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air leakage

Building Airtightness: Research and Practice

This report summarizes the state of the art on building air tightness by reviewing the current and recent literature on both research and practice. The focus of this report is on techniques to measure the tightness of the building envelope and on what has been learned by doing so. This report reviews over 100 of the most important publications relating to the topic. The report covered the fundamentals of air leakage including the hydrodynamics of leaks, which has led to all of the measurement techniques currently in use.

Duct Tape Durability Testing

Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have typically shown that these seals tend to fail over extended periods of time. The Lawrence Berkeley National Laboratory has been testing sealant durability for several years. Typical duct tape (i.e.

Field Measurements of the Interactions between Furnaces and Forced Air Distribution Systems

Measurements on three gas and two electric furnaces have been made to examine the field performance of these furnaces and their interactions with their forced-air distribution systems. The distribution systems were retrofitted as part of this study and the impact of retrofitting on furnace performance is discussed. In addition to field measurements, this paper will discuss how forced-air furnace systems are treated in proposed ASHRAE Standard 152P, and applies the resulting equations to the systems tested in the field.

Heat Recovery in Building Envelopes

Infiltration has traditionally been assumed to contribute to the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Application of such a simple formula may produce an unreasonably high contribution because of heat recovery within the building envelope. Previous laboratory and simulation research has indicated that such heat transfer between the infiltrating air and walls may be substantial.

The use of blower door data.

The role of ventilation in the housing stock is to provide fresh air and to dilute internally-generated pollutants in order to assure adequate indoor air quality. Blower doors are used to measure the air tightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, accurate understanding of the uses of blowerdoor data is critical. Blower doors can be used to answer the following questions:.

On prediction of the mold fungus formation probability on critical building components in residential dwellings

In buildings, favorable growing conditions for mold fungi can occur and cause fungusinfestation. The danger for the occupants of dwellings lies in the spreading of pathogensthrough microorganisms. Mold fungi can occur not only on the surface of external walls, butalso inside construction parts. A prerequisite for preventing mold fungus is the knowledge ofthe transient building physical boundary conditions under which fungus growth takes place.The decisive parameters of influence like temperature, humidity and substrate have to beavailable over a certain period of time simultaneously.

Influence of Air Leakage in Building’s Walls on Heat Transmission Loss through its Envelope

The energy consumption of a building is evaluated by neglecting the heat loss which can occur when the air passes through the envelope. However, recent studies showed that air leakage plays asignificant role by affecting the thermal performances of walls and the energy consumption. Moststudies have focused on the quantification of air leakage flows through the building shell, withoutaddressing the problem of the heat exchange between this airflow and the construction materials asthe air passes through the envelope.

Field characterization of the envelope leakage of houses for determining rehabilitation priorities

This paper presents the results of a field study conducted on 8 houses (out of a set of 31) owned and managed by a French social housing public leasing company. The central objective of our investigation was to evaluate and characterize the envelope leakage of these houses in order to propose and prioritize rehabilitation scenarios. For this, envelope leakage measurements were performed together with infrared thermography measurements.

Can adventitious ventilation negatively impact moisture performance of building envelopes in moderate climates ?

In moderate climates, adventitious ventilation helps in keeping the water vapor balance in a building under control. This does not hold in hot and humid climates, where the outside air is a moisture source. Adventitious ventilation should be avoided in such climates and intended ventilation flows must be dried before entering the space. Anyhow, could adventitious ventilation also generate moisture problems in moderate climates? To get an answer, a reference case was analyzed with the air leakage distributed over facades and roof.

Ventilation and air leakage

Buildings leak water and air : it is normal and impossible to avoid. So the architect and HVAC engineer's goal should be to recognize the concept of building air leakage and account for it in :- quantifying leakage- reducing it if excessive- controlling leakage by managing air pressures with the HVAC system.The aim of this article is to discuss the methods for measuring and expressing leakage and to report the results of a cas study, San Carlos Park elementary school in Fort Myers, Florida.