In order to reduce the heat loss from buildings it is common to increase the thickness of insulation in the building envelope.The consequence of this action is more expensive buildings. Building regulations in countries with cold climate require U-values far the envelope which results in thicker and therefore often stronger constructions than needed for structural capacity. Another strategy to save energy has been to reduce the ventilation rates in buildings.

This paper presents the results of a monitoring programme on a medium sized educational building which has had the external walls re-clad. The objective behind the re-cladding was to improve the durability of the building and to improve the thermal performance. The objectives of this work were to establish the viability of the calculation techniques used to simulate the ventilation, thermal and moisture performance of the re-cladding system. The results have shown that there is a good agreement between the methods currently being used and the actual performance.

A design guide for displacement ventilation (thermally induced ventilation ) has been prepared. It is based on quasi stationary experiments carried out in the Sulzer Infra laboratory in Winterthur. The significant design parameters identified by factorial analysis are the air flow rate, the internal load, the convective part of the internal load and to a lesser extent the room height. Using a linearized polynom representation for the temperature increase near the floor as well as for the vertical temperature gradient in the occupied zone a design nomogram has been obtained.

The fan and the ductnetwork is designed for 100% ventilation rate. Because the fan energy is the main important energy consumption in systems all over the year it is worthwhile to control the systems correctly. By reducing the air volume rate the pressure drop in the ductnetwork drops nearly with the second power.

The relative energy use of PSV and extract fans has been a matter of considerable controversy, particularly in the UK. A steady state methodology is presented based on the approach of BS5250 and that of Professor Meyringer (Air Infiltration Review November 85).

This paper reports on the findings from two extensive laboratory studies of ventilation of bathrooms of different sizes and layout of ventilation. The ventilation flow rates were varied. Moisture production were due to laundering and shower baths. In one of the studies the bathroom was provided with a drying cabinet. The extract air was forced to pass through the drying cabinet which was connected to the extract ventilation system of the house by a duct running from the cabinet to the extract air terminal device.

Blower Doors are used to measure the air tightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, quantification of airtightness data is critical in order to answer the following kinds of questions: What is the Construction Quality of the Building Envelope? Where are the Air Leakage Pathways? How Tight is the Building? How Much Ventilation Does the Air Leakage Supply?

The paper summarises an approach to determining the equations governing the air flow through simple cracks subject to fluctuating pressures. To this end, an experimental arrangement has been developed that enables the laboratory simulation of fluctuating driving pressure signals. A standard straight crack was subjected to this signal, which fluctuates in both magnitude and frequency. An air control system permits a high level of fluctuating pressure control.

In order to demonstrate conformity with the current Building Regulations, many house builders are incorporating sumps beneath the ground floor construction of houses within the designated Radon Affected Areas. These sumps will allow for later depressurisation of the below ground floor construction and thereby prevent radon passage to the internal building environment. There are concerns regarding the costs of these measures and also the potential for these sumps to be used by vermin as nesting sites as well as their effectiveness.

Mechanical ventilation of the underfloor space is one of the most effective ways of reducing radon levels in buildings with suspended timber floors. There is a question however whether this ventilation should be supply or extract, sometimes extract is more effective, soinetiines supply is inore effective. This report presents a simple analysis of the problem and suggests the hypothesis that the relative effectiveness of supply or extract ventilation to the underfloor space depends on the relative airtightness of the floor and the soil or oversite surface.