Health and Safety
Most of the statutory regulations that control the construction industry worldwide are there to ensure the health and safety of both construction industry operatives and end-users. Building codes cover all aspects of construction, including foundations, waterproofing, structural elements, structural stability, insulation, energy conservation, ventilation, heating, fire protection, emergency means of escape, and electric installations.
Normally architects, in association with specialist consultants such as structural and environmental engineers, must apply to the various agencies of the municipality where a project is located for a building permit prior to construction. Those agencies verify that the plans comply with applicable codes. Once construction begins, building inspectors confirm that the built work reflects the approved plans; they then issue a certificate of occupancy upon completion.
Sustainability
The world community is experiencing a growing recognition that we face imminent global crisis. Climate change threatens food and water supplies, may lead to increasingly violent storms, will endanger many species, and could raise sea levels significantly if the melting of ice caps continues at its current rate. If sea levels rise even a few feet, millions of people will be affected. Not only is the climate warming, but we also face diminishing fresh water supplies that are increasingly polluted. The hole in the ozone layer is starting to expand once more. It has become evident that oil extraction is at or near its worldwide peak, and current levels of production will not continue indefinitely.
One means of assessment that has been used to gauge the overall environmental sustainability of the world’s population is the Ecological Footprint. This metric attempts to account for the productive land area necessary to provide the resources consumed, and to absorb the waste produced, by human activity. Currently, the world’s population is overshooting global carrying capacity by 23 per cent. If everyone in the world lived like today’s U.S. citizen, it would take 4.3 planet earths to support the world’s population. Though buildings do not get as much attention as autos, they actually use more energy and create more greenhouse gas emissions that the transportation sector. Buildings account for nearly half of green house gas emissions in the USA. It is essential that we in the building industry shoulder our disproportionate share of the burden in combating the climate crisis. To do so, energy use in new buildings must be reduced dramatically to avoid the worst-case scenarios. The know-how and technology to make such dramatic cuts already exist. The challenge is in developing the will to implement changes and to educate the building community as to how and why we must do so. At the same time, we must remember that sustainability is not only about energy; we must find synergistic solutions that address a full spectrum of environmental and social issues simultaneously.
Rules Governing Construction Technology
The laws that regulate the built environment may be grouped into two broad categories: zoning and building codes. Zoning codes regulate the types of uses that may occur on a given site, site design, building massing, parking, compatibility with context, and a wide variety of other considerations. Zoning code is generally established by the city a site resides within and is tailored to the concerns of that particular community.
Building codes regulate the specific technologies implemented in any given building with the primary objectives of occupant health, safety, and fire prevention and secondary objectives of guaranteeing minimum standards of functionality and durability in the buildings. Regulating energy consumption and providing accessibility for the physically handicapped have also become major code concerns in recent years.
Codes are typically updated to reflect new knowledge and changing practices or needs of society every few years. Lessons learned from disasters such as earthquakes or major fires often lead to modifications of code requirements in the quest to guarantee the health, safety, and welfare of building occupants. The code revision process can be quite controversial because even though all stakeholders may not agree on a given provision, once incorporated into code, requirements take on the weight of law and constrain technological choice.
States or municipalities usually adopt a standard model code and modify it as required to address local conditions and preferences. The most prevalent model codes in the Unites States are the International Codes developed by the International Code Council. The most important of those codes are described here. A jurisdiction may elect to adopt only certain of the codes below and write its own rules for other sections.
Building codes rely on many standards promulgated by other organizations. For example, the ICC Electrical Code relies heavily on Standard 70 from the National Fire Protection Association (NFPA). Other commonly referenced standards organizations include ASTM International, the American National Standards Institute (ANSI), and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).
International Building Code
The IBC addresses all building types and occupancies and provides regulations on building size, occupancy types, construction types, egress, fire protection, structural design, and other basic requirements. The structural sections provide span tables and standard details to simplify design of basic conditions. For more specialized conditions, an engineer may demonstrate compliance with performance standards in order to satisfy code requirements. The IBC also contains basic handicapped accessibility standards, which reflect requirements for the Americans with Disabilities Act (ADA).
