Defining Sustainable Formwork

To define 'sustainable formwork' one must first define 'sustainable development', second restrict this definition to 'sustainable construction' and finally restrict this definition to a specific type of construction, concrete formwork.

Definitions found on the web are so loose and vague that they are of little value to making informed construction decisions with respect to formwork. Our objective is to find a rigorous definition of 'sustainable formwork' that can determine when one type of formwork is more 'sustainable' than another using market available information.

Monte Rosa Hut

Sustainable Development & Sustainable Construction

The term ‘sustainable development’ was coined in 1987 in the 'Brundtland Report':

"Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own needs."

The Holcim Foundation restricts this to define ‘sustainable construction’:

“Sustainable construction aims to meet present day needs for housing, working environments and infrastructure without compromising the ability of future generations to meet their own needs in times to come.”

However, given the interconnectedness of the world today, this definition must updated to include ALL nations, both developed and developing:

"Sustainable construction must meet today’s needs for housing and infrastructure without compromising the ability of future generations in all countries to meet their own needs in times to come."

The photo to the right shows the Monte Rosa hut in Switzerland constructed in 2008 at a cost of 6.5 million swiss francs. The 'hut' won the Holcim Sustainability Award by generating 90% of its energy requirements. Question: Is this 'sustainable' construction?

Monte Rosa Hut

Sustainability Dilemma

The world currently has a population of 6.8 billion people and a gross world product (2008) of $71.4 trillion dollars. If one assumes all countries have the right to consume resources at the level of developed countries, then the world will have a gross product of $320 trillion dollars.

Impossibility of $320 trillion

This world production level assumes no growth in current consumption levels of developed countries, and uses the USA GDP of $47,000 extrapolated to the world population of 6.8 billion people.

Given current constraints on existing resources, it appears very difficult, if not impossible, to increase world consumption of global resources by a factor of 4.5 to $320 trillion dollars US. Therefore it would not be unreasonable to say that new construction is unsustainable under this definition.

The photo to the right shows recently constructed and unoccupied houses in the Kangbashi district of Ordos City, Inner Mongolia. Is this 'sustainable' construction?

Fastfoot Conserves Resources

Comparative Sustainability

To determine if one forming method is more sustainable than another, the full resource cost of each method is determined. There are three types of concrete formwork:

Type I - Sacrificed Forms: These forms are consumed in the forming process. For example, cardboard column forms are stripped after use and end up in the land fill. Full resource cost includes:

Type II - Secondary Use Forms:  These forms remain in place to provide a secondary use in the structure. For example, insulating concrete forms provide insulation value to the concrete wall. Full resource cost includes:

Type III - Multi-use Forms: These forms are reused multiple times, either on the same project, or with multiple projects. Plywood wall forms are an example of a multi-use form. The full resource cost includes:

It is recognized that the embodied energy and pollution costs of the manufacturing process should be included in the costs noted above. At present these costs are difficult to determine and will never be used by forming contractors. Market based costing is the best current determinant of which forming technology is ‘more sustainable’ when pollution and secondary values are included.

GreenSpec Kelowna Project

Sustainability Calculator

Once the full resource cost (including pollution) are known for each forming method, we can evaluate the comparative sustainability:

One forming method is ‘comparatively more sustainable’ than another if it consumes less world resources than the other while forming equivalent concrete.

To view the Sustainability Calculator, click here.

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