ventilation

The problem of describing quantitatively the effective ventilation in a room when the air within the room is imperfectly mixed is discussed. It is suggested that the protection afforded by the ventilation to any given position against air

In this paper it is our intention to consider that ventilation is the circulation or passage of an air supply through an enclosure resulting in the displacement of some or all of the air contained in that enclosure by thesupply air. Depending on the character and condition of the supply air it can dilute or change the quality of the air in an enclosure as well as alter its temperature and humidity. A mathematical analysis of the ventilation process appears later in this paper.

The effect of ventilation in the space between a main wall and an exterior siding is examined with respect to reducing the building's cooling load. The buoyant force of the air in the space is considered as the motive force of air flow and the effect is treated as a problem of simultaneous heat and mass-transfer. A simulation program of heat and air flows in a wall has been developed using laminar flow theory, and its validity is examined by thecomparison of the simulation results with a weather exposed full-scale model test.

This paper describes part of a research on the influence of environment on physiological reactions and thermal comfort. Experimental rooms and apparatus are described and the imperfections in some of the instrumental methods - especially in respect to the measurement of air change by tracer substances - are noted. A brief description of a method to measure air change is givenin which CO2 is used. The importance of limiting the rate of air change in rooms heated by fires - as a means to save heat - is stressed.

The use of lightwells and courtyards for natural ventilation in high-rise buildings is exaimed using both wind tunnel and field measurements of the pressures and neutral pressure zone caused by wind and temperature differences. Though air flow patterns are complex for complex building designs, air exchange rates in lightwells and courtyards were generally seen great enough to assure clean air for natural ventilation via air infiltration. However the cost of land in urban settings will probably make mechanical ventilation systems the economic choice.

An analysis of ventilation necessary to maintain air quality in an above-ground fallout shelter was done, making use of theoretical models, and generalizing the results to fit measurements on actual shelter data. Results show that, at most, boundary surface heat loss serves as a safety factor for ventilation systems, and thus ventilation systems should be designed to remove the entire thermal load generated within the shelter. This, when considered in addition to weather and load expectations, establishes an upper limit on ventilation equipment size.

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.

The levels reported in diverse publications of by products of cigarette combustion (acrolein, aldehydes, aromatic hydrocarbons, carbon monoxide, nicotine, nitrogen oxides, nitrosamines, particulates, and others for which scattered information is available - HCN, ketones, nitriles) are summarized in tabular form. Summaries also include information on test conditions such as ventilation, size and types of premises, monitoring conditions, number of smokers, and rate of smoking.

The ventilation of a large room is often achieved by supplying inlet air from a small side-wall mounted opening. The velocity distribution in a typical room with a small circular inlet opening close to the ceiling is described. The supplied air forms a wall jet below the ceiling which is easy to describe in terms of velocity distribution, entrainment, etc. The jet is deflected at the end wall opposite the supply opening and the resultant flow in the lower part of the room - the occupied zone - has a rather complicated structure.