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CIBSE launches new guide to Practical Psychrometry

The Chartered Institution of Building Services Engineers (CIBSE) is pleased to announce the launch of its new publication - KS20: Practical Psychrometry. Available to order from the online CIBSE Knowledge Portal, the guide is essential reading for those involved in designing and operating the systems that achieve comfortable environments for occupants, such as air conditioning.

An understanding of psychrometry is an increasingly important issue for the building industry as a whole. It is essential primarily to prevent environments being created which are detrimental to health, either through too dry an atmosphere or conditions where damp and mould can flourish. In ill-ventilated spaces conditions can allow mould and spores to grow and dust mites to thrive.

In addition problems caused by moisture have revealed a tension between the efforts to make buildings more airtight and the need to increase ventilation in Passivhaus design for example. Here a more holistic energy efficiency strategy may need to be considered to ensure a balance between the two.

English Heritage has already warned of the potential damage caused by insulating internal walls and reducing ventilation in historic buildings; a holistic view of a building is also necessary with the planned retrofitting of UK housing stock, much of which consists of older properties, targeted by the Government's Green Deal.

Aimed at those requiring an introduction to psychrometry, the guide covers some typical examples of sample systems. The publication looks at the properties of atmospheric air; the basis for and the construction of the psychrometric chart; psychrometric processes such as heating, cooling, humidification and dehumidification and the equipment that is used.

Practical Psychrometry is available at and is free of charge to CIBSE members.