International Residential Code
The IRC goes beyond the IBC in its scope of considerations to address the full spectrum of code requirements exclusively for the design of one- and two-family dwellings. Not only does it address the building structure and fire protection, but it also includes sections on plumbing, mechanical and electrical design, among others. It also has numerous prescriptive standard structural details for light frame construction.
International Fire Code
Covers fire precautions and preparedness, fire department access to buildings, fire services and systems, means of egress, and fire protection systems. Chapter 9 of the IFC addresses requirements for automatic sprinkler and other fire suppression systems in various occupancy types. NFPA 13 is referenced for specific sprinkler design requirements.
Sets out standards for heating, ventilation, and air-conditioning systems (HVAC). It requires that all spaces be ventilated by either natural or mechanical means and provides minimum fresh air volume requirements for different occupancy types. These standards are not necessarily adequate to ensure good IAQ, and should be regarded as the absolute minimum. The IMC also regulates the installation of exhaust systems, ducting, hydronic piping, refrigeration, furnaces, boilers, and other mechanical equipment types. This code specifically mandates that HVAC systems be designed and installed for energy efficiency in accordance with the International Energy Conservation Code.
International Plumbing Code
Covers both water supply and waste water systems. Water heaters, water supply and distribution, sanitary drain systems, as well as storm drainage are addressed. The IPC gives requirements for determining the numbers of fixtures of different types that are required for a given occupant load and use, and sets standards for pipe and drain sizing. The IPC approves gray water (waste water from lavatories, bathing, and clothes washing) for recycling in toilets and urinals. Gray water may be used for irrigation only if approved by local authorities.
International Fuel Gas Code
Includes standards for gas piping, equipment venting, and specific appliances such as gas fireplaces, furnaces, and clothes dryers. These appliances generally must be tested and approved according to outside standards.
International Energy Conservation Code
Establishes minimum requirements for energy efficiency in the built environment. The IECC allows for prescriptive compliance (satisfying certain code-mandated criteria on window placement, construction type, mechanical system performance, and so on for a given climate), performance-based compliance based on an energy cost budget established according to AHSHRAE 90.1, or a hybrid component performance approach for residential buildings. The IECC covers the building envelope, mechanical systems, water heating, and lighting.
ICC Electrical Code
The ICC electrical code regulates electrical systems to ensure safety and minimize the risk of fire. It references the long-established standard, NFPA 70 - the National Electric Code (NEC) for most of its technical requirements.
ICC Performance Based Code
The performance based code allows a building professional to demonstrate conformance with broad criteria for structural stability, durability, fire safety, energy efficiency, and so on by means not covered in the standardized codes. This section is used infrequently, but has the potential to allow for innovation that might not otherwise be possible under the standard codes.
World Commission on Environment and Development (WCED) Guidelines on Sustainable Construction
The 1987 report by the United Nations’ World Commission on Environment and Development (WCED), also known as the Brundtland Report, is one of the seminal works in generating the modern conception of sustainability. It proposes at its outset what is still probably the best known definition of sustainable development: meeting “the needs of the present without compromising the ability of future generations to meet their own needs.”
This charge has become a ubiquitous concern as global warming has come to be seen, almost universally, as a major threat to the future of all of earth’s species. While the Brundtland definition is pleasingly simple, it does not provide much guidance on how one might actually implement sustainable development. William McDonough provided an elegant set of general principles for moving toward ecological sustainability for the 2000 World’s Fair:
The Hannover Principles
1. Insist on rights of humanity and nature to co-exist in a healthy, supportive, diverse, and sustainable condition.
2. Recognize interdependence. The elements of human design interact with and depend upon the natural world, with broad and diverse implications at every scale. Expand design considerations to recognizing even distant effects.
3. Respect relationships between spirit and matter. Consider all aspects of human settlement including community, dwelling, industry, and trade in terms of existing and evolving connections between spiritual and material consciousness.
4. Accept responsibility for the consequences of design decisions upon human well-being, the viability of natural systems and their right to co-exist.
