Development of a Computer Programme for the Prediction and Control of Mould Growth in Buildings Using the ESP-r Modelling System

Abstract

Based on an analysis of the best published data, critical limits for the growth of six commonly occurring indoor moulds (defined in terms of relative humidity and temperature) have been formulated into a mould prediction computer programme. The fungi were selected as representative of moulds which differ in their relative humidity and temperature requirements to sustain surface growth, and because several were known mycotoxin producing species and of potential health significance. Each growth limit curve was generated from a series of data points on a temperature-relative humidity (RH) plot and fitted using the third-order polynomial equation RH = a-)T3 + a2T2 + ajT + ao. The model was incorporated within the Environmental Systems Performance research programme for transient simulation of the energy and environmental performance of buildings, thereby enabling the system to predict the likely occurrence of mould development for fungi which exhibit similar temperature/ RH requirements to the reference moulds. The model predicts the interactive parameters which give rise to local environmental conditions that encourage mould growth. The system’s predictive capability was tested via laboratory experiments and by comparison with monitored data from a mouldy building.

Condensation Targeter II: Modelling surface relative humidity to predict mould growth in dwellings

“…Various moisture models, ranging from simple steady-state calculations to two and three-dimensional models incorporating different hygroscopic properties have been developed (5) and some moisture models have been integrated with transient thermal models (6) . All such models can play a significant role in research.…”

“…Jones has suggested that the following equation 'should be included in all but the most simple models' (31) . He continues, 'In the Bredem energy model which includes vapour pressure calculations, the Loudon steady-state equation could be amended to': (5) Converting the vapour content terms in the equation to vapour pressures gives: (6) Typical values for α and β for a wood lined room have been put forward by Jones as α = 0.6 and β = 0.4. Jones further suggests that numbers of this order could be expected to apply to normal types of buildings.…”

A System of Permeability Specification for Use in Moisture Simulation Models

“…High humidity and condensation on internal structural surfaces can promote mould growth which, apart from the obvious degradation and aesthetic effects [3], has been linked to adverse health symptoms [4]. Interstitial condensation and the accumulation of moisture within structures can lead to a serious deterioration in the performance and integrity of materials and a structural degeneration of the building fabric [5].…”

A Review of ESP-r's Flexible Solution Approach and its Application to Prospective Technical Domain Developments

“…conjugate heat and mass transfer within building materials (Nakhi, 1995), mould growth (Rowan et al, 1997), building integrated renewables (Clarke and Strachan, 1994;Clarke et al, 1996), electrical energy systems (Kelly, 1998), fuel cells (Beausoleil-Morrison et al, 2002), stochastic occupant behaviour (Bourgeois et al, 2005), and micro-CHP (combined heat and power), (Ferguson and Kelly, 2006).…”