Water vapour in the built environment
Water vapour is the phase of water (H2O) that takes the form of a gas. It is a component of the Earth’s hydrologic cycle and is abundant in the atmosphere.
Boiling liquid water can produce water vapour by a process of evaporation, while ice can produce water vapour via sublimation. The use of water vapour in the form of steam has been a fundamental part of energy production since the Industrial Revolution.
Air will generally include moisture in the form of water vapour. Absolute humidity is the mass of water vapour in a volume of air divided by the mass of dry air. When air cools, it is less able to 'hold' moisture, that is, the saturation water vapour density falls, and so the relative humidity rises. When the relative humidity reaches 100%, the air will be saturated. This is described as the dew point. If the air continues to cool, moisture will begin to condense.
For more information see: Humidity.
The presence of water vapour in a building can lead to problems with condensation and moisture which can result in mould growth, damp, staining, and so on.
Moisture in buildings can be reduced by removing or reducing the source of water (such as washing processes, leaking pipes, rising damp and so on) or by drainage, ventilation, increasing temperatures or dehumidification.
[edit] Related articles on Designing Buildings
Featured articles and news
Building safety, a shifting landscape for professionals
A commentary from the insurance perspective.
In brief with further links.
Walter Segal: self-built architect
A definitive book on a pioneer of green architecture.
Funding for heritage on the high street
Using heritage as a catalyst for reviving historic centres.
Commonwealth Heads of Government Meeting update.
Declaration prioritising sustainable urbanisation adopted.
A small hidden, often distant but key building component.
Some brief words about the actuator.
CIAT Chief Executive steps down.
After 34 years at the Institute.
Volunteer opportunity launched by the ICE
To support the next generation of engineers.
Provisional findings show illegal cartels in the industry.
CIAT reporting from the Competition and Markets Authority.
Making sustainable construction number one priority.
The future of construction report.
Interview with ECA CEO.
Many provisions came into force on June 28, 2022.
With room to expand.
An information packed session at the BSRIA conference.
Refurbishment, Energy Efficiency, Indoor air and process.
Considering building acoustics with the AT Journal.
Why building acoustic considerations must be non-negotiable.
Create a profile, write informed product articles and share.
Aluminium Composite Panels (ACP) is one example.
Top 50 Women in engineering 2022.
Inventors and innovators at ICE.
Life, death and art at the Stuart court. Book review.
Real estate, place adaptation and innovation.
Review and comment on the revised draft before July 11.
We are indeed now 10 years old, so go on and be bold !
Write about something you know, help us build and grow !
IHBC's 25th anniversary 2022 Aberdeen School.
A blended event and triumphant return.
New Construction Leadership Council Co-Chair selected.
Mark Reynolds succeeds Andy Mitchell as Co-Chair of CLC
Designing Buildings is 10 years old.
Types of work to existing buildings.
From alteration to deconstruction on DB.