TUDLab Research Projects Tropical Sustainable Design Case Studies Defining tropical expertise in the built environment

Defining tropical expertise in the built environment

The Working Group for the Case Studies project drew upon the current Australian rating, accreditation and approval systems underpinned by codes and standards for sustainable construction and supplemented it with a working knowledge of building in tropical, regional Australia. Through the process the Group created a standardised set of sustainability criteria that enabled comparison across different types:  residential, commercial, industrial, civil, civic and retrofitted/renovated buildings. It is recognised that rating tools to date are not particularly effective in providing good outcomes for tropical sustainable design in all instances.  The case study project thus evolved specific criteria for defining good tropical outcomes.

The criteria not only had to be specific to the tropics but also had to be general to work well across all Case Studies. The Working Group thus identified common rating, accreditation and approval criteria and then worked within the common categories to define what was important in each from a regional, tropical perspective. In total, the criteria provided information on the content of six primary focus areas of sustainable tropical design that were deemed critical. These areas related to: Planning and Management; Site; Design; Materials; Energy; and Water.

Tropical sustainable design expertise plans, designs, specifies and builds to deliver the following:

  • The design and construction of sustainable, resilient communities and infrastructure in tropical climates
  • The development and application of building materials and technologies for extreme heat, cyclones, humidity and heavy rainfall
  • Sustainable environmental practices through the efficient use of renewable natural resources and protection of natural assets

The following six key focus areas were defined for the purpose of this study.

This includes the sustainable planning and management of the building process, from site selection and project inception through design and construction to building commissioning and occupation.

1.1 General Planning and Management Sustainability Considerations

  • Engaging professionals with expertise in sustainable building delivery
  • Effective collaboration with project stakeholders to establish, prioritise and agree on sustainable environmental, economic and social initiatives for the project
  • Planning to minimise the life cycle cost of a building
  • Implementing an environmental management plan to minimise pollution during construction, including protecting site soil and water quality
  • Implementing a waste management plan that includes design strategies and collecting, separating and recycling demolition and construction waste
  • Providing a building user guide, along with user training for building systems
  • Building tuning post-occupancy to ensure systems are running optimally
  • Data monitoring of building systems to ensure systems continue to operate optimally

1.2 Tropical Planning and Management Sustainability Considerations

  • Managing construction sequencing to allow for wet season impacts
  • Procuring building materials with care, particularly for products that are not stocked locally, leading to possible delivery delays or freight and storage damage
  • Knowledge and expertise on suitability and durability of materials and construction detailing for tropical conditions, (eg, seasoning materials for humidity, detailing to minimise condensation, moisture traps and mould)
  • Managing the construction workforce, including risk of sun stroke, skin rashes and tropical sores, mental health issues caused by high heat and wet season work, remote work, difficult building and site conditions
  • The research, development and testing of new products, in collaboration with suppliers, to increase suitability, availability and uptake in the tropics
  • A sharing of knowledge relating to both successful and poor project outcomes in the tropics, where the experience can be used to promote better outcomes for future buildings
  • Tropical health considerations including pest and disease control in communities and around buildings
  • Planning for safe and resilient buildings in areas prone to severe tropical weather events
  • Respectful consideration for and appropriate design response to cultural imperatives, as required in specific locations and communities

Site considerations involve choices that will impact site ecology and biodiversity, and choices that will contribute to achieving sustainable communities. Sustainable site choice, location and management will minimise harm to the ecology, and will enhance site amenity and promote healthy communities.

2.1 General Site Considerations

  • Selecting previously developed/degraded land and improving its ecological value
  • Selecting a site that allows optimal orientation for effective passive design
  • Minimising site and ecology disturbance
  • Minimising vegetation clearing
  • Protecting site topsoil quantity and quality
  • Selecting a location to minimise reliance on private transport, and to provide easy amenity to infrastructure, services and supplies
  • Proximity to interconnecting foot/ cycle paths

2.2 Tropical Site Sustainability Considerations

  • Controlling the volume and quality of wet season stormwater run-off to minimise erosion and sediment/nutrient loss to waterways
  • Expertise and understanding of micro-climates relating to coastal, rainforest, highland and savannah locations
  • Selecting site location to maximise resilience and to minimise isolation, disruption and loss of property during floods, storm surges and cyclones

Sustainable building design will reduce user reliance on non-renewable energy. Sustainable design will maximise user accessibility, comfort and wellbeing, and will contribute positively to urban spaces and community. Choices made in building design and detailing will impact on building resilience, durability and maintenance.

