pressurization

Radon is one of the common contaminants inside buildings, with maximum presence in high potential areas classified as radon prone areas. This radioactive gas, which comes from the spontaneous disintegration of radium present in the earth's crust, can penetrate buildings and accumulate inside them. The spaces closest to the ground (basement and first floors) are the most affected. Its inhalation in high doses is associated with an increased risk of lung cancer. Several techniques are commonly used to mitigate its presence.

The paper describes the development of unsteady pulse pressurisation techniques for measuring the leakage of buildings. The original version of the technique (the UP technique) has been investigated experimentally and theoretically in a single cell test space. The initial results are very promising, with a good degree of repeatability and similar sensitivity to changes in leakage levels as the conventional steady (DC) technique. An interesting outcome of these early tests was the observation that quasi-steady flow could be established in a short time.

This paper discusses how ventilation and air distribution can have a positive or negative impact on chemical, biological and radiological agents entering buildings, on their movement within the buildings and on their removal. It also points out the key role played by the envelope airtightness of the building and its pressurization as a security tool.

The Delta-Q duct leakage test has been developed over the past several years as an improvement to existing duct pressurization tests. It focuses on measuring the air leakage flows to outside at operating conditions that are required for energy loss calculations for duct systems, and infiltration impacts. The Delta-Q test builds on the standard envelope tightness measurement technique of a blower door by repeating the tests with the system air handler off and on. This study uses detailed

Field tests of stairwell and vestibule pressurization systems were performed in a 32-story high-rise building. Pressure differences in the stairwell, and vestibule and average air velocity were tested under various conditions. Test results indicate that indirect pressurization through a stairwell is feasible. Ignoring stack effect, the worst door-opening condition is that the fire doors of the top or bottom three adjoining floors of the building are open simultaneously. Pressurization systems in

This paper asks questions about what is the right tightness and a warns against too tight tightness guidelines.The author gives advice :- A tight building envelope should reduce average natural infiltration (due to wind and temperature) to 0.05 to 0.1 air change per hour.- A tight building envelope should contain the desired air pressure field.- A building envelope should not be too tight because of the unbalanced airflows that can create excessive levels of depressurization.

The quantitative determination of differential pressure and airflow for proper room pressurization is an HVAC design area that has not yet developed a standard rule.In this article current design guidelines and field practices for room pressurization are investigated. Practical field tests were performed in two types of facilities: a tuberculosis research lab and a cell transplant unit.

This paper establishes the relationship between space pressurization ratio and air leakage flow through irregular cracks or through an open door . A numerical approach shows that room pressurization ratio can be estimated from room effective leakage area and from the pressure difference across the room shell.

A computer program has been developed to predict the wind pressure coefficients Cp on facades and roofs of block shaped buildings. The program is based on fits of measured data, including wind shielding by obstacles and terrain roughness. Main advantages of the program are: - it needs no expertise of its users on wind pressures; - the input is simple. It exists of building and obstacles coordinates and orientations; - generating Cp values for ventilation model calculations needs no separate action.