In the 21st century, sustainable building design is an increasingly popular and important client requirement as well as a growing focus for professional engineering firms. For the fire protection engineer, integrating sustainable, or "green," building design aspirations presents the challenge of resolving conflicts between architectural vision and code expectations for fire safety.
At the heart of fire protection engineering is meeting the challenges of clients' innovation. It is often the case that the fire protection engineer contributes to a broad spectrum of building solutions that significantly affect many other members of the design team.
By discussing the challenges that fire protection engineering must overcome to support sustainable building design, this article seeks to embellish on a simple philosophy " that the fire protection engineer's use of performance-based design can both liberate the design team from code restraints, which might other wise hinder the building's sustainability rating, and serve to address the more holistic aspects of true sustainability.
In order to understand the implications of sustainability for fire safety, it is first necessary to understand what is really meant by "sustainable building design."
In the first instance, a sustainable building is the physical end product of a design philosophy to improve the "performance" of the built environment by increasing the efficiency of the resources used in building during its lifecycle: construction, operation and demolition. Such performance is typically measured through a range of international environmental performance-rating systems for buildings.
All of the systems are fairly similar in their approach, with scores for the incorporation of sustainable design under areas such as energy, water, pollution and waste. The higher the total building score the more sustainable the design is considered to be.
In the second instance, a truly sustainable building is also a socially sustainable one; that has a positive social impact on the local environment for the duration of the building's existence. Wider issues such as societal needs, maintenance of heritage, provision of social amenity, accessibility for all and future-proofing of a building so that it continues to be useable for a longer lifespan than a more conventionally designed building can all be considered.
Clients' design aspirations and tenant demands increasingly lean towards the provision of large open floor plates, the incorporation of open atria and the interconnection of spaces and stories. These approaches maximize a building's bright and airy feel of daylight and natural ventilation while being harmonious with the principles of sustainability.
This desire for open planning alone presents the fire protection engineer with a concept design that is at odds with most international building codes that seek to limit large open compartments and the interlinking of floors. Achieving a "good" or "excellent" rating is often required for funding, good corporate governance, or for attracting tenants and premium rental returns; therefore, the design team seeks to achieve quantified reductions in the use of resources such as energy and water. Fire protection engineers, as part of these design teams, must rise to the challenge of contributing to these reductions without significantly compromising the client's aesthetic requirements, or the resulting level of fire safety.
Aside from the client-driven challenges, there are other aspects that relate to sustainability that are likely to become stronger influencing factors for designs of the future - such as the actual population of the buildings.
A global trend towards aging populations and longer working lives means sweeping code assumptions that building occupants are generally mobile are becoming less appropriate. Typically, greater provision is made where, for example, it is known that a building is designed to accommodate a high proportion of wheelchair users.
The issue of obesity, and the challenges it poses to fire safety are perhaps felt most acutely in hospitals and treatment centers.
Increasing flexibility and minimizing business loss also improves sustainability. Sprinkler protection of buildings, although using resources, can be seen as inherently improving sustainability both for flexibility and as they reduce the potential size of polluting fires. Residential sprinkler protection, particularly in higher risk occupancies, can be argued to be socially sustainable as they reduce risk of loss to life and property and protect some of the most vulnerable members of society.
Some of this may appear to lead to overly conservative designs and hence not be sustainable; however, if future flexibility can be increased, the lifespan of a building can be increased and hence its sustainability. All of these decisions should be made by the client, and the fire protection engineer can help provide their clients with information and options.
References:
- Building Code of Australia, Australian Building Codes Board, Canberra, 2009.
- NFPA 101, Life Safety Code, National Fire Protection Association, Quincy, MA, 2009.
- McGrattan, K., et al. Fire Dynamics Simulator (Version 5) User's Guide, NIST Special Publication 1019-5, National Institute of Standards and Technology, Gaithersburg, MD, 2009.
