UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Condensation risk: comparison of steady-state and transient methods

Mumovic, D; Ridley, I; Oreszczyn, T; Davies, M; (2006) Condensation risk: comparison of steady-state and transient methods. BUILD SERV ENG RES T , 27 (3) 219 - 233. 10.1191/0143624406bse163oa. Green open access

[thumbnail of BUILDING_SERV_ENG_RES_TECHNOL-2006-Mumovic-219-33.pdf]
Preview
PDF
BUILDING_SERV_ENG_RES_TECHNOL-2006-Mumovic-219-33.pdf

Download (763kB)

Abstract

Accurate assessment of both surface and interstitial condensation risk is important not only to reduce the damaging effect of moisture within the structure of buildings, but also to provide a healthy environment free from mould growth. The current British Standard (BS EN ISO 13788: 2002) contains an assessment procedure based on the assumption of a steady-state heat flow through the building envelope, neglecting the transient nature of the problem. This paper compares and evaluates numerical results of the condensation risk calculation under both steady-state and transient conditions using the existing numerical codes. Significant differences are apparent between the predictions of the simple (steady-state) and complex (transient) methods for all construction details modelled.Practical application: The current British Standard (BS EN ISO 13788: 2002) gives calculation methods for determining the internal surface temperature of a building component or building element below which mould growth is likely, given the internal temperature and relative humidity-the method can also be used to assess the risk of other surface condensation problems. The calculation methods in the Standard are steady-state. The paper concludes that for cases where the steady-state method predicts that surface RH values will remain below the key value of 80%, a transient method can predict surface RH values to be above 80% for several hours. The practical implications of this work then are that transient calculation methods may be necessary under certain circumstances. This is particularly relevant given that the issue of a time period of a few hours is now more pertinent as it relates to a new transient performance standard in the new draft Approved Document F (Building Regulations-England and Wales).

Type: Article
Title: Condensation risk: comparison of steady-state and transient methods
Open access status: An open access version is available from UCL Discovery
DOI: 10.1191/0143624406bse163oa
Publisher version: http://dx.doi.org/10.1191/0143624406bse163oa
Additional information: © The Chartered Institution of Building Services Engineers 2006. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 3.0 License (http://www.creativecommons.org/licenses/by-nc/3.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page(http://www.uk.sagepub.com/aboutus/openaccess.htm).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of the Built Environment
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of the Built Environment > Bartlett School Env, Energy and Resources
URI: https://discovery.ucl.ac.uk/id/eprint/149446
Downloads since deposit
214Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item