Despite many new and beautiful buildings around town, it would not surprise many to learn that our present approach to designing and constructing buildings inhibits innovation and change. This reality leaves us lagging most other industries in terms of productivity increases.
The problem appears to be that we are bogged down in the process of how to build safely and paying scant attention to the quickly changing environment in which we live. We may have to step back and carefully consider why we are constructing these buildings in the first place.
Performance-based building design is an approach which focuses on the objective of a building in order to prescribe desired results rather than the way and method to get things done. In a performance-based approach, the focus of all decisions is on the required performance-in-use, and the evaluation and testing, of buildings.
Requirement based approaches have been used at least since the time of Hammurabi’s code. However, over the past century, rapid advances in building science and fast accumulation of building capital stock have resulted in performance requirements being buried deep inside building codes and the focus shifting to the ways and methods of building safely and economically. Thus modern building design and construction approaches have limited capacity to accommodate major changes in performance requirements.
Currently, the primary driver of change in building performance requirements is an environment of rapid urbanization within the context of very limited access to financial, energy and material resources. If one adds to this the environmental costs that have historically been ignored then the trajectory towards change appears inevitable.
Within such a context one also finds relatively large levels of migration of urban labour towards the service sector as manufacturing shifts towards automated, lower cost or heavily subsidized spaces. Contemporary African urban growth consists of direct migration from rural life to the urban service sector. The demand for buildings in the residential and service sectors is thus large and continues to grow significantly.
Based on the drivers and trends above it may be possible to define performance requirements for buildings in the service sector. If we look at office buildings, for instance, the following four performance requirements can be generated for their design, construction and operation. There is consensus in the industry that the buildings must be:
- Architecturally expressive and economical
- Flexible to reconfiguration and space optimization
- Consumers of significantly reduced energy and materials
- Fast and safe to build and fit for occupancy
In the past developers attempted to achieve as many of these performance requirements as possible given existing methods of construction. A performance-based approach would develop methods of construction that can satisfy all of these performance requirements. In other words, all decisions would be taken with the goal of satisfying performance requirements rather than compliance with the selected methods of construction.
The past two decades have seen dramatic reductions in the price of various technologies and resources. Some of these are:
- High powered computing and simulation
- Mature testing labs and researchers
- Mature standards, literature and understanding of structures and materials
- Modern and versatile manufacturing capacity
In such an environment it is easy to assume on the one hand that the future holds within it fully integrated design-build project delivery that is paperless and efficient. On the other hand, it is possible to envision a future where much resource is spent on developing fully industrialized buildings and securing financial returns based on mass manufacturing and economies of scale.
While both methods of production are discussed frequently neither one is focused on building performance. The first simply replicates with more efficiency the existing project delivery method and neglects early integration of sustainability, speed and safety of construction requirements. The latter sacrifices the ability for architectural expression and easy building reconfiguration and space optimization – while it may satisfy sustainability, speed and safety of construction requirements.
Therefore we need a third method that can satisfy the performance requirements by making full use of increasingly accessible technologies and resources. As shown in the table below a performance-based approach requires the incremental development of building sub-system technologies. These can be manufactured in mass to cover the cost of development while being used in various permutations to provide architectural and modification freedom. They can also be developed to satisfy sustainability, speed and safety requirements.
Such a method may also encourage small and medium enterprises (SMEs) to participate in performance-based innovation since sub-systems and technologies can be quite small or may require little testing and verification. The ease with which structural steel can be handled and fabricated in controlled environments will likely make
it the framing material of choice for this method of production.
Such an approach has a critical need for multi-disciplinary collaboration and innovation. Here motivated building owners, design professionals or contractors can take the lead. Multi-disciplinary researchers, testing laboratories and students can be employed to test and verify new systems that satisfy specific performance requirements.
Moreover experienced designers and contractors can be employed to evaluate how existing prescriptive approaches can be combined with novel systems to reduce the cost of testing and verification. They would also form the link between the industry and regulators.
Promoting a shift towards performance-based approaches can have significant implications for all parties in the building industry. While many of these may be difficult to anticipate the following list includes areas that are likely to be affected.
Building codes are presently written with implicit performance requirements and provide prescriptive rules that relate to methods of construction. Performance-based approaches would require major changes in how building codes, and thus regulatory officials, operate.
Contracts between parties to a building development presently reflect a practice where designing, bidding and building occur in a linear sequence. Performance-based approaches will require early involvement of all parties upfront. Moreover, full access to all information by all parties at all times requires new ways of sharing risks and writing contracts.
Design today involves specialized professionals who work in silos and provide solutions within their area of expertise. Most performance requirements cannot be satisfied by any one specialist. They require a great deal of multi-disciplinary effort. Thus groups may have to focus on solving specific performance requirements rather than problems of one profession.
Sustainability standards for buildings are currently based on accumulating points based on application of specific products or methods to construction. For instance, as presently written the Green Building Council (SAGBC) incentivizes the steel industry to solve steel production and transportation issues for credits rather than focusing on the performance of the final building.
Safety rules and standards for construction are currently written to solve specific site or shop problems. A more holistic safety performance requirement would shift the work to environments that are safer by, for instance, promoting more modular construction.
Performance-based building design is an approach which focuses on the objective of buildings. We would be wise to go back to such an approach because present methods of project delivery are not keeping up with key social needs. Such design however, requires careful articulation of important building performance requirements, and intelligent identification of what resources are available to satisfy them adequately.
In our view, the steel industry has much to offer here since partial industrialization of building delivery is a viable method of focusing on building performance requirements. Satisfying such requirements in novel ways will be immensely rewarding. The question of how to reconfigure the construction industry to accommodate change, and address the new needs of designers, contractors and regulators, is a challenge yet to be solved. We are tackling this one building project at a time.