Sustainable Building Design – Deliver a Smaller Ecological Footprint
Construction projects have a great impact on the environment in a variety of ways. Soil erosion from rainstorms can pollute surrounding environments, particularly surrounding water bodies, which have experienced an increase in pollution due to construction in recent years. Construction waste burdens already overtaxed landfills. The extraction of building materials has a great impact on the carbon footprint (emissions of CO2 associated with the energy to produce the material) of a construction project. Material choices can also affect the long term internal environment of a building. An ecologically responsible project can take some relatively easy measures to ensure that it has little or no impact on these various elements of the environment.
Erosion control and dust control are some of the biggest issues for a construction project. Lack of Erosion control can result in significant runoff from storms. This is known as stormwater pollution. Polluted stormwater degrades lakes, rivers, wetlands and other waterways. Pesticide residue and toxic automobile chemical waste are some of the things that can get into stormwater and eventually seep into the local water supply. Mud and silt from construction projects can also find its way into nearby ocean bays and local canals impacting the quality of the water and hence have a negative impact on coral and marine life. Mud and stone debris can also accumulate on site in unwanted areas on site during heavy rainstorms. These negative impacts can be avoided with the proper choice of erosion controls and the adopting of an erosion control plan.
Development of a proper erosion control plan and getting the contractors’ cooperation with its guidelines helps ensure construction will not impact the environment negatively. A site initially needs an assessment by a qualified engineer or consultant as to the potential erosion risks from construction. Plans are then made for the best ways to control erosion. Best management practices (BMPs) are outlined in the plan to deal with possible challenges on a site after an initial assessment. Some common BMPS chosen for an erosion control plan include:
- Silt nets to prevent the spreading of mud and silt and to allow water to filter through during a rainstorm into sensitive areas.
- Retention ponds to collect water and runoff rather than have it flow into unwanted areas.
- Soakaway pits can also be used to collect runoff and water. These are pits/trenches are lined with rocks and stones in gabions and have a geotextile covering that acts as filter for sediment and allows the water to seep into the earth.
- Earth dikes, perimeter dikes or swales, or diversions can be used to intercept and convey runoff above disturbed areas. An earth dike is a temporary berm or ridge of compacted soil that channels water to a desired location.
- Soil Stabilization: Planting temporary seeding such as wildflowers helps to stabilize disturbed soil. Seeding establishes a vegetative cover on disturbed areas which reduces erosion and dust wind drift.
BMPs will require regular inspection and maintenance, particularly after significant storm events. For guidance on how to create an erosion control plan, projects can usually turn to their governments (national and local) published guidelines, usually available on their Internet site.
Dust from projects can spread to surrounding neighbors affecting the quality of the air they breathe and can also get into nearby water bodies. It also impacts the health of those working on site breathing it in day in and day out. The dust can be controlled in several ways. Dust can be managed by use of wet blankets over debris piles to prevent wind drift. Watering down temporary roads and debris piles on site also prevents dust from spreading. All internal spaces should be cleaned and swept as a matter of course, thus insuring the spread of dust inside and around the projects buildings.
Construction projects usually generate a significant amount of waste, both in construction crew daily trash and with building material waste. Landfills everywhere are already filled to capacity. Landfill waste impacts the environment in several ways.Accumulated waste releases gasses such as methane contributing to pollution and climate change. Toxic chemicals from landfill sites can leach into the soil and possibly the water table. With careful thinking much of this waste can be diverted from landfills and used on site.
On our recent hotel project in Phuket for example we had several inventive ways to reuse construction waste. Wood from trees that had to be cut down was used for benches and interior finishes. Stones gathered from excavation were used for retention walls along with building concrete waste. Foundation concrete pile ends were reused as parking pavers. Smaller wood debris on site can be ground up and used as garden mulch. A project’s ecological footprint can also be reduced by reusing materials from other Use of old materials such as those mentioned above all contribute to a project reducing the amount of energy and associated carbon involved with extraction and production of new materials.
Choosing the right materials also reduces a project’s ecological impact and makes for a healthier building indoor environment. Many products in today’s market contain recycled content; gypsum board, insulation, aerated concrete, and many wood products for example. These materials reduce the demand of energy and resources that newer virgin materials have. Projects can also make ecologically responsible choices with the kinds of virgin (new) wood they use. Wood purchases can be made from suppliers who deal with sustainable sources.
Organizations like the Forest Stewardship Council and Rainforest Alliance provide certifications for wood products, verifying that they come from ecologically responsible plantations. There are many dealers in Southeast Asia that can access wood products with these certifications. The choice of internal finishes can have a long-term effect on the project’s internal environment that can impact staff and visitors. Many interior paints, sealants, and adhesives can contain toxic chemicals which will off gas at higher temperatures. These chemicals are known as volatile organic compounds, or VOCs. Many local products now on the market have a low VOC content. Several standards for a healthy VOC content have been published and are online. They can serve as a guide to the VOC levels that are at healthy levels. Such online standards include the Green Seal Standard and the South Coast Air Quality Management Standard.
Reducing a construction project’s ecological impact may take some extra planning but these efforts will show the builder’s commitment to environmental responsibility. Most governments produce guidelines for ecologically responsible construction. Another source to reference are green building certification systems such as LEED, Living Building Challenge, Green Mark or TREES. Many consultants are available to help guide construction and project managers to build in more ecologically friendly ways. Environmentally minded project owners will benefit if they avail themselves of these resources.