Can adventitious ventilation negatively impact moisture performance of building envelopes in moderate climates ?

In moderate climates, adventitious ventilation helps in keeping the water vapor balance in a building under control. This does not hold in hot and humid climates, where the outside air is a moisture source. Adventitious ventilation should be avoided in such climates and intended ventilation flows must be dried before entering the space. Anyhow, could adventitious ventilation also generate moisture problems in moderate climates? To get an answer, a reference case was analyzed with the air leakage distributed over facades and roof.

Measurement of indoor relative humidity using a passive sampler for water vapour.

As part of the energy and indoor climate survey recently carried out in Sweden (the ELIE study) a simple, inexpensive but reliable passive sampler for estimating monthly averages of relative humidity has been developed. The diffusion sampler consists of a 5 ml plastic tube prepared with lithium chloride monohydrate as trapping medium. After necessary calibration of this particular design of sampler the relative humidity can be calculated from the weight change of the sampler, the time of sampling and the average temperature during this period.

Attic ventilation.

Moisture Admittance Model: Measurements in a Furnished Dwelling.

The BRE method of predicting water vapour conditions in houses is based on two generalised moisture admittance parameters a and p. Previous laboratory experiments suggested that it is possible to determine these coefficients for an unfurnished room with wooden panels, using measurement periods of six hours under dynamic equilibrium conditions. The present study explores the possibility of using such conditions to determine a and P in-situ for the living-room and bedroom of a furnished flat of conventional construction.

Correlations between CO2 and Steam concentrations Measured in 60 Occupied Housing Units.

Within the framework of demonstration and industrial pilot projects in the energy sector supported by the Commission of the European Economic Communities, an important experiment has been dedicated to the HYGRO-ADJUSTABLE NATURAL VENTILATION (Contrat EE/166/87/FR). The experiment took place on three sites: Les ULIS (France), NAMUR (Belgium) and SCHIEDAM (the Netherlands).

Condensation in dwellings: the gas solution.