Building construction and operation have a tremendous impact on the environment. In addition to the strategies mentioned in the previous sections, there are some others green building principles that can enhance the sustainability of buildings. These principles include water conservation in buildings and indoor environment quality (IEQ) enhancement.

Water conservation in buildings

The amount of water used in building is enormous. There are a number of strategies that can be employed to prevent the waste, overuse and exploitation of water. These strategies include water recycling or reuse, using water-efficient plumbing fixtures and preventing water system leaks.

Water recycling or reuse
Some of the water use requirement in buildings can be met with non-potable water. The non-potable resources can be obtained by treating used water and then redistributed to the required supply points. The used water is usually captured from various sources such as showers, sinks, laundries and rainwater etc. Water quality should meet appropriate wastewater treatment standards such as that outlined by ACQWS [1], the Building Research and Information Association (BSRIA) [2], or relevant guidelines. The treated water can be used for landscape irrigation, decorative fountains, toilet flushing and evaporative heat rejection system in air conditioning etc.

Using water-efficient plumbing fixtures
Using water-efficient plumbing fixtures can significantly reduce the demand of water consumption in buildings. The strategy of saving water by using water-efficient plumbing fixtures is to use minimum amount of water to satisfy the demand. For example, ultrasonic or infrared sensors are incorporated into new faucets and urinals so that the devices are automatically activated when people are detected. Other water-efficient designs of faucets and showerheads include: 1) metered valve that deliver a preset amount of water and then automatically shut off, 2) spring-loaded faucet valves for shutting off the faucets a period of time (usually a few seconds) after the user turn it on, 3) narrower spray area and greater mix of air and water then old designs.

Preventing water system leaks
Water system leaks may occur in existing and aged buildings. Even a small leak can result in the loss of large quantities of water over time. This is a kind of resource wastage. In addition to wastage, water system leaks that are not repaired immediately can damage building structures. Therefore, the amount of water use in a building should be monitored regularly.

Other than aged building, water system leaks can occur in new construction from improper installation of piping and fixtures, or damage to piping during construction process. Therefore, it is important to commission the water distribution system as part of the overall building commissioning process.

[1] Water Supplies Department. ACQWS Paper No. 14 - Treated Effluent Resuse at Ngong Ping.
[2] BSRIA, Greywater and Rainwater System: Recommended UK Requirements, The Building Services Research and Information Association, Final Report 13034/1, March 1997.

Enhance Indoor Environmental Quality (IEQ)

General guidelines
The indoor environmental quality of a building has a significant impact on occupants' health, comfort, and productivity. IEQ includes various aspects regarding the quality of thermal, visual, acoustical and indoor air etc. of the building interior. In order to ensure an acceptable IEQ for most of the occupants, the following consideration should be taken during the building design and development stage:

  • Provide thermal comfort by adopting suitable natural and mechanical ventilation strategies. When using mechanical ventilation, maximize the degree of personal control over temperature and airflow;
  • Supply adequate levels of ventilation and outside air to ensure indoor air quality. More details of ventilation by supplying outside air can be found here;
  • Avoid the use of materials that are high in volatile organic compounds (VOCs) emissions;
  • Assure acoustic privacy and comfort through the use of sound absorbing material and equipment isolation;
  • Control odors through contaminant isolation;
  • Create a high performance luminous environment through the careful integration of natural and artificial light sources. Design strategies of natural light sources can be referred to here;

Relevant codes, standards and Guidelines
The IEQ levels of various aspects listed above can be designed to meet the following codes and standards.

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