C.H. Sanders

The Measurement and Prediction of Conditions within Indoor Microenvironments

Biocontaminants, such as dust mites and microfungi, can live in building habitats with a spatial scale of only a few millimetres. With the recent development of very small size microchip-based sensors, it is now practicable to measure the humidity at different locations within these microenvironments. In the laboratory study described here, sensors were used to measure the conditions in a number of typical flooring systems using a variety of coverings. The measurements were compared with the predictions of a well-established and validated dynamic heat and moisture transfer simulation model. In order to provide an accurate input to the model, permeability and sorption tests were carried out on the flooring materials used. Finally, using monitored domestic environmental data, simulation results were coupled to a simplified growth model to predict dust mite activity in the flooring systems under realistic boundary conditions.

Domestic laundering: Environmental audit in Glasgow with emphasis on passive indoor drying and air quality

As the UK and Scottish governments aim for zero-carbon housing, with tightly sealed building envelopes becoming paramount, indoor air quality (IAQ) and its implications for health has become a concern. This context relates to a 2008–2011 study, ‘Environmental Assessment of Domestic Laundering’, concerning the prevalence of passive indoor drying (PID). Assessment of PID impacts, shaped by built and social context including occupants’ habits and trends, draws on monitored data from 22 case studies out of a wider survey of 100 dwellings in Glasgow. The smaller group included analysis of air samples and provided scenarios for enhanced dynamic modelling via laboratory work on moisture buffering. The evidence suggests PID has important implications for energy consumption and IAQ; in the latter case because moisture levels are likely to boost dust mite populations and concentrations of airborne mould spores. Thus, findings indicate possible negative impacts on health, and the paper recommends amended standards allied to design guidance for improved practice, as well as further work related to volatile organic compounds.

Principles and Calibration of Solid Phase Microextraction Fibre (Passive Sampler) for Measurements of Airflow and Air Infiltration in Dwellings

Abstract Tracer gas techniques have been the most appropriate experimental method of determining airflows and ventilation rates in houses. However, current trends to reduce greenhouse gas effects have prompted the need for alternative techniques, such as passive sampling. In this research passive sampling techniques have been used to demonstrate the potential to fulfil these requirements by using solutions of volatile organic compounds (VOCs) and solid phase microextraction (SPME) fibres. These passive sampling techniques have been calibrated against tracer gas decay techniques and measurements from a standard orifice plate. Two constant sources of volatile organic compounds were diffused into two sections of a humidity chamber and sampled using SPME fibres. From a total of four SPME fibres (two in each section), reproducible results were obtained. Emission rates and air movement from one section to the other were predicted using developed algorithms. Comparison of the SPME fibre technique with that of the tracer gas technique and measurements from an orifice plate showed similar results with good precision and accuracy. With these fibres, infiltration rates can be measured over grab samples in a time weighted averaged period lasting from 10 minutes up to several days.