This allowed a ‘clean’ calculation of all available rooms in order to automatically assign the required radiator sizes and plan the radiator design in all detail. The heat is supplied via a district heating connection.
The design services from ibz, now counting 18 employees, cover the entire range of services of a MEP engineering company. “In this project, the integrative design approach is particularly important,” Zeisig emphasizes. “The employee who was responsible for the electrical part could visualize the other disciplines in the software at any time.” This enabled him, for example, to check the exact heights of cable routes, in order to rule out possible collisions beforehand.
Comprehensively engineered is half built
BIM engineering tools are becoming more and more popular in the industry, but there are still reservations, especially regarding the initial increase of design effort. But, what is BIM in the first place? BIM (Building Information Modeling) is a design method. With the support of software, a virtual construction site is created: All physical and functional properties of a building are simulated, checked, corrected and updated in a 3D model even before the start of the actual construction. And what does BIM mean in practice for a MEP engineer?
“The integrative approach increases the design effort at the beginning of a project, until all required data is entered into the model,” says Sebastian Zeisig and adds: “But it pays off by a higher quality of the design and its reliability. Design errors can be avoided from the outset and changes can be adopted much easier at a later stage. I definitely see an advantage of integrated design in the support of the interdisciplinary clash detection.”
The additional time that is required at the beginning, saves time and costs in later project phases, since fewer revisions are necessary and engineering errors are being minimized. In addition, fewer interfaces and standardized file formats facilitate the cooperative data exchange, for example, with construction companies, resulting in overall slimmer coordination processes.
With DDS-CAD, ibz was able to create 3D models of the entire building services and thus simulate the whole project. Whether plumbing, heating, ventilation, climate or electrical systems, all information was merged inside a 3D model. For this purpose, all design-relevant data was collected and easily shared via the buildingSMART exchange format IFC.
Standardized data exchange and communication
Thanks to the BIM-compliant design approach, coordination with the structural engineer and architect turned out much easier, even when matters were complex. For this purpose, data was passed on smoothly between project stakeholders via IFC. The benefits of IFC also become apparent, when transferring data to contractors. The free DDS-CAD Viewer provides builders at the construction site with the option to view all MEP plans at any time via laptop or tablet. Zeisig states: “We experienced that the quality of construction increases sustainably and that expensive rework can be avoided.”
Nine employees at ibz are working with DDS-CAD on a day-to-day basis. To remain up-to-date, they attend trainings twice a year. “The training is not standardized, but customized to our individual needs, which we value,” Zeisig explains. “Our relationship with DDS is more of a partnership, really. And thanks to the regular training, our employees are always up-to-date in using software that is continuously being developed further.”
Ibz’s approach on the St. Johannis project shows how design and construction quality can be sustainably increased through a BIM-oriented approach. Even if the initial effort is higher using comprehensive MEP design software instead of conventional software, it ultimately leads to greater cost-effectiveness and fewer revisions. “The complexity of buildings is increasing. Hence, MEP engineers will have to adopt BIM design methods more and more in the future,” Zeisig predicts and continues: “Over the next few years, the digitalization of construction will greatly expand the service portfolio of architects and engineers. The building services industry is already on the right track. This also means that new regulations on fees, liability, data privacy as well as data protection need to be created, especially regarding BIM related services.”
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