Green Building Basics

 

Buildings account for one-sixth of the world’s fresh water withdrawals, one-quarter of its wood harvest, and two-fifths of its material flows and around half of global energy consumption. Building "green" is an opportunity to use our resources efficiently while creating healthier buildings, achieve cost savings, and to build a better environment.

 

What Makes a Building Green? 

A green building is one that is designed, built or renovated, and operated in an ecological and resource-efficient manner.

Green buildings are designed to protect occupant health, use less energy, water, and other resources, and to reduce the overall impact on the environment.

 

What Are the Economic Benefits of Green Buildings?

 

A green building may cost more up front initially, but saves money through lower operating costs over the life of the building. Payback periods on the initial 'overcost' are in the range of 3-9 years, and after that it is pure economic gain.

The green building approach applies a project life cycle cost analysis for determining the appropriate up-front expenditure, analyzing the costs over the useful life of the asset.

The full potential of these cost-savings can only be fully realised when incorporated at conceptual design phase of a project, with the assistance of an dedicated and knowledgeable professional team. This integrated approach ensures that the building is designed as one system rather than a collection of ad-hoc elements.

 

Some benefits, such as improving occupant health and comfort, reducing pollution and waste, are not easily quantified and not easily considered in cost analysis.

Even with a tight budget, many green building measures can be incorporated with minimal increased up-front costs and still yield enormous savings. 

 

What Are the Elements of Green Buildings?

 

Following is a sampling of green building practices:

 

Siting

 

Ideally, start by selecting a site well suited to take advantage of public transport, to reduce dependence on private cars. 

Protect and retain existing landscaping and natural features, use plants having low water needs, and use compost and mulches to save water and time. 

 

Energy Efficiency

 

Most buildings can reach energy efficiency levels far beyond Building Regulation standards, though most developers will only work to meet the basic standard.  It is reasonable to aim for at least 40% less energy than a regulation standards building, and higher savings, of up to 70% are economically achievable.  The following strategies contribute to this goal:

 

• Use "Passive Design" strategies to dramatically affect building energy performance.  These involve building shape and orientation, use of 'passive solar' concepts, and maximum use of natural lighting (which also has a positive impact on well-being).

•   Create a highly thermally efficient building shell, with highly insulated and air-tight construction, combined with controllable ventilation strategies.  Maximize light colors for external roofing and wall finish materials, and use minimal glass in east and west facing walls.

• Use high-efficiency lighting systems with advanced lighting controls (including motion and daylight sensors).

• Minimize the electric loads from lighting, equipment, and appliances.

• Use energy-efficient heat/cooling system(s) properly sized for reduced heating and cooling needs of the building. Computer modeling is an extremely useful tool in optimizing design of electrical and mechanical systems and the building shell.

• Where appropriate consider alternative energy sources such as photovoltaics and micro wind-generators.

 

Materials Efficiency

 

Select sustainable construction materials and products, using sustainably harvested materials, materials with high durability, longevity and recyclability,  materials produced locally and/or with  reused and recycled-content; materials with zero or low off-gassing of harmful air emissions and toxicity.

Design adequate space to facilitate recycling collection.

 

Water Efficiency

 

One should design for dual plumbing systems to use recycled water for toilet flushing, or a gray water system that recovers rainwater or other nonpotable water for site irrigation: however, currently such systems are not allowed in Israel by the Ministry of Health. 

Minimize wastewater by using ultra low-flush toilets, low-flow shower heads, and other water conserving fixtures.

Use solar water heating systems for domestic hot water needs, with highly insulated short pipe-runs to minimise water wastage: use recirculating systems for centralized hot water systems.

Sub-meter the landscape water supply separately from building water supply. Use state-of-the-art computerised irrigtion controllers for landscape watering, together with micro-irrigation systems (excluding sprinklers and high-pressure sprayers) for non-grass areas.

 

occupant health and safety

 

Recent studies reveal that buildings with good overall environmental quality reduce the rate of respiratory disease, allergy, asthma, sick building symptoms, and enhance worker performance.  The potential financial benefits of improving indoor environments exceed costs by a factor of between 8 and 14. 

Choose construction materials and interior finish products with zero or low emissions to improve indoor air quality.  Many building materials and cleaning/maintenance products emit toxic gases, such as volatile organic compounds (VOC) and formaldehyde.  These gases can have a detrimental impact on occupants’ health and productivity.

Provide adequate ventilation, and when using mechanical ventilation use a high-efficiency filtration system.  Heating and cooling systems that ensure adequate ventilation and proper filtration (including 'Passive House' standard heat-recovery mechanical ventilation systems) can have a dramatic and positive impact on indoor air quality.

Prevent indoor microbial contamination through selection of materials  and finishes resistant to microbial growth. Provide effective drainage from roofs and surrounding landscape, install adequate ventilation in bathrooms, allow proper drainage of air-conditioning coils, and design other building systems to control humidity.

 

building operation and maintenance

 

Green building measures cannot achieve their goals unless they work as intended.  Building commissioning includes testing and adjusting the mechanical, electrical, and plumbing systems to ensure that all equipment meets design criteria.  It also includes instructing the staff on the operation and maintenance of equipment.

 

Written by: Tony Rigg, Dip Arch (Hons), registered Architect Israel & UK