2008

Thursday, December 11, 2008

Wednesday, November 26, 2008

Friday, November 14, 2008

Amalgam Tray Instruments

The Blower-Door-Test to measure the tightness of a building by measuring the pressure difference.

Because of the permeability of the building, the cold air enters through cracks and cools the surface, while the warm, humid air is directed inside outward and in contact with cold surfaces can lead to condensation and mold. To avoid unpleasant surprises of this kind is necessary to achieve good airtightness of the envelope, which must, therefore, provide a continuous airtight layer.

E 'possible to evaluate the tightness of the building by measuring the flow of air exchange due to leakage, creating a pressure difference mechanically.
Through a dedicated fan, the air is injected or sucked under the building misura.La strength of the fan is adjusted in relation to the ambient pressure so that there is a difference of 50 Pa (Pascal) [up to 70 Pa ed.]

With a wind strength of about 5 there is a pressure difference of 50 Pa. (The difference in pressure between two points of the atmosphere is one that generates the wind).

It induces an airflow equal to that due to "leakage" of the building (due to depression). The measured air flow is divided by the volume of the building.

n50 Typical values \u200b\u200bare:
<= 0,6 /h
passive house building energy-efficient <= 2,0 /h
building with forced ventilation system <= 1,5 /h [valore misurato 1,4 /h]
traditional building <= 3,0 /h

are generally undesirable losses when the air speed ≥ 2.0 m / S. Air flow rate of less than 1m / s can be tolerated. N50 worth of 4 per hour means that a difference of pressure of 50 Pa the air volume of the building is changed to 4 times an hour.