Drainage ventilation systems for underground structures II: simulation of transient response.

The propagation of low-amplitude air pressure transients within the drainage and vent systems of underground habitable structures may result in system failure due to trap seal loss and foul odour ingress into the occupied space. This paper develops the simulation of such transient response, and presents comparisons between predicted system air pressures and those monitored during the operation of the drainage and vent system in a large London Underground tube railway station.

Perceived Air Quality: Should We Use a Linear or a Nonlinear Scale for the Relation between Odour Intensity and Concentration?

Assessing the perceived air quality in decipols by trained panels can be performed rather perfectly today. To calculate the olf load from these results is a little more problematic as one requires olf loads which can simply be added (linearly). The reason for this difficulty is the nonlinear relation between the perceived air quality in decipol and the pollution load in olf. The relation can be expressed by an exponential function in a range between l to 15 decipols. Unfortunately the exponent and the constant in the exponential function differ for different substances.

Experimental and analytical evaluation of VAV air conditioning system in an office building.

The flow-pressure characteristics of the AHU/VAV air-conditioning system in an open-plan office building is assessed by site experiments under various conditions. The effects of VAV supply pressure setting, return fan pressure setting and damper operation on energy consumption, fresh air intake and ex-infiltration flow rate are evaluated analytically on the basis of the VA V/ A.HU system and component characteristics.

Material odour emission test methods: review and evaluation.

This materials odour emission project was conducted for the Task Force on Materials Emissions and four industry sponsors. The objectives of the project were to review material odour test methods, conduct comparative tests of various materials by the most applicable methods and to recommend test methods for materials odour emission characterization. The review identified six test methods which were then compared in a program of odour testing of 1 0 materials. Two test methods were quantitative odour intensity methods and four methods used perceived intensity and hedonic scales.

Evaluating building IAQ and ventilation with indoor carbon dioxide.

A number of approaches exist to evaluate building ventilation and indoor air quality. In some situations, the measurement and analysis of indoor carbon dioxide concentrations can be useful for understanding indoor air quality and ventilation. On the other hand, oversimplified descriptions of measurement procedures based on carbon dioxide have been presented, and there have been many instances in which indoor carbon dioxide concentration measurements have been misinterpreted and misunderstood.

Low maintenance odour control system.