Air exchange rate

from Wikipedia, the free encyclopedia
Built-in blower door device for measuring the air exchange rate

The air exchange rate n is a measure of the supply air volume flow of the room air in relation to the construction volume of buildings. It plays a role in ventilation technology and heating technology .

definition

The air exchange rate in the unit [1 / h] indicates the multiple of the room volume that is supplied as supply air or discharged as exhaust air .

Example: n = 15rv / h: 15 times the room / building volume is exchanged in one hour. (Rv = room volume)

Strictly speaking, this statement only applies to displacement ventilation . With dilution ventilation , the rate of air actually exchanged is much lower.

Example of outside air flow

The outside air rate is determined by the number of people in the rooms to be supplied and the outside air rate per person in accordance with the applicable regulations. Recommended outdoor air rates per person are for example:

  • Open-plan offices 50 m³ / h
  • Restaurants 40 m³ / h
  • Individual offices, conference rooms, lecture halls 30 m³ / h
  • Theaters, halls, halls 20 m³ / h

If additional odor nuisance is to be expected, the stated values ​​are increased by approx. 20 to 50%.

Examples of air exchange rates

The type of room use is responsible for determining the air exchange rate. Recommended air exchange rates are for example:

  • Office rooms 3 to 6 times per hour
  • Guest rooms, meeting rooms 5 to 10 times per hour
  • Lecture halls 8 to 10 times per hour
  • Department stores 4 to 6 times per hour
  • Cinemas, theaters 4 to 6 times per hour
  • Swimming pools 3 to 4 times per hour
  • Toilets 4 to 6 times per hour
  • Laboratories 8 to 15 times per hour
  • Kitchens 20 to 30 times an hour

Regardless of the air exchange rate, however, it must be ensured that the entire room volume is recorded and changed in the affected rooms.

Air exchange rate n 50 as a measure of density

The air exchange rate n 50 is a measure of the airtightness of a building. This figure results from the air volume flow that occurs per hour if a pressure difference of 50  Pa is maintained, divided by the building volume. The smaller the number, the denser the building. For normal buildings without ventilation and air conditioning systems, an air exchange rate of , is required for those with ventilation and air conditioning systems . The following applies to passive houses . The measurement is z. B. realized with the blower door test ( differential pressure measurement method ) .

Hygienic minimum air exchange rate

The hygienic minimum air exchange rate is around 0.3 / h. It is a minimum for ensuring fresh air below which odor problems , dust and microorganism pollution and excessively high radon concentrations can occur.

literature

  • Gunhild Reuter: Mold in the apartment. Prevent - identify causes - combat, 2nd updated edition, Verlag Dashöfer, Hamburg 2010.
  • Gottfried Lohmeyer, Heinz Bergmann, Matthias Post (eds.): Practical building physics. An introduction with calculation examples, 5th edition, BG Teubner Verlag, Stuttgart 2005, ISBN 3-519-45013-5 .
  • Wolfgang Willems, Simone Dinter, Kai Schild: Vieweg Handbuch Bauphysik. Part 1, heat and moisture protection - comfort - ventilation, Friedrich Vieweg & Sohn Verlag, Wiesbaden 2006, ISBN 978-3-528-03982-0 .
  • Peter Lutz, Heinz-Martin Fischer, Richard Jenisch, Heinz Klopfer, Hanns Freymuth, Ekkehard Richter, Karl Petzold: Textbook of Building Physics. Sound - heat - moisture - light - fire - climate, BG Teubner Verlag, Stuttgart 1997, ISBN 978-3-322-94083-4 .

See also

Web links

Individual evidence

  1. ↑ Requirements for tightness and the minimum air exchange. EnEV Online, accessed on February 4, 2010 .