Waste arisings

The complete amount of waste produced by a process.

Waste hierarchy

Developed by the UK government, the waste hierarchy is a conceptual framework directed at encouraging the management of waste materials. The hierarchy sets out the order in which options for waste management should be considered based on environmental impact.

Waste to energy (Energy from waste)

The use of waste as a fuel. If carried efficiently, and including pollution prevention, burning waste can address both the issues of diverting waste from landfill while at the same time generating energy for heating or electricity.

Water conservation

A non-porous surface that generates a surface water runoff after rainfall..

Whole-of-life costing

The air quality within a building as it relates to the health and comfort of the occupants. IAQ can be affected by contaminants or gases. Ventilation is the primary method of improving IAQ, though many claim that ‘breathing wall’ construction has an equal role. 

Wind-tightness layer

An essential feature of lightweight construction or rainscreen cladding, a wind-tightness membrane, located on the external, ‘cold’ side of the insulation, prevents the driving of cool air through the insulation.

Window energy rating

Rates windows on their thermal performance. It has a scale of A to G, where A is very energy efficient and G is very energy inefficient. The rating is based on three factors- thermal transmittance (U-value), which measures how well a window prevents heat escaping; the solar factor (g-value), which measures how well a window blocks heat caused by sunlight; and air leakage. For further information see: www.bfrc.org

Wood preservatives

Chemical preservatives and processes (‘timber treatment’) designed to extend the life of timber through increased durability and resistance from being destroyed by insects or fungus. Use of the more toxic chemicals developed in the twentieth century (eg CCA and arsenic) has been recently suspended in most countries. However the majority of chemicals used today continue to be associated with environmental as well as, in some cases, health concerns. Use of any preservative should be carefully considered, but in the event of its being required, the least hazardous preservatives are borate. To avoid leaching-out, borates should be protected from contact with water or persistent moisture. Consideration should be paid too, to timbers that are naturally durable and do not require the use of preservatives.