component leakage

Last years, interest in airtightness increases among all construction fields and airtightness becomes a major issue in the reduction of energy consumption in buildings. Nevertheless, there is a lack of understanding of air displacements through weak spots in buildings (airpaths). Firstly we develop first the concept of Potential Improvement Graph (PIG chart). These graphs represent the “improvement curves” of a given airpath (airflow indicator against airpath parameter). As an airpath can have multiple significant parameters, PIG charts can be n-dimension graphs.

When one intends to evaluate buildings energy efficiency their airtightness is a fundamental parameter. Airtightness is linked to undesirable and uncontrolled ventilation and, therefore, should be minimized. Quantitative characterization of expected leaks of common building elements would be useful for practitioners that intend to improve building enclosures for airtightness optimization. The most well accepted experimental procedure to evaluate in-situ buildings’ airtightness is the fan pressurization method, typically making use of a “blower door” device.

Popular culture abounds with uses for duct tape: duct tape calendars, books like 101 Uses for Duct Tape, and more. But lab experiments have finally proved that duct tape, as it ii' generally used, should not be used to seal ducts.

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.

Describes the development of the Swedish duct tightness guidelines, the "AMA system". The latest version, due in 1998, aims to increase tightness requirements once again by introducing a tightness class D as the standard requirement for larger spiroduct systems. The concern about an increasing part of the Swedish population becoming allergic and asthmatic led to the Swedish Parliament introducing compulsory inspections of ventilation systems in 1990.

Constant injection of tracer gas was used to determine the airtightness of a straight length of300 X 300 mm square duct in a laboratory setting. Holes are performed in the ductwork which is connected to a fan with variable speed control to simulate leakages. The holes can be sealed with rubber bungs to simulate an airtight ductwork. 'Stationary' and 'mobile' methods have been developed. The stationary method is suitable for conditions where the locations of the leaks in the ductwork is known.

The National Building Code 1985 identified the need to control movement of air through the exterior walls of buildings. The upcoming 1995 National Building Code has now placed recommendations on the amount of allowable leakage.

The Air Infiltration and Ventilation Centre s Numerical Database has been developed in response to a need to establish a core of numerical data suitable for design purposes and model validation. It has also been developed to provide a focus for