Building Envelope Performance

Energy consumption in buildings is determined by the air tightness of the building. In hotter climates like in UAE as well as in very cold climates, the energy consumption can be controlled by the air tightness of the building. In hotter climates, leaky buildings cause moisture infiltration, deterioration of building materials, poor indoor temperature and humidity control. In colder climates, there is exfiltration where the indoor generated heat escapes to the colder outside air.

Air leakage is the uncontrolled flow of air through gaps and cracks in the walls, joints and roof of  buildings. A leaky building due to poor design or improper construction or wear and tear will let the moisture in warm desert air to condense and create breeding grounds for mould growth.

In Middle Eastern countries, an estimated 60 to 70% of the domestic electrical consumption is spent on artificial cooling and humidifying the air and the building envelope should protect the interiors from the infiltration of the sun's heat and hot desert air.

Pressure Testing and Infrared Thermal Imaging

Gaps and cracks in the building walls, joints and roof are difficult to detect simply by visual inspection. Gaps are often hidden by internal building finishes or external cladding. In pressure testing, air leakage is measured by the rate of airflow loss like testing a tyre puncture.

Pressurization is achieved by using variable air flow portable fans installed in doorways and other external openings. Tracing the air leakage is done by the use of non-toxic vapor generators and infrared thermal Imaging.

An infrared camera is used to measure temperature variations reflected from the surfaces of materials. This helps to detect where the energy wastage happens - conditions like hidden moisture in walls and ineffective insulation at windows. Infrared thermal imaging is used in building inspections because it does not require cutting into or damaging the walls or ceilings. This greatly reduces the time and cost of determining areas for improving energy wastage.

Exterior infrared thermography is conducted early morning or late evening when inside and outside temperature differences are greatest. Interior infrared survey for moisture intrusion or mould growth can be conducted anytime.

Following is a sample picture of infrared imaging