Theory of Air Tightness, Air Leakage & Air Sealing Measures

Terminology

Air tightness / air permeability / air leakage –

defined as the resistance of the building envelope to inward or outward air permeation. Air leakage is driven by pressure differentials between inside and outside a building caused by the wind, stack effect and mechanical ventilation systems.

Air barrier or air seal line –

the physical components that make up the airtight envelope of the building. The air barrier needs to be continuous around the whole envelope – roof, walls and ground floors – and needs to be durable and maintainable in the long term. The air seal line can be drawn on construction drawings.

Air tightness test or air leakage pressure test –

the building is pressure tested by connecting a fan and measuring the airflow rates required to keep the building at various positive pressures.

Air permeability –

expressed as the amount of air leakage in cubic metres, per hour, per square metre of envelope at a nominal pressure differential of 50 Pascals, between inside and outside the building envelope.

Q50 –

air flow rate required to pressurise the building envelope to 50 Pascals, the measured unit of which is cubic metres per second.

 

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Air Sealing - Flagship Projects

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Air Sealing Contracting - 800 retail stores for 4 major retail chains

Since 1995 for 4 major retail companies, whom HRS still work for on a regular basis

250 existing Morrisons Stores fire stopped over a period of 18 months

HRS were directly employed by Wm Morrisons to upgrade fire stopping

New & existing Tesco stores air sealed by HRS Services

For over 10 years, Kiers has appointed HRS to air seal over 50 TESCO stores