English

This report contains a brief description of an air infiltration measuring device jointly developed by the National Bureau of Standards and Princeton University's Center for Environmental Studies. The device maintains a constant concentration of a tracer gas (SF6) in each room of a structure by injection, and relates the infiltration rate for each room to the rate of gas injected. Specifics of construction and use are included.

This report describes research undertaken to investigate the various factors affecting the air infiltration through windows. These factors examined include: 1) The effect of edge and face clearance or window fit 2) The effect of groove clearance on weatherstripping 3) The effect of weatherstripping 4) The effect of locking windows 5) A comparison of infiltration and exfiltration through windows 6) The effect of sash shrinkage, and 7) Theeffect of one-piece storm windows.

The purpose of this research project is for the Thermal Engineering Section of NBS to conduct air leakage measurements on selected large buildings tovalidate calculation formula developed by Shaw and Tamura, (see Shaw, C.Y., and Tamura, G.T., 'The Calculation of Air Infiltration Rate Caused by Wind and Stack Action for Tall Buildings', ASHRAE Trans., Vol. 83 part 2).

A comprehensive computer program for the prediction of air flow and smoke migration in the building was applied to the 11 story administration building of the National Bureau of Standards. Natural air leakage rates under various climatic conditions for several ventilation system operations were obtained. The computed results were compared with measured air leakage rate by using the sulphur hexafluoride tracer gas technique. Smoke migration was simulated for the selected pressurization conditions.

This report describes a technique which models the infiltration process for an entire enclosure more accurately than standard methods. Both air flow and convective/conductive heat transfer are accounted for to (a) improve building heat load calculations, (b) determine the important characteristics of existing (and new) buildings for infiltration heat loads, and (c) account more accurately for wind effects.

The effect of ventilation on airborne contamination was studied in a new operating suite containing operating rooms with conventional ventilation (17-20 ach) and operating rooms with zonal ventilation, where the air change in the central part of the room was about 80 ach. The efficacy of the ventilation was first examined with gas tracer experiments and foundsatisfactory. Experiments using potassium iodide particles showed the transfer between adjacent rooms in the suite to be less than .001% with closed doors and from 1% to .025% when the doors were opened once a minute.

This is done by means of a fan pressing air into the interior of a not air-tight greenhouse. The amount of exchanged air is measured by equipping the fan with a wind tunnel, it is depending on the difference of pressure between the inside and outside of the greenhouse. The difference of pressure and the air exchange figures are applied to the natural conditions in the case of different air velocities.

Comfort in an air-conditioned room depends to a high degree on the prevailing movement of air. As air velocities in excess of 0.1 m/sec can be regarded as draft phenomenon, a measuring device has been developed which will facilitate measurement to a sufficient accuracy and independent of any fluctuations in the air temperature even with low velocities.

In the early stages of the project on thermal performance of our experimental masonry building, measurements were made to determine the magnitude of air exchange between the building and the surrounding chamber during the process of cyclic temperature changes. Since wind forces were negligible during the testing period,the major driving force influencing the change of air was the thermal difference between the air inside of the building and that of the surrounding air in the chamber.

Three identical houses in Houston, Texas were extensively instrumented for measuring their air conditioner energy consumption and ceiling and duct heat-gain rates. Comparative tests were conducted to investigate differences in house performance due to increased attic ventilation. The performances of a roof-mounted power ventilator, a ridge vent, and wind-driven turbines were compared to the performance of soffit venting meeting the requirements of the HUD Minimum Property Standards.