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
Mental Health Awareness Week with ABS
Architects Benevolent Society programme of activity.
CLC publishes domestic retrofit competency framework
Roadmap of Skills for net zero.
May 13-19: Moving more for our mental health.
Understanding is key to conservation.
Open industry engagement survey seeks responses
Institutions and the importance of engagement.
National Retrofit Hub unveils new guide
Digital Building Logbooks and Retrofit: An Introduction.
Top 50 firms awarded 52bn of projects in the last year
New engineering data shows.
Enhancing construction site reporting efficiency
Through digitisation and the digital revolution.
Noise in the built environment
BSRIA guide TG 20/2021.
17,000 people suffer conditions as a result of exposure to excessive noise at work.
Turning down the noise: Auditory health
A pervasive risk with far-reaching consequences.
Getting the most out of heat pumps and heating
How heat pumps work and how they work best.
Plumbing and heating for successful retrofit and renovation
Low temperature underfloor systems and heat pumps.
Cost-of-living crisis and home improvement plans
Starting on the right footing and top tips for projects.
Delays on construction projects
Types, mitigation and the acceleration of works.
From Chaucer to Fawlty Towers.
Electrotechnical excellence, now open for entries.
Net zero electricity grids BSRIA guide NZG 5/2024
Outlining the changes needed to transition to net zero.
CIOB Global Student Challenge 2024
Universitas Indonesia wins for second year running.