3.1 General Design Considerations

  • Correct building orientation to maximise passive design function
  • Individual comfort control (light, temperature, ventilation)
  • Noise level control from external sources and within parts of a building (eg air-conditioning unit placement)
  • Incorporating views well to enhance user comfort and wellbeing
  • Designing flexible spaces and structure to maximise building functionality with minimal area, and to allow for future adaptability and growth

3.2 Tropical Design Considerations

  • Effective passive design for hot, humid climates to minimise solar heat gain, and to maximise natural ventilation (cross ventilation and thermal venting) to reduce reliance on non-renewable energy, and support our wellbeing in a hot, humid climate
  • Design to allow resilience, adaptability, safety and security in severe tropical weather events and to assist with swift recovery from disaster
  • Design to facilitate comfortable outdoor living in all seasons
  • Design to reduce mould, condensation, pests and insects
  • The use of light colours to reflect heat
  • Subdivision design to support the correct orientation of buildings to allow for optimal passive design and reduce reliance on non-renewable energy sources for building cooling
  • Careful specification of doors and windows that maximises cross ventilation when open, protects the opening from rainfall, provides a good seal when closed, has glass that minimises conduction and radiant heat transfer and is designed and installed to meet high cyclonic wind speeds
  • Innovative design solutions suited to tropical climates

Material selection should consider life cycle cost implications with regards to embodied energy, carbon footprints, durability and maintenance requirements. Material selection also affects indoor air quality, which significantly affects human health.

4.1 General Material Selection Considerations

  • Specification of sustainably produced, locally sourced materials
  • Use of sustainably sourced timber (eg, local, recycled, FSC certified timber)
  • Use of materials with high recycled content (eg, concrete aggregates, recycled composite materials, steel, floor coverings)
  • Specification of materials that can be readily recovered and recycled when demolished
  • Reusing and adapting existing buildings elements, such as structure and fa├žade, in renovations or conversions
  • PVC reduction (vinyl finishes, conduits, cables)
  • Formaldehyde reduction (eg, can be present in MDF sheet)
  • Life-Cycle Analysis of material selection, including consideration for embodied energy, longevity, maintenance considerations
  • Specifying low VOC paints, glues and finishes
  • Specifying materials, such as insulation, that are low irritant

4.2 Tropical Material Selection Considerations

  • Careful specification and detailing of materials that may absorb moisture
  • Careful specification of products, materials and finishes to minimise corrosion, deterioration and maintenance in the heat and moisture of tropical environments
  • The specification and installation of appropriate insulation to minimise condensation and moisture traps
  • Specification of cladding systems and glass that is resistant to cyclonic wind and impacts from flying debris
  • Careful specification of proprietary systems and materials that rely on rubbers, adhesives, sealants, silicones, resins and binders, as these products may be subject to deterioration or delamination faster in the tropics due to high heat, humidity and mould
  • Avoiding specification of materials that may out-gas VOC’s, as high humidity and heat may accelerate its release
  • Application of building technologies suitable for use in hot humid climates with attributes that may include: condensation control, mould control, heat and UV light resistance
  • Innovative use of technologies or materials, suitable for tropical climates

A well designed building will be naturally cooled through passive design, have low solar heat gain and will have good levels of natural light. This will result in an overall reduced reliance on electrical energy. Alternative, renewable sources of energy are readily available to further reduce or even negate the need for non-renewable energy in a building.

5.1 General Energy Considerations

  • Indirect, evenly dispersed natural light to reduce the need for artificial lighting during the daytime
  • Separate metering for tenancies to allow monitoring of usage
  • Designing electrical layouts (zones) that allow greater individual user-control to monitor and minimise the amount of energy consumed
  • Specifying and installing low energy fittings and fixtures, such as fluorescent or LED lights and appliances
  • Adopting renewable energy sources

5.2 Tropical Climate Energy Considerations

  • Design buildings to function well passively for tropical climates to minimise the need for mechanical cooling
  • Careful design of efficient mechanical ventilation, dehumidification and air-conditioning suitable for hot humid climates
  • Include ceiling fans to increase evaporative cooling, and to reduce reliance on air conditioning
  • Designing outdoor lighting to minimise light pollution to neighbouring properties (encouraging night time use of openings)
  • Take advantage of great solar access in tropical latitudes with PV energy sources and solar water heating
  • Innovative use of energy technologies, fittings or applications suitable for tropical climates (eg, the wet tropics have an abundance of water to produce hydroelectricity and water sources may also be used for heat transfer technology)

Clever design and use of technology around water demand and supply can provide a significant reduction in mains water usage. An increased awareness also results in a positive contribution toward alleviating growing water problems in many areas. As our population grows we will continue to face the challenge of the rising cost of infrastructure provision. For instance, the use of rainwater tanks and onsite recycling can produce benefits such as a reduction in the use of pipe quantities, reticulation energy and waste treatment. Other benefits may be the increased lot yields in subdivisions where land may be otherwise required for water containment ponds. Another benefit may be reduced erosion through a reduction of water flows that are diverted from water courses in peak rainfall periods as well as reduced flooding risks in urban areas.

6.1 General Water Use Considerations

  • Reduced requirements for landscape irrigation
  • Rainwater collected and reticulated for use in buildings and landscapes
  • Recycling and re-use of water including grey and black water
  • Low volume water fittings, beyond legislated requirements
  • Design landscapes to suit local microclimates and reduce the need for irrigation
  • Separate water metering enables better monitoring use
  • The ability to store test water for Fire Services for reuse

6.2 Tropical Water Use Considerations

  • Designing for water supply and management for up to 1:8 dry/wet season volumes (temperate climates generally manage 1:3)
  • Management of tropical pests and water borne disease
  • Tie-down of water tanks for cyclonic winds
  • Innovative use of water related technologies or applications suited to tropical climates