Air exchange through doorways. The effect of temperature difference, turbulence and ventilation flow
- 1 August 1977
- journal article
- research article
- Published by Cambridge University Press (CUP) in Epidemiology and Infection
- Vol. 79 (1) , 141-154
- https://doi.org/10.1017/s0022172400052931
Abstract
SUMMARY: Analytical expressions have been derived for the exchange of air across doorways or similar apertures, in terms of the temperature difference between the spaces on both sides of the opening and the net volume of air flowing through this as a result of unbalanced air supply or extract. A simple allowance for turbulence which gives reasonable correspondence with observation is included. The formulae, which assume complete air mixing on both sides of the doorway up to the plane of the aperture, predict outflows from the warmer side, when there is an excess air supply to this side, which are progressively smaller than those observed as the temperature difference rises above 2–3 °C and the volume of excess air supply increases to produce an averaged outflow velocity greater than 0·1–0·15m/s. This seems to be due to lack of mixing of the warm outflowing air with the cooler air mass. A correction factor for this can be deduced as a function of the pressure difference due to the excess air supply. The limiting magnitude and general form of this function are compatible with a simple theoretical model of the air flow patterns involved.This publication has 3 references indexed in Scilit:
- Airborne infection in a fully air-conditioned hospital: III. Transport of gaseous and airborne particulate material along ventilated passagewaysEpidemiology and Infection, 1975
- Airborne infection in a fully air-conditioned hospital: I. Air transfer between roomsEpidemiology and Infection, 1975
- Airborne infection in a fully air-conditioned hospital: II. Transfer of airborne particles between rooms resulting from the movement of air from one room to anotherEpidemiology and Infection, 1975