Rising moisture from the ground has caused quite a lot of damage on foundations of Swedish buildings, in particular for the type concrete slab on the ground. Some of these constructions may be repaired by mechanical ventilation, for example below the floor or below the concrete slab , if there is an air-permeable layer below the slab. Summarized results from a few field studies and tests, which have been going on for a period of 2-3 years, are reported. Different methods with mechanical ventilation systems have been found to work quite well so far, i.e.
In the past years the need has grown for a sensitive flowrate meter with a very low pressure drop. Such a device can be used to measure flowrates of airflows through the grilles of mechanical ventilation systems with low duct pressures. Another application would be the measurement of flowrates through the different rooms of a dwelling during a blower door test. A prototype was developed based on the very simple principle of a throttled fan. The prototype proved to be accurate and capable of measuring flows on ducts with natural ventilation.
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