5. Create safe objects of long-term value. Do not burden future generations with requirements for maintenance or vigilant administration of potential danger due to the careless creation of products, processes, or standards.
6. Eliminate the concept of waste. Evaluate and optimize the full life-cycle of products and processes, to approach the state of natural systems, in which there is no waste.
7. Rely on natural energy flows. Human designs should, like the living world, derive their creative forces from perpetual solar income. Incorporate this energy efficiently and safely for responsible use.
8. Understand the limitations of design. No human creation lasts forever and design does not solve all problems. Those who create and plan should practice humility in the face of nature. Treat nature as a model and mentor, not as an inconvenience to be evaded or controlled.
9. Seek constant improvement by the sharing of knowledge. Encourage direct and open communication between colleagues, patrons, manufacturers and users to link long term sustainable considerations with ethical responsibility, and re-establish the integral relationship between natural processes and human activity.*
The generally accepted notion of sustainability today includes not only ecology and concern for future generations, but also the recognition that, if we are to move toward a more sustainable condition, we must achieve a greater level of social equity in the near-term and that the decisions must be economically viable to be implemented. The tension between these considerations is often depicted as a triangle with environmental impact, social equity, and economic viability at the vertices, and sustainable development occurring in the middle** A systems mindset suggests that, since the economy is a sub-system of society, and human society is but one of the many sub-systems of the environment, these considerations might be better depicted as three concentric circles with the environment represented by the outermost and the economy by the innermost.***
*From William McDonough Architects, “The Hannover Principles: Design for Sustainability,” paper presented at EXPO 2000, The World’s Fair, Hannover, Germany.
** From Scott Campbell, “Green Cities, Growing Cities, Just Cities?: Urban Planning and the Contradictions of Sustainable Development,” Journal of the American Planning Association, vol. 62, no. 3, Summer 1996, pp. 296-312.
***From Roger Levett, “Sustainability indicators – integration quality of life and environmental protection,” Journal of the Royal Statistical Society, vol. 161, part 3, 1998, pp. 291-302.
Leadership in Energy and Environmental Design (LEED) Green Building Rating System
In the building industry, the process of building in a way that contributes to the overall sustainability of society is often referred to as green building. In the United States, there are numerous systems that have been developed for evaluating how “green” a particular building project is. Individual cities were the first to develop such standards in local voluntary programs. For example, the city of Austin, Texas, was one of the first to develop its own green building rating system and had been very influential in the development of other such programs. Local programs are usually tailored to specific local concerns.
A number of organizations have developed green-building evaluation systems intended for national or international implementation. By far the most widely adopted of these is the Leadership in Energy and Environmental Design (LEED) Rating System from the United States Green Building Council (USGBC) (www.usgbc.org/LEED/). LEED use a checklist system that awards points based on the degree to which a project satisfies a range of criteria. There are also basic prerequisites that must be satisfied to achieve certification. LEED ratings range from Certified to Platinum based on the number of points achieved.
LEED certification is usually voluntary, but has been adopted as a requirement by some jurisdictions, especially for publicly funded projects. The system considers five basic categories – the building site, water use, energy use, material use, and indoor environment – and provides customized credits for innovations not specifically covered by other credits. Once the basic prerequisites are satisfied, one point is available for each of the criteria shown in the table. A total of 69 points are available.
To become Certified requires 26 points, 33 is considered Silver, 39 Gold, and 52 points are necessary to attain Platinum status. Critics of checklist type systems argue that this approach could actually impede progress toward sustainability by reductively focusing on specific technologies, rather than facilitating a holistic view – one that considers the building as an integrated system which regulates flows of resources and people to and from the larger environment. Other criticisms center on most evaluation systems’ lack of consideration for social factors, which are also considered to be an essential part of true sustainability. The positive side of such systems is that they are easily accessible and encourage building owners to implement green building by evaluating the practices employed and certifying those achievements with a widely recognizable stamp of approval. The exponential growth of LEED is evidence of the success of this approach.
Green-building ratings are still in their infancy. In the future, these systems will make the transition from focusing on discrete technologies as most do today, toward life-cycle assessment-based models that seek to evaluate total environmental impact of a building.