Abstract
People sometimes attribute effects to “humidity” without understanding the underlying physics. For example, we have all
experienced “hot, humid” summer weather. Yet the outdoor air relative humidity on a “hot, humid” summer day (95°F db/78°F wb [35°C db/26°C wb]) is less than 50%. By contrast, the outdoor air relative humidity on a “cold, dry” winter day is typically around 80%. This article examines the difference between relative humidity, specific humidity, and vapor pressure. It goes on to explore how those measures influence phenomena loosely attributed to “humidity.”
This is a good source for info on humidity, including identifying 'operative factors': relative humidity; specific humidity; vapour pressure. Maintaining RH < 60% 'does not guarantee against mould growth' - 'Where moisture is unavoidable…the key to eliminating mould growth is to eliminate food sources' Use of materials that don't hold or take in moisture is more effective than maintaing RH @ 60%
Categories
Background and concept, Below-ground Masonry, Crawlspaces and Basements, Existing Conditions, Insulation, Moisture in Materials, Roof structures, Wall assemblies
Files
| File | |
|---|---|
| RH-science-explanation.pdf |
Additional information
- [acf_PublicationInformation_knowl_meta_originating_url] Orginating URL
- [acf_PublicationInformation_knowl_meta_year_of_publication] Year of publication
- [acf_PublicationInformation_knowl_meta_document_type] Document accessibility
- [acf_PublicationInformation_knowl_meta_publishing_region] Relevant region
- Version
- 441 Times downloaded
- 712.20 KB File Size
- 1 File Count
- 8 March 2014 Creation Date
- 25 September 2019 Last Updated