BS 8542:2011

Provides recommendations for calculating the volume of public mains water that is consumed per head per day, per unit per day, or per building per annum for domestic use in non-domestic buildings.

This British Standard gives recommendations for calculating the volume of public mains water that is consumed per head per day, per unit per day, or per building per annum for domestic use in non-domestic buildings. It gives recommendations for estimating the total water use from the buildings’ components, allowing consumption to be indicated on a whole building level against other buildings for best practice levels.

This standard is not for use as a design guide.

It provides a framework for and details the development of water use calculation methodologies in non-domestic buildings. It provides recommendations for the quality of data used to calculate water use for each component in non-domestic buildings and also standardized reporting for product performance data.

It applies to both new and existing buildings and covers:

• water that is sourced from unwholesome sources such as rainwater harvesting systems or greywater reuse systems; and

• water that is sourced from wholesome sources including both hot and cold water.

This British Standard does not cover design, installation, testing and maintenance of services supplying water for domestic use. Water use in industrial processes or for agricultural, medical or fire suppression applications and external water use such as irrigation or building services, e.g. air conditioning plant and cooling, are also not covered.

It does not provide all data for calculating water use in non-domestic buildings, but provides recommendations for the data used to calculate water use in non-domestic buildings. This includes the product performance data for each terminal fitting and water use research data determining the frequency and duration of use for each terminal fitting.

NOTE Total water use may be determined by metering the building, although it might be difficult to differentiate between domestic water uses and water use for other purposes unless these are sub-metered.