Considerations for Designing a Sustainable Office Building
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As the world grapples with global warming and climate change, sustainable approaches to design have fast gained popularity and priority. Designs that do not deplete the earth of its resources, but instead support the needs of the present and the future generations, are referred to as sustainable designs. This perspective of designing seeks to reduce the negative impacts of construction on the environment, while improving the health and well being of the users. Some of the principles of sustainability include reducing consumption of resources, minimising waste generation, reusing and upcycling materials, minimising energy demand, and reducing water dependency from external sources.
Sustainable sourcing is a process of selecting suppliers and products that are socially, ethically, and environmentally responsible. The designer can choose materials that are quantified as low life cycle impact on the environment. Materials may be reused or reclaimed from other sites, repurposed to suit the new design, thereby largely reducing the energy required to manufacture new material. In the office interior design, one may upcycle the existing office furniture, by reusing the metal frames or wood work that are intact. Reupholstering, repainting and applying fresh finishes to old furniture creates durable furniture at low cost and energy.
While procuring new materials, one must be conscious of the distance of sourcing, and its renewability, preferring abundantly available local resources. Designers may prefer the manufacturers who comply with Extended Producer Responsibility norms, that is, choosing those sellers who take accountability of a product's end-of-life environmental impacts. Some examples of eco-friendly furniture are bamboo desks, cotton or linen finishes on chairs, recycled plastic dividers, and certified wood tables. Bamboo is preferred for its property of rapid regeneration, and is able to grow without pesticides and fertilisers. natural fibres like cotton, linen or wool, that are biodegradable at the end of life, or recycled plastic. Certified wood tables are typically made from sustainably managed forests and are certified by the Forest Stewardship Council. Recycled plastic, while reducing plastic waste on the planet, also provides us with furniture that does not deteriorate over time.
Lastly, it is important to place awareness on the constituents of the adhesives, paints, wallpapers, carpets and cleaning supplies used in the interiors, as they contribute to the release of toxic Volatile Organic Compounds (VOC), directly affecting occupant well being.
When it comes to post occupancy energy usage in a building, lighting and ventilation constitute for over 75 percent of the total energy demand. Buildings may be designed to take advantage of available natural lighting, and also employ passive techniques to provide thermal comfort for the occupants. When lighting as well as heating and cooling needs are met with minimal electricity, the office space begins to have a high energy performance, that is, its annualised energy usage per unit floor area drops significantly.
Lighting design is an exercise of fine balance, one that must allow sufficient natural daylight but avoid harmful glare. While natural lighting is known to enhance user mood and also save on building energy needs, excessive light falling on the computer screen, or around the screen can create highly contrasting illumination levels between the computer screen and the surroundings. As a thumb rule, one may orient the workstations perpendicular to the facade to deal with the problem of glare. Alternatively, the envelope may be screened by a shading device to prevent glare. The workspaces should be designed to provide adequate artificial lighting, to be employed in cloudy sky conditions and the dark hours.
When users are able to personalise the light levels to their choice, it improves mood and productivity. One can provide adjustable light knobs, colour tone choices to set the quality of artificial lights and operable sun shading devices to control sunlight.
The heating, cooling and ventilation needs of the office can be met through a combination of passive and active design strategies. Passive design strategies do not require mechanical energy for its operation. Designers are required to study the effects of the sun and wind on the built form through the use of psychrometric charts, sun path diagrams, and wind charts for the given latitude and derive the physiological design needs. This means that one needs to decide what the thermal comfort goal is, whether it is to achieve maximum ventilation, or to bring the solar radiation into the office space etc. before beginning the design.
In a temperate climatic zone where passive solar heating is desired, the design strategy may look like a combination of these ideas:
- Organising the workstations on a floor plan so that the winter sun penetrates and reaches the users.
- Zoning design can consider locating storage areas and service spaces on the side of the building facing the coldest wind to help insulate the interior work area.
- Maximising the usage of spaces adjacent to the south facade glass area to winter sun exposure, while guarding the openings with operable overhangs to shade the summer heat.
- While choosing glazing, one may prefer double pane high performance glazing (Low-E) on west, north, and east, but clear on south for maximum passive solar gain
After reducing the energy demand, designers can focus on energy efficient systems, such as usage of sensor based control for lighting, Variable air volume (VAV) air conditioning which supplies air based on occupancy, and even varying the illumination levels based on the real time illumination levels that vary based on sky conditions. Performative shading based on sensing temperature levels, and performative lighting that may vary illumination levels based on actual light availability and sky conditions can be incorporated to dynamically respond to real time interior and exterior environments.
With Snaptrude, designers can simulate the energy performance of their buildings at any stage of their project to evaluate the efficacy of proposed, passive techniques. One can visualise the sun path with respect to site location, understand the spatial daylight autonomy (an assessment of usable daylight availability on the workplane), annual sunlight exposure (an indicator of glare and excessive light), and energy use intensity (measure of energy use in the building post occupancy). These metrics represent year round data and assist designers to optimally design for daylighting and good energy performance.
Sustainable design extends beyond the realms of material and electricity usage. Designers may integrate water conservation and waste management in the design. Plumbing fixtures may be low flow fixtures and washrooms can be fitted with a water efficient dual flushing system. The office can also recycle its greywater produced and harvest rainwater. Offices can encourage non motorised commuting options to the office by providing bicycle parking and shower rooms for employees travelling by bicycle. Office can promote maintenance of a garden space, where employees can grow their own vegetables and greens. In the end, sustainability is an attitude, and a lifestyle that evolves from responsible and holistic thinking.
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