doorway

Derives analytical expressions 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.

Discusses flow of air between two rooms through an open door. Considers 6 cases with and without mechanical ventilation and with a temperature difference between the two rooms. Gives examples of the calculation of air flow. Recommends that for hospitals where the transfer of bacteria should be avoided, doors should be kept shut as much as possible and that it is not economically justifiable to choose such a high ventilation rate that no undesirable back flow occurs with the doors open.

An earlier paper gave the flow to be expected through an open door from theoretical considerations. Describes model tests designed to check these theoretical predictions. The model used was 6.3% of full size and water was used instead of air for the flow medium. Concludes there is reasonably good agreement between model and theory.

Notes that some of the main contributors to excessive ventilation in industrial buildings are external doors and loading bays. Discusses the choice of industrial doors to minimise energy loss. Discusses flexible doors, strip doors, loading bays, air curtains and door sealing.

Describes research to study movement of air through fully or partially open doorways with and without influence of temperature, and to ascertain amount of supply air required toprevent this movement. Studies door openings of 0.10 to 104 m. wide and temperature differential of 0 to 12 deg.C. States that from these results critical areas in hospitals may be designed more effectively to given requirements.

Examines air flow into air-conditioned buildings caused by opened external doors in summer. Firstly the wind velocity through open doorways was measured using puffs of smoke inentrance hallways, finding that velocities varied from 104 ft/min to 350 ft/min with a mean of 265 ft/mins. Then tests were made on the air inflow when a swing door was opened and closed. Finally tests were made of the air flow due to operating revolving doors. Results for various types of entrances are displayed in a table.